DNA replication, transcription, translation Flashcards Preview

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Flashcards in DNA replication, transcription, translation Deck (106)
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1

Nucleoside

pentose+base

2

Nukleotide

phosphate+pentose+base

3

Nucleic acid

DNA: sugar phosphate backbone and bases

4

Bond bw. bases

Hydrogen bonds (2 bw. A&T, 3 bw. G&C)

5

End of the strand

-3´end of the strand: free 3-OH-gr. of D-ribose
-5´end of the strand: free 5-P-gr.

6

Bond be. sugar and P

Esterbond

7

Deoxyribonucleic acid

DNA. Long polymer of nucleotides as units, w. a backbone of sugar and phosphate.

8

What part of DNA encodes info.?

Sequence of the 4 bases

9

What is transcription?

Reading genetic information using genetic code, by copying stretches of DNA into RNA.

10

What is translation?

Gene expression. The process where mRNA is read and translated into a string of aa.

11

What is DNA replication?

duplication of chromosomes before the cells divide

12

Within chromosomes?

chromatin proteins such as histones

13

Watson-Crick model

conformation of double helix – tertiary structure

14

Chromosomes in prokaryotes

single circular chromosomal DNA

15

Plasmid

small circular extrachromosomal DNA

16

Chromosomes in eukaryotes

many nuclear chromosomes (extrachromosomal DNA: in mitochondria)

17

Types of proteins in chromosome

histone (alkaline proteins) and non-histone(regulatory and enzyme proteins)

18

Histone proteins

core 2x (H2A, H2B, H3, H4) and (H1) to stabilize the core histone octamer

19

Nucleosome

basic unit of eukaryotic DNA. Regularly repeating unit of chromatin

20

Primary structure of DNA

sequence (order and nr.) of nucleotides

21

Secondary structure of DNA

base-pairing (H-bonding bw. bases) and the double helix

22

Tertiary structure of DNA

conformation of double helix (B, A, Z conformation)

23

Quaternary structure of DNA

-Prokaryotes: one circular chromosome w. superhelices
-Eukaryotes: nuclear chromosomes, containing regularly repeating units of chromosomal nucleoproteins=nucleosomes.

24

Tm

Define the temp. of which half of the DNA is melted. Melts into ss (single stranded) DNA. Varies on G+C content. If G+C content is more than T+A content, Tm is more. Reverse is A+T rich DNA

25

Conformation (tertiary structure)

-B form: double helix - turn every 0,34 nm -> 10 base pairs
-A form: structure change, in sol. w. higher salt conc. or alcohol added - 2,3 nm->11 base pairs
-Z form: zigzag - 4,6 nm->12 base pairs

26

Type of conformation in prokaryotic DNA

Contains superhelix (double double helix). Positive (overtwisting) or negative (untwisting).

27

Topological isomers

-Coiled DNA

28

Type I topoisomerase

cuts one strand of ds DNA, relax the strand and then reanneal the strands. No ATP is needed.

29

Type II topoisomerase

cuts both strands of DNA helix, results in undwinding, neg. superhelix. ATP is needed. E.g. DNA gyrase (derived from Escherichia coli, bacterial).

30

Topoisomerase inhibitors

antimicrobial or antitumour agents