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Flashcards in cellular Deck (112):
1

regulators of cell cycle

cyclins, CDKs, tumor suppressors

2

shortest phase of cell cycle

MITOSIS:
prophase.
metaphase.
anaphase.
telophase.

3

cyclins

regulatory proteins.
phase-specific.
ACTIVATE CDKs.

4

CDKs (cyclin-dependent kinases)

constitutive and inactive.

5

tumor suppressors

Rb and p53.
inhibit G1 to S progression.

*mutations = unrestrained growth

6

permanent cells

remain in G0.
regenerate from STEM CELLS.

neurons.
skeletal m.
cardiac.
RBCs.

7

stable (quiescent) cells

enter G1 from G0 when stimulated.

hepatocytes.
lymphocytes.

8

labile cells

never go to G0.
rapidly divide with short G1.

BM.
gut epith.
skin.
hair follicles.

9

RER

site of synth of secretory (EXPORTED) proteins.

N-linked oligosaccharide addition to many proteins.

10

which cells are rich in RER?

mucus-secreting GOBLET CELLS of small intestine.

Ab-secreting PLASMA CELLS.

11

Nissl bodies

RER of neurons-
synthesize enzs and peptide NTs.

12

free ribosomes

unattached to any memb.
synth of cytosolic and organellar prots.

13

SER

1. steroid synth (hormones).
2. detox of drugs, poisons.
3. carb metabolism.

14

which cells are rich in SER?

liver hepatocytes.
steroid-producing cells of adrenal cortex.

15

peroxisome

catabolism of VLCFA (very long chain fatty acids) and amino acids

16

proteasome

barrel-shaped protein complex.
degrades damaged/unnecessary proteins tagged with UBIQUITIN for destruction.

17

Golgi apparatus

distribution center for proteins and lipids-
from ER to plasma memb and vesicles.

18

how does Golgi change asparagine?

modifies N-oligosaccharides

19

how does Golgi change serine and threonine?

adds O-oligosaccharides

20

mannose 6-phosphate

Golgi adds mannose 6-phosphate to proteins for trafficking to LYSOSOMES

21

endosome

sorting center for material from outside cell or from Golgi - sends it to lysosomes for destruction or back to memb/Golgi for further use

22

vesicular trafficking prot: COP I

retrograde.
Golgi to ER.

23

vesicular trafficking prot: COP II

anterograde.
RER to cis-Golgi.

24

vesicular trafficking prot: clathrin

trans-Golgi
to
lysosomes, memb
to endosomes (receptor-mediated endocytosis)

25

I cell disease

(inclusion cell disease)
inherited lysosomal storage disorder.

fail to add mannose 6-phosphate tag to lysosome proteins = enzs secreted outside of cell instead of being targeted to lysosomes.

26

features of I cell disease

coarse facial features.
CLOUDED corneas.
restricted joint mvmt.
high plasma levels of lysosomal enzymes.

*often fatal in childhood

27

microtubule

cylindrical structure.
helical array of polymerized dimers (ALPHA and BETA TUBULIN) - each dimer has 2 GTP.

28

microtubules are incorporated into...?

flagella (dynein).
cilia (dynein).
mitotic spindles.
axoplasmic transport in neurons*

29

molecular motor proteins

transport cellular cargo (organelles, intracellular vesicles) toward opposite ends of microtubule tracks.

use ATP.

30

dynein

Retrograde to microtubule (+ to -)

31

kinesin

Anterograde to microtubule (- to +)

32

drugs that act on microtubules

Mebendazole, thiabendazole.
Colchicine.
Griseofulvin.
Vincristine, vinblastine.
Paclitaxel.

"Microtubules Can Grow Very Progressively"

33

Chediak-Higashi syndrome

microtubule polymerization defect =
decreased fusion of phagosomes and lysosomes.

results in recurrent pyogenic infxs, partial albinism, peripheral neuropathy.

34

cilia

9+2 arrangement of microtubules.
contains dynein.

35

dynein in cilia

axonemal dynein.
ATPase links peripheral 9 doublets and causes bending of cilium by differential sliding of doublets.

