BIO 355 - Exam 4 Study Guide

When a nucleotide is added to a growing nuclei acid strand during DNA replication, the incoming monomer is __________, and the energy required to drive the polymerization is derived from __________ A. A nucleoside triphosphate; cleaving a pyrophosphate B. A nucleoside monophosphate; cleaving ATP C. An RNA primer; cleaving a pyrophosphate D. A nucleoside triphosphate; DNA polymerase

A. A nucleoside triphosphate; cleaving a pyrophosphate

What protein forms the contractile ring during cytokinesis in animal cells? A. Actin B. Kinesin C. Dynein D. DNA polymerase

A. Actin

The length of time a G-protein will signal is determined by the A. Activity of Phosphatases that turn off G-proteins by dephosphorylating Gα B. Activity of phsophatases that turn GTP into GDP C. Degredation of the g-protein after Gα separates from Gβγ D. GTPase activity of Gα

A. Activity of Phosphatases that turn off G-proteins by dephosphorylating Gα

You are interested in cell-size regulation and discover that signaling through a GCPR called ERC1 is important in controlling cell size in embryonic rat cells. The G-protein downstream of ERC1 activates Adenylyl cyclase, which ultimately leads to the activation of PKA. You discover that cells that lack ERC1 are 15% smaller than normal cells, while cells that express a mutant, constitutively activated version PKA are 15% larger than normal cells. Given these results, which of the following statements to embryonic rat cells should lead to smaller cells? A. Addition of a drug that causes cyclic AMP Phosphodiesterase to be hyperactive B. Addition of a drug that prevents GTP hydrolysis by Gα C. Addition of a drug that activates Adenylyl cyclase D. Addition of a drug that mimics the ligand of ERC1

A. Addition of a drug that causes cyclic AMP Phosphodiesterase to be hyperactive

Which of the following statements is false? A. CDC25 dephosphorylation of WEE1 activates the kinase, promoting the G2/M transition B. Phosphorylation of Mitotic CDK by the inhibitory kinase (WEE1) makes the CDK inactive C. Inhibiting the CDC25 phosphatase will delay the G2/M transition D. The activating phosphatase (CDC25) removes the Phosphatases from Mitotic CDK that were added by WEE1, so that M-CDK will be active

A. CDC25 dephosphorylation of WEE1 activates the kinase, promoting the G2/M transition

What is the result of DNA ligase's activity? A. DNA fragments are joined together B. DNA is broken up at specific sites C. DNA translation occurs D. DNA transcription occurs E. DNA is condensed into chromosomes

A. DNA fragments are joined together

Which of the following statements is true? A. Extracellular signal molecules that are hydrophilic must bind to a cell-surface receptor so as to signal a target cell to change its behavior B. To function, all extracellular signal molecules must be transported by their receptor across the plasma membrane into the cytosol C. A cell surface receptor capable of binding only one type of signal molecule can medicate only one kind of cell response D. Any foreign substance that binds to a receptor of a normal signal molecule will always induce the same response that is produced by that signal molecule on the same cell type

A. Extracellular signal molecules that are hydrophilic must bind to a cell-surface receptor so as to signal a target cell to change its behavior

Normally, when adrenaline binds to adrenergic G-protein coupled receptors on the surface of a muscle cell, it activates a G protein, initiating an intracellular signaling pathway in which the activated α subunit activates Adenylyl cyclase, thereby increasing cAMP levels in the cell. The cAMP molecules then activate a cAMP-dependent kinase (PKA) that, in turn, activates enzymes that result in the breakdown of muscle glycogen, thus lowering glycogen levels. How would glycogen levels be affected in the presence of adrenaline in abnormal cells that lack fully functional Adenylyl cyclase? A. Glycogen levels would be higher than in normal cells treated with adrenaline B. Glycogen levels would be lower than in normal cells treated with adrenaline C. Glycogen levels would be about the same as normal cells treated with adrenaline

A. Glycogen levels would be higher than in normal cells treated with adrenaline

Normally, when adrenaline binds to adrenergic G-protein coupled receptors on the surface of a muscle cell, it activates a G-protein, initiating an intracellular signaling pathway in which the activated α subunit activated Adenylyl cyclase, thereby increasing cAMP levels in the cell. The cAMP molecules then activate a cAMP-dependent kinase (PKA) that, in turn, activates enzymes that result in the breakdown of muscle glycogen, thus lowing glycogen levels. How would glycogen levels be affected in the prescient of adrenaline in abnormal cells in which of the subunit of the g-protein has a 100-fold higher affinity for GDP? A. Glycogen levels would be higher than in normal cells treated with adrenaline B. Glycogen levels would be lower than in normal cells treated with adrenaline C. Glycogen levels would be about the same as normal cells treated with adrenaline

