Ap biology- cell membrane and cell communication for exam 3 so I actually pass this time

Site of conversion of chemical energy of glucose to ATP a- A b- B c- C d- D e- E

a- A

Which of the following components of the cell membrane is responsible for active transport? a- Phospholipid b- Protein c- Lipid d- Phosphate e- Cholesterol

B- Protein

Which of the following describes the most likely location of cholesterol in an animal cell? a- Embedded in the plasma membrane b- Dissolved in the cytosol c- Suspended in the stroma of the chloroplast d- Bound to free ribosomes

a- Embedded in the plasma membrane

All eukaryotic cells contain at least one Golgi complex, typically located in the cytoplasm and near the endoplasmic reticulum. Which of the following best describes a process that occurs within the Golgi complex? a- Enzymatic modification of newly synthesized integral membrane proteins b- Synthesis of cytosolic proteins based on the nucleotide sequences of mRNAs c- Degradation of proteins by hydrolytic enzymes contained within the complex d- Synthesis of various types of lipids

a- Enzymatic modification of newly synthesized integral membrane proteins

The following questions refer to an experiment in which a dialysis-tubing bag is filled with a mixture of 3% starch and 3% glucose and placed in a beaker of distilled water, as shown below. After 3 hours, glucose can be detected in the water outside the dialysis-tubing bag, but starch cannot. If, instead of the bag, a potato slice were placed in the beaker of distilled water, which of the following would be true of the potato slice? a- It would gain mass. b- It would neither gain nor lose mass. c- It would absorb solutes from the surrounding liquid. d- It would lose water until water potential inside the cells is equal to zero. e- The cells of the potato would increase their metabolic activity.

a- It would gain mass.

Which of the following best supports the statement that mitochondria are descendants of endosymbiotic bacteria-like cells? a- Mitochondria and bacteria possess similar ribosomes and DNA. b- Mitochondria and bacteria possess similar nuclei. c- Glycolysis occurs in both mitochondria and bacteria. d- Both mitochondria and bacteria have microtubules. e- Neither mitochondria nor bacteria possess chloroplasts.

a- Mitochondria and bacteria possess similar ribosomes and DNA.

Carbon dioxide most likely enters a cell through which of the following processes? a- Simple diffusion through the membrane b- Facilitated diffusion through membrane proteins c- Active transport through membrane proteins d- Active transport through aquaporins

a- Simple diffusion through the membrane

The following questions refer to an experiment in which a dialysis-tubing bag is filled with a mixture of 3% starch and 3% glucose and placed in a beaker of distilled water, as shown below. After 3 hours, glucose can be detected in the water outside the dialysis-tubing bag, but starch cannot. Which of the following best describes the condition expected after 24 hours? a- The bag will contain more water than it did in the original condition. b- The contents of the bag will have the same osmotic concentration as the surrounding solution. c- Water potential in the bag will be greater than water potential in the surrounding solution. d- Starch molecules will continue to pass through the bag. e- A glucose test on the solution in the bag will be negative.

a- The bag will contain more water than it did in the original condition.

In an experiment, the efficiency of oxygen exchange across the plasma membrane is being assessed in four artificial red blood cells. The table above lists some properties of those artificial cells. Other conditions being equal, which artificial cell is predicted to be the most efficient in exchanging oxygen with the environment by diffusion? a- The cuboidal cell b- The tetrahedral cell c- The cylindrical cell d- The spherical cell

a- The cuboidal cell

Which of the following outcomes will most likely result from the irreversible binding of GDP to the G protein? a- The intracellular concentration of glycogen will increase. b- The intracellular concentration of activated protein kinase A will increase. c- The intracellular concentration of cyclic AMP will increase. d- The intracellular concentration of glucose-1-phosphate will increase.

a- The intracellular concentration of glycogen will increase.

Which of the following best explains how the phospholipid bilayer of a transport vesicle contributes to cellular functions? a- The phospholipid bilayer allows the vesicle to fuse with the Golgi apparatus and the plasma membrane, allowing the exocytosis of proteins. b- The phospholipid bilayer physically connects the nuclear envelope to the rough endoplasmic reticulum, thus increasing the rate of transcription and translation. c- The phospholipid bilayer of a transport vesicle contains chemicals that digest the proteins made in the rough endoplasmic reticulum. d- The phospholipid bilayer contains enzymes that catalyze the conversion of hydrogen peroxide to water and oxygen.

a- The phospholipid bilayer allows the vesicle to fuse with the Golgi apparatus and the plasma membrane, allowing the exocytosis of proteins.

