Chapter 6 Bio

The blood clotting cascade in a mammal consists of a series of serine proteases (indicated by circles and ovals in the figure). Each protease activates the next enzyme in the cascade. Some creationists use this as an example of irreducible complexity, arguing that if any one piece is removed the whole system will not work, and thus it must have been intelligently designed all at once. Biologists would counter that this is not necessary to explain the evolution of a complex cascade like this. Which of the following arguments would a biologist most likely make?

Your friend is studying a specific exergonic reaction. Your friend hypothesizes that the addition of enzyme X will reduce the delta-G of this reaction, thus allowing it to proceed spontaneously. What do you think of your friend's hypothesis?

Based on the animation (A Biochemical Pathway), which of the following observations is true?

Consider the biochemical pathway below, where A, B, and C are substrates and products and E1 and E2 are the enzymes that catalyze the reactions. Enzyme 1 (E1) can utilize: A---E1---> B---E2--->C

Consider the biochemical pathway below, where A, B, and C are substrates and products and E1 and E2 are the enzymes that catalyze the reactions. If Enzyme 1 (E1) is inactive, which of the following compounds will accumulate?: A---E1---> B---E2---> C

In a biochemical pathway, the product released by the first enzyme becomes the substrate for the second enzyme.

If a chemical that inhibits Enzyme #3 was added to the system containing the biochemical pathway illustrated in the animation, which of the following would result?

What function do many B vitamins serve in the production of energy?

Enzymes catalyze reactions by

In the example shown, which best describes the role of thiamine pyrophosphate in the reaction to cleave pyruvate?

Consuming B vitamins in excess of need will

If thiamine pyrophosphate was not available to the enzyme in the animation which of the following would occur?

FAD is a coenzyme associated with the succinate dehydrogenase enzyme complex in the respiratory citric acid cycle and electron transport chain. FAD becomes reduced due to the oxidation of succinate. Which of the following would occur if the FAD coenzyme were not associated with succinate dehydrogenase?

Where is sucrase found in the human body?

Sucrase uses ____ to cleave sucrose into two monosaccharides.

What happens to sucrase when it binds to sucrose?

How often can a sucrase molecule be used to hydrolyze sucrose?

Based on the reaction in the animation, what can you say about the change in free energy of the cleavage of sucrose into glucose and fructose?

A mutation occurred in the gene that encodes the enzyme sucrase, resulting in a single amino acid substitution in the active site of the enzyme; a polar amino acid changed to a nonpolar amino acid. What is probably the result of this mutation.

L-Arabinose is an naturally occurring, non-caloric sweetener that is a non-competitive inhibitor of sucrase. If L-Arabinose is consumed, what will happen to the Vmax of the reaction and Km of the substrate?

In feedback inhibition, the inhibitor of the biochemical pathway is often

In the example above, how does the final product of the pathway inhibit the pathway?

Consider the biochemical pathway used to synthesize the amino acid proline. A large increase in the level of proline will most likely lead to

If the end product of the biochemical pathway in the animation increases it would eventually result in an increase in substrate 1.

If the end product of the biochemical pathway in the animation increases it would eventually result in an increase in substrate 2.

Consider the biochemical pathways illustrated below. Product D will act as an allosteric inhibitor of what enzyme to regulate its own production? : A---E1---> B---E2---> C ---E3---> D | E4 | V E

Consider the biochemical pathways illustrated below. If product D is abundant, why is it preferable to inhibit E2 rather than E1? : A---E1---> B---E2---> C ---E3---> D | E4 | V E

Enzymes are

Which of the following binds most tightly to the active site of an enzyme?

The enzyme in the animation is most likely catalyzing ______.

An enzyme binds the product more tightly than the substrate.

An enzyme catalyzes a chemical reaction in the cell, but can only be used once.

Which of the following statements about enzymes is TRUE?

An enzyme may catalyze a reaction by stressing or destabilizing the bonds of the substrates. This point in the enzymatic reaction is known as the

Cells obtain energy by ________ food molecules such as glucose.

What happens when the coenzyme NAD+ gains an H atom?

A hydrogen atom consists of

Whenever a molecule is oxidized, another molecule must be reduced.