A. Glycogen levels would be higher than in normal cells treated with adrenaline

Normally, when adrenaline binds to adrenergic G-protein coupled receptors on the surface of a muscle cell, it activates a G-protein, initiating an intracellular signaling pathway in which the activated α subunit activates Adenylyl cyclase, thereby increasing cAMP levels in the cell. The cAMP molecules then activate a cAMP-dependent kinase (PKA) that, in turn, activates enzymes that result in the breakdown of muscle glycogen, thus lowering glycogen levels. How would glycogen levels be affected in the presence of adrenaline in abnormal cells that lack the G-protein coupled adrenaline receptor? A. Glycogen levels would be higher than in normal cells treated with adrenaline B. Glycogen levels would be lower than in normal cells treated with adrenaline C. Glycogen levels would be about the same as normal cells treated with adrenaline

A. Glycogen levels would be higher than in normal cells treated with adrenaline

Which enzyme moves outward from the origin of replication and breaks hydrogen bonds between DNA nucleotides? A. Helicase B. RNA polymerase C. topoisomerase II D. DNA polymerase

A. Helicase

The following enzymes play an important role in DNA replication: DNA polymerase, primate, ligase, and helical. In what order do they work during replication? A. Helicase, primase, DNA polymerase, ligase B. Primase, helicase, ligase, DNA polymerase C. DNA polymerase, helicase, primase, ligase D. DNA polymerase, primase, ligase, helicase E. Ligase, helicase, DNA polymerase, primase

A. Helicase, primase, DNA polymerase, ligase

Which of the following correctly describes a chromosome in G2 of the Mitotic cell division cycle? A. One replicated chromosome consisting of two sister chromatids B. One replicated chromosome consisting of two a-single stranded DNA molecules C. Two replicated chromosomes, each consisting of two sister chromatids D. Two replicated chromosomes, each consisting of two a-single stranded DNA molecules

A. One replicated chromosome consisting of two sister chromatids

The point at which DNA synthesis is initiated is called the: A. Origin of replication B. Primate C. Start codon D. Replication fork E. Primer

A. Origin of replication

When RAS is activated, cells will divide. A dysfunction form of RAS clings too tightly to GDP. You introduce the dysfunctional form of RAS into cells that also have a normal version of RAS. Which of the following statements is true? A. The cells you create will divide less frequently than normal cells in response to the extracellular signals that typically activate RAS B. The cells you create will run out of the GTP necessary to activate RAS C. The cells you create will divide more frequently compared to normal cells in response to the extra cellular signals that typically activate RAS D. The normal RAS in the cells you create will not be able to bind GDP because the dominant-negative RAS binds to GDP too tightly

A. The cells you create will divide less frequently than normal cells in response to the extracellular signals that typically activate RAS

Activated protein kinase C (PKC) can lead to the modification of the membrane lipids in the vicinity of active PKC. Figure 16.17 shows how G-proteins can indirectly activate PKC. You have discovered the enzyme activated by PKC that mediates the lipid modification. You call the enzyme "Rafty" and demonstrate that activated PKC directly phosphorylates "Rafty", activating it to modify the plasma membrane lipids in the vicinity of the cell where PKC is active; these lipid modification can be detected by dyes that bind to the modified lipids. Cells lacking "Rafty" do not have these modification, even when PKC is active. Which of the following conditions would lead to signal-independent modification of the membrane lipids by "rafty"? A. The expression of a constitutively active phospholipase C B. A mutation in the GCPR that binds the signal more tightly C. The Ca2+ channel in the endoplasmic reticulum with an increased affinity for IP3 D. A mutation in the gene that encodes "Rafty' such that the enzyme can no longer be phosphorylate d by PKC

A. The expression of a constitutively active phospholipase C

Okazaki fragments are found on ____________ strand of DNA. A. The lagging B. The leading C. The parental D. Both leading and lagging

A. The lagging

The centromere is: A. The microtubule organizing center for the Mitotic spindle B. A region of the chromosome where kinetochores attach C. A region of the chromosome where microtubules attach to chromosomes during mitosis D. A region of the chromosome where sister chromatids are attached to each other

A. The microtubule organizing center for the Mitotic spindle

What is the function of the centromere? A. To attach the sister chromatids to each other B. To attach the chromosome to the spindle C. to attach the DNA to the plasma membrane D. To organize the microtubules to form a spindle

A. To attach the sister chromatids to each other

The growth factor RGF stimulated proliferation of cultured rat cells. The receptor that binds RGF is a receptor tyrosine kinase called RGFR. Which of the following types of alteration would be most likely to prevent receptor dimerization? A. A mutation that increases the affinity of RGFR for RGF B. A mutation that prevents RGFR from binding to RGF C. Changing the tyrosines that are normally phosphorylated on RGFR dimerization to alanines D. Changing the tyrosines that are normally phosphorylated on RGFR dimerization to glutamic acid

