Which of the following best predicts the effect of a mutation that results in a loss of the glucocorticoid receptors ligand binding function?

Vertebrate immune responses involve communication over short and long distances. Which of the following statements best helps explain how cell surface proteins, such as MHC proteins and T cell receptors, mediate cell communication over short distances?

A. The proteins receive electrical signals from nerve cells.
B. The proteins leave the cell and travel in the bloodstream to other cells.
C. The proteins interact directly with proteins on the surfaces of other cells
D. The proteins bind to molecules secreted by cells located in other parts of the body.

C. The proteins interact directly with proteins on the surfaces of other cells.

When the concentration of GAl is highest, the average height of the control seedlings is approximately

A. 10 cm
B. 30 cm
C. 60 cm
D. 85 cm
E. 95 cm

a. 10

Which of the following is a correct conclusion that can be drawn from the data in Figures 1, 2, and 3?
A. Most of the increase in the concentration of all gibberellins 40 to 45 days after planting is due to an increase in the concentration of GAl.
B. The concentration of all gibberellins is three times as great at 75 days as it is at 30 days after planting.
C. An increase in GAl levels occurs a day or two before the seedlings start to grow rapidly.
D. An increase in the concentration of GAl inhibits the synthesis of other gibberellins.
E. The concentration of GAl is a thousand times as great at 45 days as it is at 30 days after planting.

A. Most of the increase in the concentration of all gibberellins 40 to 45 days after planting is due to an increase in the concentration of GAl.

Which of the following statements best describes how a growth factor stimulates cell division from outside a cell?

A. The growth factor binds to other cells in the same area and holds them together to form a large, multicellular structure.
B. The growth factor binds to receptors on the cell surface, initiating a signal transduction pathway that activates specific target genes.
C. The growth factor binds to sugar molecules in the extracellular fluid and provides them to the cell as a source of energy.
D. The growth factor binds to phospholipids in the plasma membrane, creating a channel through which substances enter the cell.

B. The growth factor binds to receptors on the cell surface, initiating a signal transduction pathway that activates specific target genes.

Type 1 diabetes results from the destruction of insulin-producing cells in the pancreas. Individuals with type 1 diabetes produce insufficient amounts of insulin, a hormone that regulates the concentration of glucose in the blood.
Which of the following best explains how treatment with a drug that stimulates the production of insulin receptors on target cells will affect the insulin signaling pathway in an individual with type 1 diabetes?

A. The drug will have little or no effect on the signaling pathway because the receptors will not be activated in the absence of insulin.
B. The drug will have little or no effect on the signaling pathway because insulin receptors will not be allowed to enter the cells.
C. The drug will restore the function of the signaling pathway because insulin levels will return to normal.
D. The drug will restore the function of the signaling pathway because nonpancreatic cells will begin to produce insulin receptors.

A. The drug will have little or no effect on the signaling pathway because the receptors will not be activated in the absence of insulin.

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 diagram above illustrates feedback control as exerted by the hormone thyroxine. Following surgical removal of the thyroid gland, the level of TSH in the blood will increase. Which of the following best explains this increase?

A. Residual blood thyroxine, from prior to thyroid gland removal, will bind to cells in the anterior pituitary, signaling more TSH secretion.
B. Thyroxine will remain bound to thyroxine receptors on various body cells, and these body cells will secrete additional hormones that stimulate the anterior pituitary to secrete TSH.
C. Thyroxine that was stored in the anterior pituitary prior to thyroid gland removal will signal more TSH secretion.
D. A decrease in thyroxine levels means a loss of inhibition to the hypothalamus and anterior pituitary, leading to increased TSH secretion.

D. A decrease in thyroxine levels means a loss of inhibition to the hypothalamus and anterior pituitary, leading to increased TSH secretion.

The model shown in the figure represents the role of two hormones, calcitonin and parathyroid hormone (PTH), in maintaining normal blood calcium levels in humans. If a dietary change results in an increase in blood calcium concentration above normal levels, which of the following is the most likely effect on calcium homeostasis?

A. Calcitonin levels will decline, thus stimulating the release of PTH.
B. Calcitonin levels will rise, thus promoting the deposit of calcium into bones.
C. PTH levels will decline, thus stimulating the loss of calcium from bones.
D. PTH levels will increase, thus preventing the release of calcitonin.

B. Calcitonin levels will rise, thus promoting the deposit of calcium into bones.

Trypsinogen is split by the enzyme enterokinase to form an activated molecule of the protease trypsin. Which of the following would confirm that the activation of trypsin is an example of how a positive feedback mechanism can amplify a biological process?

