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Flashcards in Biochem miscellaneous Deck (123)
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1

exceptions to degeneracy of genetic code

methionine + tryptophan (each encoded by only 1 codon)

2

codon for methionine

AUG

3

codon for tryptophan

UGG

4

nucleotides methylated in replication

cytosine + adenine

5

how is uracil derived?

deamination of cytosine

6

what makes thymine unique?

Has a methyl grow.

7

when does NER occur?

G1

8

sequence of events in base excision repair

glycosylase removes altered base and creates AP site --> AP endonuclease cleaves 5' end --> lyase cleaves 3' end --> pol fills gap --> ligase seals it

9

significance of N-formylmethionine (fMET)

- initiates protein synthesis in bacteria.
- Nucleic acid coded by start codon.
- Stimulates neutrophil chemotaxis.

10

polyadenylation signal

AAUAAA

11

describe mRNA quality control

Occurs at cytoplasmic processing bodies (P-bodies), which contain exonucleases, decapping enzymes, and microRNAs. mRNAs may be stored in P-bodies for future translation.

12

what initiates protein synthesis?

GTP hydrolysis

13

describe trimming

removal of N- or C-terminal propeptides from zymogen to generate mature protein (eg trypsinogen --> trypsin).

14

labile cell types

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

15

stable cell types

hepatocytes + lymphocytes

16

golgi functions

1) protein distribution
2) modifies N-oligosaccharides on asparagine
3) adds O-oligosaccharides on serine and threonine.
4) adds mannose-6-phosphate

17

Signal recognition particle (SRP)

abundant, cytosolic ribonucleoprotein that traffics proteins from the ribosome to the RER. Absent or dysfunctional SRP leads to protein accumulation in the cytosol.

18

examples of intermediate filaments

vimentin + desmin + cytokeratin + lamins + glial fibrillary acid proteins (GFAP) + neurofilaments

19

Vimentin

stains for mesenchymal tissue (eg., fibroblasts, endothelial cells, macrophages).

20

microvilli

microfilament

21

cilia structure

9+2 arrangement of microtubule doublets. Base (basal body) consists of 9 microtubule triplets with no central microtubules.

22

axonemal dynein

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

23

frequency of an x-linked recessive disease in males

q

24

frequency of an x-linked recessive disease in females

q squared

25

what is wrong in prader willi vs. angelmans

codebook

26

2 rules for inheritance chart

1) look for recessive/dominance
2) who's passing it down (only moms --> mitochondrial inheritance)

27

gene mutated in myotonic dystrophy type 1

DMPK

28

myotonia

Delayed relaxation of skeletal muscles after voluntary contraction or electrical stimulation. Feature of myotonic dystrophy.

29

medical word for night blindness

nyctalopia

30

medical word for dry, scaly skin

xerosis cutis