UCLA Bio 7C

We breathe more quickly and deeply when we exercise. Why does this make sense? (Select all that apply). A. Because when we exercise, we consume more CO2 and must increase ventilation to supply the CO2. B. Because when we exercise, we use more ATP, and additional O2 is necessary to generate sufficient ATP. C. Because when we exercise, we produce more CO2 and increased ventilation is necessary to rid ourselves of CO2. D. Because when we exercise, we hydrolyze more ATP to ADP and Pi, and O2 is necessary for the hydrolysis, so we increase our intake of oxygen.

Which of the following statements is FALSE? 1. Ventilation increases the concentration of oxygen in the air on the outside of the respiratory surface. 2. Larger, more complex animals rely on bulk flow and diffusion to deliver oxygen to their cells, whereas some smaller, simpler animals rely on diffusion alone. 3. Circulation requires a pump to generate pressure to drive flow, whereas ventilation does not. 4. Oxygen and carbon dioxide both move across the respiratory surface by diffusion. 5. The same amount of oxygen enters the blood through diffusion as is transported by circulation.

In mammals, bulk flow only refers to the movement of oxygen (either into or out of the lungs and within the bloodstream). Bulk flow never refers to the movement of carbon dioxide. T/F?

The partial pressure of a gas is: 1. A measure of how quickly a gas moves across a respiratory surface. 2. The difference in concentration of that gas inside and outside of a cell. 3. The weight of a given volume of the gas. 4. Equivalent to the total atmospheric pressure. 5. The fractional concentration of the gas multiplied by the overall, atmospheric pressure.

If the partial pressure of oxygen outside of a cell is 100 mmHg and the partial pressure of oxygen inside of a cell is 25 mmHg, which of the following statements is CORRECT? 1. There will be a net movement of carbon dioxide out of the cell. 2. There will be no net movement of oxygen in either direction. 3. There will be a net movement of oxygen from outside the cell to inside the cell. 4. There will be a net movement of oxygen from inside the cell to outside the cell. 5. There will be a net movement of carbon dioxide into the cell.

What are desirable characteristics for a gas exchange surface, such as the endothelial cells lining the inside of lung? (Select all that apply.) 1. a small surface area 2. a thickness under 10 micrometers 3. a large surface area 4. a thickness of 100 micrometers

Which of the following INCREASES the amount of oxygen that a fish can extract from the surrounding seawater? 1. gills with a large surface area 2. All of these choices are correct. 3. very thin lamellae 4. ventilation of the gills with the aid of an operculum 5. countercurrent exchange

Which of the following statements about bird respiration is FALSE? 1. The unidirectional flow of air through a bird's lungs maintains a larger concentration gradient for diffusion than can be obtained through tidal breathing. 2. Oxygen is exchanged between the air and the bloodstream in the lungs, but not in the air sacs. 3. Bird lungs receive fresh air during both inhalation and exhalation. 4. Air flowing through the air channels in the lungs moves in a tidal fashion. 5. It takes two ventilation cycles for a single breath of air to move through a bird's respiratory system.

What percentage of oxygen in the air is typically extracted by the mammalian lung when an animal is resting? 1. 91-100% 2. 26-50% 3. 76-90% 4. 51-75% 5. less than 25%

What is meant by "tidal ventilation"? 1. Air moves into the lungs during inhalation and air moves out of the lungs during exhalation. 2. The ventilation rate increases and decreases at regular intervals. 3. Water is pumped back and forth across the respiratory system. 4. Air moves in a continuous, unidirectional flow through the lungs. 5. None of the answer options is correct.

Imagine that a young girl suffers a horseback-riding injury, and one of her ribs punctures her diaphragm. How will this injury affect the girl's breathing? 1. The injury will make it more difficult to decrease negative air pressure in her chest cavity, making inhalation more difficult. 2. The injury will not affect her at all, as intercostal muscles are responsible for breathing. 3. The injury will make it easier to increase negative air pressure in her chest cavity, making inhalation easier. 4. The injury will make it more difficult to increase negative air pressure in her chest cavity, making inhalation more difficult.

Which of the following organisms would be able to extract the GREATEST percentage of oxygen from their respiratory medium? 1. seagulls 2. humans 3. salmon 4. blue whales 5. sparrows

In complex multicellular organisms, bulk flow is an important physiologic character. Why is bulk flow a necessary condition of complex multicellularity? 1. Bulk flow is necessary to move large amounts of liquid through the organism depending on physiologic needs. The tissues can all receive necessary nutrients from the environment, but bulk flow speeds the rate of diffusion. 2. Organisms exhibiting complex multicellularity are large and have cells/tissues that are not in contact with their environment. Systems that can overcome the limits of diffusion must occur for basic physiologic processes to occur. 3. Complex multicellularity is related to the increase in oxygen in the environment. Because bulk flow systems are only related to the delivery of oxygen to tissues, higher environmental oxygen selected for individuals with bulk flow systems. 4. Complex multicellularity reflects cell adhesion between cells, and this cannot happen without bulk flow of signaling molecules from the environment.

A key difference between hormonal regulation of the reproductive systems of males and females is that: 1. LH is released continuously in males and FSH is released cyclically in females. 2. LH and FSH are released only in females. 3. LH and FSH are released cyclically in females but nearly continuously in males. 4. LH and FSH are released only in males. 5. LH is released in males and FSH is released in females.

You measure levels of Ca2+ in various locations within a motor neuron and a skeletal muscle fiber when the motor neuron is NOT depolarized, and the muscle fiber is at rest. Where do you expect to find high levels of Ca2+? 1. bound to troponin 2. within the T-tubules 3. diffusing into the motor neuron through specialized channels in the plasma membrane 4. binding to the receptors at the motor endplate of the muscle cell 5. within the sarcoplasmic reticulum of the muscle fiber

Bisphosphoglyceric acid (BPG) is a byproduct of glycolysis released into the bloodstream when an animal's supply of oxygen is low. Like protons, it decreases hemoglobin's affinity for O2. The effect of high BPG levels would be that: 1. hemoglobin now binds more oxygen at low partial pressures than at high partial pressures. 2. hemoglobin picks up more O2 in the lungs than it would without BPG. 3. hemoglobin loses its cooperative binding of oxygen. 4. hemoblobin releases more of its bound O2 than it would without BPG. 5. hemoglobin holds on to more of its O2 than it would without BPG.

You discover a new type of marine organism that has the kidneys of a fish but no gills. What effect would the absence of gills have on excretion of nitrogenous waste? 1. Nitrogenous excretion increases at the kidneys because it cannot be lost at the gills. 2. No effect. Nitrogenous wastes diffuse across the skin. 3. No effect. Fish kidneys excrete all nitrogenous waste. 4. Nitrogenous excretion decreases because no nitrogen uptake is occurring at the gills.

Referring to Figure 10.14, identify which type of cell-cell interaction is most likely to force the products of digestion to be absorbed across microvilli of intestinal cells rather than allowing them to leak between cells. 1. gap junctions 2. desmosomes 3. plasmodesmata 4. tight junctions 5. hemidesmosomes

Using current DNA-sequencing technology, it is possible to sequence an entire chromosome (e.g., human chromosome 1, which contains approximately 250 million nucleotides) as one long molecule. True False

Assume that blood pressure drops in a person because of an injury. Indicate "true" or "false" for the following statements: 1. Circulating levels of aldosterone will increase. 2. Circulating levels of renin will decrease. 3. The sympathetic nervous system stimulates the adrenal glands. 4. Water absorption by the distal convoluted tubule will decrease. 5. Circulating levels of angiotensin II will increase.

