L2- Cell cycle mitosis, their regulation

Question 1

Cell cycle

Answer 1

prokaryotic cells- cell cycle occurs via a process termed binary fission.
eukaryotic cells, the cell cycle can be divided in two periods- a) interphase b) mitosis

Question 2

Interphase

Answer 2

G1 phase:-
Growing
Synthesize new proteins and organelles
Doing their jobs
Longest phase of cell cycle

S Phase
Chromosomes(DNA) are replicated
Key proteins associated with replication are made (centromeres)

G2 Phase
Shortest of the 3 phases of interphase
Organelles and molecules for cell division are produced (centrioles)
Check-up phase before mitosis.

Question 3

Checkpoints

Answer 3

A checkpoint in the cell cycle is a critical control point where stop and go signals regulate the cycle.

Question 4

cell cycle regulators

Answer 4

Protein kinases

Question 5

Internal Regulators

Answer 5

Cdk
MPF
p53
p27

Question 6

Cdk

Answer 6

Adds phosphate to a protein
major control switches for the cell cycle
to move the cell from g1 to s and s to g2

Question 7

MPF

Answer 7

Cdk and cyclin that triggers progression through the cell cycle.

Question 8

p53

Answer 8

protein that blocks the cell cycle if dna is damaged

Question 9

p27

Answer 9

protein that binds to cyclin and cdk to block entry into s phase.

Question 10

Endogenous hormones

Answer 10

Auxin, cytokinins, abscisic acid, gibberellins and brassinosteroids.

Question 11

Interphase

Answer 11

chromosomes are extended form and seen as chromatin.

Nucleus is visible

Question 12

Prophase

Answer 12

nucleus and nuclear envelope break down
chromatin condenses into chromosomes
spindle fibres grow from centrioles
centrioles migrate to opposite poles

Question 13

Metaphase

Answer 13

chromosomes align at the center
spindle fibers are attached
nuclear membrane has disappeared

Question 14

Anaphase

Answer 14

centromere split and sister chromatid are pulled to poles

Question 15

Telophase

Answer 15

chromosomes again become longer and thin
new nuclear membrane formed
cell division almost complete