A. The activated trypsin enzyme can use enterokinase as a substrate.
B. The trypsin produced by the reaction is capable of splitting and activating additional trypsinogen molecules.
C. If levels of trypsin were to get too high, the trypsin molecules would inhibit the enzyme enterokinase.
D. Each mRNA molecule that codes for trypsinogen can be translated repeatedly to form many peptide molecules.

B. The trypsin produced by the reaction is capable of splitting and activating additional trypsinogen molecules.

A student claims that the Y chromosome contains the sex-determining region gene, known as the SRY gene, which causes male fetuses to develop testes.
Which of the following provides correct information about cell signaling that supports the claim?

A. The SRY gene produces a protein that binds to specific regions of DNA in certain tissues, which affects the development of these tissues.
B. The SRY gene produces a protein that deletes portions of the XX chromosome in males so that male characteristics can develop.
C. The SRY gene produces an RNA segment that is exported from specific cells and targets the developing gonads.
D. The SRY gene is found only in tissues of the developing gonads.

A. The SRY gene produces a protein that binds to specific regions of DNA in certain tissues, which affects the development of these tissues.

An antigen can induce an immune response in a host organism. Antigens are targeted by antibodies that are produced by the organism's immune system in response to contact with the antigen. Antibodies are specific to antigens. Many different cell types are involved in immune responses.
Which of the following best describes the role of cell-to-cell communication during a response to an invasion of antigens?

A. Chemicals that are secreted from antigen-presenting cells then activate helper T cells.
B. A macrophage cell engulfs a pathogen in the blood.
C. Antigens attaching to receptors on memory B cells stimulate the memory B cells to become plasma cells.
D. Antigen-presenting cells engulf antigens at the first exposure.

A. Chemicals that are secreted from antigen-presenting cells then activate helper T cells.

Adjacent plant cells have narrow channels called plasmodesmata that pass through the cell walls of the connected cells and allow a cytoplasmic connection between the cells.
Which of the following statements best describes a primary function of plasmodesmata?

A. They allow the movement of molecules from one cell to another, enabling communication between cells.
B. They prevent the cell membrane from pulling away from the cell wall during periods of drought.
C. They eliminate the need to produce signaling molecules and eliminate the need for cells to have receptors for signaling molecules.
D. They increase the surface area available for attachment of ribosomes and thus increase protein synthesis.

A. They allow the movement of molecules from one cell to another, enabling communication between cells.

A hydrophilic peptide hormone is produced in the anterior pituitary gland located at the base of the brain. The hormone targets specific cells in many parts of the body.
Which of the following best explains a possible mechanism that would enable the hormone to efficiently reach all of the target cells in the body?

A. The hormone interacts with the nerves at the base of the brain and directs signals to the target cells through the nervous system.
B. The hormone diffuses into target cells adjacent to the anterior pituitary gland, where the hormone is degraded.
C. The hormone is released into the bloodstream where it can be transported to all cells with the correct receptors.
D. The hormone moves through cytoplasmic connections between cells until it has reached all cells with the correct intracellular binding sites.

C. The hormone is released into the bloodstream where it can be transported to all cells with the correct receptors.

G proteins are a family of receptor proteins that are involved in transmitting signals from outside a cell to inside a cell. When a signaling molecule binds to a G protein, the G protein is activated. The G protein then activates an enzyme that produces a second messenger called cAMP.
Which of the following describes a critical role of cAMP during the transduction stage of a G protein signal transduction pathway?

A. cAMP carries the signal to the nucleus of the cell and results in new sequences of nucleotides being added to the cell's DNA.
B. cAMP binds the extracellular signal molecule and carries it to the intracellular target specified by the signal.
C. cAMP modifies a specific monomer so that it can be added to an elongating structural macromolecule.
D. cAMP results in the activation of an enzyme that amplifies the signal by acting on many substrate molecules.

D. cAMP results in the activation of an enzyme that amplifies the signal by acting on many substrate molecules.

Metformin is a drug used to treat type 2 diabetes by decreasing glucose production in the liver. AMP-activated protein kinase (AMPK) is a major cellular regulator of glucose metabolism. Metformin activates AMPK in liver cells but cannot cross the plasma membrane. By blocking AMPK with an inhibitor, researchers found that AMPK activation is required for metformin to produce an inhibitory effect on glucose production by liver cells.
Which of the following best describes the component that metformin represents in a signal transduction pathway that regulates glucose production in the liver?

