Molecular Biochemistry Flashcards Preview

Biochemistry > Molecular Biochemistry > Flashcards

Flashcards in Molecular Biochemistry Deck (39):
1

snRNP function in? Name some antibodies?

Splicesome

i.e. Anti-smith, anti-U1 RNP

2

Anti-smith antibodies is highly specific for?

SLE

3

Splicesomes function to splice?

pre-mRNA

4

Three Stop Codons?

UAG, UGA, UAA

5

DNA polymerase III vs polymerase I

Polymerase III- Elongates leading and lagging strand
Polymerase I-Degrades RNA primer

6

Fluoroquinolones inhibit? What do these class of enzymes do?

Topoisomerase II and IV
Add or Remove supercoils

7

Telomerase activity is increased in?

Cancer cells

8

Frameshift vs nonsense vs missense vs silent. Rank from worst to best

Frameshift, non sense, missense, silent
Worst to Best

9

UGA has a mutation for UAG, what is this mutation called?

Silent=> both produce termination sequences

10

Sickle cell disease (substitution of glutamic acid with valine) is a example of?

missense

11

Nonsense mutations result in early? Why?

Stop Codon

Because the C terminal would be completely removed

12

Duchenne muscular dystrophy is an example of what kind of mutation?

Frameshift mutation

13

Frameshift mutations produce?

Truncated, nonfunctional protein

14

For a lac operon, a repressor protein exists when there is?

No Lactose

15

How does low glucose increase CAP activity?

low glucose=>increased cAMP=>CAP=>transcription

16

How does Nucleotide excision repair work?

endonuclease=>DNA polymerase =>ligase

17

When does Nucleotide excision repair work? When does Base Excision Repair work?

G1
Repairs ONE nucleotide at a time

Base Excision
"spontaneous deamination can happen at any time"

18

How does Base Excision excision repair work?

Spontaneous Deamination (C=>U) => Uracil Glycolyase=>AP endonuclease=>Lyase=>DNA polymerase =>ligase

19

Xeroderma pigmentosum is representative of what disease? is due to? Results in?

Nucleotide excision repair defect

Cause: UV Result: thymine dimers

20

Mismatch Repair defect leads to?

Microsatilite instability

21

MisMatch Repair defect occurs in? How does it work? In what disease do you see it?

Occurs in: G2 (MisMatch has two M's)
Finds: GATC sequence that has not been methylated (It will usually distort the DNA)
Cuts: Enzyme cuts that sequence

Disease: HNPCC

22

Brings together 2 ends of DNA fragments to repair double-stranded breaks? Give 2 examples of them?

Nonhomologous end joining (dsDNA repair)

Ataxia telangiectasia, Fanconi's anemia

23

BRCA genes are what kind of genes?

DNA repair genes

24

Drugs blocking DNA replication and creating Chain termination have modified? Give an example?

3'OH

Acyclovir

25

Promotor mutation leads to? Is the promoter ever transcribed?

Dramatic decrease in level of gene transcription

No

26

rRNA stands for? mRNA stands for? tRNA stands for? Who makes these RNAs

RNA polymerase I-rRNA=rampant=numerous
RNA polymerase II-mRNA=massive
RNA polymerase III-tRNA=tiny

27

α-amanitin inhibits? How does it do this?

RNA polymerase II

How: interferes with translocation of RNA & DNA needed to empty the site for the next round of RNA synthesis

28

Rifampin inhibits? How does it do this?

RNA polymerase in prokaryotes

How: blocking the formation (Ri-Form-pin) of the phosphodiester bond in the RNA backbone=>truncated RNA

29

ß-thalassemia is a result of what abnormal process?

Splicing

30

In Protein Synthesis, ATP is used for? GTP is used for?

Activation (charging)
Going places (Translocation)

31

Zyomyogen=>mature protein; this process is called?

trimming

32

Heat Shock Proteins are called?

Chaperone proteins

33

What activity is increased in cancer cells and decreased in progeria?

Telomerase activity

34

Transition vs Transversion?

Transition: purine to purine
Transversion: purine to pyrimidine (conVERTing to something different)

35

Prokaryote's mRNA start codon? What is its significance?

N-formylmethionine (fMet)

fMet induces neutrophil chemotaxis

36

What clinical findings do you get from alpha amanitin? What is the mechanism? Treatment?

Stops DNA/RNA translocation=>decreases RNA synthesis=>destruction of liver cells

Tx: Silymarin: prevents toxins from entering and allows for regeneration of liver

37

Actinomycin D or Called Dactinomycin inhibits? Difference between Actinomycin and Rifampin? How does it do this?

RNA polymerase

Actinomycin or Dactinomycin (2 words) blocks polymerase in both (2) prokaryotes and eukaryotes while Rifampin only blocks prokaryotes

How: binding DNA at the transcription initiation complex=> prevents elongation of RNA

38

What is the purpose of Capping and Tailing?

Capping: orients mRNA on ribosome
Tailing: gives it a longer half-life

39

Anti-U1 RNP is associated with?

Mixed Connective Tissue Disease