One of the functions of the cardiovascular and respiratory systems is to rid the body of CO2. Where does the CO2 come from? A. CO2 is a breakdown product of the carbohydrates oxidized in cellular respiration. B. CO2 is a breakdown product of the carbohydrates reduced in cellular respiration. C. CO2 is produced when inhaled oxygen combines with carbon atoms from carbohydrates. D. CO2 is produced when the oxygen atoms of water combine with carbon atoms.

The lungs are highly branched. What is the primary purpose of this branching? A. It increases the surface area of the lungs B. It increases the volume of the lungs C. A and B are correct D. None of the above

A red blood cell has just left the right ventricle of the heart. It travels to the lungs, back to the heart, to the liver, and then back to the heart again. At each point on its journey (A-D), determine the oxygen saturation level (%) of the hemoglobin molecules found in this red blood cell. (You may assume the pH of the blood is 7.4.) What is the approximate O2 saturation at point D? A. 75% B. 30% C. 40% D. 10% E. None of the above

How does blood pH at muscle tissue compare to blood pH at the lungs? A. Blood pH is higher at the muscle B. Blood pH is lower at the muscle C. Blood pH is the same at the muscle

If carbonic anhydrase stopped working, the amount of oxygen delivered to systemic tissues would _________. A. Increase B. Decrease C. Not change

The same red blood cell leaves the heart again, but this time instead of traveling to the liver, it travels to a skeletal muscle that is actively respiring. At each point on its journey (A-D), determine the oxygen saturation level (%) of the hemoglobin molecules found in this red blood cell. What is the approximate O2 saturation at point D? A. 75% B. 25% C. 40% D. 10%

When the diaphragm contracts, the volume of the lungs _____ and the pressure in the lungs ______ A. Increases; increases B. Increases; decreases C. Decreases; increases D. Decreases; decreases

At high altitudes, the partial pressure of oxygen is ______ the partial pressure of oxygen at sea level. A. Higher than B. Lower than C. The same as

At high altitudes, the percentage of oxygen is ___________ the percentage of oxygen at sea level. A. Higher than B. Lower than C. The same as

A climber is scaling Mt. Everest. As her elevation increases, the average amount of oxygen bound to the hemoglobin in her red blood cells ________. A. Increases B. Decreases C. Does not change

A condition called "hypoxia" occurs when not enough oxygen is being delivered to the body. Chemoreceptors on the ________ sense oxygen levels in the blood and relay this information to respiratory control centers in the brain. A. Aorta B. Pulmonary trunk C. Pulmonary vein D. Superior vena cava

A condition called "hypoxia" occurs when not enough oxygen is being delivered to the body. What is acting as the homeostatic sensor? A. Oxygen B. Carbon Dioxide C. Heart D. Brainstem E. Diaphragm

A condition called "hypoxia" occurs when not enough oxygen is being delivered to the body. When brainstem senses hypoxic conditions, the rate of ventilation will ... A. Increase B. Decrease C. Not change

How many cell membranes does a carbon dioxide molecule diffuse through to move from the cytosol of a red blood cell to the inside of an alveolus in the lungs? A. 1 B. 2 C. 3 D. 4 E. 5 or more

Patient A received a complete blood count while Patient B received a chemistry panel. Based on the results, which test analyzes the composition of the cellular portion of the blood? A. Complete blood count B. Chemistry panel C. No way to know

Mark A for True or B for False Patient B's blood pH is buffered by the appropriate amount of bicarbonate

Mark A for True or B for False Patient A's blood will likely exhibit difficulty clotting.

Mark A for True or B for False Patient B likely exhibits some swelling of the body tissues ("edema") due to an osmotic imbalance in his blood.

Which of the following correctly represents the order in which blood flows through structures of the heart? A. Right ventricle, left atrium, pulmonary artery B. Left atrium, pulmonary artery, right atrium C. Pulmonary artery, aorta, left ventricle Pulmonary Circuit D. Superior vena cava, pulmonary vein, aorta

Mark A for True or B for False The pulmonary vein carries deoxygenated blood.

At the beginning of ventricular diastole, blood pressure in atria is _______ blood pressure in the ventricles A. Higher than B. Lower than C. The same as D. No way to know!

The ventricles begin to empty at which region of the cardiac cycle?

At the time that the ventricles begin to empty, blood pressure in aorta is _______ blood pressure in the ventricles. A. Higher than B. Lower than C. The same as D. No way to know!

During a typical cardiac cycle, cell depolarization triggers muscle _______ and repolarization triggers muscle ________. A. Contraction; contraction B. Contraction; relaxation C. Relaxation; contraction D. Relaxation; relaxation

Depolarization and repolarization... sounds like we're talking about action potentials. Do muscles have action potentials? A.Totally! B.No way! C.How should I know?

During a typical cardiac cycle, the atria of the heart contract ______ the ventricles contract. A. Before B. After C. At the same time as

The ventricles finish filling with blood after the _______. A. Atria depolarize B. Atria repolarize C. Ventricles depolarize D. Ventricles repolarize

When do the ventricles depolarize? A. P wave B. PR segment C. QRS complex D. ST segment E. T wave

When do the atria repolarize? A. P wave B. PR segment C. QRS complex D. ST segment E. T wave

What does the ST interval represent? A. The heart is relaxing B. The ventricles are filling C. The atria are filling

What happens during the P wave? A. Atria depolarize B. Atria repolarize C. Ventricles depolarize D. Ventricles repolarize

Which region on the EKG corresponds to number 2 on the figure?

Signals from the sympathetic nervous system cause arteriole B to constrict. As a result, the amount of blood flowing through the other three arterioles will ____________. A. Increase B. Decrease C. Not change

In systemic tissue fluids, the enzyme carbonic anhydrase catalyzes the reaction CO2 + H2O ? H2CO3 (which then can dissociate into H+ and HCO3-). In fact, CO2 released from cells is converted to HCO3- ions and travels in that form in the bloodstream. HCO3- is reconverted to CO2 + H2O in the pulmonary capillaries by the same enzyme, and there the CO2 is exhaled. How is it possible for the same enzyme to catalyze reverse reactions? 1. The lungs contain an allosteric inhibitor that prevents the formation of carbonic acid. 2. The direction of a reversible reaction is influenced by the concentrations of reactants and products. In pulmonary circulation, the low CO2 concentration favors the formation of CO2 and H2O. 3. There must be two forms of carbonic anhydrase. One form catalyzes the forward reaction CO2 + H2O ? H2CO3 and the other catalyzes the reverse reaction H2CO3 ? CO2 + H2O.

Which of the following relationships BEST describes the partial pressure of oxygen (pO2) in the lung (alveolar air), red blood cells, and blood plasma? 1. pO2 red blood cell < pO2 blood plasma < pO2 lung 2. pO2 lung < pO2 blood plasma < pO2 red blood cell 3. pO2 blood plasma < pO2 lung < pO2 red blood cell 4. pO2 red blood cell < pO2 lung < pO2 blood plasma

A rightward shift in the oxygen dissociation curve means that: 1. the affinity of hemoglobin for O2 has decreased. 2. the CO2 levels in the blood have decreased. 3. less O2 is released by hemoglobin to the body cells. 4. the pH of the blood has increased. 5. the hemoglobin protein has denatured.

