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Flashcards in Biochem - Cellular Deck (140)
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1

A patient presents with blue sclera that results in an inability to form procollagen from pro-α chains. What disease does he have?

Osteogenesis imperfecta

2

List the four main phases of mitosis in order.

Prophase, metaphase, anaphase, and telophase

3

When does mitosis occur in the cell cycle?

Mitosis occurs after G2 and before G1 in the cell cycle

4

When does DNA synthesis occur in the cell cycle?

After G1 and before G2 in the cell cycle

5

In this image, what two tumor suppressor genes normally inhibit G1-to-S progression?

Rb and p53

6

During which phase of the cell cycle can a cell enter G0?

G1

7

Which phase of the cell cycle is usually the shortest?

Mitosis

8

Which phase of the cell cycle is shortened in rapidly dividing cells?

G1

9

What is the relationship between cyclin-dependent kinases and cyclins?

Cyclins are regulatory proteins that are translated and activate cyclin-dependent kinases at appropriate times in the cell cycle

10

Permanent and stable cells are typically in which phase of the cell cycle?

G0

11

Rb and p53 tumor suppressors prevent which transition in the cell cycle?

Transition from G1 to S phase; defective cells are not allowed to undergo DNA synthesis

12

_____ (Permanent/stable/labile) cells remain in G0 and regenerate from stem cells.

Permanent

13

_____ (Permanent/stable/labile) cells enter G1 from G0 when stimulated.

Stable

14

_____ (Permanent/stable/labile) cells never go to G0 and divide rapidly with a short G1.

Labile

15

Neurons, skeletal and cardiac muscle, and red blood cells are examples of _____ (permanent/stable/labile) cells.

Permanent

16

Hepatocytes and lymphocytes are examples of _____ (permanent/stable/labile) cells .

Stable

17

Name four examples of labile cells

Labile cells (bone marrow, gut epithelium, skin, and hair follicles)

18

What happens to cell cycling when there is a mutation in a tumor suppressor such as Rb or p53?

There is unrestrained growth in the cell, and thus an increased likelihood to develop a malignancy

19

List the three components of interphase.

G1, S phase, and G2

20

What are the main functions of the rough endoplasmic reticulum?

The synthesis of secretory (exported) proteins and the addition of N-linked oligosaccharides to proteins

21

Name two types of cells that are rich in rough endoplasmic reticulum.

Goblet cells (secrete mucus) and plasma cells (secrete antibodies)

22

What is the histologic term for rough endoplasmic reticulum in neurons? What substances are synthesized there?

Nissl bodies, which are the site of enzyme (such as ChAT) and neuropeptide synthesis

23

_____ (Free/Attached) ribosomes synthesize cytosolic and organellar proteins, whereas _____ (free/attached) ribosomes synthesize secretory proteins.

Free; attached

24

List two functions of the smooth endoplasmic reticulum.

Steroid synthesis and the detoxification of drugs and poisons

25

Give two examples of cells that are rich in smooth endoplasmic reticulum.

Liver hepatocytes and steroid-hormone-producing cells of the adrenal cortex

26

The Golgi apparatus functions as the distribution center for what?

Synthesized proteins and lipids

27

List three places to which the Golgi apparatus sends proteins and lipids.

The plasma membrane, lysosomes, and secretory vesicles

28

Clathrin is a protein that transports vesicles from the trans face of the Golgi apparatus to where?

Clathrin directs from trans-golgi to lysosomes and from plasma membrane to endosome

29

What type of protein-bound saccharides is modified in the Golgi apparatus?

N-oligosaccharides (on asparagine)

30

In patients with I-cell disease, the failure to add mannose-6-phosphate to proteins in the Golgi apparatus leads to what deficit?

There is no signal that targets lysosomal enzymes to the lysosome, resulting in exocytosis of the enzymes