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FIRST AID > Biochem: cellular > Flashcards

Biochem: cellular Flashcards

1
Q

Where do Rb and p53 regulate the cell cycle?

A

G1/S phase checkpoint

therefore, mutations lead to unrestrained cell division

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2
Q

What cell types are permanent? What does permanent mean?

A

remain in G0, regenerate from stem cells

neurones, skeletal and cardiac muscle, RBCs

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3
Q

What cell types are stable? What does stable mean?

A

hepatocytes, lymphocytes

enter G1 from G0 when stimulated

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4
Q

What cell types are labile? What does labile mean?

A

never go to G0, divide rapidly with a short G1

bone marrow, gut epithelium, skin, hair follicles, germ cells

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5
Q

What takes place in the RER?

A

synthesis of secretroy proteins

N-linked oligosaccharide addition to many proteins

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6
Q

What does the SER do?

A

synthesize steroids
detoxify drugs and poisons
(prominant in hepatocytes and steroid hormone producing cells of the adrenal cortex)

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7
Q

What does golgi apparatus do?

A

distribution center for proteins and lipids from the ER to the vesicles and plasma membrain
modified N oligosaccharides on asparagine
adds O oligosaccharides on serine nad threonine
adds mannose 6 phosphate to proeteins for trafficking to lysosomes
glycosylates core proteins to form proglycans
adds sulfate groups to sugar and tyrosine

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8
Q

What is I cell disease caused by?

A

failure of addition of mannose 6 phosphate to lysosome proteins (enzymes sent to outside of cell instead of lysosome)

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9
Q

What are the sx of I cell disease?

A

coarse facial features, clouded corneas, restricted joint movement, high plasma level of lysosomal enzymes
often fatal in childhood

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10
Q

Which protein traffics from golgi to golgi (retro) or golgi to ER?

A

COPI

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11
Q

Which protein traffics from golgi to golgi (antero) or ER to golgi?

A

COPII

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12
Q

What does clathrin do?

A

traffics from trans golgi to lysosomes or from plasma membrane to endosomes

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13
Q

What do peroxisomes do?

A

catabolize very long fatty acids and amino acids

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14
Q

What are the 3 methods of proteolysis?

A
  1. lysosomal degradation
  2. proteasomal degradation
  3. Ca 2+ dependent enzymes
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15
Q

What does the proteasome do?

A

degrade damaged or unnecessary proteins tagged for destruction with ubiquitin

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16
Q

What does dynein do?

A

retrograde microtubule transport (+ —> - )

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17
Q

Waht does kinesin do?

A

anterograde microtubule transport ( - —> + )

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18
Q

What drugs act on microtubules?

A 
mebendazole/thiabendazole
griseofulvin
vincristine/vinblastine
paclitaxel
colchicine
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19
Q

What casues chediak higashi syndrome?

A

mutation in lysosomal trafficking regulator gene LYST, whose product is required for microtubule dependent sorting of endosomal proteins into late multivesicular endosomes

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20
Q

What are the sx of Chediak higashi syndrome?

A

recurrent pyogenic infections, partial albinism, peripheral neuropathy
(lysosomes of phagocytes are neffective and there is abnormal storage of melanin)

21
Q

Where is a 9 + 2 arrangement of microtubules found?

A

cilia

22
Q

What coordinates cilia movement?

A

gap junctions between cells

23
Q

What causes Kartagener’s syndrome? Sx?

A

immotile cilia due to a dynein arm defect

infertility (M & F) , bronchiectasis, recurrent sinusitis, assoc w/situs inversus

24
Q

What cell type is vimentin found in? what type of ccancer does it denote?

A

connective tissue

sarcoma

25
Q

What cell type is desmin found in? What type of cancer does it denote?

A

desmin

myosarcoma

26
Q

What cell type is cytokeratin found in? What type of cancer does it denote?

A

epithelial cells

carcinoma

27
Q

What cell type is GFAP found in? What type of cancer does it denote?

A

neuroglia

astrocytomas/glioblastoma

28
Q

What cell type is neurofilaments found in? What type of cancer does it denote?

A

neurons
neuroblastoma, etc
any primitive neuroectoderm tumor

29
Q

What drugs inhibit the sodium potassium pump?

A

digoxin & ouabain

30
Q

Where is type I collagen found?

A

bone, skin, tendon, late wound repair

31
Q

When is defective type I collagen found?

A

in osteogenesis imperfecta

32
Q

Where is type II collagen found?

A

cartilage, vitreous body, nucleus pulposis

33
Q

Wher is type III collagen found?

A

reticulin-skin, blood vessels, uterus, fetal tissue, granulation tissue

34
Q

When is defectivetype III collagen found?

A

Ehlers-Danlos

35
Q

Where is type IV collagen found?

A

Basement membrane/basal lamina

36
Q

When is defective type IV collagen found?

A

Alport s/o

37
Q

What steps of collagen synthesis occur inside the fibroblast?

A

synthesis (RER)
hydroxylation (ER)
Glycosylation (ER) {osteogenesis imperfecta (problems forming triple helix)}
Exocytosis

38
Q

What steps of collagen synthesis occur outside the fibroblast?

A 
Proteolytic processing (cleavae of terminal regions of procollagen [procollagen ---> tropocollagen])
Cross Linking to make collagen fibrils {ehlers danlos}
39
Q

How is osteogenesis imperfecta inherited?

A

AD (most common)

AR (OI II, perinathal lethal type)

40
Q

What are sx of OI?

A

blue sclera
mutliple fractures
hearing loss
dental imperfections (lack of dentin)

41
Q

What are the sx of Ehlers danlos?

A

2 types
1. hyperextensible skin, hypermobile joints
2. tendency to bleed (vascular ED)
may be associaed with join dislocation, berry aneurysms and organ rupture

42
Q

What causes a keloid?

A

too much collagen in the scar, inject with glucocorticoid to try and help

43
Q

What are the sx of alport s/o? Inheritance?

A

XR
progressive hereditary nephritis and deafness
may get occular disturbances
“can’t see, can’t ee, can’t hear high C”

44
Q

What breaks down elastin? What inhibits elastin breakdown?

A

elastase

a1 antitrypsin

45
Q

Where is elastin commonly found?

A

skin, lungs, large arteries, ligaments, vocal cords, ligamenta flava

46
Q

What AAs is elastin rich in?

A

proline & glycine (non hydroxylated)

47
Q

What serves as scaffolding for elastin? When is it defective?

A

fibrillin

Marfan’s

48
Q

When a patient has panacinar emphysema, young onset, with liver disease, what is likely deficient?

A

a1 Antitrypsin

49
Q

What causes wrinkles?

A

reduced collagen and elastin production

FIRST AID (8 decks)

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