A. It is a secondary messenger that amplifies a signal through a cascade reaction.
B. It is a ligand that activates the signal transduction pathway of the activation of AMPK.
C. It is an allosteric regulator that binds to a crucial section of the DNA that makes the enzymes needed for glucose uptake.
D. It is a competitive inhibitor that binds to glucose and prevents it from entering the cell.

B. It is a ligand that activates the signal transduction pathway of the activation of AMPK.

Which of the following steps in a signaling pathway typically occurs first once a chemical messenger reaches a target cell?
A. Specific genes are activated.
B. A second messenger molecule is produced.
C. A ligand binds to a receptor.
D. Specific proteins are synthesized.

C. A ligand binds to a receptor.

During a fight-or-flight response, epinephrine is released into the body's circulatory system and transported throughout the body. Some cells exhibit a response to the epinephrine while other cells do not.
Which of the following justifies the claim that differences in components of cell signaling pathways explain the different responses to epinephrine?

A. Cell signaling depends on the ability to detect a signal molecule. Not all cells have receptors for epinephrine. Only cells with such receptors are capable of responding.
B. Cell signaling depends on the transduction of a received signal by the nervous system. Not all cells are close enough to a synapse to receive the signal and respond.
C. Cell signaling depends on the signal being able to diffuse through the cell membrane. Epinephrine is incapable of diffusing through some plasma membranes because of the membrane's phospholipid composition.
D. Cell signaling requires reception, transduction, and response. All cells can receive epinephrine, all cells respond with a pathway, but only select cells have the proper coding in their DNA to respond.

A. Cell signaling depends on the ability to detect a signal molecule. Not all cells have receptors for epinephrine. Only cells with such receptors are capable of responding.

Signal transduction may result in changes in gene expression and cell function, which may alter phenotype in an embryo. An example is the expression of the SRY gene, which triggers the male sexual development pathway in mammals. This gene is found on the Y chromosome.
Which statement provides the evidence to justify the claim that signal transduction may result in an altered phenotype?

A. If the SRY gene is absent or nonfunctional, the embryo will exhibit male sexual development.
B. If the SRY gene is absent or nonfunctional, the embryo will exhibit female sexual development.
C. An embryo with a male sex chromosome will always exhibit male sexual development.
D. An embryo with two male sex chromosomes will always exhibit male sexual development.

B. If the SRY gene is absent or nonfunctional, the embryo will exhibit female sexual development.

Researchers have discovered details about apoptosis (programmed cell death) by studying embryologic development of a nematode worm, Caenorhabditis elegans. Apoptosis is a normal developmental process in C. elegans. They found several genes involved in apoptosis, including ced−9 and ced−3 . The ced−3 gene was found to promote cell death, and ced−9 to inhibit it. The ced−9 gene serves as a regulator that prevents apoptosis in the absence of a signal promoting apoptosis.
Which of the following statements best justifies the claim that changes in the expression of ced−9 in C. elegans can affect regulation of apoptosis in the cell?

A. An experiment showed that a mutation in the ced−9 gene led to excessive cell death in C. elegans.
B. An experiment showed that the ced−9 gene normally produces a protein that promotes excessive cell death in C. elegans.
C. A mutation in ced−3 will cause ced−9 to be incorrectly transcribed.
D. Apoptosis is dependent on a signal from the ced−9 gene in C. elegans.

A. An experiment showed that a mutation in the ced−9 gene led to excessive cell death in C. elegans.

Which of the following statements best predicts the effect of a loss of function of the insulin receptor's intracellular domain?

A. The stimulation of the signal transduction pathway will increase.
B. The storage of GLUT4 in vesicles inside the cell will increase.
C. The number of GLUT4 molecules in the plasma membrane will increase.
D. The concentration of glucose inside the cell will increase.

B. The storage of GLUT4 in vesicles inside the cell will increase.

Which of the following outcomes will most likely result from the inactivation of the beta-2 adrenergic receptor?

A. The cellular concentration of cyclic AMP will increase.
B. The enzymatic activity of protein kinase A will increase.
C. The activation of glycogen phosphorylase will increase.
D. The rate of glycogen synthesis in the cell will increase.

D. The rate of glycogen synthesis in the cell will increase.

Which of the following changes in the FGFR signaling pathway is most likely to result in uncontrolled cell proliferation?