When a substance moves across the plasma membrane along a concentration gradient at a rate faster than would be expected by simple diffusion alone but without the expenditure of metabolic energy, the process is best described as a- facilitated diffusion b- osmosis c- active transport d- pinocytosis e- the work of an ion pump

a- facilitated diffusion

This group of questions refers to the following groups of biological compounds. (A) Proteins (B) Carbohydrates (C) Nucleic acids (D) Lipids (E) Steroids Synthesized at the ribosome a- proteins b- carbohydrates c- nucleic acids d- lipids e- steroids

a- proteins

Evolved from a photoautotrophic prokaryote a- A b- B c- C d- D e- E

b- B

The following questions refer to the following diagram. For each phrase or sentence, select the labeled part to which it is most closely related. Each option may be used once, more than once, or not at all for each group. Site of glucose synthesis a- A b- B c- C d- D e- E

b- B

Plant cell walls are composed of cellulose, while fungal cell walls are composed of chitin. A group of scientists hypothesize that this difference means the cell wall has largely different functions in plant cells and fungal cells. Alternatively, another group of scientists hypothesize that despite their biochemical differences, plant and fungal cell walls serve similar functions. Which of the following observations would best support the alternative hypothesis described above? a- Plant cell walls are found just outside the plasma membrane, while fungal cell walls are found just beneath the plasma membrane. b- In both plant cells and fungal cells, the cell wall surrounds the outside of the cell membrane. c- Some plant cells have secondary cell walls that confer additional rigidity, while fungal cells do not. d- Photosynthesis occurs in plant cells, but it does not occur in fungal cells.

b- In both plant cells and fungal cells, the cell wall surrounds the outside of the cell membrane.

The epinephrine signaling pathway plays a role in regulating glucose homeostasis in muscle cells. The signaling pathway is activated by the binding of epinephrine to the beta-2 adrenergic receptor. A simplified model of the epinephrine signaling pathway is represented in Figure 1. Based on Figure 1, which of the following statements best describes the epinephrine signaling pathway? a- It involves the opening and closing of ion channels. b- In involves enzymes activating other enzymes. c- It involves changes in the expression of target genes. d- It involves protons moving down a concentration gradient.

b- In involves enzymes activating other enzymes.

Which of the following organelles modifies and packages for secretion the materials produced by the ribosomes? a- The chloroplast b- The Golgi apparatus c- The nucleus d- The nucleolus e- The mitochondrion

b- The Golgi apparatus

Glucocorticoids are steroid hormones that control cellular responses through several different signaling pathways. One of the signaling pathways involves the glucocorticoid receptor, an intracellular protein that is activated by binding to a glucocorticoid molecule. A simplified model of the glucocorticoid receptor signaling pathway is represented in Figure 1. Which of the following statements best predicts the effect of a mutation that results in a loss of the glucocorticoid receptor's ligand binding function? a- The transduction of the glucocorticoid signal across the plasma membrane will be blocked. b- The glucocorticoid receptor will remain associated with the accessory proteins. c- The rate of diffusion of glucocorticoid molecules into the cell will increase. d- The concentration of glucocorticoid receptors inside the nucleus will increase.

b- The glucocorticoid receptor will remain associated with the accessory proteins.

The following questions refer to an experiment in which a dialysis-tubing bag is filled with a mixture of 3% starch and 3% glucose and placed in a beaker of distilled water, as shown below. After 3 hours, glucose can be detected in the water outside the dialysis-tubing bag, but starch cannot. From the initial conditions and results described, which of the following is a logical conclusion? a- The initial concentration of glucose in the bag is higher than the initial concentration of starch in the bag. b- The pores of the bag are larger than the glucose molecules but smaller than the starch molecules. c- The bag is not selectively permeable. d- A net movement of water into the beaker has occurred. e- The molarity of the solution in the bag and the molarity of the solution in the surrounding beaker are the same.

b- The pores of the bag are larger than the glucose molecules but smaller than the starch molecules.