If a hemoglobin molecule comes into close contact with a respiring cell, the presence of CO2 in the environment will cause hemoglobin to bind to more oxygen molecules (if it is not already bound to four). True False

How many molecules of O2 can a single hemoglobin molecule carry when fully saturated? 8 4 2 1 16

Imagine that a doctor encounters a patient carrying a mutation that reduces collagen production. As a result, the arteries of this patient will likely be stronger and more resistant to aneurysms compared to arteries in an individual not carrying this mutation. True False

In the disease elephantiasis, lymph vessels become blocked as a result of infection with parasitic worms. Which of the following processes would be impacted by this disease? 1. the generation of pressure to filter materials through the capillary walls 2. the return of excess interstitial fluid to the bloodstream 3. the diffusion of water and small molecules across the wall of the capillary 4. the flow of water back into the capillaries by osmosis 5. the exchange of oxygen and other materials between the blood and body cells

As fluid moves through a vessel, which factors determine the flow resistance? (Select all that apply.) 1. the radius of the vessel 2. the length of the vessel 3. the pressure exerted by the heart 4. the viscosity of the fluid

Insects possess _____ circulatory systems, circulatory systems in which hemolymph completely "bathes" the organs and is not typically contained in distinct arteries or veins. open closed fluid solid

What function do collagen and elastin have in arteries? 1. All of these choices are correct. 2. They help to control blood flow within the body by contracting with the smooth muscles in the arterial wall. 3. They line the interior to provide a smooth surface for blood flow. 4. They form valves to prevent the backflow of blood. 5. They provide elastic rebound of the arterial wall to help smooth out blood flow.

Diffusion of materials between the blood and body tissues occurs at which of the following blood vessels? venules capillaries veins arterioles arteries

The initiation of the mammalian heart contraction: 1. takes place at the AV node and requires neural input. 2. takes place at the SA node. 3. takes place at the SA node and requires neural input. 4. requires neural input. 5. takes place at the AV node.

In which of the following heart chambers would deoxygenated blood be found? 1. right atrium and left ventricle 2. left atrium and right ventricle 3. right atrium and left atrium 4. left atrium and left ventricle 5. right atrium and right ventricle

Consider the mammalian heart. Why is the muscular wall of the left ventricle thicker than that of the right ventricle? 1. The left ventricle has more nerve endings for contraction, and more muscle mass must be there to accommodate the extra neurons. 2. The left ventricle must contract with more force in order to send blood to the body's extremities. 3. This difference stems from the fact that frogs have a thicker left ventricular muscle mass. 4. The ventricle wall must be thicker to inhibit diffusion between the right and left ventricle.

Which of the following occurs during systole? Both atria contract. The atria fill with blood. The ventricles fill with blood. The left ventricle contracts. Both ventricles contract.

Which of the following animals has a heart in which oxygenated and deoxygenated blood mix? mammal frog fish human bird

Atrioventricular valves separate the: 1. right and left ventricles. 2. right atrium from the left atrium and the right ventricle from the left ventricle. 3. left atrium from the left ventricle and the right atrium from the right ventricle. 4. aorta from the left ventricle.

Bisphosphoglyceric acid (BPG) is a byproduct of glycolysis released into the bloodstream when an animal's supply of oxygen is low. Like protons, it decreases hemoglobin's affinity for O2. The effect of high BPG levels would be that: 1. hemoglobin now binds more oxygen at low partial pressures than at high partial pressures. 2. hemoglobin picks up more O2 in the lungs than it would without BPG. 3. hemoglobin holds on to more of its O2 than it would without BPG. 4. hemoblobin releases more of its bound O2 than it would without BPG. 5. hemoglobin loses its cooperative binding of oxygen.

Which of the following statements explains why there is an elastic layer found in arteries, but not veins? 1. Arteries are thicker than veins, and the elastic layer is necessary to support the additional weight of arteries. 2. Blood pressure is higher in arteries than veins, and the elastic layer helps maintain the structure of the artery. 3. Valves present in veins provide a mechanism for withstanding high blood pressure flow going through veins. 4. The total length of arteries in the body is more than the total length of veins, and the elastic layer helps push the blood over the longer length.

What are desirable characteristics for a gas exchange surface, such as the endothelial cells lining the inside of lung? (Select all that apply.) 1. a thickness under 10 micrometers 2. a small surface area 3. a large surface area 4. a thickness of 100 micrometers

During certain stressful moments, some individuals will begin to hyperventilate—that is, their breathing will be very shallow and quick. A by-product of hyperventilation is much lowered levels of CO2 in the blood. Which of the following would you also expect to find? (Select all that apply.) 1. decreased blood pH, less than 7.2. 2. increased blood pH, greater than 7.2 3. decreased stimulation of chemoreceptors in the brainstem 4. increased stimulation of chemoreceptors in the brainstem

Stimulation by the parasympathetic nervous system increases the permeability of the SA node to potassium ions, whereas stimulation by the sympathetic nervous system decreases the permeability of the SA node to this same ion. False True

Chemoreceptors in the circulatory system detect changes in circulating pCO2. If pCO2 concentrations get too high, the rate of ventilation increases. Why does this make sense? 1. It makes sense because hemoglobin carries CO2 and therefore blocks oxygen binding to the heme site, creating an oxygen deficiency. 2. Actually it doesn't make sense. There is no relationship between CO2 and ventilation rate. 3. It makes sense because tissues that are more actively working produce more CO2. 4. It makes sense because CO2 is formed from O2, and therefore CO2 is a sign that oxygen is being consumed.

Cells can regulate their internal osmotic pressure by controlling the solute concentration inside of the cell. True False

If solution X has a 2% concentration of NaCl and solution Y has an 8% concentration of NaCl, which of the following statements is CORRECT? 1. Solution X is hypotonic relative to solution Y. 2. Solution X is hypertonic relative to solution Y. 3. Solution X has a higher osmotic pressure than solution Y. 4. Solution X has a higher solute concentration than solution Y. 5. Solution X has a lower concentration of water than solution Y.

Fish in a marine environment must maintain a relatively constant ion concentration in their tissues and blood. How do the chloride cells in the gills aid fish in the removal of excess ions? 1. The chloride cells actively remove ions from the body and water follows by osmosis. 2. The chloride cells create a countercurrent system where ions are lost from the body and water is absorbed to dilute other ions (NaCl). 3. The chloride cells actively move ions into the body and water follows by osmosis. 4. The chloride cells create a countercurrent system where water is lost from the body and chloride ions are absorbed.

Osmoregulators have _____ internal solute concentrations compared to their external environment. 1. always higher 2. the same 3. always lower 4. different

In most organisms, the excretion of wastes is closely tied to the maintenance of water and electrolyte balance. True False

Two solutions of water and dissolved potassium and glucose are separated by a selectively permeable membrane that only permits the passage of water. If the two solutions have the same total solute concentration, but solution 1 has a higher concentration of potassium and a lower concentration of glucose than solution 2, which of the following statements is CORRECT? 1. There will be no net movement of water molecules between the solutions. 2. There will be net water movement from solution 1 to solution 2. 3. There will be net glucose movement from solution 2 to solution 1. 4. There will be net potassium movement from solution 1 to solution 2. 5. There will be net water movement from solution 2 to solution 1.

The body fluid of sharks has a much lower concentration of sodium chloride than that of the surrounding seawater, and sharks are able to remain in osmotic equilibrium with the external environment. How can this be the case? 1. None of the answer options is correct. 2. Sharks maintain high levels of sodium chloride in their skin. 3. Sharks drink large volumes of seawater to compensate for the low salt concentration of their body fluids. 4. Sharks are osmoregulators. 5. Sharks store enough urea to match the total solute concentration of the surrounding seawater.

If a saltwater fish were unable to regulate chloride - what would happen? A. The fish would swell with water. B. Nothing, sodium would still be secreted. C. The fish would find fresh water to live. D. The fish would loose water and shrivel up.