B. A mutation that prevents RGFR from binding to RGF

The growth factor RGF stimulates proliferation of cultured rat cells. The receptor that binds RGF is a receptor tyrosine kinase called RGFR. Which of the following types of alteration would be most likely to prevent receptor dimerization? A. A mutation that increases the affinity of RGFG for RGF B. A mutation that prevents RGFR from binding to RGF C. Changing the tyrosines that are normally phosphorylated on RGFG dimerization to alanines D. Changing on the tyrosines that are normally phosphorylated on RGFR dimerization to glutamic acid

B. A mutation that prevents RGFR from binding to RGF

Normally, when adrenaline binds to adrenergic G-protein coupled receptors on the surface of a muscle cell, it activates a G-protein, initiating an intracellular signaling pathway in which the activated α subunit activates Adenylyl cyclase, thereby increasing cAMP levels in the cell. The cAMP molecules then activate a cAMP-dependent kinase (PKA) that, in turn, activates enzymes that result in the breakdown of muscle glycogen, thus lowering glycogen levels. How would glycogen levels be affected in the presence of adrenaline in abnormal cells that lack cAMP Phosphodiesterase? A. Glycogen levels would be higher than in normal cells treated with adrenaline B. Glycogen levels would be lower than in normal cells treated with adrenaline C. Glycogen levels would be about the same as normal cells treated with adrenaline

B. Glycogen levels would be lower than in normal cells treated with adrenaline

Which of the following statements is true? A. MAP kinase is most important for phosphorylating MAP kinase kinase B. PI-3 kinase phosphorylated a lipid in the plasma membrane C. RAS becomes activated when an RTK phosphorylates its bound GDP to create GTP D. Dimerization of GPCR's leads to Gα activation

B. PI-3 kinase phosphorylates a lipid in the plasma membrane

Progression through the cell cycle requires a cyclic to bind to a CDK because... A. The cycling are the molecules with the enzymatic activity in the complex B. The binding of a cyclic to CDK is required for CDK enzymatic activity C. Cyclic binding inhibits CDK activity until the appropriate time in the cell cycle D. Without cyclin binding, a cell-cycle checkpoint will be activated

B. The binding of a cyclin to CDK is required for CDK enzymatic activity

Which of the following must be present if net diffusion is occurring? A. A concentration gradient and the movement of atoms or molecules from an area of high concentration to one of lower concentration B. A concentration gradient, the movement of atoms or molecules from an area of high concentration to one of lower concentration, and the random movement of atoms or molecules due to kinetic energy C. A Concentration gradient D. The movement of atoms or molecules from an area of high concentration to one of lower concentration E. The random movement of atoms or molecules due to kinetic energy

B. The concentration gradient, the movement of atoms or molecules from an area of high concentration to one of lower concentration, and the random movement of atoms or molecules due to kinetic energy

Which of the following is false about noncompetitive inhibition? A. The binding of the inhibitor causes the enzyme to undergo a conformational change B. The inhibitor binds to the active site of the enzyme C. It is an example of allosteric regulation D. The shape of a noncompetitive inhibitor is usually very different from the substrate of the target enzyme

B. The inhibitor binds to the active site of the enzyme

Which of the following events does not usually occur during interphase? A. Cells grow in size B. The nuclear envelope breaks down C. DNA is replicated D. The centromeres are duplicated

B. The nuclear envelope breaks down

What is the function of the kinetochores? A. To attach the sister chromatids to each other B. To attach the chromosome to the spindle C. To attach the DNA to the plasma membrane D. To organize the microtubules to form a spindle

B. To attach the chromosome to the spindle

How many replication forks are formed when an origin of replication is opened? A. 1 B. 2 C. 3 D. 4

C. 2

At the end of DNA replication, the sister chromatids are held together by the A. Kinetochores B. Securins C. Cohesins D. Histones

C. Cohesins

DNA replication is considered semi conservative because A. After many rounds of DNA replication, the original DNA double helix is still intact B. Each new daughter DNA molecule consists of two new strands copied from the parent DNA molecule C. Each new daughter DNA molecule consists of one strand from the parent DNA molecule and one new strand D. New DNA strands must be copied from a DNA template

C. Each new daughter DNA molecule consists of one strand from the parent DNA molecule and one new strand

The concentration of Mitotic cyclin (M-cyclin) A. Rises markedly during M phase B. Is activated by phosphorylation C. Falls toward the end of M phase as a result of ubiquitylation and degredation D. Is highest in G1 phase

C. Falls toward the end of M phase as a result of ubiquitylation and degredation

The process of DNA replication requires that each of the parental DNA strands be used as a __________ to produce a duplicate of the opposing strand. A. Catalyst B. Competitor C. Template D. Copy

