Cell division, death and specialisation

Question 1

What is the result of mitosis?

Answer 1

2 identical daughter cells from 1 parent cell

Question 2

What is the result of meiosis?

Answer 2

4 genetically diverse cells from one parent cell

Question 3

What is a centromere?

Answer 3

Region of repetitive DNA sequences
Place where sister chromatids attatched

Question 4

What is a kinetochore?

Answer 4

Specialised structure on centromere where spindle fibers attach during mitosis

Question 5

Why is the cell cycle controlled?

Answer 5

To replace injured or dead cells
Must be controlled to regulate cell division

Question 6

What are CDK?

Answer 6

Cyclin-dependent kinase
Form complex with cyclins

Question 7

What do CDKs and cyclins do?

Answer 7

Control and coordinate cell division

Question 8

What are cyclins?

Answer 8

Proteins that have cyclic fluctuating concentrations

Question 9

What is the G1 checkpoint?

Answer 9

Go ahead and start process
Stop: enter non-diving G0 phase

Question 10

What is the G2 checkpoint?

Answer 10

Ensure DNA is replicated

Question 11

What is the M checkpoint?

Answer 11

Sister chromatids are attached to spindle microtubules

Question 12

What are the types of stem cells?

Answer 12

Embryonic
Somatic: undifferentiated cells located in “mature” tissue
Induced pluripotent stem cells

Question 13

What do tumor cells express?

Answer 13

Express the CHEMOKINE RECEPTOR CXCR4

Question 14

What does the bone marrow express?

Answer 14

Naturally high expression of CHEMOKINE CXCL12

Question 15

How do chemokines and chemokine receptor influence tumor cells?

Answer 15

Tumor cells migrate towards high concentrations of CXCL12

Question 16

What are cell junctions?

Answer 16

Specialized regions of plasma membrane that connect cells

Question 17

What are the types of cell junctions?

Answer 17

Desosomes
Tight junctions
Gap junctions

Question 18

Explain tight junctions

Answer 18

Seal cells together
Allow small molecules to move through

Question 19

Explain gap junctions

Answer 19

Mediate passage of chemicals or electrical signals
Have channels to allow passage

Question 20

What is apoptosis?

Answer 20

Programmed cell death

Question 21

Explain the process of apoptosis

Answer 21

Nucleus shrinks
Chromatin condenses
DNA fragments
Cell detaches from neighbors
Cell “round up”
Cell shrinks
Cell fragments burst out
Neighbor cells/macrophages eat fragments

Question 22

What is the intrinsic pathway of apoptosis

Answer 22

Response to internal damage
Controlled by release of cytochrome C from mitochondria

Question 23

What is the extrinsic pathway of apoptosis?

Answer 23

Triggered by immune system
Binds to cell-surface death receptors

Question 24

What is necrosis?

Answer 24

Disruption of membranes

Question 25

What are a few causes of necrosis?

Answer 25

O2 deprivation Infectious agents Chemical agents DNA disruption Nutritional imbalance

Question 26

What are ROS?

Answer 26

Reactive oxygen species By products of normal cellular respiration

Question 27

What are the cell defence mechanisms against oxidative stress?

Answer 27

Antioxidants and enzymes

Question 28

What is ischemia?

Answer 28

Lack of blood supply to organs

Question 29

What is reperfusion?

Answer 29

Tissue damage after blood supply returns after period of O2 lack