Insects, reptiles, and birds excrete uric acid as their form of nitrogenous waste. Uric acid is much less water-soluble than urea. Why does this allow these organisms to conserve more water than a mammal with extensive kidney tubules for water reabsorption? A. The high solubility of uric acid allows the excretory system to reabsorb water. B. Uric acid levels stay high in the blood maintaining a strong osmotic gradient, which allows water to be reabsorbed. C. After precipitation*, uric acid no longer influences osmolarity; water returns to the hypertonic tissues. D. After precipitation*, uric acid no longer influences osmolarity; water leaves the hypertonic tissues.

In the proximal convoluted tubule, which of the following molecules is being secreted? A. Sodium B. Potassium C. Glucose D. Urea E. All of the above

Increased osmolarity of body fluids__________ ADH secretion A. Increases B. Decreases C. Has no effect on

Increased ADH secretion__________ urine output A. Increases B. Decreases C. Has no effect on

Decreased Na+ in body fluids (Na+ depletion) __________ renin secretion A. Increases B. Decreases C. Has no effect on

When the volume of blood passing through the kidney increases, renin production by the kidney will most likely _________. A. Increase B. Decrease C. Stay the same

ACE inhibitors are drugs that inhibit an enzyme called ACE that converts angiotensin I into angiotensin II. Treatment with an ACE inhibitor will cause blood pressure to _________. A. Increase B. Decrease C. Stay the same

Carbonic anhydrase inhibitors are commonly prescribed to treat glaucoma. A side effect could be ___________ in stomach pH. A. An increase B. A decrease C. No change

Secretin stimulates the release of bicarbonate ions into the duodenum, which neutralizes acidic chyme from the stomach. One consequence of neutralizing the pH in the intestine is that: A. Carbohydrates are not as easily broken down in this neutral environment B. Enzymes that catalyze the breakdown of carbohydrates are denatured C. Enzymes that catalyze the breakdown of carbohydrates are active D. The enzymatically catalyzed breakdown of carbohydrates that began in the stomach is halted in the duodenum

When stomach acid reaches the duodenum, it triggers the release of bicarbonate ions, which increase the pH of the duodenum. This is an example of: A. Negative feedback B. Positive feedback C. Neither; this is not a feedback system

Antacids like pepto-bismal are commonly taken to increase the pH of the stomach. If you take an antacid with your meal, _____ secretin will be released by your duodenum compared with eating an identical meal without an antacid. A. More B. Less C. An equivalent amount of

The motility of the digestive tract and secretion of digestive enzymes are optimized for digestion and absorption. For most nutrients, once material is in the digestive tract, the digestive system does not vary its rate of absorption according to body needs. A. This is an example of a homeostatic positive feedback mechanism B. This is an example of a homeostatic negative feedback mechanism C. This response is not homeostatic

Most mammals excrete _____; most aquatic animals excrete _____; birds, insects, and many reptiles excrete _____. 1. uric acid; ammonia; urea 2. urea; uric acid; ammonia 3. urea; ammonia; uric acid 4. uric acid; urea; ammonia 5. ammonia; urea; uric acid

Which of the following statements about the protonephridia of freshwater flatworms is CORRECT? 1. The fluid passing through the tubules is not modified before excretion. 2. Muscular contractions drive fluid movement through the excretory tubules. 3. The urine leaving the body of a freshwater flatworm is more concentrated than its body fluids. 4. Fluid from the body enters the protonephridia without first being filtered. 5. Protonephridia are surrounded by a capillary network to allow for selective reabsorption and secretion.

Metanephridia differ from protonephridia in all of the following ways EXCEPT that: 1. selective reabsorption of materials occurs via cells lining the tubules in protonephridia and via capillaries in metanephridia. 2. the urine produced in both systems is more dilute than the body fluids. 3. fluid enters metanephridia through a funnel-shaped opening. 4. fluid from the body cavity enters protonephridia without first being filtered. 5. metanephridia are surrounded by an extensive capillary network, whereas protonephridia are not.

You discover a new type of marine organism that has the kidneys of a fish but no gills. Based on what you know about other aquatic organisms, the newly discovered organism is _____ compared to the surrounding water. 1. hypotonic 2. isotonic 3. hypertonic

Which process is responsible for creating MOST of an animal's nitrogenous waste? 1. consuming nitrogen in food 2. protein breakdown during metabolism 3. toxins in the environment 4. respiration

Which of the following statements about the control of blood volume and blood pressure is NOT true? 1. Angiotensin II causes the smooth muscle in the walls of the arterioles to contract. 2. Angiotensin II stimulates the release of antidiuretic hormone, which increases salt and water uptake by the distal convoluted tubule. 3. A drop in blood pressure stimulates the cells of the juxtaglomerular apparatus to release renin. 4. None of the answer options is false. 5. Inactive angiotensinogen is converted to angiotensin II by an enzyme released from the lungs.

Which of the following processes occur within Bowman's capsule? 1. filtration, selective reabsorption, and secretion 2. selective reabsorption 3. filtration 4. filtration and selective reabsorption 5. secretion

Which of the following CORRECTLY describes the path of excretory fluids through a mammalian nephron? 1. Bowman's space, glomerulus, proximal convoluted tubule, distal convoluted tubule, loop of Henle, collecting duct 2. glomerulus, Bowman's space, loop of Henle, proximal convoluted tubule, distal convoluted tubule, collecting duct 3. glomerulus, Bowman's space, proximal convoluted tubule, distal convoluted tubule, loop of Henle, collecting duct 4. collecting duct, proximal convoluted tubule, loop of Henle, distal convoluted tubule, Bowman's space, glomerulus 5. glomerulus, Bowman's space, proximal convoluted tubule, loop of Henle, distal convoluted tubule, collecting duct

An increase of _____ increases the permeability of the collecting duct to water. 1. caffeine 2. ADH (antidiuretic hormone) 3. diuretic drug 4. alcohol

A person's blood pressure falls. Which of the following would you expect to occur? (Select all that apply.) 1. water uptake by the distal convoluted tubule will increase 2. circulating concentrations of aldosterone will decrease 3. circulating concentrations of angiotensin II will decrease 4. circulating concentrations of renin will increase

Water levels are adjusted to meet the osmoregulatory needs of the organism in the _____ of the nephron under the control of _____, also called vasopressin. 1. loops of Henle; antidiuretic hormone 2. distal convoluted tubule; antidiuretic hormone 3. distal convoluted tubule; diuretic hormone 4. collecting ducts; diuretic hormone 5. collecting ducts; antidiuretic hormone

What is the function of the vasa recta? 1. None of the answer options is correct. 2. It helps determine the final concentration of the urine. 3. It filters the blood within the glomerulus. 4. It secretes the hormone renin in response to a drop in blood pressure. 5. It maintains the concentration gradient established by the loop of Henle.

When an individual has an energy surplus, he or she stores the extra energy as: 1. proteins. 2. nucleic acids. 3. carbohydrates. 4. None of the answer options is correct. 5. lipids.

An individual with vitamin D deficiency will experience which of the following problems? 1. difficulty absorbing sufficient amounts of calcium from the diet 2. slow wound healing 3. nervous system disorders 4. anemia 5. bleeding gums and loss of teeth

Essential amino acids are those that: 1. can only be found in plants. 2. include minerals such as calcium and iron. 3. provide essential vitamins. 4. cannot be synthesized biochemically and must be taken in through the diet.

During starvation, humans and other animals deplete glycogen and fat reserves first, followed by protein. False True

The pancreas produces a variety of secretions, including: (Select all that apply.) 1. lipase for fat digestion. 2. methane from fermentation. 3. bicarbonate ions to neutralize stomach acid. 4. gastrin to stimulate HCl production. 5. trypsin for further protein digestion.