A. The irreversible association of FGFR proteins
B. The loss of the FGFR protein kinase function
C. A decrease in the intracellular concentration of ATP
D. A decrease in the extracellular concentrations of fibroblast growth factors

A. The irreversible association of FGFR proteins

A researcher found a mutation that resulted in the PFK enzyme being unable to bind ATP to the allosteric site. Which of the following best predicts the effect of the mutation?

A. The activity of the enzyme will not be affected because the active site is not involved in substrate binding at the allosteric site.
B. Negative feedback regulation does not occur, so the enzyme will be active when glycolysis is not needed.
C. Positive feedback does not occur, and the activity of the enzyme will decrease when glycolysis is needed.
D. The activity of the enzyme will fluctuate independent of the ATP concentration.

B. Negative feedback regulation does not occur, so the enzyme will be active when glycolysis is not needed.

Which of the following best predicts what will happen to the blood glucose level if the person has another meal at 5 p.m.?

A. Immediately after the meal, the blood glucose level will decrease because of the increase in glucagon levels.
B. Immediately after the meal, the blood glucose level will increase, and then insulin will be secreted to counter the increase.
C. Several hours after the meal, the blood glucose level will increase sharply because of an increase in the amount of glucagon secreted.
D. The blood glucose level will not change after the 5 p.m. meal because the person has already consumed two meals and the blood glucose level has been adjusted to a steady-state level.

B. Immediately after the meal, the blood glucose level will increase, and then insulin will be secreted to counter the increase.

Warfarin is a drug used to treat certain blood clots. Warfarin blocks the formation of the active form of vitamin K-dependent clotting factors. Based on the model, which of the following best predicts the effects of warfarin on a patient?

A. Fibrinogen will form fibrin, but the clot will not form because Factor XIII will not be synthesized.
B. The intrinsic pathway will take over because the clotting factors are part of that pathway.
C. Thrombin will be converted to prothrombin because Factor X will reverse the reaction.
D. Factor X will not be activated, which will prevent thrombin from forming.

D. Factor X will not be activated, which will prevent thrombin from forming.

Based on Table 1, what percent of the life cycle of yeast cells is spent in DNA replication?

A. 5 percent
B. 10 percent
C. 25 percent
D. 50 percent

C. 25 percent

Based on the sample means, which of the following conclusions about the cells in the growing root tips of Zea mays seedlings is best supported by the results of the experiment?

A. The cells of the root tips grow to larger sizes when the seedlings are planted in compact sand than when the seedlings are planted in loose sand.
B. The average rate of mitotic cell division is greater for the root tips growing in loose sand than for the root tips growing in compact sand.
C. The average cell cycle time is greater for the root tips growing in compact sand than for the root tips growing in loose sand.
D. More cells are produced per unit of time in the root tips growing in compact sand than in the root tips growing in loose sand.

D. More cells are produced per unit of time in the root tips growing in compact sand than in the root tips growing in loose sand.

Based on Figure 1, which of the following statements correctly links a stage of the cell cycle with the event occurring at that stage?

A. Stage II represents the G2 phase of the cell cycle.
B. Synthesis of sufficient DNA for two daughter cells occurs in stage IIII.
C. Stage IIIIII includes mitosis.
D. The replication of genetic material occurs in stage IVIV.

B. Synthesis of sufficient DNA for two daughter cells occurs in stage IIII.

Which of the following statements is consistent with the data in Figure 1?

A. The cells have a haploid chromosome number of 3.
B. The cells have a diploid chromosome number of 6.
C. There is a change from 3 to 6 picograms of DNA because DNA is replicated before each round of cell division.
D. There is a change from 6 to 3 picograms of DNA after each cell division because the chromosomes lengthen following cell division.

C. There is a change from 3 to 6 picograms of DNA because DNA is replicated before each round of cell division.

Which of the following most accurately describes an observation and an effect of the viral infection indicated by the data in Table 1?

A. Normal cells spend 98 percent of their time cycling in and out of interphase. The virus reduces this to 5 percent of the time.
B. Twenty percent of the virus-infected cells are in interphase. These cells are no longer part of the cell cycle.
C. Forty percent of the virus-infected cells are in interphase. These cells are preparing for replication of genetic material.
D. Seventy-five percent of the virus-infected cells are found in mitosis. The virus stimulates frequent cell division.

D. Seventy-five percent of the virus-infected cells are found in mitosis. The virus stimulates frequent cell division.

Based on the data, the percent of the mitotic cells that were in metaphase is closest to which of the following?

