CH 14 DNA Structure Flashcards Preview

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Flashcards in CH 14 DNA Structure Deck (39):
1

DNA Helicase

Uses energy from ATP to unwind DNA

2

DNA Ligase

Enzyme that facilitates the joining of DNA Strands together by catalyzing the formation of phosphorites bond

3

Replication fork

Area where the replication of DNA will actually take place

4

Which bases are purines?

A and G

5

Which are pyrimidines?

C and T

6

What are Chargaff’s rules?

A=T
C=T

7

What is the structure of DNA?

Double helix structure.
Proposed by Watson and Crick.

8

What does it mean that the two strands of DNA are complementary?

The strands are polymers of nucleotides and are antiparallel

9

DNA replication is

Semiconservative

10

Where does DNA replication occur in prokaryotes?

Cytoplasm

11

Where does DNA replication occur in eukaryotes?

Nucleus

12

SSBP

Single Stand Binding Proteins.
Coat strands to keep them apart

13

Primase

Short pieces of RNA used to start, without it DNA polymerase can’t start

14

RNA Primer

RNA polymerase makes the primer

15

Leading strand

Synthesized continuously from an initial primer

16

Lagging strand

Synthesized discontinuously with multiple priming events

17

What are telomeres?

Found in the ended of eukaryotic chromosomes. Project the ends of chromosomes from nucleases and maintain the integrity of linear chromosomes

18

The 2 major DNA repair mechanisms

1) Specific repair; Targets a single kind of lesión in DNA and repairs only that damage.

2) Nonspecific; Use a single mechanism to repair multiple kinds of lesions in DNA

19

Photorepair

Specific repair.
For particular damage caused by UV light

20

Thymine dimers

Covalent link of adjacent thymine based in DNA

21

Photolyase

Absorbs light in visible range and uses this energy to cleave thymine dimer

22

Excision repair

Nonspecific repair
Damage region is removed and replaced by DNA Synthesis.

1) Recognition of damage.
2) Removal of damage region.
3) Re-synthesis using the info on the un damage strand as a template

23

Telomerase

Enzyme that helps overcome the shorting

24

DNA Gryrase

Used in replication, link the two strands

25

DNA Polymerase (pol 1)

Acts on lagging strand to remove RNA primera and replace them with DNA

26

DNA Polymerase (pol 2)

Involved in DNA repair process

27

DNA Polymerase (pol 3)

Main replication enzyme

28

RNA Polymerase (primase)

Makes primer.
Short pieces of the RNA

29

DNA Polymerase

Expands primer
Can’t start without RNA Primase

30

DNA Replication requires 3 things

1) Something to copy; Parental DNA molecule.
2) Something to do the copying; Enzymes.
3) Building blocks to make copy; Nucleotide triphosphates

31

DNA Replication phases

1) Initiation; Replication begins
2) Elogation; New strands of DNA are synthesized by DNA polymerase
3) Termination; Replication is terminated.

32

Phosphodiester

Bond between adjacent nucleotides

33

Transformation

Info specifying virulence passed from dead S strain cells into the live R Strain cells.

34

3’-to-5’ exonuclease activity

DNA Polymerase (Pol 1)
DNA Polymerase (pol 2)
DNA Polymerase (pol 3)

35

5’-to-3’ exonuclease

DNA Polymerase (pol 1)

36

DNA polymerase can synthesize only in

One direction

37

Okazaki fragments

From lagging strands

38

Mutagens

Any agent that increases the number of mutations above background level.
(Radiation and chemicals)

39

Meselson-Stahl experiment demonstrates that

DNA replication is semi-conservative