The Cell Cycle

How many chromosomes are in the middle cell? 1 2 4 8 Answer: A

How many chromosomes are in the middle cell? 1 2 4 8 3

At what part of the cell cycle would you see a chromosome that looks like this? G1 G2 M S Answer: C 4

At what part of the cell cycle would you see a chromosome that looks like this? G1 G2 M S 5

Although the chromosome begins M phase looking as shown below, when is it split? prophase prometaphase metaphase anaphase telophase Answer: D 6

Although the chromosome begins M phase looking as shown below, when is it split? prophase prometaphase metaphase anaphase telophase 7

Which of the following best describes the kinetochore? a structure composed of several proteins that associate with the centromere region of a chromosome and that can bind to spindle microtubules the centromere region of a metaphase chromosome at which the DNA can bind with spindle proteins the array of vesicles that will form between two dividing nuclei and give rise to the metaphase plate the ring of actin microfilaments that will cause the appearance of the cleavage furrow the core of proteins that forms the cell plate in a dividing plant cell Answer: A Students should be able to differentiate kinetochore from centromere. 8

Which of the following best describes the kinetochore? a structure composed of several proteins that associate with the centromere region of a chromosome and that can bind to spindle microtubules the centromere region of a metaphase chromosome at which the DNA can bind with spindle proteins the array of vesicles that will form between two dividing nuclei and give rise to the metaphase plate the ring of actin microfilaments that will cause the appearance of the cleavage furrow the core of proteins that forms the cell plate in a dividing plant cell 9

A new cell is found and separation of its chromosomes is examined A new cell is found and separation of its chromosomes is examined. How would you interpret this result? Chromosomes are separated by microfilaments. Chromosomes are not separated. Microtubules shorten at the centrosome end. Microtubules shorten at the chromosome end. Answer: C 10

A new cell is found and separation of its chromosomes is examined A new cell is found and separation of its chromosomes is examined. How would you interpret this result? Chromosomes are separated by microfilaments. Chromosomes are not separated. Microtubules shorten at the centrosome end. Microtubules shorten at the chromosome end. 11

Which of the following statements about typical eukaryotic chromosomes just before and after M phase is INCORRECT? These chromosomes are not in a fully condensed state. Both contain double-stranded DNA molecules. Both would have just one kinetochore structure associated with their centromere. Each has many proteins associated with the chromosomal DNA. Typically both are linear structures with distinct ends. Answer: C

Which of the following statements about typical eukaryotic chromosomes just before and after M phase is INCORRECT? These chromosomes are not in a fully condensed state. Both contain double-stranded DNA molecules. Both would have just one kinetochore structure associated with their centromere. Each has many proteins associated with the chromosomal DNA. Typically both are linear structures with distinct ends.

Which of the following does NOT need to happen during a successful mitotic cell division? Single-chromatid chromosomes must be segregated in full sets of the genome. Exchange of DNA between homologous chromosomes must happen before metaphase. The chromatin must condense fully so that the chromosomes are compact. Microtubules must be assembled as part of the spindle apparatus. Each of the chromosomes must start mitosis containing two DNA molecules. Answer: B

Which of the following does NOT need to happen during a successful mitotic cell division? Single-chromatid chromosomes must be segregated in full sets of the genome. Exchange of DNA between homologous chromosomes must happen before metaphase. The chromatin must condense fully so that the chromosomes are compact. Microtubules must be assembled as part of the spindle apparatus. Each of the chromosomes must start mitosis containing two DNA molecules.

Which of the following is a INCORRECT description of how cytokinesis (see figures on next slide) in animals differs from that in most plants? Animal cytokinesis separates the two new nuclei but not the cytoplasm, while plant cytokinesis separates both. Animal cytokinesis does not involve the fusion of Golgi-derived vesicles. Microfilaments play a role in animal cytokinesis but not in plant cytokinesis. The new separating plasma membrane is pulled inward in animals but grows outward in plants. Animal cytokinesis produces no new cell wall regions, while plant cytokinesis does. Answer: A

Which of the following is a INCORRECT description of how cytokinesis in animals differs from that in most plants? Animal cytokinesis separates the two new nuclei but not the cytoplasm, while plant cytokinesis separates both. Animal cytokinesis does not involve the fusion of Golgi-derived vesicles. Microfilaments play a role in animal cytokinesis but not in plant cytokinesis. The new separating plasma membrane is pulled inward in animals but grows outward in plants. Animal cytokinesis produces no new cell wall regions, while plant cytokinesis does.

