Cells- Topic 5- cell cycle

Question 1

describe the stages in the cell cycle

Answer 1

G1: Growth of cell and organelle replication.
S: DNA replication occurs.
G2: Cell completes growing.
M: Mitosis.
C: Cytokinesis.

Question 2

what is the first checkpoint in the cell cycle?

Answer 2

Checkpoint 1: Before G1 ends, Checkpoint 1 checks for DNA damage (mutations), enough nutrients, enough growth factors, and appropriate cell size.

Question 3

what is the second checkpoint in the cell cycle?

Answer 3

Checkpoint 2: Before G2 ends, Checkpoint 2 checks chromosomes replicated properly and no mutations.

Question 4

what is the third checkpoint in the cell cycle?

Answer 4

Checkpoint 3: Before metaphase ends, Checkpoint 3 checks if chromosomes are attached to spindle via centromere.

Question 5

explain how hormones may regulate cell division

Answer 5

Cyclins increase strongly before division and is linked to promoting mitosis. Cyclin binds to CDK to form MPF which, in high concentrations, stimulates the onset of mitosis. Eventually breaks down to allow for competition.

Question 6

what is a carcinogen?

Answer 6

Carcinogens are physical or chemical factors that increase the rate of mutations in cells. These mutations may cause uncontrolled cell division (cancer), especially if the tumour suppressor gene or oncogene have been mutated. Examples of carcinogens include:
1. Increased temperature.
2. Viruses.
3. Ionising radiation.
4. Mutagenic chemicals.

Question 7

Describe techniques of cell culture and discuss the applications and limitations of contemporary examples.

Answer 7

cell culturing is used to increase the number of cells
1. Tissue containing the cells is dissected.
2. Cells are isolated.
3. Cells placed in culture medium.
4. Cells divide via mitosis for use.

Question 8

what does the medium in cell culturing require?

Answer 8

1. Glucose: for aerobic respiration and an energy source.
2. Oxygen: for aerobic respiration.
3. Antibiotics: to ensure no growth of bacteria.
4. Moist environment: so, cells don’t dry out.
5. Water: for dissolved solutes.
6. Amino acids: for protein synthesis.
7. Nucleotides: for DNA replication.

Question 9

what are the environmental requirements of cell culturing?

Answer 9

1. Suitable temperature.
2. Optimal pH.

Question 10

what is an example of the use of cell culturing?

Answer 10

An example of Cell Culture is bacterial culturing for antibiotic testing. This is beneficial to society as we can use findings to cure bacterial infections and reduce deaths. Applications of Cell Culture: artificial skin, insulin production, IVF. Limitations: cost, availability, time to produce.