Cell Biology Chapter 20-22 Questions

During which stage of the cell cycle is the chromosome content of a mammalian liver cell 1n (haploid)?

none of the above

Which of the following statements about the cell cycle is FALSE?

once a cell decides to enter the cell cycle, the time from start to finish is the same in all eukaryotic cells (The DNA content is duplicated during S phase, A cell has more DNA during G2 than it did in G1, and An unfavorable environment can cause cells to arrest in G1 are true)

Cell cycle checkpoints

are critical points that determine whether or not the cell cycle proceeds to the next phase of cell division

levels of cyclin-dependent kinase (Cdk) activity change during the cell cycle as a result of 

the Cdks binding different cyclins to become active

A cell at the interphase of cell division does not undergo dramatic change morphologically as in the M phase, but it is biochemically active because it is actively engaged in

DNA synthesis 

Cells in the G₀ state

do not divide

progression through the cell cycle requires a cyclin to bind to a Cdk because

the binding of a cyclin to Cdk is required for Cdk enzymatic activity

Levels of Cdk activity change during the cell cycle, in part beacuse

the levels of cyclins change during the cycle

Mitotic cyclin (M cyclin)

falls in concentration at the end of the M phase as a result of degradation

Which of the following statements is FALSE concerning sister chromatids?

Sister chromatids separate during G2 phase.

How does a somatic cell that has just completed the S phase of its cell cycle compare in respect to its number of chromosomes and amount of DNA with a gamete of the same species?

it has twice the number of chromosomes and four times the amount of DNA

Which of the following statements about the cell cycle is correct?

when the S phase of the cell cycle is finished, a cell has twice as much DNA as it did during the G1 phase

Many growth factors are

extracellular signals that stimulate cell division

a cell that is terminally differentiated (at G0 phase) will

inactivate its cell-cycle control system

the process by which haploid cells are produced from diploid cells is called

meiosis

which of the following statements is TRUE?

the mitotic spindle helps segregate the chromosomes to the two daughter cells 

which of the following statements regrading the G1 phase of the eukaryotic cell cycle is NOT true?

most organells are duplicated at the G1 phase (If environmental conditions are favorable during the G1 phase, the cell will prepare to replicate its DNA, Most cells spend the majority of their lives in the G1 phase of the cell cycle, and Cells that are terminally differentiated may exit the G1 phase and enter the G0 phase are TRUE)

which of the following precede the cytokinesis in animals cells?

assembly of the contractile ring

a cell that lacks Cdk activity in M phase will be unable to

disassemble its nuclear lamina at prometaphase

which of the following is NOT an accurate description of a checkpoint that controls the progression of the cell cycle?

timing the cytokinesis to separate daughter cells