41. Checkpoints a. Controlled by chromosomes attachment to spindle 42. Restricti

Question

41. Checkpoints a. Controlled by chromosomes attachment to spindle 42. Restriction point b. Hold sister chromatids together. c. Depolymerize to mediate chromosome-to-pole 43. Electrical synapse movement. d. Cdk inhibitor 44. Origin recognition complex 45. Retinoblastoma proteirn 46. p27 e. Degradation of cohesin. f. Activating phosphatase for M-phase Cdk g. Gap junctions. h. Involved in replication licensing. i. Intracellular Calcium sensing. 47. Cdc25 48. Kinetochore microtubules 49. Separase j. Quality control of the cell cycle. 50. Cohesins k. Molecular switch. 51. Metaphase-Anaphase transition L. Real start point of the cell cycle. m. Prevents the expression of S-phase genes. n. Prevents the premature separation of sister chroma o. Ligand-independent signaling. 52. Securirn 53. G protein 54. Calmodulin 5. Constitutively active pathway

Explanation / Answer

41. j

The checkpoints ensure that incomplete or damaged chromosomes are not replicated and passed on to daughter cells.

42. l

Restriction point is a G1 phase checkpoint at which a cell becomes committed to DNA replication and completes a cell cycle.

43. g

At electrical synapse, action potentials conduct directly between adjacent cells through structures called gap junctions. This allows rapid communication between cells.

44. h

Once origin recognition complex is laid, MCM helicases are recruited. This makes cell licensed to replication.

45. m

Retinoblastoma protein binds a transcription factor E2F and renders it inactive. E2F is required for expression of S phase cyclins.

46. d

p27 is a member of CIP/KIP family of CdK inhibitors which usually inhibits cyclin A/CdK2 activity.

47. f

Cdc25 is a phosphatase which removes the deactivating phosphate of M Cdk.

48. c

Kinetochore microtubules attach at kinetochores. The depolymerization helps to pull chromosomes towards poles.

49. e

Separase is involved in degradation of cohesins. This helps to separate the sister chromatids at metaphase to anaphase transition.

50. b

Cohesins are members of SMC proteins which are invoved in holding together of sister chromatids.

51. a

Metaphase to anaphase transition involves microtubule dynamics in which chromosomes are attached to spindle by microtubules. The depolymerization of the microtubules then lead to separation of chromatids.

52. n

Securin is an inhibitor of the enzyme separase, which prevents premature separation of sister chromatids.

53. k

G protein acts as a molecular switch. It switches between GTP-bound active form and GDP-bound inactive form.

54. i

Calmodulin is a calcium binding protein. It senses the calcium levels of the cell and helps to activate various proteins.

55. o

A constitutive pathway does not require ligand. It is always active even in absence of ligand.

Related Questions

Navigate

• Browse (All)
• Browse 4
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.