Cell, Apoptosis & Cancer

Question 1

What are the stages of enbryonic development?

Answer 1

1. Fertilization
   - produces a zygote
2. Cleavage
   - cells divide to form a blastula
3. Gastrulation
   - cells move and fold to form layers from which tissues are built
4. Neurulation
   - the formation of a neural tuve from which the nervous system develops
5. Organogenesis
   - Initiation of organ developemtn in the embryo

Question 2

What is apoptosis?

Answer 2

Programmed cell death

Question 3

What is the function of apoptosis?

Answer 3

1. control cell numbers in the normal development and fuctioning of the organism
2. Eliminate cells that threaten the organism’s survival

Question 4

What is the role of apoptosis in embryonic development?

Answer 4

Contibutes to the appropriate formation of various organs and structures.

Question 5

What are the consequences of apoptosis?

Answer 5

Lead to carcinogenesis (cancer) and participates in the pathogenesis (development) of Alzheimer disease, Parkinson disease, or AIDS.

Question 6

What causes apoptosis?

Answer 6

1. Withdrawal of positive signals

2. Receipt of negative signals

Question 7

What is a anti-apoptotic gene?

Answer 7

Anti-apoptotic genes Produce proteins that prevent apoptosis

eg. Bcl-2 gene

Question 8

What is a pro-apoptotic gene?

Answer 8

Pro-apoptotic genes Produce proteins that cause apoptosis

eg. Bax gene

Question 9

How does bax gene kill a cell?

Answer 9

The bax protein is coded by the bax gene
The bax protein binds to permeability pore of the cell’s mitochondria
Increased permeability causes mitochondria to pop and release Cytochrome C
Cytochrome C activate enzymes called caspases that causes cell to burst

Question 10

What causes cancer?

Answer 10

Over expression of anti-apoptotic genes
Under expression of pro-apoptotic genes

leads to uncontrolled cell division

Question 11

What is cancer?

Answer 11

Cells that grow in an uncontrolled manner, spreading throughout the body and interfering with the fuction of normal tissues and organs

Cancer cells are immortal and they do not respond to signals.

Question 12

What is the term for spread of cancer cells?

Answer 12

metastasis

Question 13

what are the effects of mutation of proto-oncogenes to oncogenes?

Answer 13

1. Loss of control of growth
2. Failure of cells to differentiate
3. Prevention of apoptosis

Question 14

What is tumor suppresor genes?

Answer 14

1. Genes that protect cells from cancer

2. Necesarry for apoptosis

Question 15

What happens when tumor suppressor genes mutate?

Answer 15

Cancer :(

Question 16

What are the types of tumour?

Answer 16

1. Malignant

2. Benign

Question 17

What are the three main groups of cancer?

Answer 17

1. Carcinomas
   - Malignancy of epithelial cells (skin, organs, etc.)
2. Sarcomas
   - solid tumors of connective tissues (bone, muscles, etc.)
3. Leukemias, lymphomas
   - Malignancy of blood forming cells and immune cells

Question 18

What is the p53 gene?

Answer 18

If the dna is damaged, p53 gene is expressed, causing the cell cylce to stop and lead to apoptosis

If p53 is damaged, cell cycle continues, and can lead to cancer

abnormal p53 causes 50-55% of human tumors