NAD+ is a coenzyme for many enzymes involved in redox reactions. This means that

NAD+ is made from niacin, a B vitamin. Based on the animation, if someone is deficient in niacin, which of the following symptoms might they experience?

When a person is in a state of fear, the hormone epinephrine is released. This hormone stimulates the activation of energy-generating, catabolic, pathways, in order to provide the body with enough energy to respond to the element that is inducing the fear. How would that be helpful to a person who unexpectedly finds themselves in close proximity to a lion?

Chronic Myelogenous Leukemia (CML) is a type of cancer that is caused by a specific chromosomal alteration that leads to the inappropriate expression of a kinase called Abl. Kinases are enzymes that put phosphate groups onto macromolecules such as proteins. A drug used to treat CML, imatinib, binds to the active site of Abl kinase. Why does this drug work to treat this type of cancer?

The polymerase chain reaction (PCR) has revolutionized biology and medicine, by allowing small regions of DNA to be amplified up to a billion-fold over 30 cycles in a few hours. Each cycle involves heating the DNA to 95°C to separate the two strands, the sample is then cooled to allow primers to bind, and finally the temperature is raised to the optimal temperature for the DNA polymerase to replicate the DNA. This process makes use of the DNA polymerase from a species of bacteria isolated from hot springs, Thermus aquaticus, which grows at 70°C. Human body temperature is 37°C. What would you predict about the DNA polymerase from T. aquaticus compared with DNA polymerases from human cells?

You are cooking beans over a campfire. By the light of the fire, you read that one serving of beans is 120 calories. After eating the beans, you go for a hike along a stream. All of the items described here have energy. Identify the form of energy each contains. POTENTIAL ENERGY:

You are cooking beans over a campfire. By the light of the fire, you read that one serving of beans is 120 calories. After eating the beans, you go for a hike along a stream. All of the items described here have energy. Identify the form of energy each contains. KINETIC ENERGY:

What is the ultimate source of most energy in the biosphere?

Reduction/oxidation or redox reactions involve the transfer of energy through electron transfer. True or false, the following reactions are reduction reactions. a. NAD+ + e- + H => NADH b. Fe+2 => Fe+3 c. Pyruvate + 2e- => lactate d. NO2- => NO3-

You and a friend are eating dinner together, and a number of events occur during your dinner that call to mind the Laws of Thermodynamics. Match the event to the proper Law of Thermodynamics. 1ST LAW OF THERMODYNAMICS:

You and a friend are eating dinner together, and a number of events occur during your dinner that call to mind the Laws of Thermodynamics. Match the event to the proper Law of Thermodynamics. 2ND LAW OF THERMODYNAMICS:

Rank these reactions from least to most energetically favorable. a. Glucose-6-P to Fructose-6-P, +0.4kcal/mol b. Glucose to Glucose-6-P, +3.3kcal/mol c. ATP to ADP and Pi, -7.3kcal/mol d. PEP to pyruvate, -14.8kcal/mol

a. B is influenced by temperature b. A is lowered by an enzyme c. B is lowered by an enzyme

A. When ATP is used in a reaction, the last phosphate is transferred to the substrate. B. Release of the last phosphate from ATP is endergonic. C. Once phosphates are released from ATP they can be added back in an endergonic reaction. D. The creatine-Phosphate to creatine reaction has a ΔG of -11kcal/mole and thus can be used to generate ATP from ADP. E. When ATP is hydrolyzed to form ADP, the energy is released into the cytoplasm where enzymes use it to run endergonic reactions.

Match each description with the appropriate step in enzyme catalysis.

Click and drag the correct terms to complete the following sentences. a. Anabolic reactions ________ NADH and ATP. b. Catabolic reactions ________ NADH and ATP. c. Molecules are broken down in _________ reactions. d. Molecules are synthesized in __________ reactions.

Identify which descriptions represent a metabolic pathway, and which descriptions are not describing a metabolic pathway. METABOLIC PATHWAY:

Identify which descriptions represent a metabolic pathway, and which descriptions are not describing a metabolic pathway. NOT A METABOLIC PATHWAY:

The ultimate source of energy for humans comes from what source?

The chemistry of living systems representing all chemical reactions is called

While standing at the top of the stairs, you have a potential energy of 40 Joules. If you walk all the way down the stairs, what would your potential energy be at the bottom of the stairs?

