AP Bio Chapter 12

Multiple Choice

How many chromosomes are in the middle cell?

• 1

• 2

• 4

• 8

Multiple Choice

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

Multiple Choice

At what part of the cell cycle would you see a chromosome that looks like this?

• G₁

• G₂

• M

• S

Multiple Choice

The chromosome begins M phase looking as shown. When does it split?

• prophase

• prometaphase

• metaphase

• anaphase

• telophase

Multiple Choice

Which event will likely occur next in a eukaryotic cell entering 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.

Multiple Choice

Which 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 where 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

Multiple Choice

Which statement 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 have just one kinetochore structure associated with their centromere.

• Both have many proteins associated with the chromosomal DNA.

• Typically, both are linear structures with distinct ends.

Multiple Choice

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.

Multiple Choice

If you used a very fine glass needle to pull one chromosome away from the metaphase plate during metaphase, which checkpoint would not be passed until this was corrected?

• G₁ checkpoint

• G₂ checkpoint

• M checkpoint

• S checkpoint

• any checkpoint

Multiple Choice

You are observing a line of rat cells and see that they repeatedly make mistakes in the cell cycle by going through the G₂ checkpoint too early. This could be due to a

• problem with expression of a cyclin.

• misplaced MPF.

• defective chromosome.

• misfolded centromere protein.

Multiple Choice

Which statement comparing cancer cells and normal somatic cells would lose points on a test?

• Cancer cells often deactivate their apoptosis systems.

• Cancer 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.