36

Kartagener's syndrome

IMMOTILE CILIA due to dynein arm defect.

results in male and female infertility (sperm immotile), bronchiectasis, recurrent sinusitis.
assoc. with situs inversus.

37

cytoskeleton: actin, myosin

microvilli.
muscle contraction.
cytokinesis.
adherens junctions (intermediate).

38

cytoskeleton: microtubules

movement:

cilia.
flagella.
mitotic spindle.
axonal trafficking.
centrioles.

39

cytoskeleton: intermediate filaments

structure:

vimentin.
desmin.
cytokeratin.
lamins.
GFAP.
neurofilaments.

40

plasma membrane

asymm lipid bilayer:
cholesterol 50%.
phospholipids 50%.
sphingolipids.
glycolipids.
proteins.

41

high chol or long saturated FA content of plasma memb means....?

increased melting temp.
decreased fluidity.

42

vimentin

conn tissue

43

desmin

muscle

44

cytokeratin

epith cells

45

GFAP

neuroGlial cells (astrocytes)

46

neurofilaments

neurons

47

Na-K ATPase

ATP site on cytoplasmic membrane:
1 ATP consumed.
3 Na out.
2 K in.

48

ouabain

inhibits Na-K ATPase by binding to K site

49

cardiac glycosides (digoxin, digitoxin)

directly inhibit Na-K ATPase
= indirect inhibition of Na/Ca exchange
(increase intracellular Ca = increase cardiac contractility)

50

most abundant protein in human body?

collagen

51

collagen function

organizes and strengthens ECM

52

type I collagen

90%.
bone
skin
tendon
dentin
fascia
cornea
late wound repair (scars)

53

type I collagen defect in...

osteogenesis imperfecta

54

type II collagen

cartilage (including hyaline)
vitreous body
nucleus pulposus

55

type III collagen

AKA reticulin.
skin
blood vessels
lungs
intestine
RES
uterus
fetal tissue
granulation tissue

56

type III collagen defect in...

Ehlers-Danlos

57

type IV collagen

basement memb
or basal lamina

58

type IV collagen defect in...

Alport syndrome

59

collagen formation step 1: synthesis

in RER:
translate collagen alpha chains (preprocollagen).

usually GLY-X-Y polypeptide where
X and Y are proline and lysine.

60

collagen formation step 2: hydroxylation

in RER:
hydroxylate specific proline and lysine residues.

*REQUIRES VIT C*

61

collagen formation step 3: glycosylation

in RER:
glycosylate pro-alpha-chain hydroxylysine residues.

form PROCOLLAGEN via hydrogen and disulfide bonds (TRIPLE HELIX of 3 pro-alpha-chains)

62

collagen formation step 4: exocytosis

procollagen triple helix exocytosed into extracellular space

63

collagen formation step 5: proteolytic processing

outside fibroblast:
cleave terminal regions of procollagen to transform into insoluble TROPOCOLLAGEN

64

collagen formation step 6: cross-linking

outside fibroblast:
reinforce numerous tropocollagen molecules with covalent lysine-hydroxylysine cross-linkage by LYSYL OXIDASE to make COLLAGEN FIBRILS

65

what step in collagen formation does scurvy affect?

vit C deficiency --- affects hydroxylation of proline and lysine residues

66

osteogenesis imperfecta

genetic bone disorder (BRITTLE BONE) caused by various gene defects.

most commonly auto dom with abnormal collagen type I.

67

features of osteogenesis imperfecta

1. multiple fractures with minimal trauma.
2. BLUE SCLERA due to translucency of conn tissue over choroid.
3. hearing loss due to abn middle ear bones.
4. dental imperfections due to lack of dentin.

may be confused with child abuse.

68

which form of OI is most fatal?

type II - in utero or neonatal period

69

Ehler-Danlos syndrome

faulty collagen synthesis.

varying inheritance and severity.
auto dom or recessive.

70

what type of collagen is most often affected in Ehler-Danlos syndrome?

type V (classic syndrome)

*6 types total

71

features of Ehler-Danlos syndrome

1. hyperextensible skin.
2. tendency to bleed (easy bruising).
3. hypermobile joints.

may be assoc with joint dislocation, berry aneurysms, organ rupture.