From prophase through metaphase of mitosis, each chromosome has _____ DNA molecules, while from anaphase through telophase of mitosis, each chromosome has _____ DNA molecule(s). two; one 2n; 1n homologous; nonhomologous condensed; decondensed nonsister chromatid; sister chromatid Answer: A

From prophase through metaphase of mitosis, each chromosome has _____ DNA molecules, while from anaphase through telophase of mitosis, each chromosome has _____ DNA molecule(s). two; one 2n; 1n homologous; nonhomologous condensed; decondensed nonsister chromatid; sister chromatid Answer: A

Of the events of a typical cell division listed below, which is most likely to occur THIRD in an animal cell that is going through mitosis? Kinetochore proteins associated with the centromeres bind with associated microtubules. Segregation of complete genomic sets of chromosomes occurs. The nuclear envelope membranes are converted from flat bilayers into many spherical vesicles. The number of chromosomes in the cell doubles as double-chromatid chromosomes are split into pairs of single-chromatid chromosomes. Vesicles fuse to one another to form new nuclear envelope membranes. Answer: D The order would be 1) c. 2) a. 3) d. 4) b. 5) e.

Of the events of a typical cell division listed below, which is most likely to occur THIRD in an animal cell that is going through mitosis? Kinetochore proteins associated with the centromeres bind with associated microtubules. Segregation of complete genomic sets of chromosomes occurs. The nuclear envelope membranes are converted from flat bilayers into many spherical vesicles. The number of chromosomes in the cell doubles as double-chromatid chromosomes are split into pairs of single-chromatid chromosomes. Vesicles fuse to one another to form new nuclear envelope membranes.

Which event will likely occur next in a eukaryotic cell that is ending prophase (see figure) and will next enter prometaphase? The chromosome material will condense. Chromosomes will be moved toward alignment at the metaphase plate. Kinetochores will link some microtubules to the centromeres. The nuclear membranes will fragment into vesicles. Microtubules will elongate into the nuclear space. Answer: D

Which event will likely occur next in a eukaryotic cell that is ending prophase (see figure) and will next enter prometaphase? The chromosome material will condense. Chromosomes will be moved toward alignment at the metaphase plate. Kinetochores will link some microtubules to the centromeres. The nuclear membranes will fragment into vesicles. Microtubules will elongate into the nuclear space.

Which of the following is NOT a typical trait of cancerous cells that makes them different from normal somatic cells? Cancer cells often deactivate their apoptosis systems. Cancerous cells are not as sensitive to contact inhibition. The cell cycle often proceeds faster in cancer cells. Cancer cells are more mobile and less dependent on anchorage. Cancer cells have more effective DNA repair activities. Answer: E

Which of the following is NOT a typical trait of cancerous cells that makes them different from normal somatic cells? Cancer cells often deactivate their apoptosis systems. Cancerous cells are not as sensitive to contact inhibition. The cell cycle often proceeds faster in cancer cells. Cancer cells are more mobile and less dependent on anchorage. Cancer cells have more effective DNA repair activities. Answer: E

Which of the following statements INCORRECTLY describes an aspect of an indicated point in the cell cycle? During S phase, the DNA of each chromosome is replicated. Each chromosome during telophase has a single double-stranded DNA molecule. At the beginning of anaphase, the kinetochore on the chromosome loses its attachment to microtubules of the spindle. During G1, the DNA in the nuclear chromosomes is not all highly condensed. During metaphase, each chromosome consists of two double-stranded DNA helices linked together at a centromere. Answer: C

Which of the following statements INCORRECTLY describes an aspect of an indicated point in the cell cycle? During S phase, the DNA of each chromosome is replicated. Each chromosome during telophase has a single double-stranded DNA molecule. At the beginning of anaphase, the kinetochore on the chromosome loses its attachment to microtubules of the spindle. During G1, the DNA in the nuclear chromosomes is not all highly condensed. During metaphase, each chromosome consists of two double-stranded DNA helices linked together at a centromere.

Which of the following statements best explains this observation Which of the following statements best explains this observation? A cell in prophase of mitosis is successfully fused to a cell in G2 of interphase, and then after fusion both nuclei are seen to have fully condensed chromosomes and to proceed on through mitosis. Fusion of these cells is stressful, and stress induces cells to enter mitosis. A cytosolic mitotic promoting factor from the cell in prophase induced the nucleus from the cell in interphase to enter M phase. The production of items by the cell in G2 helps to induce the next stage of the cell cycle in both nuclei. The swapping of genes between the nuclei causes the induction of mitosis. The condensation of the chromosomes occurs whenever cells are fused. Answer: B

Which of the following statements best explains this observation Which of the following statements best explains this observation? A cell in prophase of mitosis is successfully fused to a cell in G2 of interphase, and then after fusion both nuclei are seen to have fully condensed chromosomes and to proceed on through mitosis. Fusion of these cells is stressful, and stress induces cells to enter mitosis. A cytosolic mitotic promoting factor from the cell in prophase induced the nucleus from the cell in interphase to enter M phase. The production of items by the cell in G2 helps to induce the next stage of the cell cycle in both nuclei. The swapping of genes between the nuclei causes the induction of mitosis. The condensation of the chromosomes occurs whenever cells are fused.