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Chapter 7-test 2 Flashcards

(72 cards)

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1
Q

pairs of complementary bases are held together by

A

H bonds

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2
Q

dna has 3 components

A
  1. deoxyribose sugar
  2. one of 4 nitrogenous bases
  3. up to 3 phosphate groups
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3
Q

purine

A

double ringed form.

A and G

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4
Q

pyrimidines

A

single ringed form

C and T (and U)

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5
Q

deoxynucleotide monophosphate dNMPs

A

where N=any four nucleotides

adenosine, guanosine, cytidine, thymidine

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6
Q

deoxynucleotide triphosphate dNTPs

A

nucleotides in their triphosphate configurations. dATP, dGTP, dCTP, dTTP. not part of polynucleotide chain.

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7
Q

the two polynucleotide strands that make up double helix have two rules:

A
  1. nucleotide bases of one strand are complementary to the other nucleotide bases of the second strand (A pairs with T, G pairs with C)
  2. two stands are antiparallel to each other. 5’, other must be 3’.
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8
Q

how many hydrogen bonds in A-T?

how many in C-G?

A

two.

three.

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9
Q

1 angstrom =

A

10^-10 meters

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10
Q

base pairs are spaced at intervals of

A

3.4 A

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11
Q

base stacking

A

base pairs rotate so their planes are parallel.

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12
Q

alternating grooves

A

major groove(12 A wide) and minor groove(6 A wide). this is where dna binding proteins gain access to nucleotides.

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13
Q

complementary base pairs only consist of 1 purine and 1 pyrimidine.

A

if it was two purines, it would measure more than 20 A. if it was two pyrimidines, it would measure less than 20A. it would give the molecule an irregular diameter.

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14
Q

why does it have to be antiparallel?

A

if it was parallel, H bonds wouldnt form. H+ would be opposite of one another, and negatively charged N and O would be too.

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15
Q

dna replication is

A

semiconservative and bidirectional

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16
Q

dna replication is shared by all organisms:

A
  1. parental dna molecule remains intact during replication
  2. parental strand serves as template directing synthesis of a complementary, antiparallel daughter strand.
  3. dna replication results: 2 identical daughter duplexes, each composed of one parental and one new daughter strand.
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17
Q

semiconservative strand

A

each daughter duplex contains one original parent strand and one complementary, newly synthesized daughter strand.

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18
Q

replication bubble

A

expansion around origin of replication. the two regions are the replication forks.

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19
Q

how many origins of replication do archaea have?

A

one.

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20
Q

how many origins of replication do eukaryotes have?

A

hundreds to thousands.

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21
Q

sister chromatids remain joined through

A

G2 and separate at anaphase.

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22
Q

dna polymerase III

A

dna strands are synthesized at the replication fork. starts at 3’ oh end of rna primer (3 to 5)

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23
Q

replisome

A

large protein complex that carries out DNA replication. one replisome at each replication fork.

