Cell Proliferation and Mitosis

Question 1

What is proliferation?

Answer 1

Physiological process of cell division
Results in an increased number of cells
Occurs in almost every tissue

Question 2

What causes rate of proliferation to decrease

Answer 2

Cell differentiation

Question 3

Cell that are unable to proliferate

Answer 3

Cardiac myocytes

Neurons

Question 4

Cells that can resume proliferation from G0

Answer 4

Skin fibroblasts, smooth muscle cells, epithelial cells of internal organs

Question 5

Cell that undergo continual proliferation

Answer 5

Blood cells, skin epithelial cells

Question 6

Factors that contribute to and regulate proliferation

Answer 6

Environmental - nutrients, temperature, pH, oxygen
Positive and negative - cell adhesion, growth factors
Intracellular - p53, cytochrome C, Bcl proteins

Question 7

What is the purpose of germ cell

Answer 7

Give rise to the gametes
Make it possible for organisms to reproduce
Meiosis and Mitosis

Question 8

What are somatic cells

Answer 8

Give rise to all cell in the body apart from gametes
Cells are differentiated
Mitosis

Question 9

What are the two main phases of cell cycle

Answer 9

S-phase: DNA synthesis

M-phase: Nuclear division, cytoplasmic division

Question 10

What are the four phases of the cell cycle

Answer 10

G1 phase
S-phase
G2 phase
M-phase

Question 11

What is the purpose of gap phases

Answer 11

Allow cell to grow

Monitor internal and external conditions

Question 12

What is the purpose of G1 checkpoint

Answer 12

Makes sure the cell is large enough to enter S-phase

If conditions unfavourable - can enter G0

Question 12

What is the purpose of G1 checkpoint

Answer 12

Makes sure the cell is large enough to enter S-phase

If conditions unfavourable - can enter G0

Question 13

What is the point of G2 checkpoint

Answer 13

Makes sure the cell has been completely replicated
replication errors have been corrected
the cell is large enough the divide

Question 14

How is cell cycle contolled

Answer 14

Fixed amount of time for each event

information from the cell cycle events and external environment (cyclins and CDKs)

Question 15

Characteristics of CDK’s

Answer 15

At the heart of the cell cycle control system
Activity is cyclic as the cell progresses through the cell cycle
Each CDK modifies specific proteins that initiate or regulate events in the cell cycle
Dependant on cyclins for their activity

Question 16

How to cyclins regulate CDK activity

Answer 16

Regulatory proteins bind to CDK resulting in phosphorylation and activation
These proteins are found in varied concentration throughout the cell cycle

Question 17

What does disruption of cyclin activity result in

Answer 17

Cell cycle arrest or uncontrolled proliferation

Question 18

What happens in S-phase

Answer 18

Chromosomes undergo replication
New DNA is synthesised - duplicate constructed
Chromosome only visible during the division

Question 19

What happens in prophase

Answer 19

Chromosomes condense and are visible and threadlike
Nuclear membrane and nucleoli disappear
Mitotic spindle forms
Centrosomes move away from each other

Question 20

What happens in prometaphase

Answer 20

Nuclear envelop fragments
Microtubules attach to the chromatids at the kinetochores
Other microtubules interact connecting from different poles

Question 21

What happens in metaphase

Answer 21

Centrosomes are now at opposite poles
Chromosomes are lined up on the metaphase plate
all chromosome are attached to each of the poles

Question 22

What happens in anaphase

Answer 22

connection between chromatids at the centromere are cleaved
Chromosomes are pulled to opposite poles as cell elongates
Anaphase ends when the chromosomes reach the poles

Question 23

What happens in anaphase

Answer 23

connection between chromatids at the centromere are cleaved
Chromosomes are pulled to opposite poles as cell elongates
Anaphase ends when the chromosomes reach the poles

Question 24

What happens in telophase

Answer 24

Nuclear envelope forms
Nucleolus appears
Cytoplasm divides
Chromosomes become less dense

Question 25

What occurs in cytokinesis

Answer 25

Contractile ring begins to assemble
Actin and myosin filament
Divide the cytoplasm in two
Creates two daughter cells

Question 26

What is cell proliferation involved in

Answer 26

Aging, regenerative medicine and oncogensis

Question 27

Why is cell proliferation important

Answer 27

critical to regulation of development

Maintaining size, morphology and function of organs