The _____ is the first section of the small intestine, where food enters from the stomach. 1. duodenum 2. ileum 3. gizzard 4. jejunum

Which part of the digestive tract is the predominant location for water and mineral absorption? 1. hindgut 2. crop 3. midgut 4. foregut

Glucose enters the epithelial cells of the small intestine against its concentration gradient. Select the BEST explanation from the following. 1. Glucose enters by diffusion. 2. Glucose follows the water that is pumped into the cell. 3. Glucose is co-transported with Na+, which moves down its concentration gradient into the cell. 4. Glucose is transported through a glucose pump in the apical membrane that hydrolyzes ATP to ADP and Pi. 5. Glucose is co-transported in the Na+/K+ pump.

The loop of Henle is a countercurrent exchanger because it creates a concentration gradient rather than simply maintaining it. False True

In humans, the stomach secretes: (Select all that apply.) 1. cellulase. 2. enzymes that digest lipids. 3. amylase. 4. hydrochloric acid. 5. pepsin, an enzyme that digests proteins.

The duct that connects the pancreas to the duodenum can sometimes become blocked. What is the result? 1. The digestive enzymes back up into the pancreas and may start to digest the pancreas. 2. Nothing happens because the pancreas does not produce digestive enzymes. 3. The digestive enzymes are not affected because they are stored in the gallbladder until they are needed in the duodenum. 4. The digestive enzymes produced by the pancreas enter the large intestine instead and digestion proceeds as normal. 5. The digestive enzymes produced by the pancreas still enter the duodenum because they travel by the blood to reach the duodenum, not by a duct.

One of the effects of the hormone secretin is to stimulate the release of bicarbonate ions into the duodenum, which neutralizes the acid that enters the duodenum with food from the stomach. One consequence of neutralizing the pH in the intestine is that: 1. the enzymatically catalyzed hydrolysis of carbohydrate that began in the stomach is halted in the duodenum. 2. enzymes that catalyze the hydrolysis of carbohydrates are denatured. 3. enzymes that catalyze the hydrolysis of carbohydrates are active. 4. carbohydrates are not as easily broken down in this neutral environment.

One of the hormones not mentioned in the text is GIP (glucose-dependent insulin trophic peptide), which stimulates the secretion of insulin. It is secreted by cells of the duodenum in response to the presence of glucose. Its secretion and action on insulin production is an example of a: 1. homeostatic positive feedback mechanism amplifying the response to glucose ingestion. 2. homeostatic negative feedback mechanism keeping a system near a set point. 3. homeostatic negative feedback mechanism changing the set point.

Freshwater fish are in a hypotonic environment. How do their gill chloride cells function in this environment? 1. Freshwater fish have chloride cells that actively move chloride ions into the gills, with sodium ions following. 2. Freshwater fish have chloride cells that actively move chloride ions out of the gills into the surrounding water, with sodium ions following. 3. Freshwater fish have chloride cells that actively move chloride ions into the gills, with sodium ions moving in the opposite direction. 4. Freshwater fish have chloride cells that actively move chloride ions out of the gills into the surrounding water, with sodium ions moving in the opposite direction.

Sometimes while traveling, people are infected with a protist parasite, Giardia. One of the side effects of Giardia infection is diarrhea. When someone has diarrhea, they lose excessive water and salt from the body. The result is loss of Na+, dehydration that leads to decreased extracellular volume and plasma volume, and decreased arterial blood pressure. Given this, would the vasopressin secretion of a person infected with Giardia: 1. stay the same 2. decrease 3. increase

You discover a new type of marine organism that has the kidneys of a fish but no gills. What effect would the absence of gills have on excretion of nitrogenous waste? 1. Nitrogenous excretion increases at the kidneys because it cannot be lost at the gills. 2. Nitrogenous excretion decreases because no nitrogen uptake is occurring at the gills. 3. No effect. Fish kidneys excrete all nitrogenous waste. 4. No effect. Nitrogenous wastes diffuse across the skin.

Choose the correct statement that refers to either beneficial or pathogenic microbes: 1. Beneficial microbes develop a symbiotic relationship with the host and pathogenic microbes do not and cause disease symptoms in the host. 2. Pathogenic bacteria help hosts utilize food sources, which they are not normally able to use. 3. All microbes are beneficial but some are considered pathogenic because the host immune system does not recognize it. 4. All microbes are pathogenic but we still tolerate some species without showing disease symptoms.

Choose the correct statement that refers to human gut microbiome resilience after antibiotic exposure: 1. Antibiotics are food sources for beneficial microbes only and allow their population sizes to increase due to the greater amount of food that is available for only these beneficial bacteria. 2. Antibiotics educate the host immune system to defend against only the bacteria that are causing the disease so after the antibiotic treatment only beneficial microbes are present. 3. Antibiotics can directly kill all of the bacterial species present in the gut and the observed resilience of the microbiota is due to new bacteria we introduce from the food we eat or other environmental exposure events. 4. Antibiotics can directly kill most of the bacterial species present in the gut but the ones that survive the antibiotic treatment can then increase their population sizes after the antibiotic treatment is finished.

Which of the following is not a component that contributes to human gut microbiome stability: 1. Direct bacterial defense against other bacterial species 2. All of these answer choices are correct. 3. Bacterial niche specialization and colonization 4. Host immune system defense against specific of bacterial species 5. Bacterial competition for resources

Gut microbial food sources do not include: 1. Host consumed complex sugars 2. Bacterial produced simple sugars 3. Host produced intestinal mucosal complex sugars 4. Host epithelial cell components

Principal Coordinate (PC) analysis plots are a tool that can provide information on the similarities and differences between microbiome samples. False True

Bacteria are able to utilize energy sources present in their extracellular environment because: 1. They can consume complex and simple sugars through specific transporters and enzymes present in their membrane. 2. They can consume complex and simple sugars through endocytosis 3. They can absorb complex and simple sugars in their extracellular environment through simple diffusion. 4. They can consume complex and simple sugars through exocytosis

Choose the correct statement that describes bacterial feeding strategies in the developing and mature microbiome: A. Humans are born with the greatest amount of unique microorganism Bacterial feeding strategies of the developing microbiome is the same as the mature microbiome B. Bacteria in the developing microbiome consume complex sugars and degrade them in to simple sugars in their intracellular environment while bacteria in the mature microbiome mostly degrade complex sugars in the extracellular environment and consume the simple sugars that result. C. Bacteria present in the mature microbiome utilize a feeding strategy in which they consume complex sugars and degrade them in to simple sugars in their intracellular environment. D. Bacteria present in the developing microbiome utilize a feeding strategy in which they degrade complex sugars in the extracellular environment and consume the simple sugars that result.

Choose the correct statement that describes the development of the human gut microbiome: A. Humans are born with the least amount of unique microorganism species in their gut, but by the time they reach an elderly age they have the greatest amount of unique microorganism species. B. Humans are born with the greatest amount of unique microorganism species in their gut and as they get older specific microbial species are eliminated through competition for resources. C. Humans have the same type and number of microorganism species present in their gut at birth and at death. D. Humans are born with the least amount of unique microorganism species in their gut and have greatest amount of unique species once they develop in to adulthood.

Milk-oriented Microbiota refers to: 1. The enrichment of select microbes during development that can degrade human milk oligosaccharides. 2. The type of baby formula invented that includes human milk oligosaccharides. 3. The difference between lactose tolerant and lactose intolerant human microbiota. 4. The presence of microbes in store bought milk made from dairy cows.