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24
Q

leading strand

A

synthesized continuously

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25
lagging strand
synthesized discontinuously. made opposite of the replication fork (3-->5)
26
okazaki fragments
result of lagging strand, short segments of newly replicated dna.
27
dna pol I
replaces dna pol III when there is a gap. it replaces rna nucleotides with dna nucleotides.
28
5 to 3 exonuclease activity
dna pol 1 removes rna primers.
29
5 to 3 polymerase activity
dna pol 1 adds DNA nucleotides to the 3′ end
30
dna ligase
joins okazaki fragments. (joins gap)
31
both pol I and dna ligase are
acting on leading and lagging strands.
32
sliding clamp
auxiliary protein complex. carries out bulk of replication. when there are no more template nucleotides available, it drops dna pol III and replaces it w dna pol I.
33
dna proofreading
dna polymerases stops and reverses replication to remove incorrect nucleotide, replacing it w correct one. 3 to 5 exonuclease activity
34
supercoiling
puts strain on other parts of the molecule. like holding a rubber band, but twisting the other end of it.
35
dna topoisomerases
unwinding dna strands.
36
linear chromosomes
unable to replicate fully. lagging strand not replicated, so they get shorter with each replication cycle.
37
telomeres
protect important genes from being deleted as DNA strands shorten during replication.
38
telomerase
protects against chromosome shortening in germ line cells.
39
t loop
protects telomere from enzymatic degradation by joining w a protein complex known as shelterin.
40
telomeric repeats and shelterin protected t loops preserves telomeres for
several cycles of dna replication.
41
hayflick limit
limit to the length of cell's life span
42
polymerase chain reaction pcr
begins with few short dna sequence, then produces million of copies in a few hours.
43
pcr denaturation- primer annealing- primer extension -
- heats mixture at 95 C, causing double stranded dna to denature into single strands. - temp= 45-68 C. one primer binds to each of the dna strands. - 72C. Taq polymerase synthesizes dna, starting at 3' end at each strand. extends primers.
44
nitrogenous bases
purine and pyrimidine.
45
both dna and rna contain
a,c, g. but dna contains t and rna contains u.
46
atp: instead of deoxyribose, the structure is
ribose. (2 OH groups)
47
polynucleotide
20 or more nucleotides in a chain
48
nucleotides are linked together by a
phosphodiester bond between the 3'-OH of the “new” dNTP and the 5' phosphate of the “previous” one
49
each helical twisting is
34 A and 10.5 base pairs.
50
why does dna twist? what else can this twisting be protecting?
from water. it is surrounded by water. nitrogenous bases dont like water.
51
Why would DNA binding proteins need to interact with nucleotides in DNA ?
proteins need to interact with nucleotides to replicate it. it gives dna the capacity to carry information.
52
What do you think would need to happen to DNA for a DNA binding protein to interact with it?
it needs to separate. "melting" of dna. however, dna doesn't have to be separated. the (major and minor groove)
53
dna binding protein more likely to approach
approach dna molecule through the major groove, it can access more, bc more space there.
54
is the general mechanism of DNA replication the same in all organisms?
yes, but as organisms become more complex, some differences did develop in replication proteins.
55
helicase
separates the two strands, and expose single stranded binding proteins.
56
error occurs every
10 milli nucleotides
57
rate of mutation
one every billion base pairs.
58
telomerases are made in
germline cells, cancer cells, and stem cells.
59
in e coli primase joins
DnaA, DnaB, and DnaC at oriC
60
uses for pcr
amplify a specific region of dna clone a dna sequence into diff context find out the number of sequence copies (paternity tests and forensics) introduce a mutation
61
which of the following is not a pcr reagent? primers double stranded dna human dna polymerase dNTPs (fancy name:nucleotides attacked by polymerase)
human dna polymerase.
62
how many amplicon copies do we expect after 25 pcr cycles?
2^25= approx. 33 milli
63
how do you normally separate pcr products?
by gel electrophoresis (have electric field, + and - end)
64
which is more negatively charged? longer or shorter dna
longer dna
65
smalller pieces of dna
move faster.
66
taq polymerase
Thermus aquaticus. this bacterium lives in hot springs at boiling temps.
67
pcr limitations
1. having some knowledge of sequences needed for primers. | 2. difficulty producing amplification products longer than 10-15 kb.
68
How would you introduce a mutation into a DNA sequence that you know and would like to mutate by PCR?
instead of thymine, use uracil. increase the number of cycles. few G's, but you have a lot of C's, T's, and A's. mutated primers. do pcr under uv radiation or x rays.
69
if there is a 3' H,
partial replication products terminate at a G, C, T, or A.
70
ddNTP dideoxynucleotide triphosphate
lacks one 3'OH compared to the deoxyribose and coupled to a fluorescent dye.
71
pcr requirements
``` – double-stranded DNA template – A supply of the four DNA nucleotides – A heat-stable DNA polymerase (taq) – Two diff single-stranded DNA primers – A buffer solution ```
72
sanger sequencing (dideoxynucleotide dna sequencing)
uses DNA polymerase and DNA primers to replicate new DNA from a single-stranded template. dNTPs are present in large amounts. also contains one ddNTP.

Genetics (13 decks)

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