A scientist designed an experiment to test an artificial membrane that mimics the phospholipid bilayer of a cell. The scientist built a tube that was divided by an artificial membrane and filled with distilled water. The scientist put a known amount of a protein into the water on one side of the membrane. After some time, the scientist measured the concentration of the protein on either side of the membrane but found that there had been no change. Which of the following experimental changes would allow the scientist to observe transport of a solute across the artificial membrane? a- Increase the solute concentration in the solution b- Use a small, nonpolar solute instead of a protein c- Increase the temperature of the solution d- Add artificial aquaporins to the membrane

b- Use a small, nonpolar solute instead of a protein

Which statement best describes the effect on water transport across the cell membrane if the aquaporin in the figure ceases to function? a- Water molecules will no longer be able to move across the cell membrane. b- Water molecules will still be able to move across the cell membrane but at a slower rate. c- Water molecules will only be able to enter the cell by active transport. d- water molecules will move across the cell membrane at a faster rate without the aquaporin regulating their flow.

b- Water molecules will still be able to move across the cell membrane but at a slower rate.

Dialysis tubing is permeable to water molecules but not to sucrose. Four dialysis tubes are half filled with 5 percent, 10 percent, 20 percent, and 40 percent sucrose solutions, respectively, and two dialysis tubes are half filled with distilled water. The dialysis tubes are all sealed at both ends, and the initial masses are determined. Five dialysis tubes are placed into beakers containing distilled water, and the sixth dialysis tube, containing distilled water, is placed into a 40 percent sucrose solution. The masses of the dialysis tubes are recorded at 30-minute intervals for 90 minutes, as shown in the table below. To model a plant cell, a permeable, nonflexible case is placed around each piece of dialysis tubing. The greatest pressure potential will develop within dialysis tube number a- 2 b- 3 c- 4 d- 5 e- 6

c- 4

A student peeled the skins from grapes, exposing cells with membranes that are only permeable to water and small diffusible solutes. The student measured the mass of the peeled grapes. The student then placed each peeled grape into one of five solutions. After 24 hours, the student removed the peeled grapes from the solutions, measured their final mass, and calculated the percent change in mass (Table 1). In a second experiment (Table 2), the student placed a peeled grape into a solution containing both small diffusible solutes and solutes to which the membrane is impermeable (nondiffusible solutes). Based on Table 1, which of the following percentages is closest to the solute concentration of the grape? a- 0.0% b- 1.3% c- 5.5% d- 10.1%

c- 5.5%

An investigator wants to understand whether a newly found membrane protein is involved in membrane transport of a certain particle. Which investigation will help determine whether the new membrane protein is a channel protein involved in membrane transport? a- add small nonpolar molecules to the extracellular space and measure the direction of particle movement of the molecules. b- Measure the rate of extracellular fluid movement into the intracellular space. c- Add more of the proteins to the plasma membrane and measure the rate of the particle movement. d- remove ATP from the intracellular space and measure the rate of the particle movement into the intracellular space.

c- Add more of the proteins to the plasma membrane and measure the rate of the particle movement.

Which of the following is a characteristic of mitochondria and chloroplasts that supports the endosymbiotic theory? a- Both have bacteria-like polysaccharide cell walls. b- Both can reproduce on their own outside of the cell. c- Both contain DNA molecules. d- Both contain endoplasmic reticulum and Golgi bodies. e- Both contain ribosomes that are identical to ribosomes of the eukaryotic cytoplasm.

c- Both contain DNA molecules.

Site of modification and packaging of proteins and lipids prior to export from the cell a- A b- B c- C d- D e- E

c- C

Which of the following statements best describes the role of adenylyl cyclase in the epinephrine signaling pathway? a- It converts a polymer to its monomer subunits. b- It moves substances across the plasma membrane. c- It accelerates the production of a second messenger. d- It transfers phosphate groups from ATP to protein substrates.

c- It accelerates the production of a second messenger.

If ATP breakdown (hydrolysis) is inhibited, which of the following types of movement across cell membranes is also inhibited? a- Movement of oxygen into a cell b- Movement of water through aquaporins c- Passage of a solute against its concentration gradient d- acilitated diffusion of a permeable substance

c- Passage of a solute against its concentration gradient

Cell communication is critical for the function of both unicellular and multicellular eukaryotes. Which of the following is likely true of cell signaling? a- Cell signaling uses the highest molecular weight molecules found in living cells. b- Cell signaling has largely been replaced by other cell functions in higher mammals. c- Similar cell signaling pathways in diverse eukaryotes are evidence of conserved evolutionary processes. d- Cell signaling functions mainly during early developmental stages.

c- Similar cell signaling pathways in diverse eukaryotes are evidence of conserved evolutionary processes.