Choose the correct statement that describes how humans gain a gut microbiota: 1. Humans gain a gut microbiota from the birthing process. 2. Bacteria can but usually don't colonize the human gut during birth. 3. Humans gain a gut microbiota from the first foods they eat. 4. Bacteria colonize the human gut while they are in the womb

The sterile womb hypothesis refers to: 1. The distinct microbiota present in the developing fetus gut and the newborn child gut. 2. An old hypothesis that has been proven wrong by recent technological advancements in microbiology research. 3. The absence of microorgamism in the environment of a developing fetus. 4. The strict maternal regulation of microorganism species that are able colonize a child before and after birth.

Microbiome refers to: 1. All the functional genes within microorganisms that inhabit a location. 2. All the microorganisms that inhabit a location as well as all their functional genes and metabolites. 3. An organism and all its symbiotic microorganisms. 4. All the microorganisms that inhabit a location.

Immunological memory is a feature of which of the following? 1. the innate immune system 2. both the innate and adaptive immune systems 3. neither the innate and adaptive immune systems 4. the adaptive immune system

What type of pathogen causes cholera? worm virus protist fungus bacterium

The immune system usually responds to _____ cells and molecules, but not _____ cells and molecules. 1. nonself; self 2. self; nonself 3. host; foreign 4. host; self

Lupus is an autoimmune disorder. Which of the following would you expect to be a symptom of lupus? 1. an increase in ciliary action of the esophagus 2. increased phagocytosis of bacterial pathogens in the body 3. B cells binding to antigens on host cells and targeting their degradation 4. increased blood clotting if the skin is cut.

Allergies result when the immune system: 1. responds to harmless nonself molecules and cells. 2. responds to self molecules and cells. 3. does not respond to self molecules and cells. 4. responds to harmful nonself molecules and cells.

Two of the classic signs of infection, swelling and redness, are a result of: 1. changes in osmotic balance due to the presence of cytokines. 2. the effect of histamines on blood vessels. 3. the increase in cell density due to migration of phagocytes. 4. All of the answer options are correct.

Probiotics are foods, like yogurt, or dietary supplements that contain living bacteria. Why would someone want to knowingly consume bacteria? 1. to reduce or eliminate gastrointestinal problems 2. All of these choices are correct. 3. to reduce the ability of pathogens to populate the gut 4. to populate their gut with "good" bacteria

The job of a natural killer cell is to: 1. destroy invading pathogens through phagocytosis. 2. destroy infected or abnormal host cells. 3. trigger inflammation. 4. release histamine.

Which of the following statements is(are) true regarding bacteria in the human body? (Select all that apply.) 1. Human bodies may contain pathogenic bacteria, but these are often kept in check by other (nonpathogenic) species. 2. Human bodies contain bacteria that are beneficial to certain processes (for example, digestion). 3. Cholera is caused by a bacterium that infects and disables part of the immune system.

What is the function of a toll-like receptor? 1. to bind to surface molecules present on pathogens 2. to facilitate the extravasation of phagocytes 3. to bind to surface molecules present on phagocytes 4. to bind to cytokines

A man is scratched by his cat. A phagocyte near the scratch site recognizes and engulfs a bacterium. Shortly thereafter, more phagocytes arrive in the tissue surrounding the scratch. How are the additional phagocytes recruited to the site of the scratch? 1. by antigens secreted by the initial phagocyte 2. by cytokines secreted by the initial phagocyte 3. by cytokines produced by the bacteria 4. by antigens secreted by the bacteria

How does a macrophage destroy a pathogen? 1. phagocytosis 2. production of antigens 3. secretion of histamine 4. production of antibodies

The complement system refers to: 1. proteins present on macrophages that recognize foreign proteins. 2. proteins circulating in the blood that are activated by opsonization. 3. proteins that are activated when histamine levels increase. 4. proteins circulating in the blood that are activated by antibodies or molecules on pathogens.

Where do B cells mature in mammals? thymus lymph nodes blood bone marrow

The large number of antibodies that can be produced in a single individual is a result of a single B cell: 1. producing a unique antibody from all other B cells by genomic rearrangement. 2. secreting multiple antibodies that will be presented on the surface of other B cells. 3. producing multiple unique antibodies by genomic rearrangement. 4. being able to produce unique antibodies from both the maternal and paternal alleles.

Given the B cell's role in the adaptive immune response, it is reasonable to assume that a B cell has: 1. All of the other answer options are correct. 2. an enlarged nucleus. 3. extensive rough endoplasmic reticulum. 4. a large number of pseudopods.

Which of the following type of cell produces antibodies? 1. helper T cells 2. natural killer cells 3. mast cells 4. cytotoxic T cells 5. B cells

How does a vaccination help to prevent a disease? 1. It generates a population of memory cells that speed up response to an actual infection. 2. It reduces the severity of symptoms to a disease. 3. It generates a population of plasma cells that increase the concentration of antibody in the bloodstream. 4. It establishes defenses that prevent a pathogen from returning to the body.

What is the function of major histocompatibility complex (MHC) proteins? 1. They trigger endocytosis of the antigen. 2. They facilitate antigen recognition by T cell receptors. 3. They stimulate cell division. 4. They promote phagocytosis by binding to antigens.

Which of the following statements is true regarding T cell receptors? (Select all that apply.) 1. They recognize antigen-MHC complexes. 2. They contain variable and constant regions. 3. They can be found in the bloodstream independent of T cells. 4. They are formed by the rearrangement of V, J, C, and D gene segments. 5. They are composed of two heavy (H) chains and two light (L) chains.

Cells with class I MHC proteins that contain a foreign antigen will be destroyed after: 1. being bound by cytotoxic T cells. 2. being bound by helper T cells. 3. releasing histamine. 4. stimulating the MAC.

Virus-infected cells are detected and destroyed by which cell-mediated immune response? 1. helper T cells 2. cytotoxic T cells 3. macrophages 4. B cells

You are a doctor examining a patient's blood test reports. You are looking at the ratio of helper T cells to cytotoxic T cells. Helper T cells _____; cytotoxic T cells _____. You can tell them apart by the type of protein they _____. 1. kill altered host cells; activate other immune system cells; express on their plasma membrane 2. activate other immune system cells; kill altered host cells; express on their plasma membrane 3. activate other immune system cells; kill altered host cells; secrete 4. activate antigens; destroy antigens; digest 5. kill altered host cells; activate other immune system cells; secrete

Which of the following is NOT part of the structure of an antibody? 1. a major histocompatibility complex 2. light chains 3. heavy chains 4. a hypervariable region 5. an antigen-binding site

You are a doctor and have a patient who has been injured by a rusty nail. As a precaution, you vaccinate her against tetanus. In response to the vaccine, how does her body produce antibodies against C. tetani and prevent future illness due to tetanus? 1. The B cell that produces the appropriate antibody undergoes genomic rearrangement in order to produce other cells that produce the same antibody. 2. Every cell in her immune system produces antibodies against C. tetani. 3. The B cell with appropriate antibody is stimulated to divide, producing plasma cells that make antibodies to C. tetani, and memory cells that "remember" C. tetani. 4. Every B cell in her body produces antibodies against C. tetani.

The human body has about 10 bacterial cells for every eukaryotic cell. Bacteria coat our skin, gut, and mouth. Also present are protists, Archaeans, and viruses. Collectively, these organisms are our microbiota. For most members of our microbiota, our body provides their environment (or space to live). They, in turn, have no effect on us. This is an example of: 1. an antagonistic relationship. 2. predation. 3. mutualism. 4. commensalism.

Which of the following statements is TRUE regarding the bacteria present in the stomachs or intestines of humans? 1. Intestinal bacteria may play a role in immune system function. 2. Some stomach bacteria have been associated with cancers. 3. Many intestinal bacteria aid in digestion. 4. Intestinal bacteria can produce important vitamins. 5. All of these choices are correct.