C. Template

The desaturation of an enzyme occurs when __________ A. Environmental conditions deviate substantially from the enzymatic optimum conditions B. The active site is destroyed, and environmental conditions deviate substantially from the enzymatic optimization conditions C. The active site is destroyed, the tertiary structure of the enzyme is altered, and the environmental conditions deviate substantially from the enzymatic optimum conditions D. The tertiary structure of the enzyme is altered E. The active site is destroyed

C. The active site is destroyed, the tertiary structure of the enzyme is altered, and the environmental conditions deviate substantially from the enzymatic optimum conditions

Which of the following must be present if diffusion is occurring? A. A concentration gradient, the movement of atoms or molecules from an area of high concentration to one of lower concentration, and the random movement of atoms or molecules due to kinetic energy B. The movement of atoms or molecules from an area of high concentration to one of lower concentration C. The random movement of atoms or molecules due to kinetic energy D. A concentration gradient and the movement of atoms or molecules from an area of high concentration to one of lower concentration E. A concentration gradient

C. The random movement of atoms or molecules due to kinetic energy

Curve C

Cells growing in culture were treated with a growth factor and were monitored as they progressed through the cell cycle. The amounts of cyclin B, CDK1 and DNA polymerase III activity were measured. Based on what you know about the different phases of the cell cycle and its regulation by cyclins and CDK's answer the following question using the graph to the right. Which of the curve represents the abound of cyclin B?

Adrenaline stimulates glycogen breakdown in skeletal muscles by ultimately activating glycogen phosphorylase, the enzyme that breaks down glycogen. Which of the following statements is false? A. A constitutively active mutant form of PKA in skeletal muscle cells would lead to a decrease in the amount of i phosphorylated phosphorylase kinase B. A constitutively active mutant from of PKA in skeletal muscle cells would not increase the affinity of adrenaline for the adrenergic receptor C. A constitutively active mutant form of PKA in skeletal muscle cells would lead to an excess in the amount of glucose available D. A constitutively active mutant form of PKA in skeletal muscle cells would lead to an excess in the amount of glycogen available

D. A constitutively active mutant form of PKA in skeletal muscle cells would lead to an excess in the amount of glycogen available

In which phase of the cell cycle do cells check to determine whether the DNA is fully and correctly replicated? A. At the transition between G1 and S B. When cells enter G0 C. During M D. At the end of G2

D. At the end of G2

During nervous-system development is drosophila, the membrane-bound protein Delta acts as an inhibitory signal to prevent neighboring cells from developing into neuronal cells. Delta is involved in __________ signaling. A. Endocrine B. Paracrine C. Neuronal D. Contact-dependent (Juxtacrine)

D. Contact-dependent (juxtacrine)

Levels of CDK activity change during the cell cycle, in part because A. The CDK's phosphorylate each other B. The CDK's activate the cyclins C. CDK degradation precedes entry into the next phase of the cell cycle D. Cyclin activity change during the cycle

D. Cyclin activity change during the cycle

Levels of CDK activity change during the cell cycle, in part because... A. The CDK's phosphorylate each other B. The CDK's activate the cyclins C. CDK degradation precedes entry into the next phase of the cell cycle D. Cyclin levels change during the cycle

D. Cyclin levels change during the cycle

The length of time a G protein will signal is determined by the: A. Activity of phsophatases that turn off G-proteins by dephosphorylating Gα B. Activity of phosphatases that turn GTP into GDP C. Degradation of the G protein Adler Gα separates from Gβγ D. GTPase activity of Gα

D. GTPase activity of Gα

All members of the nuclear receptor family A. Are cell-surface receptors B. Do not undergo conformational changes C. Are found only in the cytoplasm D. Interact with signal molecules that diffuse through the plasma membrane

D. Interact with signal molecules that diffuse through the plasma membrane

A. Hypotonic

In a lab, a dialysis bag was gilled with a 15% sucrose solution and placed in an unlabeled beaker filled with clear liquid. The dialysis bag was made of a semipermiable membrane that allowed the free passage of water but was not permeable to sucrose. After two hours, the bag in the beaker decreased in size and became flaccid. Therefore, at the beginning of the experiment, the solution in the bag was __________ compared to the solution in the beaker. A. Hypotonic B. Isotonic C. Hypertonic

True

Two solutions are present in a beaker and are separated by a membrane that is permeable to water, but not to glucose. The concentration of glucose will increase in side A and decrease in side B.

False

Two solutions are present in a beaker and are separated by a membrane that is permeable to water, but not to glucose. The concentration of water will change in both sides overtime, but the glucose concentrations will remain the same.

Diagram D

Which diagram accurately represents the directionality of DNA strands at one side of a replication fork?