72

Alport syndrome

due to various gene defects leading to abnormal TYPE IV collagen.

most common is X-linked recessive.

73

features of Alport

1. progressive hereditary nephritis
2. deafness
3. ocular disturbances

*type IV important struct component of BM in kidney, ears, eyes

74

elastin

stretchy protein in lungs, large arteries, elastic ligaments, vocal cords, ligamenta flava.

75

ligamenta flava

connect vertebrae: relaxed and stretched conformations

76

elastin is rich in which AA?

proline.
glycine.
lysine.
alanine.
valine.

(nonpolar, non-hydroxylated forms)

77

tropoelastin

elastin precursor.
has fibrillin scaffolding.

78

what breaks down elastin?

elastase

79

what inhibits elastase?

alpha 1 antitrypsin

80

wrinkles of aging

due to reduced collagen and elastin prod.

81

Marfan's syndrome

defect in fibrillin

82

emphysema

can be caused by alpha 1 antitrypsin deficiency resulting in EXCESS ELASTASE activity

83

PCR purpose

amplify desired fragment of DNA

84

PCR steps

1. denaturation.
2. annealing.
3. elongation.

*repeated multiple times for DNA sequence amplification (25-35 cycles)

85

PCR: denaturation

DNA denatured by heating to generate 2 separate strands

86

PCR: annealing

during COOLING, excess premade DNA primers anneal to specific seq on each strand to be amplified

87

PCR: elongation

heat-stable DNA polymerase replicates the DNA seq that follows each primer

88

components needed for PCR

1. DNA template (seq may be unknown).
2. two primers complementary to regions flanking DNA template.
3. heat-stable DNA polymerase that replicates target sequence between primers.
4. deoxynucleiotide triphosphates to build new DNA.

89

agarose gel electrophoresis after PCR

for SIZE separation of PCR products (small molecules travel further).

compared against DNA ladder.

90

Southern blot

DNA

91

Northern blot

RNA

92

Western blot

protein

93

Southwestern blot

DNA-binding proteins (TFs, nucleases, histones)

94

microarray

thousands of nucleic acid sequences arranged in grids on glass or silicon.
DNA/RNA probes are hybridized to chip.
scanner detects relative amts of COMPLEMENTARY BINDING.

95

purpose of microarray

to profile gene expression levels of thousands of genes simultaneously.

can detect SNPs.

96

ELISA

enzyme-linked immunosorbent assay.
rapid immunologic test for AG-AB REACTIVITY.

97

ELISA with test Ag

Ag coupled to color-generating enzyme.
see if imm system recognizes Ag.

(if target is acquired in sample, test soln will have intense color rxn to indicate positive result)

98

ELISA with test Ab

Ab coupled to color-generating enzyme.
see if a certain Ag is present.

(if target is acquired in sample, test soln will have intense color rxn to indicate positive result)

99

Sn and Sp of ELISA

both approach 100% though FP and FN possible

100

FISH

fluorescence in situ hybridization.
fluorescent DNA or RNA probe binds specific gene site of interest on chromosomes.

101

FISH use

for specific localization of genes.
direct visualization of anomalies.

102

no fluorescence in FISH

= gene has been deleted

103

what phase are chromosomes used in karyotyping in?

METAPHASE

104

karyotype can be performed with samples of...?

blood
BM
amn fluid
placental tissue

105

karyotype use

diagnose chromosomal imbalances

106

cloning

prod of recombinant DNA molec that is self-perpetuating

107

what is the first component of cloning?

euk mRNA of interest

108

what enzyme acts on mRNA in cloning?

reverse transcriptase produces cDNA from mRNA

109

what is used to produce a cDNA library?

insert cDNA into bacterial plasmids containing antibiotic resistance genes - those that survive on Abx medium produce library

110

transgenic strategies

to modify gene expression (in mice) by:

1. random insertion of gene into mouse genome (constitutive).

2. targeted insertion or deletion of gene through homologous recombination with mouse gene (conditional).

111

Cre-lox system

can inducibly manipulate genes at specific development points using Abx-controlled promoter

112

RNAi

dsRNA complementary to mRNA sequence of interest - transfected into humans and promotes degradation of target mRNA (thus knocking down gene expression)