Biology Chapter 4 Quiz attempt 1 and 2

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

True

If we inspect 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 explains this continuous flow? a. Cell metabolism is constantly using up oxygen and raw materials; this lowers their concentration, so more will diffuse into the cell. b. Cell metabolism is constantly producing waste molecules; this increases their concentration, so more will diffuse into the cell. c. Cells produce useful secretions; this increases their concentration, and more will diffuse into the cell. d. Cell metabolism constantly produces oxygen in respiration; this increases the cell's affinity for carbon dioxide which diffuses into the cell. e. Cells are non-living and therefore anything can pass in and out of the cell.

a. Cell metabolism is constantly using up oxygen and raw materials; this lowers their concentration, so more will diffuse into the cell.

How can marine animals such as sharks live in salt water? a. They increase or decrease the amount of urea in their blood until the blood is isotonic with the environment. b. They increase the amount of urea in their blood until the blood is hypertonic with the environment. c. They decrease the amount of urea in their blood until the blood is hypotonic with the environment. d. They contain impermeable membranes which do not allow the salt water to cross into their cells. e. They block the movement of salt into their cells and maintain a constant blood salt concentration.

a. They increase or decrease the amount of urea in their blood until the blood is isotonic with the environment.

Receptor-mediated endocytosis a. involves receptor proteins binding to specific molecules. b. protein pumps moving substances from low concentration to high concentration. c. protein pumps moving substances from high concentration to low concentration. d. the cell engulfing large particles. e. secretion of materials from a cell.

a. involves receptor proteins binding to specific molecules.

Label the following image with the correct terms to describe the structure and function of a plasma membrane. peripheral protein integral protein glycoprotein cytoskeleton filaments glycolipid extracellular remix (ECM) cholesterol phospholipid

1. glycoprotein 2. glycolipid 3. phosolipid 4. peripheral protein 5. cholesterol 6. integral protein 7. cytoskeleton filaments 8. extracellular remix (ECM)

A cell is placed in a solution of large carbohydrate 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? a. 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 become more red. b. The color will remain the same since all future transfer will stop. c. The color will fade as the import of the nutrient stops and diffusion evens the concentrations as it moves the nutrient molecules out of the cell. d. The cell will continue to get darker since the import of the nutrient does not involve ATP. e. The cell will die without access to ATP.

b. The color will remain the same since all future transfer will stop.

When you cut into most active plant tissue, water appears almost immediately because plant cells contain a. a hypertonic solution that produces turgor pressure. b. a hypotonic solution that produces turgor pressure. c. an isotonic condition and you cut the cell open. d. a hypertonic condition and cutting it reversed this to hypotonic. e. a hypotonic condition and cutting it reversed this to hypertonic.

b. a hypotonic solution that produces turgor pressure.

Which of the following molecules add stiffness and strength to the plasma membrane? a. glycoproteins b. cholesterol c. phospholipids d. enzymatic protein e. phosphate groups

b. cholesterol

The definition of osmosis is the: a.the movement of solute molecules from a higher concentration to a lower concentration. b. diffusion of water across a selectively permeable membrane. c. likelihood that water will diffuse in a particular direction. d. lower concentration of a solute in a solution. e. movement of water toward a low solute concentration.

b. diffusion of water across a selectively permeable membrane

Permeability refers to a. the movement of molecules from an area of greater concentration to an area of lesser concentration. b. the extent to which a membrane allows a substance to pass through. c. the amount of solute in a solution. d. the state of being permanent. e. the ability to establish a permanent solute level in a solution.

b. the extent to which a membrane allows a substance to pass through.

Of the following conditions, which is absolutely necessary for diffusion to take place? a. a differentially permeable membrane b. low temperatures c. a concentration difference d. a non-permeable membrane e. a living cell

c. a concentration difference

Active transport a. moves molecules or ions along their concentration gradient. b. involves carbohydrate pumps. c. is associated with large numbers of mitochondria. d. is associated with fat and skin cells. e. cannot be done by animal cells.

c. is associated with large numbers of mitochondria.

An isotonic solution means that the solute concentration outside the cell a. is greater than inside the cell. b. is less than inside the cell. c. is the same as inside the cell. d. has no effect on the cell. e. is greater than outside the cell.

c. is the same as inside the cell.

Blood type is determined by proteins. Blood type A has a different protein than blood type B. Blood type AB has both types of proteins and type O does not have either type of protein. When blood is transfused, the recipient's immune system will detect any new or foreign proteins. The blood type proteins must be located a. in the red blood cell nucleus. b. inside the red blood cell cytoplasm. c. on the outer surface of the red blood cell membrane. d. in the nuclear membrane. e. in the endoplasmic reticulum of the red blood cells.

c. on the outer surface of the red blood cell membrane.

Proteins do not pass through cell membranes because a. the membrane is made of protein. b. they contain nitrogen. c. they are very large molecules. d. they cause emulsification. e. they cause digestion of the cell.

c. they are very large molecules.

A student sitting in 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 phenomenon was due to a. osmosis. b. molecules moving from an area of low concentration to high concentration. c. an allergic reaction. d. diffusion e. active transport

d. diffusion

Which components of a cell membrane are used for cell-to-cell recognition? a. phospholipids b. channel proteins c. glycolipids d. glycoproteins e. cholesterol molecules

d. glycoproteins

Which statement is true concerning movement of molecules across the cell membrane? a. Water and gas molecules cannot easily pass through the membrane. b. Small uncharged molecules do not pass through easily. c. Large molecules pass through easily. d. Charged molecules pass through easily. e. Lipid molecules pass through easily.

e. Lipid molecules pass through easily.

When you add sugar to your coffee or tea, the sugar is the a. permeable b. solvent c. gradient d. solution e. solute

e. solute