Unit 1: cells and proteins KA 1.5: protein control of cell division

Question 1

What is the cytoskeleton made of?

Answer 1

A polymer called microtubules. These are composed of protein monomer called tubulin.

Question 2

name the structure microtubules form during cell division

Answer 2

spindle fibres

Question 3

name the monomer that forms microtubules

Answer 3

tublin monomer

Question 4

where do the microtubules radiate from in the cell?

Answer 4

Microtubule organising centre (MTOC) also known as the centrosome

Question 5

The cell cycle can be divided into two parts what are their names?

Answer 5

interphase and mitotic (M) phase

Question 6

Function of mitosis

Answer 6

provides new cells for growth repair of damaged tissues and replacement of dead or damaged cells.

It also maintains the cells diploid chromosome complement.

Question 7

function of interphase

Answer 7

growth and DNA synthesis including-

G1-a growth phase

S phase-during which DNA is replicated and

G2-a further growth phase

Question 8

what is the acronym for the mitotic phase?

Answer 8

PMAT

Question 9

What happens in prophase?

Answer 9

DNA condenses into chromosomes each consisting of two sister chromatids

nuclear membrane breaks down

spindle microtubules extend from the MTOC by polymerisation and attached to chromosomes to be their kinetic course in the centromere region

Question 10

what happens in metaphase?

Answer 10

Chromosomes are aligned at the metaphase plate (equator of the cell)

Question 11

what happen anaphase?

Answer 11

A spindle microtubules shortened by T polymerisation chromatids are separated and chromosomes are pulled apart to the opposite poles

Question 12

what happens in Telophase?

Answer 12

The chromosomes de condense and the nuclear membrane are formed around them

Question 13

What happens in cytokinesis?

Answer 13

The cytoplasm is separated into two daughter cells

Question 14

what is checked for at the G1 checkpoint?

Answer 14

DNA damage, growth factors and nutrients

Question 15

what is checked for at the G2 checkpoint?

Answer 15

DNA replication and cell size

Question 16

what is checked for at the M (metaphase) checkpoint?

Answer 16

chromosomes are properly attached to spindle fibres and aligned the equator/metaphase stage

Question 17

what can P53 do

Answer 17

stimulate DNA repair arrest the cell cycle or cause cell death (apoptosis) and is also a tumour suppressor

Question 18

what accumulates during the G1 growth phase?

Answer 18

cyclins

Question 19

which proteins act as tumour suppressors in the cell cycle?

Answer 19

P53 and retinoblastoma

Question 20

which molecule inhibits RB and how does this occur?

Answer 20

Phosphate. Phosphate group added by the activated CDKs (cyclin dependent kinases)

Question 21

What does a decrease in cell division cause?

Answer 21

Degenerative disease diseases such as Alzheimer’s

Question 22

What does an increase in cell division cause?

Answer 22

tumour formation, i.e. cancer

Question 23

define the term proto-oncogene

Answer 23

A proto-oncogene is a normal gene usually involved in the control of cell growth or division which can mutate to form a tumour promoting oncogene

Question 24

What is an internal signal that begins the process of apoptosis?

Answer 24

DNA damage (checked for mostly in G2)

Question 25

What are 2 external signal that begins the process of apoptosis?

Answer 25

production of death signal molecules from lymphocytes or lack of growth factors

Question 26

what are two types of signals that can trigger apoptosis?

Answer 26

Internal and external

Question 27

What protein cascade leads to the breakdown of cellular organelles?

Answer 27

caspade cascade

Question 28

where does an external signalling molecule bind to?

Answer 28

Extra cellular membrane receptor

Question 29

What protein is activated when an internal signal is received?

Answer 29

Caspases

Question 30

where can external death signals originate from?

Answer 30

lymphocytes