Cell Cycle/mitosis

Question 1

State the 2 forms of cell division and how they differ

Answer 1

Mitosis, produces 2 daughter cells with the same number of chromosomes as parent cell. Meiosis, produces 4 daughter cells, each with half the amount of chromosomes as the parent cell

Question 2

Mitosis full definition

Answer 2

The process of nuclear division where 2 genetically identical daughter nuclei are produced, that are also genetically identical to the parent cell nucleus (same number of chromosomes)

Question 3

Describe the stage of prophase

Answer 3

1) chromosomes condense and become visible, exist as a pair of chromatids joined by centromere 2) centrioles move to opposite poles of cell 3) spindle fibres develop from the centrioles which span cell 4) nucleolus disappears and nuclear envelope breaks down

Question 4

Describe the stage of metaphase

Answer 4

Centrioles reach opposite poles and spindle fibres continue to extend from them, chromosomes line up at the equator of the spindle and the spindle fibres attach to the centromeres

Question 5

Describe the stage of anaphase

Answer 5

Chromatids are separated at the centromere and are pulled to opposite poles by the spindle fibres (energy for this is from mitochondria)

Question 6

What happens in the stage of telophase

Answer 6

Chromosomes arrive at opposite poles and chromosomes decondense/become longer and thinner and become indistinct. Spindle fibres disintegrate, nuclear envelope and nucleoli reform

Question 7

What happens in cytokines

Answer 7

The cytoplasm divides, producing 2 new cells

Question 8

Why is mitosis important

Answer 8

Increase size of tissue during development (growth) replace dead and worn out cells (repair)

Question 9

What is the process of cell division in prokaryotic cells called

Answer 9

Binary fission

Question 10

Describe binary fission

Answer 10

Circular dna molecule replicates and both copies attach to the cell membrane, plasmids also replicate. Cell membrane begins to grow in between the 2 dna molecules, dividing the cytoplasm. A new cell wall forms between the 2 molecules of dna, dividing the cell to produce 2 daughter cells

Question 11

What can viruses not do

Answer 11

Undergo cell division, as they are non living

Question 12

How is viral genetic material replicated

Answer 12

They attach to a host cell, using their attachment proteins. They inject their nucleus acid into the host cell. The host cells metabolic processes start producing the viral components (including nucleic acid, enzymes, structural proteins) these are then assembled into a new viruses

Question 13

Not all cells, within multicellular organisms retain the ability to what?

Answer 13

Divide

Question 14

What are the 3 stages of the cell cycle

Answer 14

interphase (biggest, no division takes place) nuclear division and cytokines

Question 15

How long is the typical mammalian cell cycle and what % is interphase

Answer 15

24 hours,interphase is 90%

Question 16

Eukaryotic cells that do not retain the ability to divide show what

Answer 16

A cell cycle

Question 17

What are the 3 phases of interphase

Answer 17

G1, S and G2

Question 18

What happens in g1 of interphase

Answer 18

Dna in nucleus replicates, cells make rna, enzymes and other proteins

Question 19

What happens in s in interphase

Answer 19

Synthesis of dna

Question 20

What happens in g2 of interphase

Answer 20

Cell continues to increase in mass and size, new dna made is checked for errors

Question 21

What generally happens in interphase

Answer 21

Cell increases in mass and size, synthesis of proteins and replication of dna

Question 22

What is cancer

Answer 22

When there is damage to cells that regulate mitosis, leads to uncontrollable growth and division which makes tumours

Question 23

The difference between malignant and benign tumours

Answer 23

Malignant grow rapidly, less compact and more likely to be life threatening. Benign grow slower, more compact and less life threatening

Question 24

How do drugs like chemotherapy disrupt the cell cycle

Answer 24

By preventing dna from replicating and inhibiting metaphase of mitosis (by interfering with spindle formation)

Question 25

What is the problem with cancer- inhibiting drugs

Answer 25

They disrupt the cell cycle of normal cells, especially those which divide rapidly like hair producing cells because they drugs are more effective against rapidly diving cells (cancer cells)