BMB 252 Exam

Which phase is not part of the interphase? - -M When does the cytokinesis start? - -Anaphase T/F: cell can exit from the cell cycle at any stage and survive. - -False The fact that all chromosomes are attached to the spindle is verified during: - -metaphase checkpoint T/F: Cyclins are kinases - -False T/F: both activity and concentration of CDKs go through cyclic changes - -False Phosphorylation can activate or inactivate CDK - -BOTH T/F: S-cyclin is only active during the S-phase - -False A CKI P27 inhibits cyclin by - -forming a complex with cyclin-cdk Ubiquitin ligases cause protein degradation by - -marking it for degradation in proteasome Which of the following is a ubiquitin ligase: cyclin, Cdk, a complex of APC/C and cdc20 - -a complex of APC/C and cdc20 What is true: m cyclin concentration depends on the presence of the APC-cdc20, APC-cdc20 activity depends on the concentration of the M cyclin, or both - -BOTH Which are intermediate filaments: actin, desmin, myosin, neurofilament, keratin - -desmin, neurofilament and keratin Which motor protein moves mostly to the minus end - -dynein Which motor protein movement is based in a ring rotation? - -dynein ER is spread in the cell and not collapsed to the center because of the action of which motor protein - -kinesin Which is NOT a correct statement about microtubules: composed of tubulin, alpha tubulin can hydrolyze ATP, beta tubulin can hydrolyze GTP or tubulin mostly gets added and dissociates at the plus end - -Alpha tubulin can hydrolyze ATP In which phase of the cell cycle do prereplicative complexes assemble on DNA? - -G1 T/F: phosphorylated ORC can assemble MCM on it - -False Which enzyme phosphorylates ORC - -S-cdk Cdc25 removes: - -inhibitory phosphate on M-cdk What does S-cdk inactivate by phosphorylation: ORC, cdc6, cdt1 or all of the above - -all of the above Which enzyme removes the inhibitory phosphate form M-cdk - -cdc25 M-cdk inhibitory phosphate is removed at the entrance to which phase - -M-phase Chromosomes start to bind to microtubules in which phase - -prometaphase What makes the sister chromatids arms stay together - -cohesins T/F: In early prophase, most microtubules are shrinking to prepare to grow again to form the mitotic spindle - -True When do centrosomes duplicate - -S-phase T/F: centrioles are dispensable for cell division - -True What keeps the inter polar microtubules together - -kinesins T/F: plus end attached to kinetochore can still add tubulin subunits - -True Cohesins are destroyed in which phase - -anaphase Separase is degrading cohesins by - -cleaving them Poles moving apart is a movement A or B of anaphase - -B Contractile ring consists of: actin, myosin, or microtubules - -actin and myosin The middy contains - -overlapping microtubules inside the contractile ring Mitochondria division correlates more with the stages of the cell cycle or the energy needs of the cell - -the energy needs of the cell Which cells divide by meiosis? - -germ cells and germ cell precursors T/F: there is an S phase in between meiotic divisions one and two - -False Two divisions of meiosis result in - -Four haploid cells T/F: In metaphase II, chromosomes arms are connected all the way through their lengths - -False T/F: Bivalent can form in mitosis - -False Crossovers are the result of recombination or replication? - -Recombination Chiasmata are the sites of crossovers or synapsis? - -Crossovers Synaptonemal complex forms in which cell cycle phase? - -Prophase I Crossover is the same as: synapsis, chiasma, or synaptonemal complex - -chiasma Chiasmata are severed at the transition to which cell cycle phase - -Anaphase I At which stage of prophase I does the egg stay until ovulation - -diplotene How many chiasmata usually form in meiosis? - -1-4 Kinetochores of sister chromatids or homologs are connected? - -sister chromatids T/F: in meiosis, each gamete can get a maternal or paternal chromosome with equal probability - -True In which phases of the cell cycle do the DNA damage controls take place? - -Late G1 phase and M phase Which protein inhibits exit from G1 by blocking E2F? - -Rb Which of the following phosphorylates Rb: E2F, G1-cdk, Myc - -G1-cdk Which of the following also phosphorylates Rb: G1/s cdk, S cdk, G1 cdk - -All of the above