Which of these would be involved in the body's main response to viral infection? 1. MHC I 2. Macrophages 3. Cytotoxic T cell 4. Dendritic cell 5. Helper T cell 6. MHC II

Innate immunity activation depends on: 1. diversity of antibodies in the blood stream. 2. None of the answer options is correct. 3. previous exposure to a foreign antigen. 4. memory B cells. 5. MHC class II proteins.

The complement system refers to: 1. proteins circulating in the blood that are activated by opsonization. 2. proteins that are activated when histamine levels increase. 3. proteins circulating in the blood that are activated by antibodies or molecules on pathogens. 4. proteins present on macrophages that recognize foreign proteins.

The reasoning behind the use of fecal transplants from healthy individuals is that: 1. antibiotics are administered with the fecal transplant, thus controlling populations of C. difficile. 2. C. difficile feeds on other bacteria that are introduced with the fecal transplant. 3. the competition from the introduction of other bacteria into the gastrointestinal tract keeps C. difficile numbers down. 4. the fecal matter from healthy patients does not have C. difficile.

16s rRNA sequencing utilizes RNA to identify microbial species present in a microbiota sample. True False

Suppose this cut gets infected by the bacterium Staphylococcus aureus. While fighting off the infection, some of your immune cells learn to recognize and "remember" this particular bacterium. Which immune cells are these? A. Neutrophils B. Macrophages C. Mast Cells D. B Cells E. T Cells

Small mutations are usually found in the protein-coding regions of the genome. True False

Which one of the following steps comes FIRST in shotgun sequencing? 1. breaking the DNA into small fragments 2. reconstructing the long sequence of nucleotides 3. putting the sequences in the correct order 4. sequencing the DNA 5. matching regions of overlap

Repeated DNA sequences represent a special challenge in genome sequence assembly. Which of the following would be harder to assemble correctly, assuming the number of copies of the repeat can be determined? 1. sequences containing repeats longer than the DNA fragments to assemble 2. sequences containing repeats shorter than the DNA fragments to assemble

Which one of the following pairs of people has the exact same genome? 1. father and son 2. identical twins 3. fraternal twins 4. None of the other answer options is correct. 5. mother and daughter

Select the answer option that lists the levels of genetic information in order from smallest to largest. 1. DNA strand; chromosome; gene; genome 2. gene; chromosome; DNA strand; genome 3. DNA strand; gene; genome; chromosome 4. gene; DNA strand; chromosome; genome 5. genome; gene; chromosome; DNA strand

Which one of following statements explains why genome annotation is an ongoing, dynamic process in need of continued updating? 1. All of these choices are correct. 2. The functions and interactions of macromolecules are never the same. 3. Certain structures like hairpins are not predictable using older annotation techniques. 4. Our understanding of genes and gene function changes. 5. Sequences change daily because mutation rates are extremely high.

All DNA sequences are transcribed into RNA. True False

Imagine that a researcher is comparing the sequence of several protein-coding genes among mice, rabbits, and humans. She finds that, for most of these genes, the rabbit sequences are more similar to the human sequences than are the mouse sequences. What can she deduce? 1. Mice and humans share a more "recent" common ancestor than do rabbits and humans. 2. Mice and rabbits do not share a common ancestor. 3. No similar proteins exist in mice and humans. 4. Humans and mice do not share a common ancestor. 5. More sequences are conserved between rabbits and humans than between humans and mice.

Which of the following are sequence motifs? 1. open reading frame 2. All of these choices are correct. 3. hairpin structures 4. coding region 5. promoters

How can researchers distinguish exons from introns in a segment of DNA? 1. The sequence of exons complements mRNA molecules in the cell. 2. Exons have a characteristic sequence. 3. Only exons contain three-base sequences that can code for amino acids. 4. Primers won't bind to introns.

When an open reading frame (ORF) is identified, it may not actually correspond to the amino acid sequence of any polypeptide in the cell. Why not? (Select all that apply.) 1. The DNA may not be transcribed into RNA. 2. The amino acid sequence may not match any known sequence. 3. The ORF could be due to chance. 4. It may contain one or more stop codons in the middle.

Imagine a genomic researcher who is analyzing the genome of different types of cats. She finds that a particular sequence in the North American Bobcat genome is exactly identical to a sequence found in the common house cat, while most other sequences in those two genomes differ at many nucleotides. (The most recent common ancestor between bobcats and house cats is estimated to be about 6.8 million years, plenty of time for mutation to generate DNA sequence variation.) Which of the following could explain the identical sequence in these otherwise differing genomes? (Select all that apply.) 1. The sequence is contained in a retrovirus that has infected both species. 2. The sequence encodes a protein critical for the production of fur color. 3. The sequence encodes a gene that is critical for life and cannot be easily mutated while retaining function. 4. The sequence is from an intron of a gene that encodes a muscle protein.

Imagine a gene in which the sequence that is transcribed into a GAG codon, which codes for glutamic acid, is mutated to GUG, which codes for valine. What type of mutation is this? 1. silent 2. frameshift 3. nonsense 4. missense 5. base pair deletion

Deletions that eliminate a multiple of three nucleotides can: 1. cause nonsense mutations in an open reading frame. 2. shorten chromosomes from the telomeres inward. 3. delete amino acids in a polypeptide chain. 4. cause cancer in a subset of somatic cells. 5. cause frameshift mutations in an open reading frame.

Which of the following point mutations is unlikely to change a protein's ability to function? (Select all that apply.) 1. one that occurs in germ cells 2. one that creates a new codon that codes for an amino acid of the same size as that coded for by the original codon 3. one that occurs in somatic cells 4. one that occurs in a noncoding region of DNA 5. one that creates a new codon code for the same amino acid as the original codon

Point mutations that cause amino acid replacements are called: 1. transition mutation. 2. nonsense mutation. 3. synonymous (silent) mutation. 4. nonsynonymous (missense) mutation. 5. stop mutation.

A point mutation that changes a UAC codon into a UAG codon is a _____ mutation. silent nonsense frameshift missense

Point mutations can impair a protein if they result in a: (Select all that apply.) 1. shift in reading frame. 2. nonsynonymous codon. 3. synonymous codon. 4. nonsense codon.

Insertions and deletions of single nucleotides: 1. cause frameshift mutations. 2. add or delete amino acids to or from the normal polypeptide. 3. shorten chromosomes. 4. cause missense mutations. 5. cause cancer.

Which of the following statements applies to frameshift mutations? 1. They create a premature stop codon at the site of mutation. 2. They change the amino acid sequence downstream from the mutant site. 3. They are known risk factors in breast cancer, but not colon cancer. 4. They cause the insertion or deletion of a single amino acid from the polypeptide chain. 5. They are known risk factors in most forms of cancer, including breast and colon cancer.

A retrotranspon known as LINE1 is about 1000 base pairs in length and is present in the human genome in about 516,000 copies. Approximately what percentage of the human genome is accounted for by this transposon? 1. 1.7% 2. 17% 3. 0.017% 4. 0.0017% 5. 0.17%

Which one of the following is a feature of DNA that could allow you to distinguish between a DNA sequence that is protein coding and a DNA sequence that is not? 1. Protein-coding sequences are sets of amino acids; others are sets of nucleotides. 2. Protein-coding sequences are single stranded; others sequences are double stranded. 3. Protein-coding regions frequently contain long open reading frames; others rarely do. 4. Protein-coding DNA sequences contain U (Uracil), and nontranscribed sequences contain T (Thymine). 5. All of these choices are correct.

