Mitosis, Meiosis and Karyotypes

Question 1

What are the four phases of Interphase?

Answer 1

G1, S, G2, M

Question 2

How are chromosomes counted?

Answer 2

By their centromeres

Question 3

How is cytokinesis different from animal cells and plant cells?

Answer 3

During cytokinesis in animal cells, the cell cleaves. During cytokinesis in plant cells, the cell plate is formed.

Question 4

Why shouldn’t mitosis and cell division be used interchangeably?

Answer 4

Cell division includes interphase and cytokinesis. Mitosis does not.

Question 5

What are the stages of cell division?

Answer 5

Interphase (G1, S, G2, M), Mitosis (Prophase, Metaphase, Anaphase, Telophase) and Cytokinesis.

Question 6

What takes place during G1?

Answer 6

The cell grows.

Question 7

What takes place during the S phase?

Answer 7

DNA replication.

Question 8

What takes place during G2?

Answer 8

The cell prepares for mitosis.

Question 9

What takes place during the M phase?

Answer 9

Cell division

Question 10

How is mitosis different from the M phase?

Answer 10

The M phase includes cytokinesis and mitosis doesn’t.

Question 11

What takes place during prophase?

Answer 11

The nuclear membrane breaks down, chromatin condenses into chromosomes, creation of spindle fibers, centrioles move to opposite poles.

Question 12

What is one way to identify Interphase?

Answer 12

Chromatin, not chromosomes.

Question 13

What takes place during metaphase?

Answer 13

Chromosomes line up single file down the middle of the cell.

Question 14

What takes place during anaphase?

Answer 14

Sister chromosomes are pulled from one another. Each chromosome contains one centromere.

Question 15

What takes place during telophase?

Answer 15

Chromosomes arrive at opposite poles of the cell and unwind to become chromatin. The nuclear membrane starts to reform.

Question 16

What takes place during cytokinesis?

Answer 16

The cell cleaves, the cytoplasm divides, membranes from around the cells.

Question 17

What is the result of mitosis?

Answer 17

Two genetically identical diploid cells

Question 18

What cells undergo mitosis?

Answer 18

Body cells

Question 19

What is G0?

Answer 19

A phase which a cell can sometimes enter after G1 where it is neither dividing nor preparing to divide. Cells may enter G0 because they no longer need to divide or because they lack the nutrients necessary for cell division.

Question 20

What are cell cycle regulators?

Answer 20

Proteins that control the progression of the cell through the cell cycle, they can either stimulate or inhibit the cell cycle.

Question 21

What are proto-oncogenes?

Answer 21

Proteins that stimulate the cell cycle.

Question 22

What are tumor suppressor genes?

Answer 22

Proteins that inhibit the cell cycle

Question 23

What are the most important cell cycle regulators?

Answer 23

Cyclin-dependent kinases.

Question 24

What are kinases?

Answer 24

An enzyme which add a phosphate to other proteins to activate or inhibit their function, a process known as phosphorylation.

Question 25

Are CDKs always present in the cell?

Answer 25

Yes, but they are only activated when they are bound to a cyclin protein.

Question 26

How does the cell know when to progress from G1 to S and G2 to M?

Answer 26

Growth factors bond to receptors on the cell membrane. These growth factors then trigger active transcription factors, which have a positive impact on a gene. This gene will produce more transcription factors, which will have a positive impact on another gene. This gene will release cyclins. These cyclins bond to CDKs, which phosphorylate to release progression enzymes.

Question 27

What are important proteins regulate the cell cycle at the G1 checkpoint?

Answer 27

p53 and and Rb. p53 inhibits the CDK complex if the cell's DNA is damaged, if DNA cannot be repaired, p53 will initiate cell death. Rb prevents the cell from entering S phase in the absence of growth factors.

Question 28

What important proteins regulate the cell cycle at the S checkpoint?

Answer 28

ATM and BRCA1. ATM halts the cell cycle if DNA is damaged and it activates other proteins to repair the DNA. One of these proteins is BRCA1 if DNA is too badly damaged to be repaired, BRCA1 will initiate cell death.

Question 29

What important proteins regulate the cell cycle at the G2 checkpoint?

Answer 29

p53. If DNA is damaged, p53 will halt the cell cycle. If DNA can't be repaired, then p53 will initiate cell death.

Question 30

What important proteins regulate the cell cycle at the M checkpoint?

Answer 30

MAD. When chromosomes are not properly attached to the spindle fibers, MAD proteins inhibit the APC/C, preventing entry into anaphase.