Unit 9: Cell Cycle Flashcards
Eukaryotic chromosomes in a typical cell…
a) consist of a single circular loop of DNA
b) are visible in the cell once they condense during S phase
c) spend most of their time as tangled threads, not distinguishable by light microscopy
d) spend most of their time in pairs, joined by centromeres
e) pair up along the metaphase plate during mitosis, with connections between parental homologs
c)
When chromosomes are pulled apart at anaphase of mitosis, ____ are being separated.
a) homologous chromosomes
b) sister chromatids
c) maternally and paternally-inherited genetic material
d) identical copies of genetic material
e) b and d
e)
When viewed using light microscopy, the most obvious sign that a cell has completed mitotic prophase and transitioned into prometaphase is
a) separation of chromatids to opposite poles of the cell
b) lining up chromosomes along the equator of the cell
c) breakdown of the nuclear envelope
d) replication of DNA resulting in two sister chromatids
e) presence of synaptonemal complexes between sister chromatids
c)
Which of the following describes an event that occurs in meiosis II?
a) crossing over of non-sister chromatids
b) tetrads migrate to the metaphase plate
c) sister chromatids separate and begin moving to opposite sides of the cell
d) homologous chromosomes separate and begin moving to opposite sides of the cell
c)
Compared to somatic cell in G0, a germ cell at the completion of meiosis I has ___ amount of DNA and ___ number of chromosomes
a) half the; half the
b) the same; the same
c) the same; half the
d) double the; the same
c)
An epithelial cell lining your intestine spends most of its time in ____ of the cell cycle
a) M-phase
b) metaphase
c) interphase
d) S-phase
e) prophase
c)
G1-Cdk
a) transfers phosphate groups to target proteins
b) varies in concentration as the cell goes through the cycle
c) varies in activity as the cell goes through the cycle
d) a and b
e) a and c
e)
As a cell completes mitosis, M-Cdk (MPF) activity must decrease. How is this achieved?
a) M-Cdk is completely degraded
b) The kinase component of M-Cdk is converted to G1-Cdk, which then drives the next phase of the cycle
c) The kinase takes on a function unrelated to mitosis
d) The cyclin component is degraded
e) the kinase is degraded; concentration of the cyclin remains constant, but without the cyclin-dependent kinase, active M-Cdk is not formed
d)
A cell that is terminally differentiated
a) will never divide again
b) is capable of carrying out a specific function within the organism
c) can no longer function, and will soon die
d) a and b
e) a and c
d)
Cdk inhibitors
a) remove phosphates from Cdks, thereby inactivating them
b) can bind to G1 / S-Cdk and prevent progression into S Phase
c) promote unregulated cellular proliferation
d) can prevent division in cells with damaged DNA
e) both b and d
e)
Many tumour suppressor genes code for proteins that
a) lead to the halting of the cell cycle if DNA damage is detected
b) block the effects of mitogens
c) drive the transcription of Cdk inhibitors
d) are activated once cells become cancerous
e) a and c
e)
A cell that express a proto-oncogene will
a) probably become cancerous
b) become terminally differentiated
c) undergo uncontrolled cell division
d) undergo normal cell division in response to appropriate signals
e) a and c
d)
In response to DNA damage that is not able to repair, a human cell should
a) release cytochrome c from the mitochondria and activate caspases
b) shift the balance of Bcl-2 regulatory proteins to pro-apoptotic members
c) undergo apoptosis
d) a and c
e) a, b and c
e)
Rb is an example of
a) oncogene
b) proto-oncogene
c) mitogen
d) tumor supressor
d)
Inheriting a non-functional copy of a tumour suppressor gene (e.g. p53) from one of your parents would
a) cause non-disjunction
b) predispose you to cancer if your other copy of p53 becomes mutated
c) promote mitosis in your terminally differentiated cells
d) prevent mitosis in all your cells
e) cause uncontrolled cell division in cells lining your intestine
b)