Under standard conditions, ATP can release for every molecule converted to ADP

When an atom or molecule gains one or more electrons, it is said to be:

The organic non-protein components that aid in enzyme functioning are called:

A new antibiotic has been developed. It acts as a noncompetitive inhibitor. How will this antibiotic affect delta G for the enzyme-catalyzed reaction?

RNA molecules that also act as enzymes are given the name:

Metabolic reactions fall under two general categories: anabolic and catabolic. What type of chemical reactions are these two classes of metabolic reactions?

The energy needed to destabilize existing chemical bonds and start a chemical reaction is called:

In order to reuse an enzyme after the conclusion of an enzyme catalyzed reaction, what must occur?

A particular chemical reaction is exergonic. What can you say about the relationship between the reactants and the products in this exergonic reaction?

When the substrate is bound to the enzyme, the shape of the enzyme may change slightly, leading to:

A calorie is the commonly used unit of chemical energy. It is also the unit of:

The amount of energy available to do work is called:

A ribozyme catalyzes a reaction on itself and actually changes shape. This is an example of what?

The term oxidation is derived from the name of the element oxygen. This is reasonable, because oxygen:

Energy is defined as:

It is summer, and you are excited about going to your local amusement park, and specifically about riding the new roller coaster that was just built. You imagine waiting at the top of the stairs for the roller coaster to pull into the station, climbing into the car, strapping yourself into the seatbelt, and pulling down the harness. You can imagine the cars slowly chugging up to the top of the first hill, coming down on the other side, and the excitement you expect to feel as you go along for the ride. Of all of the things that you have imagined, which is an example of potential energy?

In an experiment described in a chemistry lab book, the directions state that after mixing two chemicals (A and B) and waiting 5 minutes that A will be oxidized. This means that:

Does ADP contain the capacity to provide energy for the cell?

AMP-activated protein kinase (AMPK) is an enzyme that is activated by high levels of AMP in cells. If levels of AMP are high in cells, that means that levels of ATP are low. Once active, AMPK activates catabolic pathways and inhibits anabolic pathways in the cell. Why do you think that is the case? Choose the answer that best explains the role of AMPK.

Oxidation and reduction reactions are chemical processes that result in a gain or loss of:

You eat a bowl of beans as part of your dinner. As you digest the beans, the proteins that are present get broken down to their component amino acids. As your body destroys the macromolecules that were present in the beans, is the energy present in those molecules destroyed?

For a particular chemical reaction, the enthalpy of the reactants is -400 kJ. The enthalpy of the products is -390 kJ. The entropy of the reactants is 0.2 kJ/K. The entropy of the products is 0.3 kJ/K. The temperature of the reaction is 25oC. What can you conclude about this reaction?

Enzyme 1 converts substrate A into product B. Is this an example of a metabolic pathway?

Kinases are enzymes that can phosphorylate (transfer phosphate groups onto) macromolecules such as proteins. A particular kinase, Kinase 1 is known to promote cell division. It promotes cell division by phosphorylating Protein X. Phosphorylation of Protein X activates Protein X. Once activated, Protein X stimulates the production of other proteins such as Protein Y and Z that directly promote cell division. In order to function, Kinase 1 requires the presence of Metal A. However, in the presence of Protein A, Kinase 1 is nonfunctional. From the description, what is considered the substrate of Kinase 1?

A particular reaction has a negative delta G. However, this reaction takes many years to proceed in the absence of enzyme. Why is this the case?

In a chemical reaction, 1,3-bisphosphoglycerate + ADP yields 3-phosphoglycerate plus ATP. What is the delta G for this reaction?

The Law of Thermodynamics that states that energy cannot be created or destroyed is:

You are studying an enzyme-catalyzed reaction that induces a particular cellular activity in the lab. If you wanted to slow down that particular cellular activity by controlling the enzyme, what could you do?

A current problem in modern medicine is the development of drug resistance mutations. This occurs when a mutation arises in a patient making him/her resistant to a drug and thus rendering the drug useless in treating a specific disease. Many useful drugs are competitive inhibitors of specific enzymes, and the drug-resistance mutations prevent the binding of the drug. These types of mutations, in addition to preventing competitive inhibitor binding, can also sometimes reduce the activity of the enzyme. Why is that the case?