A. 5%
B. 11%
C. 18%
D. 66%

C. 18%

The epidermal growth factor receptor EGFR is a cell surface receptor. When a growth factor binds to EGFR, the receptor is activated. The activated EGFR triggers a signal transduction pathway, which leads to increased frequency of cell division.
Which of the following best predicts the effect of a mutation that causes EGFR to be active in the absence of a growth factor?

A. Increased apoptosis will lead to abnormal growth of the tissue.
B. Increased cell division will lead to the formation of a tumor.
C. Cells will exit the cell cycle, entering a non-dividing G0 phase.
D. Fewer cells will be in any of the stages of mitosis.

B. Increased cell division will lead to the formation of a tumor.

The tumor suppressor protein p53 binds to DNA and activates target genes, which results in the synthesis of p21, CD95, and other proteins. The p21 protein promotes cell-cycle arrest, whereas the CD95 protein promotes apoptosis.
Which of the following will most likely result from a loss of p53 function?

A. Rapid cell growth without cell division
B. Immediate activation of apoptosis pathways
C. Uncontrolled cell proliferation
D. Increased expression of p53 target genes

C. Uncontrolled cell proliferation

Which statement best predicts why a cell's progression through the cell cycle might be halted at the G1/S checkpoint?

A. Spindle fibers have not correctly attached to chromosomes.
B. There are not enough nucleotides available to construct new DNA.
C. Damage occurred to DNA when it was being copied in G1.
D. Proteins necessary for M phase of the cell cycle have not been produced.

B. There are not enough nucleotides available to construct new DNA

When epinephrine binds to cardiac (heart) muscle cells, it speeds up their contraction. When it binds to muscle cells of the small intestine, it inhibits their contraction. How can the same hormone have different effects on muscle cells?

a. Cardiac cells have more receptors for epinephrine than do intestinal cells.
b. Epinephrine circulates to the heart first and thus is in higher concentration around cardiac cells.
c. The two types of muscle cells have different signal transduction pathways for epinephrine and thus have different cellular responses.
d. Cardiac muscle is stronger than intestinal muscle and thus has a stronger response to epinephrine.
e. Epinephrine binds to G-protein-linked receptors in cardiac cells, and these receptors always increase a response to the signal. Epinephrine binds to receptor tyrosine kinases in intestinal cells, and these receptors always inhibit a response to the signal.

c. The two types of muscle cells have different signal transduction pathways for epinephrine and thus have different cellular responses.

A signal molecule that binds to a plasma-membrane protein functions as a
a. Ligand
b. Second messenger
c. Protein phosphatase
d. Protein kinase
e. Receptor protein

a. Ligand

How do receptor tyrosine kinases transduce a signal?

a. They transport the signal molecule into the cell, where it binds to and activates a transcription factor. The transcription factor then alters gene expression.
b. Signal binding causes a conformational change that activates membrane-bound tyrosine kinases relay proteins that phosphorylate serine and threonine amino acids.
c. Their activated tyrosine kinases convert ATP to cAMP; cAMP acts as a secondary messenger to activate other protein kinases.
d. When activated, they cleave a membrane phospholipid into two second-messenger molecules. One of the molecules opens Ca2+ ion channels on the endoplasmic reticulum.
e. They form a dimer; they phosphorylate each other's tyrosoines; specific proteins bind to and are activated by these phosphorylated tyrosines.

e. They form a dimer; they phosphorylate each other's tyrosoines; specific proteins bind to and are activated by these phosphorylated tyrosines.

Which of the following can activate a protein by transferring a phosphate group to it?

a. cAMP
b. G protein
c. Phosphodiesterase
d. Protein kinase
e. Protein phosphatase

d. Protein kinase

Many signal transduction pathways use second messengers to

a. Transport a signal through the lipid bilayer portion of the plasma membrane
b. Relay a signal from the outside to the inside of the cell.
c. Relay the message from the inside of the membrane throughout the cytoplasm.
d. Amplify the message by phosphorylating proteins.
e. Dampen the message once the signal molecule has left the receptor.

c. Relay the message from the inside of the membrane throughout the cytoplasm.

Signal amplification is most often achieved by

a. An enzyme cascade involving multiple protein kinases.
b. The binding of multiple signal molecules.
c. Branching pathways that produce multiple cellular responses.
d. Activating transcription factors that affect gene expression.
e. The action of adenylyl cyclase in converting ATP to ADP.

a. An enzyme cascade involving multiple protein kinases.

