Ch 4 - Membrane Structure And Function

What two components are commonly found in the extracellular matrix that help resist stretching and provide resilience? ( ) proteins & polysaccharides ( ) proteins & phospholipids ( ) polysaccharides & phospholipids ( ) amino acids & phospholipids ( ) nucleic acids & proteins

Which function does the lipid bilayer component of the plasma membrane NOT provide for the cell? ( ) defines a permeable boundary between the organized interior and the chaotic external environment ( ) provides an impermeable, self-sealing membrane that keeps all internal living processes sealed inside ( ) controls the exchange of molecules between one cell and adjacent cells or the environment ( ) provides a fluid and flexible boundary that insulates the interior from the variations in humidity, food, and other external conditions ( ) provides a matrix for proteins that regulate the exchange of molecules between the inside and outside of the cell

The cell membrane is composed of

In certain cancerous cells, the cell divides continuously even in the absence of a growth factor (signaling molecule) that indicates the cell should divide. Which of the following could NOT explain this? ( ) a receptor molecule that is always turned off ( ) a receptor molecule that is always activated ( ) a transduction pathway that is always turned on ( ) a target protein that is always activated ( ) a gene for cell division that is expressed when it should not be

Radioactive isotopes are used to tag proteins in the cell membranes of mouse cells. These cells are then fused with human cells in cultures. What is the likely consequence of the tagged mouse proteins?

Which membrane transport process can continue whether the cell is alive or dead?

When an intestinal cell ingests substances inside very small vesicles that can only be seen with an electron microscope, this is

How can marine animals such as sharks live in a salt water?

The extracellular matrix is responsible for which of the following features?

Kidney dialysis relies on diffusion of various dissolved waste molecules (solutes) across a non-living semipermeable membrane. If the concentration of solutes in the blood increases over time before dialysis is administered, what will happen to the rate of dialysis when it occurs?

A student sitting on the back row opened a bottle of foul-smelling perfume and dabbed it on her wrists. One-by-one (beginning from the back of the room) the students began to cough due to the foul smell. This phenomena was due to

Which intercellular junction allows for the rapid movement of small molecules or ions to flow from one animal cell to the next?

If a molecule crosses a plasma membrane faster than it diffuses in water, then the process is likely to involve active transport.

Which is true of facilitated transport by carrier proteins? ( ) Facilitated transport only applies to small and lipid soluble molecules. ( ) It is represented by the glucose carrier that can transport hundreds of molecules a second. ( ) After a carrier has transported a molecule, it is unable to transport any more. ( ) Facilitated transport requires expenditure of chemical energy and is therefore active transport. ( ) One carrier protein can carry a variety of different molecules

Certain individuals with a Y chromosome develop into females because testosterone is not able to induce the formation of male sexual characteristics. This is most likely due to a defect in

Which type of membrane protein will be used to bind to hormones? ( ) channel proteins ( ) carrier proteins ( ) cell recognition proteins ( ) receptor proteins ( ) enzymatic proteins

Which components of a cell membrane are used for cell-to-cell recognition? ( ) phospholipids ( ) proteins ( ) glycolipids ( ) cholesterol molecules

Which of the following refers to materials only leaving the cell? ( ) diffusion ( ) exocytosis ( ) endocytosis ( ) pinocytosis ( ) phagocytosis

When you add sugar to your coffee or tea, the sugar is the

Dead plants seen alongside a salted roadway died because the saline solution caused the cells to

Oxygen leaves the alveoli in the lungs and enters the capillaries by endocytosis. True or False?

If 0.9% NaCl were isotonic to a cell, then

If you have a 10% sugar solution and a 35% sugar solution how does the 10% solution compare to the 35% solution?

The same signaling molecule that binds to the receptor on the outside of the cell is used to alter gene expression in the nucleus. True or False?

What will happen to the protein solution of side A in Figure 4.1? {image of U shaped tube with 20% protein & 80% water on side A & 100% water on side B with a differentially permeable membrane between the sides}

What will happen to the water level in Figure 4.1? {image of U shaped tube with 20% protein & 80% water on side A & 100% water on side B with a differentially permeable membrane between the sides}

A cell placed in a hypotonic solution will

When you cut into most active plant tissue, water appears almost immediately because plant cells are in

What will happen to dye crystals if placed in the bottom of a beaker of water over a long period of time?

If the proteins forming the cell junctions within the stomach were denatured, what is a likely consequence?

Which of the following molecules add stiffness and strength to the plasma membrane? ( ) glycoproteins ( ) cholesterol ( ) phospholipids ( ) enzymatic proteins ( ) phosphate groups

Osmosis can occur when a membrane is

When water enters a plant cell

What property of phospholipids make them suitable for the formation of the double layer found in membranes?

Which is the most common type of intercellular junction between skin cells?

If a particular molecule is brought into the cell by receptor-medicated endocytosis, then changing the receptors will change the molecule that is being transported. True or False?

Insulin formed by the Golgi apparatus in insulin-producing cells leaves those cells by

An isotonic solution means that the solute concentration outside the cell

Proteins do NOT pass through cell membranes because

Which statement is FALSE concerning movement of molecules across the cell membrane? ( ) Water and gas molecules have no difficulty ( ) Small uncharged molecules pass through easily ( ) Large molecules do not pass through easily ( ) Charged molecules do not pass through easily ( ) Lipid molecules do not pass through easily

Which is a correct association of protein types?

