Biochem 76

Question 1

CDK (cyclin-dependent kinases) are:

Answer 1

constitutive and inactive

Question 2

Cyclins are what? (2)

Answer 2

1) regulatory proteins that control cell cycle events

2) activate CDK

Question 3

Which tumor suppressors normally inhibit G1-S progression? (2)

Answer 3

1) p53

2) Hypophosphorylated Rb

Question 4

Mutations in p53 and Rb result in what syndrome?

Answer 4

Li-Fraumeni

Question 5

Permanent cell types remain in what state?

Answer 5

G0

Question 6

What are examples of permanent cell types? (4)

Answer 6

1) Neurons
2) Cardiac muscle
3) Skeletal muscle
4) RBCs

Question 7

Permanent cell types regenerate from which cells?

Answer 7

Stem cells

Question 8

Stable (quiescent) cells display what cell cycle characteristic? Example?

Answer 8

Enter G1 from G0 when stimulated

1) Hepatocytes
2) Lymphocytes

Question 9

Describe labile cells? (3)

Answer 9

1) Never enter G0.
2) Divide rapidly with a short G1
3) Most affected by chemotherapy

Question 10

Examples of Labile cells?

Answer 10

1) Bone marrow
2) Gut epithelium
3) Skin
4) Hair follicles
5) Germ cells

Question 11

What occurs in Nissl Bodies?

Answer 11

synthesize peptide neurotransmitters for secretion

Question 12

Which cell types are rich in RER? (2)

Answer 12

1) Mucus secreting goblet cells of the small intestine

2) antibody-secreting plasma cells

Question 13

Free ribosomes are the sites of what?

Answer 13

Synthesis of cytosolic and organellar proteins

Question 14

Which cells are rich in SER?

Answer 14

1) Liver hepatocytes
2) Steroid hormone producing cells of Adrenal cortex
3) Gonads