d1.1 dna replication Flashcards

1
Q

3 types of replication

A
  1. full conservative replication
  2. semi conservative replication
  3. dispersive replication
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2
Q

what is dna replication used for [3]

A
  1. reproduction
  2. growth
  3. tissue replacement in multicellular organisms
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3
Q

advantages of semi conservative dna replication

A

high degree of accuracy in copying base
sequences

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4
Q

what is one monomer of dna called

A

nucleotide

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5
Q

how are strands of polypeptides arranged

A

antiparallel

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6
Q

end of pentose

A

c5 prime end
bc shape of ribose

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7
Q

what bonds link carbon tgt + which ones

A

carbon bonds
c3 + c5

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8
Q

bond between srtands of polypeptide

A

h bond

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9
Q

y can the dna spiral

A

h bonds holding the antiparallel strands of polypeptides together

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10
Q

process of dna replication

A
  1. dna helicase
    - unzips the double helix
    - replication fork is formed
  2. dna polymerase
    - chases dna helicase + elongate the strands
    - new daughter strands formed
    = end up with 2 new double helixes
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11
Q

limitation of dna polymerase

A

can only travel form 5’ to 3’ end
- dna polymerase has to leap or else a gap will form

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12
Q

name of 2 strands during dna replication

A
  • leading strand
  • lagging strand
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13
Q

relationship of the 2 strands during dna replication

A

complementary

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14
Q

what is around when the dna replication occurs

A

free dna nucleotides

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15
Q

how to speed up the replication process in eukaryotic cells

A

multiple replication forks to speed up the replication

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16
Q

purpose of polymerase chain reaction

A

amplify dna sample

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17
Q

when is polymerase chain reaction needed

A

if you only have a small samples of DNA but you want to have a lot in order to use them for tests

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18
Q

real life application for polymerase chain reaction [3]

A
  1. test for viruses’ dna
  2. amplify insulin gene and insert in bacteria’s plasmids (recombination)
  3. dna fingerprinting/profiling
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19
Q

why is Taq polymerase used in polymerase chain reaction

A

heat resistant
- opt temp is 72c
- wont denature at 90c

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20
Q

why is dna helicase not needed in polymerase chain reaction

A

the double helix will just separate under heat (h bonds are very weak)

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21
Q

before polymerase chain reaction

A
  1. know the target sequence
  2. design primers that are complementary to the target sequence
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22
Q

primers definition

A

short pieces of dna that will attach on either end of the target

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23
Q

what is needed during polymerase chain reaction [4]

A
  1. many copies of the 2 primers
  2. dna polymerase
  3. nucleotides
  4. water + salt
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24
Q

purpose of dna polymerase during polymerase chain reaction

A

copies dna

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25
purpose of nucleotides during polymerase chain reaction
act as dna building blocks
26
purpose of water + salt during polymerase chain reaction
mimic conditions inside the cell
27
how is the process of polymerase chain reaction regulated
through repeated cycles of temperature changes
28
temperature cycles of polymerase chain reaction (brief)
1. 95c - disrupts the complementary base pairing 2. 50c - complementary strands re-join - primers lock onto their complementary sequences before the longer strand can come back tgt 3. 72c - activates dna polymerase - attaches at the ends of the paired primers + extends them
29
95c detailed description
- close to boiling- disrupts the complementary base pairing - 2 dna strand come apart
30
50c detailed description
- complementary strands re-join - primers are present in much greater numbers- lock onto their complementary sequences before the longer strand can come back tgt
31
72c detailed description
- activates Taq polymerase - attaches at the ends of the paired primers + extends them - moves along the single-stranded dna, adding complementary nucleotides - goes until it falls off, reaches the end of the strand or temp change
32
cycle 2 of pcr
1. 95c - dna strands separate 2. 50c - primers find their complementary sequences - bind not only to the original target dna + products from cycle 1 3. 72c - polymerase extends to primers, adding complementary nucleotides as it goes
33
cycle 3 of pcr
- desired products appear - shorter copies of just the target sequence
34
what does the primer consist of
a few nucleotides (short complementary sequence of dna/rna)
35
what needs to occur before a dna polymerase bind to the parent strand
primer bind to the parent strand first
36
problem with primers
con only bind at 54c
37
what does primer sequence determine
where the copying starts and end
38
purpose of restriction endonuclease
cut at the ends of the tandem repeats to create fragments of dna of different lengths
39
2 types of cutting sites
1. sticky end 2. blunt end
40
y is restriction enzyme used to compare dna
for fair comparison since the cuts occur at the same places
41
gel electrophoresis pro
much faster
42
process of gel electrophoresis
1. use pcr to amplify dna samples collected 2. use 1 restriction endonuclease to cut the dna specifically into fragment 3. fluorescent marker to tag a specific dna sequence 4. match the fluorescent bands for results
43
y will the dna move during gel electrophoresis
dna is negatively charged. the shorter fragments will travel further than the longer fragments, as they are attracted by the positive side of the gel
44
y r the dna different lengths during gel electrophoresis
short ones travel quicker
45
process of dna replication
1. helicase unzips and unwinds the dna 2. the replication fork forms 3. single strand binding porteins keep the dna from binding together again 4. dna primase adds rna primers to the template strands 5. dna polymerase III binds at the primers and begins to synthesise the new strands 6. dna polymerase I removes rna primers and replaces them with dna necleotides 7. dna ligase connects the Okazaki fragments
46
function of gyrase
relives the tension in the dna as it is unwound
47
function of dna helicase
unwinds and unzips the dna by breaking hydrogen bonds between bases
48
function of dna polymerase III
builds the new strands of DNA using the original strands as templates + proofreading function helps to prevent DNA replication errors
49
function of dna primase
places rna primers on the template strands
50
function of dna polymerase I
replaces rna primers with dna nucleotides
51
function of dna ligase
connects the okazaki fragments by forming phosphodiester bonds
52
function of single strand binding proteins
keep the two strands of dna separated and stable during replication
53
what would happen if the dna polymerase I didnt do its job
rna primers would remain in the dna molecule
54
what would happen if dna polymerase III didnt to its job
if mutation occurs, then it would trigger apoptosis
55
how translation depends on complementary base pairing
1. translation converts a sequence of mRNA nucleotides/codons to a sequence of amino acids/polypeptide/protein 2. triplets of nucleotides/bases on «activated» tRNAs pair with complementary «triplets of» nucleotides/bases on mRNA / vice versa 3. base pairing occurs when adenine/A pairs with uracil/U and guanine/G pairs with cytosine/C 4. specific amino acids are attached to specific of tRNA e. mRNA has codons AND tRNA has anticodons
56
function of Taq DNA polymerase
- forms new double-stranded DNA by adding complementary bases/nucleotides - primers binds to targeted DNA sequences at a lower temperature
57
why use Taq DNA polymerase
can withstand high temperatures without denaturing
58
process of pcr w temp
1. denaturation (95c) 2. annealing (54c) 3. elongation (72c)
59
sense strand nucleotides
same as mRNA but T instead of U
60
r sense strands transcribed
non-transcribed
61
what are the non-coding regions in DNA used as
telomeres and coding for production of tRNA
62
which cell component synthesises actin and myosin
free ribosomes
63
which processes do nucleosomes play a role in eukaryotes [2]
1. transcription regulation 2. dna supercoiling
64
functions of dna
1. code amino acid sequence of polypeptides 2. regulation of gene expression 3. introns (regulation too) 4. telomeres (form caps at chromosome ends) 5. coding for tRNA/rRNA 6. allow genes to be passed to offspring