If a cell lacks ATP, which of the following processes would cease to operate immediately? ( ) diffusion ( ) sodium/potassium pump ( ) facilitated diffusion ( ) osmosis ( ) tonicity

Receptor-mediated endocytosis involves all of the following EXCEPT ( ) receptor proteins to bind to specific molecules ( ) a coated pit due to a layer of fibrous protein on the cytoplasmic side of the membrane ( ) various outcomes from destruction of the vesicle to restoration of the surface configuration ( ) the mechanism for regulating exchange between a mother and fetus ( ) secretion of materials from a cell

Which is a correct example of tonicity? ( ) Water is hypertonic to red blood cells ( ) Turgor pressure is created when a plant cell swells in a hypotonic solution ( ) Plasmolysis results from plant cells in hypotonic solutions. ( ) Crenated red blood cells result when they are placed in a hypotonic solution. ( ) If a cell is placed in a hypertonic solution, water enters the cell.

A cell is placed in a solution of large nutrient molecules tagged with a red dye. Soon the cell is dark red, showing a concentration of the nutrient much higher than the external solution. We add a reagent that blocks the use of ATP. What result would you expect from this experiment? ( ) The nutrient would continue to rapidly enter the cell by diffusion because as a nutrient it is constantly being used in cell metabolism, so the cell will get redder ( ) The color will remain the same since all future transfer will stop ( ) The color will fade as the import of the nutrient stops and diffusion evens the concentrations ( ) The cell will continue to get darker since the import of the nutrient does not involve ATP ( ) The cell will die without access to ATP

Which of the following factors could cause the cell membrane to become less permeable? ( ) If the channel proteins were to denature and become inactive ( ) If the molecules trying to enter the cell were decreased in size ( ) If the hydrophilic head of the phospholipids were to become hydrophobic while the hydrophobic tails become hydrophilic ( ) If the size of the protein channel was to increase ( ) All of these choices would cause the cell membrane to become less permeable

Which of the following is not a function of the cell membrane? ( ) It provides mechanical strength to the cell ( ) It gives shape to the cell ( ) It regulates passage of molecules into and out of the cell ( ) It is largely responsible for cellular homeostasis ( ) Serves as a site for protein synthesis

Permeability refers to

Oxygen diffuses into the capillaries of the lungs because there is

One way to determine whether something is being actively transported across a membrane, is to compare its rate of transport with and without a chemical that blocks ATP production. True or False?

Red blood cells come in many blood types including A, B, AB and type O (lacking proteins A and B), Rh positive, Rh negative (lacking Rh+), and many others. If blood is transfused, the recipient detects any new or foreign proteins. The blood type proteins are

Once a solute and a solvent are evenly distributed in a solution, they will

When blood supplies oxygen and food to a cell surface and these molecules diffuse across, we might expect some "resting time." However, if we inspected most cell membranes in a living human body, we would find a nearly continuous flow of substances back-and-forth across the plasma membrane. Which of the following is NOT a reason why? ( ) Cell metabolism is constantly using up oxygen and raw materials; this lowers their concentration so more will diffuse into the cell. ( ) Cell metabolism is constantly producing waste molecules; this increases their concentration so more will diffuse out of the cell. ( ) Cells produce useful secretions; this increases their concentration and more will diffuse out of the cell. ( ) Cell metabolism constantly produces carbon dioxide in respiration; this increases its concentration so more will diffuse out of the cell. ( ) Cells are living entities and in order to live can never "rest".

According to the fluid-mosaic model of membrane structure,

The term hypertonic means

Carrier molecules are required for

A membrane sac filled with large molecules of potassium is suspended in a beaker of water. What will happen?

A differentially permeable membrane separates a molasses solution from distilled water. Over time, the

Molecules such as glucose and amino acids are NOT lipid soluble and therefore they

Which component of the extracellualr matrix is responsible for forming proteoglycans?

Exocytosis and endocytosis are carried out by proteins in the cell membrane. True or False?

The number of mitochondria in a cell would be a general indicator of the extent of

The inside and outside of the plasma membrane are

Of the following conditions, which is absolutely necessary for diffusion to take place? ( ) a differentially permeable membrane ( ) a true solution ( ) a concentration difference ( ) a non-permeable membrane ( ) a living cell

The definition of osmosis is the

When a substance moves from an area of low concentration to an area of high concentration while using energy, the process is termed

Which of the following is NOT true regarding active transport? ( ) moves molecules or ions against their concentration gradient ( ) involves protein pumps ( ) is associated with large numbers of mitochondria ( ) is associated with nerve and muscle cells ( ) cannot be done by animal cells

In the Malpighian tubules of an insect (blind, threadlike excretory tubule attached to the gut of an insect), salt molecules are actively transferred from body fluids to the inside of the tubule. Which of the following is NOT true? ( ) Water is also "pulled" by osmosis into the Malpighian tubule. ( ) The concentration of salt is normally higher in the body fluids than it is inside the tubule. ( ) The process decreases the salt concentration of the body fluids. ( ) Insects must excrete excess salt through the Malpighian tubules. ( ) The tubules have the same tonicity as the body fluids.

In the emergency room, saline solutions are often run into a person's vein. The saline solution must be

When a plant cell is placed in a hypotonic solution, the cell wall prevents

Our body recognizes the foreign nature of a parasite or disease agent and we soon build up antibodies. A few parasites can change their identity to evade our immune system. How could cells do this on a regular basis?

In the new procedures developed to clone a mammalian cell, the nucleus is removed from an egg cell and the nucleus from the adult to be cloned is injected inside this cell. If we did this process with a basketball, we would permanently damage the shell. What property of the cell repairs this damage?

The pressure that is generated when water flows through a differentially permeable membrane is termed

Macrophages, a type of white blood cells, are able to remove bacteria from our bloodstream and tissues by