Genetics: Rep/Transcript/Translate/Modification Flashcards Preview

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Flashcards in Genetics: Rep/Transcript/Translate/Modification Deck (77)
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1

Direction of DNA Polymerases (2)

Read in 3'-5' and synthesize in 5'-3'

2

DNA Gyrase

Topoisomerase II in proks that acts to relieve superhelical tension and decatenate replicated chromosomes

3

Mitotic Clock

In normal human somatic cells, linear chromosomes shorten w/ each cell division and once they reach a critical length they cannot divide and enter senesence

4

Telomerase (2)

Enzyme used to lengthen telomeres by repeated addition of ssDNA to 3' end. Causes immortalization and can be reactivated by cancer

5

2.5 Processes of DNA Replication Initiation

Origin of Replication - DNA sequence/recognizing protein
DNA strand separation - Helicase loader, helicase, single-strand binding proteins

6

4 Steps of DNA Replication Strand Elongation

Primer
Elongation
Primer excision
Gap filling

7

DNA Ligase

Catalyzes 3'-5' phosphodiester bond formation bw original DNA strand and gap-filled DNA strand

8

Prok/Euk Difference in Origin DNA Sequence

Proks have discreet, clear AT-rich regions
Euks have broad, less clear AT-rich regions

9

Prok/Euk Difference in DNA Polymerization

Proks have 3 different DNA pols w/ different functions
Euks have 1 DNA pol with many subunits

10

Prok/Euk difference in Primer Excision

Proks: Pol I does it
Euks: Have ribonuclease

11

Deamination

DNA damage in which exocyclic amino groups in pyrimidine rings (including those in purines) undergo spontaneous hydrolysis, generating a carbonyl and release of ammonia

12

Thymine Dimers

UV energy causes covalent cross linking bw adjacent thymines on same DNA strand

13

Psoralen (2)

Intercalates into dsDNA and upon UV irradation forms covalent links w thymine. Has two reactive sites so can crosslink thymines from opposite strands

14

Base Excision Repair 2 Repairs

1. Deamination of adenine, guanine, and cytosine
2. Losses of single bases

15

Nucleotide Excision Repair 2 Repairs

1. Intrastrand thymine dimers
2. Mismatches from errors in proofreading

16

DNA Repair of Double Strand Breaks (2)

Nonhomologous end joining (easy) and homologous recombination (complex)

17

4 Necessary Components for PCR

Template DNA
Primer DNA
dNTPs
Taq (temperature resistant) polymerase

18

Prokaryotic RNA Processing

tRNA and rRNA have modifications, mRNA has few little modification

19

Jobs of 3 Euk RNAPs

I: 18S, 5.8S, and 28S rRNA
II: mRNA precursors
III: tRNA and 5S rRNA

20

3 Euk Response Elements for RNA Transcription

Core promoter elements - TATA box at -25
Proximal Promoter Elements - CAAT box at -75
Distal Regulatory Sequences - enhancers or silences

21

3 Characteristics of Euk RNA Transcription

Nuclear membrane
Complex response elements
Complex mRNA processing

22

Euk RNA Transcription Initiation

GTFs bind TATA which assemble pre-initation complex/recruit RNA Pol

23

Serine Phosphorylation and Regulation of RNAPII (4)

S2/S5: PIC assembly
S2/S5P: Promoter clearance
S2P/S5: downstream elongation
S2/S5: termination, disengagement

24

Euk RNA Transcription Termination

Poly-A termination sequence transcribed and endonucleases cleave to terminate transcription

25

Lariats (2)

What introns are cast off as, formed by 2 transesterification reactions

26

Rifampin Mech and Use

Binds bacterial RNAP adjacent to P active site and prevents elongation of RNA
Used for TB treatment

27

Actinomycin D Mech and Use

Inhibits euk RNA transcription by binding DNA template at PIC
First antibiotic for cancer

28

Difference in P/E Promoters

Proks are -10/-35
Euks have CREs (-25), PREs (-75), and DREs

29

Difference in P/E RNA Polymerases

Prok: core-RNAP does everything
Euk: 3 RNAPs

30

Difference in P/E Promoter Recognition

Prok: sigma factor
Euk: GTFs and Mediator