BIO ch 12
Which of the following statements describes a characteristic feature of metaphase? - alignment of chromosomes on the equator of the cell -separation of the centromeres -separation of sister chromatids -cytokinesis
- alignment of chromosomes on the equator of the cell
In a diploid cell with four chromosome pairs (2n = 8), how many sister chromatids will be found in a nucleus at prophase of mitosis? -32 -4 -8 -16
-16
Which of the following properties is associated with a cyclin-dependent kinase (Cdk)? -A Cdk is an enzyme that attaches phosphate groups to other proteins. -A Cdk is inactive, or "turned off," in the presence of a cyclin. -The number of Cdk molecules increases during the S and G2 phases and decrease during M. -A Cdk is an enzyme that catalyzes the attachment of kinetochores to microtubules.
-A Cdk is an enzyme that attaches phosphate groups to other proteins
Eukaryotic chromatin is composed of which of the following macromolecules? -DNA and phospholipids -DNA and RNA -DNA and proteins -DNA only
-DNA and proteins
Which of the following statements best describes what would happen if MPF (maturation-promoting factor) is introduced into immature frog oocytes that are arrested in G2? -The cells would begin DNA synthesis. -The cells would enter mitosis. -The cells would remain arrested in G2 -.The cells would enter G0.
-The cells would enter mitosis.
Which of the following statements best describes a cleavage furrow? -the separation of divided prokaryotes -the space that is created between two chromatids during anaphase -a ring of vesicles forming a cell plate -a groove in the plasma membrane between daughter nuclei
-a groove in the plasma membrane between daughter nuclei
In which phase of mitosis do the sister chromatids become daughter chromosomes? -metaphase -prophase -anaphase -telophase
-anaphase
Which of the following molecules is maintained at a relatively constant level throughout the cell cycle but requires a cyclin to become catalytically active? -Cdk -cyclin -PDGF -MPF
-cdk
What is the name of the microtubule-organizing center found in animal cells as an identifiable structure present during all phases of the cell cycle? -centromere -centriole -kinetochore -centrosome
-centrosome
A research team used a culture of lymphocytes with radioactively labeled T nucleotides to study the cell cycle. They found that the lymphocytes incorporated the labeled nucleotide at a significantly higher rate after a pathogen was introduced into the culture. Which of the following conclusions is most consistent with the results? -infection causes lymphocytes to divide more rapidly -.Infection causes lymphocytes to increase in size -.The pathogen consumed radiolabeled nucleotides. -Infection causes lymphocyte cultures to skip some parts of the cell cycle
-infection causes lymphocytes to divide more rapidly
If all chromosomes are not attached to the mitotic spindle at the M phase checkpoint, the cells would most likely be arrested at which of the following points in the cell division cycle or mitosis? -prophase -telophase -G2 -metaphase
-metaphase
Which of the following cellular events occur in the G1 phase of the cell division cycle? -DNA replication -break down of the nuclear membrane -normal growth and cell function -the beginning of mitosis
-normal growth and cell function
Which of the following events would be most likely to produce cells with several nuclei? -repeated cytokinesis without mitosis -multiple S phases without mitosis -repeated mitosis with simultaneous cytokinesis -repeated mitosis without cytokinesis
-repeated mitosis without cytokinesis
Which of the following events occurs during interphase of the cell cycle? -spindle formation -separation of the spindle poles -condensation of the chromosomes -replication of the DNA
-replication of the DNA
The mitotic spindle plays a critical role in which of the following processes? -splitting of the cell (cytokinesis) following mitosis -dissolving the nuclear membrane -separation of sister chromatids -triggering condensation of chromosomes
-separation of sister chromatids
Movement of the chromosomes during anaphase would be most directly affected by a drug that prevents which of the following events? -formation of a cleavage furrow -shortening of microtubules -nuclear envelope breakdown -elongation of microtubules
-shortening of microtubules
After DNA replication, each duplicated chromosome consists of two of which of the following structures? -daughter nucleosome -ssister chromatins -daughter chromosomes -sister chromatids
-sister chromatids
What is the name of the region on duplicated chromosomes where the sister chromatids are most closely attached to each other? -the chromatin -the centrosome -the cohesin -the centromere
-the centromere
Which of the following statements best describes how cytokinesis differs between plant and animal cells? -The contractile filaments found in plant cells are structures composed of carbohydrates; the cleavage furrow in animal cells is composed of contractile proteins. -Cytokinesis occurs between metaphase and anaphase in plant cells; it occurs after anaphase in animal cells -.Plant cells deposit vesicles containing cell wall building blocks on the metaphase plate; animal cells form a cleavage furrow. -The structural proteins of plant cells separate the two cells; in animal cells, a cell membrane separates the two daughter cells.
.Plant cells deposit vesicles containing cell wall building blocks on the metaphase plate; animal cells form a cleavage furrow.
If a cell at metaphase of mitosis contains 32 sister chromatids, how many chromosomes will be present in a G1 cell? -64 -32 -8 -16
16
In a diploid cell with four chromosome pairs (2n = 8), how many centromeres will be found in a nucleus at G2 of the cell division cycle? -16 -4 -8 -32
8
Which of the following statements best describes density-dependent inhibition? -As cells become more numerous, they begin to squeeze against each other, restricting their size -.As cells become more numerous, the protein kinases they produce begin to compete with each other, such that the proteins produced by one cell essentially cancel those produced by its neighbor. -As cells become more numerous, the cell surface proteins of one cell contact the adjoining cells, and they signal each other to stop dividing. -As cells become more numerous, the level of waste products increases, which slows metabolism and inhibits growt
As cells become more numerous, the cell surface proteins of one cell contact the adjoining cells, and they signal each other to stop dividing.
Which of the following pairs of molecules make up an active MPF? -a growth factor and mitotic factor -ATP synthetase and a protease -cyclin and a cyclin-dependent kinase -cyclin and tubulin
cyclin and a cyclin-dependent kinase
At which phase of the cell cycle do centrioles begin to move apart in animal cells? - metaphase -anaphase -telophase -prophase
prophase