Intravenous (IV) solutions administered to patients are normally isotonic. Which of the following is most likely if an IV of distilled water is administered to a patient? a- The cells that are exposed to hypotonic solutions will shrink as a result of salt moving into the blood. b- The liver will secrete additional bile salts into the blood to raise the tonicity of the administered fluid. c- The cells that are exposed to hypotonic solutions will expand as water moves osmotically into the cells from the blood. d- The patient's respiration rate will slow to compensate for the higher levels of circulating blood.

c- The cells that are exposed to hypotonic solutions will expand as water moves osmotically into the cells from the blood.

Which of the following provides evidence to best support the researchers' claim? a- The organelle has a phospholipid membrane. b- The organelle has protein in the membrane. c- The organelle has a double membrane. d- The organelle has an internal aqueous environment that is similar to the cytosol of the larger cell.

c- The organelle has a double membrane.

The diagram above represents a typical rod-shaped bacterium. Which of the following best describes a feature shown in the diagram that is unique to archaea and bacteria? a- The organism is surrounded by a cell wall. b- The organism contains ribosomes. c- The organism does not have a nuclear membrane surrounding its genetic material. d- The organism is not capable of making or providing itself with ATP.

c- The organism does not have a nuclear membrane surrounding its genetic material.

Which of the following scientific questions is most relevant to the model represented in the figure above? a- Is ATP required for the transportation of sugars across the outer mitochondrial membrane? b- Do the types of phospholipids in a membrane affect the rate at which molecules enter a cell by passive diffusion? c- Which molecular substance is actively transported across the plasma membrane? d- How does temperature affect the movement of molecules into lysosomes?

c- Which molecular substance is actively transported across the plasma membrane?

Aquaporins are channel proteins that facilitate the transport of water across the cell membrane. One group of researchers hypothesizes that without functional aquaporins, no water will be able to enter the cell. A different group proposes an alternative hypothesis, stating that even with nonfunctional aquaporins, a small amount of water will still cross the cell membrane. An experiment is set up in which plant cells with mutated (nonfunctional) aquaporins and plant cells with normally functioning aquaporins are both placed in distilled water. Which of the following data would support the alternative hypothesis? a- Cells with functional aquaporins exhibit low turgor pressure and are hypertonic. b- Cells with functional aquaporins exhibit high turgor pressure and are hypotonic. c- Cells with mutated aquaporins exhibit an absence of turgor pressure and are completely plasmolyzed. d- Cells with mutated aquaporins exhibit moderate turgor pressure and are hypertonic.

d- Cells with mutated aquaporins exhibit moderate turgor pressure and are hypertonic.

Site of transport of materials into and out of the cell a- A b- B c- C d- D e- E

d- D

A researcher claims that the epinephrine signaling pathway controls a catabolic process in muscle cells. Which of the following statements best helps justify the researcher's claim? a- Epinephrine is a signaling molecule that binds to a transmembrane protein. b- The G protein in the epinephrine signaling pathway consists of three different subunits. c- Phosphorylase kinase catalyzes the hydrolysis of ATP. d- Glycogen phosphorylase catalyzes the conversion of glycogen to glucose-1-phosphate.

d- Glycogen phosphorylase catalyzes the conversion of glycogen to glucose-1-phosphate.

A cell is treated with a drug that prevents the formation of new lysosomes. The cell continues to transcribe the genes that code for the hydrolytic enzymes that are normally found in lysosomes and continues to translate the mRNAs for those proteins on membrane-bound ribosomes. The hydrolytic enzymes are most likely to accumulate in which of the following cellular structures? a- Nucleus b- Mitochondrion c- Smooth endoplasmic reticulum d- Golgi complex

d- Golgi complex

Water is constantly diffusing into the cytosol of freshwater single-celled organisms. In order to maintain the proper solute concentrations in the cytosol, contractile vacuoles pump out the excess water. An experimenter placed single-celled organisms into various saline concentrations and recorded the ATP used by the contractile vacuole. The data are shown in the graph. Of the following, which additional investigation can be used to determine when the cells are in an isotonic solution? a- Decreasing the salinity of the environment a little at a time until the ATP usage reaches a maximum b- Decreasing the salinity of the environment a little at a time until ATP usage reaches a minimum c- Increasing the salinity of the environment a little at a time until ATP usage reaches a maximum d- Increasing the salinity of the environment a little at a time until the ATP usage reaches a minimum

d- Increasing the salinity of the environment a little at a time until the ATP usage reaches a minimum