Which of the following is incorrectly matched with its description?

a. Scaffolding protein- large relay protein that may bind with several other relay proteins to increase the efficiency of a signaling pathway.
b. Protein phosphatase- enzyme that transfers a phosphate group from ATP to a protein, causing a conformational change that usually activates the protein.
c. Adenylyl cyclase- enzyme attached to plasma membrane that converts ATP to cAMP in response to an extracellular signal.
d. G protein- relay protein attached to the inside of plasma membrane that, when activated by an activated G-protein-linked receptor, binds GTP and then usually activates another membrane attached protein.

b. Protein phosphatase- enzyme that transfers a phosphate group from ATP to a protein, causing a conformational change that usually activates the protein.

Based on Figure 1, which of the following statements best describes the epinephrine pathway?

a. It involves the opening and closing of ion channels.
b. It 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. It involves enzymes activating other enzymes.

Which of the following statements best describes the role of adenyl 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.

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.

In a certain signal transduction pathway, the binding of an extracellular molecule to a cell-surface protein results in a rapid increase in the concentration of cyclic AMP inside the cell. The cyclic AMP binds to and activates cytosolic enzymes that then activate other enzymes in the cell. Which of the following statements best describes the role of cyclic AMP in this pathway?

a. It acts as the signaling molecule that passes the signal from the cell to other cells.
b. It acts as a receptor that carries the signal from outside the cell to inside the cell.
c. It acts as a second messenger that helps relay and amplify the signal within the cell.
d. It acts as a channel protein that transmits the signal across the cell's nuclear membrane.

c. It acts as a second messenger that helps relay and amplify the signal within the cell.

Air is less dense at very high elevations, so less oxygen is available than in the denser air at sea level. Based on the model in figure 1, if a person travels from sea level to a high elevation location, which of the following correctly predicts the response to the decreased blood oxygen level?

a. More erythropoietin will be secreted from the kidneys, decreasing production of erythrocytes.
b. More erythropoietin will be secreted from the kidneys, increasing production of erythrocytes.
c. Less erythropoietin will be secreted from the kidneys, decreasing production of erythrocytes.
d. Less erythropoietin will be secreted from the kidneys, increasing production of erythrocytes.

b. More erythropoietin will be secreted from the kidneys, increasing production of erythrocytes.

Which of the following best describes how the amount of DNA in the cell changes during M phase?
a. The amount of DNA doubles as the DNA is replicated.
b. The amount of DNA slightly increases as a result of new organelle synthesis.
c. The amount of DNA does not change while the cell grows.
d. The amount of DNA is halved as the cell divides into two daughter cells.

d. The amount of DNA is halved as the cell divides into two daughter cells.

Sister chromatids

a. have one-half the amount of genetic material as does the original chromosome.
b. start to move along kinetochore microtubules toward opposite poles during telophase.
c. each have their own kinetochore.
d. are formed during prophase.
e. slide past each other along nonkinetochore microtubules.

c. each have their own kinetochore.

Which of the following would not be exhibited by cancer cells?

a. changing levels of MPF concentration
b. passage through the restriction point
c. density-dependent inhibition
d. metastasis
e. response to growth factors

c. density-dependent inhibition

A cell that passes the restriction point in G1 will most likely

a. undergo chromosome duplication.
b. have just completed cytokinesis.
c. continue to divide only if it is a cancer cell.
d. show a drop in MPF concentration.
e. move into the G0 phase.

a. undergo chromosome duplication.

The rhythmic changes in cyclin concentration in a cell cycle are due to

a. its increased production once the restriction point is passed.
b. the cascade of increased production once its enzyme is phosphorylated by MPF.
c. its degradation, which is initiated by active MPF.
d. the correlation of its production with the production of Cdk.
e. the binding of the growth factor PDGF.

c. its degradation, which is initiated by active MPF.

What is the expected percent change in DNA content of a typical eukaryotic cell as it progresses through the cell cycle from the start of G1 phase to the end of G2 phase?

a. -100%
b. -50%
c. +50%
d. +100%

d. +100%

Figure 1, what percent of the time required to complete a full cycle do the cells typically spend in interphase?(G1-9hrs, S- 7hrs, G2- 3 hrs, M- 1hr)

a. 5%
b. 35%
c. 50%
d. 95%

d. 95%

Which of the following best predicts the effect of the mutation?

Which of the following best predicts what will happen to the blood glucose level of the person has another meal at 5 pm?

Which of the following outcomes will most likely result from the irreversible binding of GDP to the G protein quizlet?

Which of the following will most likely result from a loss of p53 p53 function?