AP Bio Unit 4

At which phase of mitosis do the sister chromatids become daughter chromosomes? A) prometaphase B) metaphase C) cytokinesis D) prophase E) anaphase

E

Cells will usually divide if they receive the proper signal at a checkpoint in which phase of the cell cycle? A) cytokinesis B) G2 C) S D) M E) G1

E

Which is the first checkpoint in the cell cycle where a cell will be caused to exit the cycle if this point is not passed? A) G0 B) G2 C) S D) M E) G1

E

A group of cells is assayed for DNA content immediately following mitosis and is found to have an average of 8 picograms of DNA per nucleus. How many picograms would be found at the end of S and the end of G2? A) 16; 16 B) 12; 16 C) 16; 8 D) 8; 16 E) 8; 8

A

A plant-derived protein known as colchicine can be used to poison cells by blocking the formation of the spindle. Which of the following would result if colchicine is added to a sample of animal cells in G2? A) Chromosome condensation would occur, but the chromosomes would fail to align at the metaphase plate. B) The cells would be unable to begin M and stay in G2. C) The cells would immediately die. D) The chromosomes would segregate but in a disorderly pattern.

A

Cells from advanced malignant tumors frequently have very abnormal chromosomes as well as an abnormal number of chromosomes. What might explain the association between malignant tumors and chromosomal abnormalities? A) Cell cycle checkpoints are not in place to stop cells with chromosome abnormalities. B) Cells with abnormal chromosomes have increased metabolism. C) Cancer cells replicate chromosomes multiple times per cell cycle. D) Cancer cells are no longer anchorage dependent.

A

During mitosis in animal cells, at which phase do centrioles begin to move apart? A) prophase B) telophase C) prometaphase D) anaphase E) metaphase

A

Taxol is an anticancer drug extracted from the Pacific yew tree that binds to microtubules and prevents their depolymerization. Actively dividing cells treated with Taxol become blocked in which phase of mitosis? A) metaphase B) telophase C) prophase D) prometaphase E) anaphase

A

Which of the following are primarily responsible for cytokinesis in plant cells but not in animal cells? A) Golgi-derived vesicles B) spot desmosomes C) tubulin and dynein D) actin and myosin E) centrioles and centromeres

A

Which statement provides the best description of the interphase portion of the cell cycle? A) During interphase, a cell is metabolically active. B) Interphase is a resting stage prior to cell division. C) Interphase is a brief period between mitosis and chromosome duplication.

A

The cell cycle is regulated at the molecular level by a set of proteins known as A) cohesins. B) separase proteins. C) cyclins. D) ATPases.

C

A group of cells is assayed for DNA content immediately before beginning mitosis and is found to have an average of 16 picograms of DNA per nucleus. How many picograms would be in a cell nucleus following completion of mitosis and cytokinesis? A) 4 B) 8 C) 16 D) 32

B

A human bone marrow cell, in prophase of mitosis, contains 46 chromosomes. How many chromatids does it contain? A) 23 B) 92 C) 46 or 92, depending on the portion of prophase examined D) 23 or 46, depending on the portion of prophase examined E) 46

B

Besides the ability of some cancer cells to divide uncontrollably, what else could logically result in a tumor? A) enhanced anchorage dependence B) lack of appropriate cell death C) inability to form spindles D) changes in the order of cell cycle stages

B

Compared to most prokaryotic cells, eukaryotic cells typically have A) the same number of DNA molecules and similarly sized genomes. B) more DNA molecules and larger genomes. C) the same number of DNA molecules but larger genomes. D) fewer DNA molecules and smaller genomes. E) fewer DNA molecules but larger genomes.

B

If a eukaryotic cell is in the G1 phase of the cell cycle, which statement about the cell's chromosomes must be correct? A) Each chromosome consists of two identical chromatids. B) Each chromosome is made of a complex of DNA and associated proteins. C) The chromosomes are preparing for DNA synthesis.

B

If there are 20 centromeres in a cell at anaphase of mitosis, how many chromosomes are there in each daughter cell following cytokinesis? A) 5 B) 10 C) 20 D) 40

B

Nucleoli are present during _____. A) prometaphase B) interphase C) prophase D) anaphase C) metaphase

B

Spindle fibers attach to kinetochores during _____. A) telophase B) prometaphase C) anaphase D) metaphase E) interphase

B

What is true of all cancers? A) They are caused by chemical carcinogens. B) They have escaped normal cell cycle controls. C) They are inherited.