The manner in which several different ions and molecules move through a cell membrane is shown in the diagram above. For each ion or molecule, the relative concentration on each side of the membrane is indicated. Which of the following accurately describes one of the movements taking place? a- Glucose is transported into the cell by active transport. b- Na+ is transported into the cell by active transport. c- The movement of glucose through the membrane requires ATP hydrolysis. d- Na+ transport out of the cell requires ATP hydrolysis.

d- Na+ transport out of the cell requires ATP hydrolysis.

Which of the following statements best supports the claim that certain organelles within eukaryotic cells evolved from free-living prokaryotic cells? a- The cytoplasm of both eukaryotes and prokaryotes is surrounded by a plasma membrane. b- Eukaryotes and prokaryotes both contain ribosomes, but the ribosomes of eukaryotes are more complex in structure than those of prokaryotes. c- Eukaryotes exchange segments of internal membranes between the endoplasmic reticulum and Golgi apparatus, but prokaryotes have no such internal membranes. d- Some organelles contain their own DNA that is more similar to prokaryotic DNA in structure and function than to the eukaryotic DNA found in the cell's nucleus.

d- Some organelles contain their own DNA that is more similar to prokaryotic DNA in structure and function than to the eukaryotic DNA found in the cell's nucleus.

A student peeled the skins from grapes, exposing cells with membranes that are only permeable to water and small diffusible solutes. The student measured the mass of the peeled grapes. The student then placed each peeled grape into one of five solutions. After 24 hours, the student removed the peeled grapes from the solutions, measured their final mass, and calculated the percent change in mass (Table 1). In a second experiment (Table 2), the student placed a peeled grape into a solution containing both small diffusible solutes and solutes to which the membrane is impermeable (nondiffusible solutes). A student hypothesizes that the solute concentration of grape juice is higher than the solute concentration of the actual grape because the grape juice has added sugar. Based on the data in Table 1, which of the following best evaluates the student's hypothesis? a- The hypothesis is supported because the mass of the grape decreased in the grape juice. b- The hypothesis is supported because the grape juice has a greater solute potential than the grape has. c- The hypothesis is not supported because the grape was isotonic to the grape juice. d- The hypothesis is not supported because the mass of the grape increased in the grape juice.

d- The hypothesis is not supported because the mass of the grape increased in the grape juice.

All of the following cell components are found in prokaryotic cells EXCEPT a- DNA b- ribosomes c- cell membrane d- nuclear envelope e- enzymes

d- nuclear envelope

Dialysis tubing is permeable to water molecules but not to sucrose. Four dialysis tubes are half filled with 5 percent, 10 percent, 20 percent, and 40 percent sucrose solutions, respectively, and two dialysis tubes are half filled with distilled water. The dialysis tubes are all sealed at both ends, and the initial masses are determined. Five dialysis tubes are placed into beakers containing distilled water, and the sixth dialysis tube, containing distilled water, is placed into a 40 percent sucrose solution. The masses of the dialysis tubes are recorded at 30-minute intervals for 90 minutes, as shown in the table below. The contents of which dialysis tube are initially isotonic to the distilled water in the beaker? a- 1 b- 2 c- 3 d- 4 e- 5

e- 5

Dialysis tubing is permeable to water molecules but not to sucrose. Four dialysis tubes are half filled with 5 percent, 10 percent, 20 percent, and 40 percent sucrose solutions, respectively, and two dialysis tubes are half filled with distilled water. The dialysis tubes are all sealed at both ends, and the initial masses are determined. Five dialysis tubes are placed into beakers containing distilled water, and the sixth dialysis tube, containing distilled water, is placed into a 40 percent sucrose solution. The masses of the dialysis tubes are recorded at 30-minute intervals for 90 minutes, as shown in the table below. A net movement of water into the beaker occurs in which of the following dialysis tubes? a- 2 b- 3 c- 4 d- 5 e- 6

e- 6