Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Biol 243 Midterm > 1C > Flashcards

1C Flashcards

1
Q

Models of DNA replication

A
  1. Semi conservative (daughter + complimentary parental)
  2. Conservative (daughter+daughter)
  3. Dispersion (mix daughter and parent)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Meselson and Stahl goal

A
  1. Track parental and newly synthesize DNA over many generation with nitrogen isotope incorporated into DNA molecules through nitrogenous base (15N)

(Line test thing)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Where are nucleotides added for DNA synthesis

A

At 3’-OH so DNA synthesis occurs in 5’->3’ direction…

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

During DNA synthesis what provides E for the formation of new phosphodiester bonds

A

Hydrolysis of pyrophosphate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Properties of DNA poly

A

-synthesize new DNA in 5->3
-read template DNA strand in 3->5
-CANNOT synthesize from scratch needs RNA primer + 3’-OH for synthesis
-single active site catalyze 4 diff rxns (dATP, dCTP, dGTP,dTTP)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Replisome

A

Molecular machine of enzymes that replicates DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Helicase

A

Unwinds double helix by breaking h-bons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Primase

A

Synthesize RNA primer for DNA poly

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Single strand binding protein

A

Stabilise ssDNA before replication… how? Prevent reannealing so strand can serve as template

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

DNA topoisomerase/gyrase

A

Remove super coil that form ahead of replication fork… relieve torque of mainly circular DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

DNA poly III

A

Synthesize DNA by adding nucleotides to new DNA strand

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

DNA poly I

A

Remove RNA primer and fill gaps with DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Sliding clamp

A

Attaches DNA Pol III to DNA template…replication more efficient

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

DNA ligase

A

Join ends of DNA segments by forming phosphodiester bonds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Replication forks??

A

Site of DNA synthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Which strand is synthesized continuously and which is synthesized discontinuously during DNA replication

A
  1. lagging is discontinuous
  2. Leading is continuous (Okazaki fragments)
17
Q

DNA replication enzymes in order

A
  1. DNA helicase-unwind double helix
  2. RNA primase-put RNA primer
  3. Topoisomerase/gyrase- prevent twisting ahead of replication fork during unwinding
    4.DNA pol. III-extend RNA primer
  4. DNA helicase keepsunwinding leading and lagging strand by DNA Pol III
  5. DNA Pol I-removes RNA primer of Okazaki fragments and fill gap with dNTPs (deoxynucleotide triphosphate)
  6. DNA ligase-seal gap with phosphodiester bond
18
Q

DNA replication of bacterial chromosomes

A
  1. Initiation: unwind and separate 2 template DNA strands at oriC (origin of replication site)
    2.elongation: synthesis of 2 new DNA strands from template strands by DNA poly (simultaneous)
  2. Termination: DNA replication stop at termination site (circular) or at end of chromosome (linear)
19
Q

DNA replication of eukaryotic chromosome

A

-linear chromosome
-Multiple origin
-replication in opp. Direction (away from origin)
-end of linear chromosome has problem replicating

20
Q

PCR

A

Polymerase chain rxn (DNA replication and amplification in test tube)

21
Q

Issue replicating ends of linear chromosomes (end of replication probem)

A

-need RNA primer, why? Intimate new DNA synthesis so 3’end of linear chromosome replication is complicated
-no DNA poly can fill gap at chromosomal end=> additive loss at end
-gene at end of chromosome can be deleted….=> death of organism

22
Q

How do telomeres fix the end replication problem

A

-add noncoding ssDNA to 3’ end by telomerase
-telomeres worn away after each DNA replication/division
-if telomere region is gone=?cell stop dividing

23
Q

Telomerase?

A

Enzyme=>restore shortened teloemres

24
Q

Is telomerase in eukaryotic cells?

A

NOOO…=> short telomeres in old peep

Telomerase in gametes and stem cells (as get older, shorter telomeres cause less telomerase)

25
Q

HTERT

A

Gene mutation (human telomerase)=>biomarker in cancer

26
Q

DNA high fidelity…

A

-replicated fully
-no errors

… if not,
-> defective genome (and maybe death)

So,
DNA repair mechanism by enzyme complex lower replication error rate

27
Q

Telomere role in replication

A

Ensure ends of linear chromosomes are fully replicated

28
Q

Which way does DNA Pol III synthesize new strand

29
Q

DNA poly proofreading

A

-optimum conformation
-DNA pol III see mistake and uses 3->5 exonuclease to remove mismatched nucleotides and replace correct to contîntes synthesis in 5->3

30
Q

MMR

A

DNA mismatch repair

31
Q

Use of MMR

A

Cover replication errors not corrected by proofreading

32
Q

How does MMR work… process?

A
  1. recognize mismatch damage by DNA binding protein (MutS and MutL)…
  2. MutH endonuclease daughter strand away from mismatch
  3. Exo1 5’-3’ exonuclease excise region of daughter strand around mismatch
  4. DNA Pol III fills gap and repais mismatch
  5. Gap waged by DNA ligase

Biol 243 Midterm (8 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions