Final Exam Quiz #2 Study Guide : Cell Biology

M-Cdk phosphorylates proteins involved in__________ and __________. (a) chromosome condensation; disassembly of the nuclear envelope (b) chromosome condensation; assembly of the nuclear envelope (c) DNA synthesis; disassembly of the nuclear envelope (d) DNA synthesis; chromosome condensation

(a) chromosome condensation; disassembly of the nuclear envelope

Normal cells grown under standard conditions (without ligand) are 20 μm in diameter while cells exposed to TRK ligand are 10.5 μm in diameter. Which of the following conditions do you predict will activate this pathway and lead to smaller cells? (a) addition of TRK ligand and a drug that stimulates the GTPase activity of Ras (b) addition of TRK ligand and a drug that inhibits the activity of the phosphatase that acts on SZE (c) addition of TRK ligand and a drug that stimulates the degradation of Pig1 (d) addition of TRK ligand and a drug that inhibits SZE binding to DNA

(b) addition of TRK ligand and a drug that inhibits the activity of the phosphatase that acts on SZE

M-Cdk phosphorylates ___________ so that the nuclear envelope breaks down and the chromosomes can be separated during mitosis. (a) kinetochores (b) nuclear lamins (c) separase (d) p53

(b) nuclear lamins

Progression through the cell cycle requires a cyclin to bind to a Cdk because _________. (a) the cyclins are the molecules with the enzymatic activity in the complex. (b) the binding of a cyclin to Cdk is required for Cdk enzymatic activity. (c) cyclin 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.

Indicate which of the following conditions would increase the effect of acetylcholine. (a) addition of a drug that stimulates the GTPase activity of the Gα subunit (b) mutations in the K+ channel that keep it closed all the time (c) inhibition of the GTPase activity of the Gα subunit by cholera toxin (d) a mutation that decreases the affinity of the βγ complex of the G protein for the K+ channel (e) a mutation in the acetylcholine receptor that prevents its localization in the plasma membrane

(c) inhibition of the GTPase activity of the Gα subunit by cholera toxin

Mitogens cause cells to enter the cell cycle by activating cell signaling pathways that result in ______________. (a) phosphorylation of p53 (b) phosphorylation of ras (c) phosphorylation of Rb (d) phosphorylation of M-Cdk.

(c) phosphorylation of Rb

Which component of the electron-transport chain does not act as a proton pump? (a) NADH Dehydrogenase (b) cytochrome c oxidase (c) ubiquinone (d) cytochrome c reductase

(c) ubiquinone

The citric acid cycle generates NADH and FADH2, which are then used in the process of oxidative phosphorylation to make ATP. If the citric acid cycle (which does not use oxygen) and oxidative phosphorylation are separate processes, as they are, then why is it that the citric acid cycle stops almost immediately when O2 is removed? (a) glycolysis is inhibited (b) NADH levels decrease (c) NAD+ levels increase (d) NAD+ levels decrease

(d) NAD+ levels decrease

The anaphase-promoting complex (APC) ________. (a) Phosphorylates S cyclin leading to its degradation. (b) Phosphorylates p53 (c) Is continuously active throughout the cell cycle. (d) Ubiquitylates M cyclin leading to its degradation.

(d) Ubiquitylates M cyclin leading to its degradation.

How is cancer a microevolutionary process? (a) cancer cells acquire mutations (b) cancer cells adapt to a low nutrient environment (c) cancer cells adapt to a low O2 environment (d) all of the above

(d) all of the above

The concentration of mitotic cyclin (M cyclin) ________________. (a) rises markedly during G1 phase. (b) is activated by phosphorylation. (c) is highest in interphase (d) falls at the metaphase to anaphase transition when a ubiquitin tag is put on by APC

(d) falls at the metaphase to anaphase transition when a ubiquitin tag is put on by APC

The G1 DNA damage checkpoint ________________. (a) causes cells to proceed through S phase more quickly. (b) involves the degradation of p53. (c) causes dephosphorylation of p53. (d) involves the inhibition of S-Cdk by p21.

(d) involves the inhibition of S-Cdk by p21.

ATP synthase converts _________ energy in to ___________ energy. (a) chemical bond; thermal (b) chemical bond; mechanical (c) mechanical; radiation (d) mechanical; chemical bond

(d) mechanical; chemical bond

Tumor suppressors inhibit entry in to the cycle. An example of tumor suppressors are _________. (a) ras (b) p53 (c) Rb (d) ras and p53 (e) p53 and Rb

(e) p53 and Rb

Which of the following genetic changes cannot convert a proto-oncogene into an oncogene? a. A mutation that introduces a stop codon immediately after the codon for the initiator methionine. b. A mutation within the coding sequence that makes the protein hyperactive. c. An amplification of the number of copies of the proto-oncogene, increasing expression. d. A mutation in the promoter of the proto-oncogene, causing the protein to be transcribed and translated at an abnormally high level.

a. A mutation that introduces a stop codon immediately after the codon for the initiator methionine

Sister chromatid separation occurs because __________ are destroyed by the APC/C so that separase can cleave the cohesins. a. securins b. cohesins c. kinetochores d. condensins

a. securins

Which of the following statements about apoptosis is TRUE? a. Cells that have DNA damage are less prone to undergo apoptosis. b. Bax and Bak promote apoptosis by binding to procaspases in the apoptosome. c. Apoptosis can be promoted by the release of cytochrome c into the cytosol from mitochondria. d. all of the above.

c. Apoptosis can be promoted by the release of cytochrome c into the cytosol from mitochondria.

Metastatic tumors are more dangerous than a benign tumor because a. its cells are proliferating faster. b. it causes neighboring cells to mutate. c. its cells attack and phagocytose neighboring normal tissue cells. d. its cells invade other tissues.

d. its cells invade other tissues.