Cell Division and Cell Fate

Question 1

What is the primary difference between mitosis and meiosis?

Answer 1

Mitosis results in 2 diploid daughter cells identical to the parent cell, while meiosis produces 4 haploid daughter cells with half the number of chromosomes.

Question 2

In what type of cells does mitosis occur?

Answer 2

Mitosis occurs in somatic cells, which are typical of ordinary tissue growth.

Question 2

What is the main purpose of meiosis?

Answer 2

The main purpose of meiosis is sexual reproduction, producing gametes and spores.

Question 3

Describe the G1 phase of the cell cycle.

Answer 3

The G1 phase is a growth phase where cells increase in size and duplicate their cellular contents in preparation for proliferation.

Question 4

What occurs during the S phase of the cell cycle?

Answer 4

During the S phase, DNA replication occurs, resulting in the doubling of chromosomes.

Question 5

What happens in the G2 phase?

Answer 5

The G2 phase involves preparation for cell division, with rapid cell growth and protein synthesis.

Question 6

What is the significance of the G0 phase?

Answer 6

The G0 phase is a resting phase where cells that cannot divide enter a state of quiescence or senescence, potentially leading to apoptosis.

Question 7

What are cell cycle checkpoints, and why are they important?

Answer 7

Cell cycle checkpoints are control mechanisms that monitor the progression of the cell cycle, ensuring that conditions are favourable for cell division. They help prevent errors such as DNA damage.

Question 8

What role do cyclins play in the cell cycle?

Answer 8

Cyclins regulate cell cycle progression by activating cyclin-dependent kinases (CDKs), facilitating the transition between different phases of the cell cycle.

Question 9

What happens when CDK and cyclin bind?

Answer 9

When CDK and cyclin bind, it activates the CDK, which phosphorylates target proteins to trigger the next phase of the cell cycle.

Question 10

What is the role of CDK inhibitor proteins (CDKIs)?

Answer 10

CDKIs act as tumour suppressors, inhibiting cell cycle progression and helping prevent uncontrolled cell growth.

Question 11

What is cell differentiation?

Answer 11

Cell differentiation is the process by which a cell becomes specialized to perform a specific function, despite all cells sharing the same genome.

Question 12

What is quiescence in the context of the cell cycle?

Answer 12

Quiescence is a reversible state of inactivity or dormancy during which a cell is not actively dividing but can re-enter the cell cycle when stimulated.

Question 13

How does senescence differ from quiescence?

Answer 13

Senescence is an irreversible cell cycle arrest often due to aging or damage, while quiescence is a reversible state that allows for potential reactivation.

Question 14

What are the intrinsic and extrinsic apoptotic pathways?

Answer 14

The intrinsic pathway is regulated by internal stress signals (e.g., DNA damage), while the extrinsic pathway is triggered by external signals (e.g., receptor activation).

Question 15

What role do caspases play in apoptosis?

Answer 15

Caspases are enzymes that break down proteins and are crucial for executing the apoptotic process, with initiator caspases starting the apoptosis and effector caspases causing cell death.

Question 16

What is apoptosis, and how does it differ from necrosis?

Answer 16

Apoptosis is a controlled form of programmed cell death, whereas necrosis is an uncontrolled, sudden cell death often resulting from injury.

Question 17

Why is apoptosis considered beneficial for an organism?

Answer 17

Apoptosis helps eliminate damaged or unnecessary cells, maintaining tissue homeostasis and preventing diseases such as cancer.

Question 18

What are the two main types of cell division?

Answer 18

The two main types of cell division are mitosis (for somatic cells) and meiosis (for gametes).

Question 19

What are the stages of mitosis?

Answer 19

The stages of mitosis are prophase, metaphase, anaphase, and telophase, followed by cytokinesis.

Question 19

What is the significance of crossing over during meiosis?

Answer 19

Crossing over allows for genetic recombination between homologous chromosomes, increasing genetic diversity in the resulting gametes.

Question 20

How does the cell cycle contribute to tissue repair?

Answer 20

The cell cycle allows for the proliferation of cells, which is essential for replacing damaged or lost cells during tissue repair.

Question 21

What role do growth factors play in cell fate decisions?

Answer 21

Growth factors can influence cell fate by promoting proliferation, differentiation, or survival, depending on the context and signals received.

Question 22

How does apoptosis differ from autophagy?

Answer 22

Apoptosis is a programmed cell death process that eliminates cells without causing inflammation, while autophagy is a cellular recycling process that degrades damaged organelles and proteins.

Question 23

What are terminally differentiated cells?

Answer 23

Terminally differentiated cells are specialized cells that have permanently exited the cell cycle and no longer divide, such as neurons and muscle cells.

Question 24

What factors can trigger quiescence in stem cells?

Answer 24

Factors such as nutrient availability, cellular stress, and signalling from neighbouring cells can induce quiescence in stem cells.

Question 25

What is the purpose of the G1 checkpoint in the cell cycle?

Answer 25

The G1 checkpoint ensures that the cell has sufficient size and resources to proceed with DNA synthesis, preventing damaged or incomplete cells from entering the S phase.

Question 26

What can lead to cellular senescence?

Answer 26

Cellular senescence can be induced by factors such as telomere shortening, oxidative stress, and DNA damage, resulting in a permanent cell cycle arrest.

Question 27

How do intrinsic factors influence cell differentiation?

Answer 27

Intrinsic factors, such as specific transcription factors and epigenetic modifications, guide the process of cell differentiation by activating or silencing certain genes.

Question 28

In what ways can extrinsic signals affect cell fate?

Answer 28

Extrinsic signals, such as hormones and growth factors, can dictate cell fate decisions by activating specific signalling pathways that influence proliferation, differentiation, or apoptosis.

Question 29

What is a stem cell niche, and why is it important?

Answer 29

A stem cell niche is a specialized microenvironment that provides signals and support for stem cells, maintaining their undifferentiated state and regulating their fate.

Question 30

What is the role of p53 in the cell cycle?

Answer 30

p53 is a tumour suppressor protein that monitors DNA damage and can induce cell cycle arrest, allowing for repair or triggering apoptosis if the damage is irreparable.

Question 31

What are the consequences of dysregulated cell division?

Answer 31

Dysregulated cell division can lead to uncontrolled cell growth, resulting in cancer or other diseases characterized by tissue overgrowth or loss of normal function.

Question 32

How does the body utilize apoptosis during development?

Answer 32

During development, apoptosis helps shape organs and tissues by eliminating excess cells, ensuring proper structure and function.

Question 33

What is the difference between programmed cell death and accidental cell death?

Answer 33

Programmed cell death (apoptosis) is a controlled process that occurs under normal physiological conditions, whereas accidental cell death (necrosis) results from injury or stress and often triggers inflammation.