B

Which of the following is true of kinetochores? A) They are the primary centromere structures that maintain the attachment of the sister chromatids prior to mitosis. B) They are sites at which microtubules attach to chromosomes. C) They are located at the center of the centrosome; their function is to organize tubulin into elongated bundles called spindle fibers. D) They attach to the ring of actin along the cytoplasmic surface of the plasma membrane, causing the actin to contract to form the cleavage furrow. E) They interdigitate at the cell's equator and then move apart, causing the cell to elongate.

B

Why is it difficult to observe individual chromosomes with a light microscope during interphase? A) They leave the nucleus and are dispersed to other parts of the cell. B) They have uncoiled to form long, thin strands. C) The DNA has not been replicated yet. D) Sister chromatids do not pair up until division starts. E) The spindle must move them to the metaphase plate before they become visible.

B

Centromeres divide and sister chromatids become full-fledged chromosomes during _____. A) telophase B) metaphase C) anaphase D) interphase E) prometaphase

C

Cytokinesis often, but not always, accompanies _____. A) metaphase B) prometaphase C) telophase D) interphase E) anaphase

C

During _____ the cell grows and replicates both its organelles and its chromosomes. A) S B) G1 C) interphase D) mitosis E) cytokinesis

C

How do cancer cells differ from normal cells? A) Cultured cancer cells exhibit anchorage dependence B) .Cancer cells trigger chromosomal changes in surrounding cells. C) Cancer cells may be immortal.

C

The cell cycle control systems of cancer cells differ from those of normal cells. Select the best explanation for this fact. A) Cancer cells divide excessively and invade other tissues. B) Cancer cells are immortal. C) Genetic changes alter the function of the cancer cell's protein products.

C

What is a cleavage furrow? A) a ring of vesicles forming a cell plate B) an indentation between daughter prokaryotic cells C) a groove in the plasma membrane between daughter nuclei D) the metaphase plate where chromosomes attach to the spindle

C

What is produced if a cell completes mitosis but does not undergo cytokinesis? A) two cells, each cell with an identical nucleus containing the genetic material of the parent cell B) one cell with one nucleus containing half of the genetic material of the parent celltwo cells, one cell containing two nuclei and a second cell without a nucleus C) one cell with two nuclei, each identical to the nucleus of the parent cell D) two cells, each cell with half of the genetic material of the parent cell

C

Where do the microtubules of the spindle originate during mitosis in animal cells? A) centriole B) kinetochore C) centrosome D) centromere E) chromatid

C

Which of the following is true concerning cancer cells? A) They must be attached to a substrate to divide in culture. B) They stop dividing in culture when growth factors are depleted. C)They exhibit density-dependent inhibition when growing in culture. D) They evade the normal controls that trigger programmed cell death.

D

A particular cell has half as much DNA as some other cells in a mitotically active tissue. The cell in question is most likely in __________. A) G2 B) metaphase C) prophase D) G1

D

Chromosomes become visible during _____. A) prometaphase B) interphase C) anaphase D)prophase E) metaphase

D

Eukaryotic chromatin is composed of A) DNA and carbohydrates. B) DNA and ribosomes. C) condensed DNA only. D) DNA and proteins. E) DNA and RNA.

D

Movement of the chromosomes during anaphase would be most affected by a drug that prevents A) cell wall formation. B) formation of a cleavage furrow. C) elongation of microtubules. D) shortening of microtubules. E) nuclear envelope breakdown.

D

Which of the following correctly matches a phase of the cell cycle with its description? A) G2: cell division B) M: duplication of DNA C) S: immediately precedes cell division D) G1: follows cell division E) All of the listed responses are correctly matched

D

Which of the following does NOT occur during mitosis? A) separation of sister chromatids B) condensation of the chromosomes C) spindle formation D) replication of the DNA

D

Humans produce skin cells by mitosis and gametes by meiosis. The nuclei of skin cells produced by mitosis will have A) twice as much DNA as the nuclei of gametes produced by meiosis. B) four times as much DNA as the nuclei of gametes produced by meiosis. C) the same amount of DNA as the nuclei of gametes produced by meiosis. D) half as much DNA as the nuclei of gametes produced by meiosis.

a