42. CELL DIVISION

Question 1

1. What is Cell Division?

Answer 1

• it is the reproduction of cells
• this is what allows for the continuation of life

Question 2

2. What is the role of Cell Division in Unicellular Organisms?

Answer 2

• the reproduction of cells through cell division
• EG: Binary Fission

Question 3

3. What is the role of Cell Division in Multicellular Organisms?

Answer 3

• growth
• development from a fertilised cell
• repair of the damaged tissue

Question 4

4. What happens when an amoeba divides into 2 cells?

Answer 4

• amoeba is a single celled eukaryote
• it divides into two new cells
• each cell will be a individual organism

Question 5

5. What are the 2 Main Processes of Cell Division?

Answer 5

1. Mitosis
2. Meiosis

Question 6

6. What is Mitosis?

Answer 6

• it is the production of Somatic Cells
• these are diploid cells

Question 7

7. What is Meiosis?

Answer 7

• this is the production of gametes
• these are haploid cells
• they are the sex cells

Question 8

8. Finish the sentence:
   Mitosis _______ the number of cells

Answer 8

• conserves

Question 9

9. What does Mitosis produce?

Answer 9

• 2 genetically identical cells
• these cells are also genetically identical to the
  parental cell

Question 10

10. What does Meiosis do to the Chromosome Number?

Answer 10

• it reduces the chromosome number
• it reduces it to a half

Question 11

11. Where does Meiosis produce the Gametes?

Answer 11

• in the gonads
• these are the ovaries and the testes

Question 12

12. What is Fertilisation?

Answer 12

• this is when a male and a female gamete fuse - male and female gametes are Haploid cells
• their fusion produces a zygote
• this zygote has a complete set of
  chromosomes
• these chromosomes are diploid cells

Question 13

13. What is Cancer?

Answer 13

• it is the abnormal growth of cells
• these cells tend to replicate and proliferate in
  an uncontrolled way
• they can also metastasise and spread in some
  cases
• it is an unregulated cell production and
  division

Question 14

14. What do cells do to their Genetic Material before they undergo Mitosis?

Answer 14

• they duplicate their genetic material
• each daughter cell receives an exact copy of
  the genetic material (DNA)

Question 15

15. How would we describe the Cell Cycle in a basic way?

Answer 15

• it is a functional process a cell goes through
• it does this until it is divided into 2 identical
  daughter cells

Question 16

16. What are the 4 main stages of the Cell Cycle?

Answer 16

1. G1 (Gap 1)
2. S Phase (Synthesis)
3. G2 (Gap 2)
4. M Phase (Mitotic Phase)

Question 17

17. What happens during the G1 phase?

Answer 17

• the preparation of the cell for DNA replication

Question 18

18. What happens during the S Phase?

Answer 18

• DNA replication

Question 19

19. What happens during the G2 phase?

Answer 19

• the preparation for cell division

Question 20

20. What happens during the M Phase?

Answer 20

• cell division
• mitosis

Question 21

21. What are the two main stages of the Cell Cycle?

Answer 21

1. Interphase
2. Mitotic Phase

Question 22

22. What phases does the Interphase stage consist of?

Answer 22

• G1 Phase
• S Phase
• G2 Phase

NB:
Interphase is the longer stage of the Cell Cycle

Question 23

23. What phases does the Mitotic Stage consist of?

Answer 23

• Mitosis
  (Division of the nucleus)
• Cytokinesis
  (Division of the Cytoplasm)

NB:
the Mitotic Stage is the shorter stage of the Cell Cycle

Question 24

24. What phases does the M Phase consist of?

Answer 24

• Prophase
• Prometaphase
• Metaphase
• Anaphase
• Telophase

NB:
the M Phase starts with the end of the division of the nucleus

Question 25

25. Is Cytokinesis a part of Mitosis?

Answer 25

• no
• it is the process that follows after Mitosis

Question 26

26. What is the G0 Phase?

Answer 26

• this is the resting phase where non-dividing
  cells rest
• this is known as the Quiescent phase

Question 27

27. What is the the Ligand of EGFR responsible for?

Answer 27

• it stimulates the pathway for cell division

Question 28

28. When do differentiated cells enter from G0 to G1?

Answer 28

• after the action of the Growth Factors

Question 29

29. When do cells exit G1 and enter G0?

Answer 29

• they do this when they need to differentiate

Question 30

30. What two factors control Cell cycles?

Answer 30

1. Extracellular Signals
   (Such as the presence of Growth Factors)
2. Intracellular Signals
   (Such as cell size)
   (A cell must divide if it becomes too big)

Question 31

31. What are Post Mitotic Cells?

Answer 31

• they are terminally differentiated cells
• they have lost their ability to replicate
• they are permanently arrested at the G0
  phase

Question 32

32. What are 3 examples of Post-Mitotic cells?

Answer 32

• Neural cells
• Cardiac Muscle Cells
  (Issues with these cells can cause heart attacks
  and failures)
• Red Blood Cells
  (they have no nucleus= they cannot replicate)

Question 33

33. What are Cells that divide upon Appropriate Stimulation?

Answer 33

• they are the cells that divide based on a signal - these cells only divide when they need to

Question 34

34. What is an example of a Cell that divides upon appropriate Stimulation?

Answer 34

• most of the cells in our body
• they only divide upon stimulation by the
  growth factors
• they can also divide based on other signals

Question 35

35. What is an example of a cell in the human body that divides upon stimulation?

Answer 35

• lymphocytes
• they divide upon antigenic presentation
• these are foreign antigens

Question 36

36. What are Cells with high Mitotic Activity?

Answer 36

• these are the cells that are dividing all the
  time
• these cells are the most susceptible to cancer
  treatment

Question 37

37. What are three examples of Cells with High Mitotic Activity?

Answer 37

• germ cells
• stem cells
• epithelial cells
  (these are often damaged and forced to
  regenerate)
  (this is because they are found lining bodily
  vessels and surfaces)

Question 38

38. What did Traditional Chemotherapy used to block?

Answer 38

• cell division
• this led to many side effects