A retrotransposon known as Alu1 is about 300 base pairs in length and is present in the human genome in about 1 million copies. Approximately what percentage of the human genome is accounted for by this transposon? 30% 0.03% 10% 1% 0.1%

Using current DNA-sequencing technology, it is possible to sequence an entire chromosome (e.g., human chromosome 1, which contains approximately 250 million nucleotides) as one long molecule. True False

A template strand of DNA is read in the _____ direction in order to direct synthesis of RNA in the _____ direction. 1. 3'-5'; 3'-5' 2. 3'-5'; 5'-3' 3. 5'-3'; 3'-5' 4. 5'-3'; 5'-3

Whichever DNA strand is transcribed, the RNA polymerase reads the template strand from 3? to 5?. True False

In eukaryotes, activator proteins bind to _____; generalized transcription factors bind to _____. 1. terminators; RNA polymerases 2. promoters; enhancers 3. enhancers; promoters 4. DNA polymerases; RNA polymerases 5. promoters; terminators

A template DNA strand contains the sequence 3'-ATGCTGAC-5'. This strand is transcribed: 1. from right to left. 2. from left to right.

An intron is: 1. part of an intact, mature mRNA that leaves the nucleus. 2. a polypeptide that is clipped out of a larger protein post-translationally. 3. an RNA sequence that is removed during the processing of an RNA molecule in the nucleus. 4. part of an RNA transcript that is not present in the DNA template. 5. a type of transfer RNA.

Among the possible errors listed below, which would prevent an mRNA with the correct sequence from being translated appropriately? 1. The DNA sequence was incorrect. 2. None of the other answer options is correct. 3. The poly(A) tail was not formed. 4. The 5? cap was not added. 5. Either the 5? cap was not added or the poly(A) tail was not formed.

All introns have identical lengths and sequences. False True

Most proteins retain metabolic activity when denatured. False True

You are studying a protein that you call Protein X. There is an aspartic acid at a key position in Protein X that is important in the folding and stabilization of that protein. If this aspartic acid is changed to a different amino acid, which one of the following amino acid substitutions is MOST likely to allow the protein to fold normally? 1. serine 2. glycine 3. threonine 4. glutamic acid 5. arginine

Which of the following statements is TRUE regarding a basic amino acid? 1. The R group of a basic amino acid would only be able to form covalent bonds with other molecules. 2. A basic amino acid would be considered both polar and hydrophobic. 3. All of these choices are correct. 4. The hydrophilic R group of a basic amino acid will be located in the interior of a protein. 5. The positively charged R group of a basic amino acid could bind DNA.

Which of the following statements about amino acids is INCORRECT? 1. The more glycines that are found in a polypeptide's primary sequence, the more flexible the backbone of that polypeptide. 2. The bridge between cysteines, which connects parts of a protein, is a stable but noncovalent interaction. 3. A turn or kink in a protein is more likely to be induced by a proline than by a glycine. 4. Not every amino acid is asymmetric. 5. At typical cellular pH, the R groups of basic amino acids are positively charged.

Amino acids with hydrophobic R groups are most often found buried in the interior of folded proteins. False True

The HER2 protein is a type of epidermal growth factor receptor, which when activated promotes cell proliferation. What type of gene is HER2? A. Proto-oncogene B. Tumor suppressor gene

What type of loss of function mutations could lead to over expression of the HER2 protein? A. A mutation in the HER2 promoter. B. A mutation in the coding region of the HER2 gene. C. A mutation in a gene for the HER2 repressor protein. D. A mutation in the enhancer region of the HER2 gene.

What type of gain of function mutations could lead to over expression of the HER2 protein? A. A mutation in the HER2 promoter. B. A mutation in the coding region of the HER2 gene. C. A mutation in a gene for the HER2 repressor protein. D. A mutation in the enhancer region of the HER2 gene.

What type of mutations would most likely lead to a loss of function of the HER2 protein A. Silent mutations in the HER2 ligand binding domains B. Missense mutations in the gene coding regions for the intracellular tyrosine residues. C. In-frame insertion mutations in the HER2 membrane spanning region D. In-frame deletion mutations in the HER2 membrane spanning region

A common HER2+ cancer therapy drug (Herceptin) utilizes a protein that inhibits the activation of the receptor tyrosine kinase HER2. Which of the following is most likely the function of the Herceptin protein? A. A protein that binds the intracellular portion of the HER2 protein dimers B. A protein that prevents the dimerization HER2 proteins C. A protein that competitively binds the HER2 promoter D. A protein that competitively binds the HER2 enhancer

Increased circulating estrogen can activate cell proliferation in HER2+/ER+ cancer cells True False

A common ER+ cancer therapy drug (Tamoxifen) Inhibits the activation of estrogen receptor. Which of the following is most likely NOT the function of the Tamoxifen? A. A molecule that tags the estrogen receptor for degradation. B. A competitive agonist to estrogen receptors. C. A competitive antagonist to estrogen receptors. D. A molecule that binds to estrogen receptor mRNA and prevents translation.

During the ovarian and menstrual cycles, females exhibit rapid proliferation of cells in breast and uterine tissues. True False

Aromatase inhibitors would reduce the proliferation of HER2+/ER+ cancer cells. True False

In order to metastasize, cancer cells must break away from the tissue they were originally associated with. Loss of function of which of the following adhesions would most likely allow cancer cells to metastasize? A. Adherens junctions B. Gap junctions C. Hemidesmosomes D. Tight junctions

Which of the approaches to evaluating functionality may depend on the particular state or identity of a cell? A. Biochemical approach B. Evolutionary approach C. Genetic approach D. More than one of the above E. None of the above

You are interested in using CRISPR to edit a particular gene in the genome. Select the correct order of events that must occur to introduce a double stranded DNA break using CRISPR/Cas9. 1. small guide RNA (sgRNA) hybridizes with the target DNA 2. Cas9 cuts DNA 3. Cas9/sgRNA complex binds PAM sequence 4. sgRNA binds Cas9 5. Cas9 unzips DNA a. 4, 3, 5, 1, 2 b. 5, 4, 3, 1, 2 c. 4, 1, 3, 5, 2 d. 5, 1, 4, 3, 2

Cas9 cleaves both strands of the target DNA. Which of the following could occur when cells will try to repair the damage after cleavage by Cas9? (Select all that apply.) 1. deletions of the targeted gene 2. the insertion of a DNA sequence into the targeted gene 3. mutations that result in changes to the open reading frame (ORF) of the targeted gene 4. no change in the targeted gene 5. loss-of-function mutations within the targeted gene

Researchers can change the sequence of small guide RNA (sgRNA) to cut DNA at a specific location in the genome. True False

In DNA editing by means of CRISPR, the function of the CRISPR-associated protein 9 (Cas9) is to: (Select all that apply.) 1. cleave target DNA. 2. translate sgRNA. 3. bind sgRNA. 4. bind target DNA. 5. transcribe CRISPR DNA.

Researchers noted that about half of all species of bacteria contain small segments of DNA of about 20-50 base pairs derived from plasmids or viruses. The phrase clustered regularly interspaced short palindromic repeats (CRISPR) describes the organization of these viral DNA segments in the bacterial genome. Bacteria use CRISPR to: (Select all that apply.) 1. transcribe RNA that combines with a protein that has a RNA-cleaving function. 2. "remember" the first time it was infected with a virus. 3. identify viral DNA by complementary base pairing with template DNA. 4. copy part of the bacteria genome and incorporate it into a viral genome. 5. transcribe RNA that combines with a protein that has a DNA-cleaving function. 6. identify viral DNA by complementary base pairing with RNA.

In addition to introducing mutations in a gene, DNA editing by means of CRISPR can also correct mutations in a gene. False True