Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

eBMS1062 > TOPIC 1/2 - STRUCTURE/REPLICATION/TECHNOLOGY OF DNA > Flashcards

TOPIC 1/2 - STRUCTURE/REPLICATION/TECHNOLOGY OF DNA Flashcards

(58 cards)

Start Studying
1
Q

What is the central dogma of molecular biology

A

that DNA is transcript to RNA and translated to polypeptides

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

where is DNA found

A

nucleus and mitochondria

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

pyrimidines

A

single carbon nitrogen ring

Uracil and Thymine

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

purines

A

double carbon nitrogen ring (6 and 5)

Adenine, Cytosine and Guanine

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

how are nucleotides linked

A

by a phosphodiester bond between 3’ OH and 5’OH using a phosphate group.

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

outline dna structure

A 
10^6-10^7 nucleotides long
4 nucleotides, phosoribose back bone, weak h bonds
major and minor grooves
2nm diameter
right handed twist = 10-10.5bp per turn
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

outline rna structure

A

70-10000 nucleotides long

3 main types: messenger, transfer and ribosomal

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

differences between DNA and RNA

A

RNA only 1 strand, shorter
base sequence of RNA forms a message
RNA migrates to site of protein synthesis and directs machinery
RNA is transient

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

properties of DNA

A 
solubility
charge
viscosity
UV absorption
Denaturation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

outline DNA solubility

A

polyanionic due to phosphate backbone

insoluble in alcohol

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

outline dna charge

A

negatively charged phosphate groups make DNA acidic

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

outline dna viscosity

A

very viscous
long, rigid
hydrodynamic volume due to H2O phosphate attraction

breaking h bonds, mechanical shearing decreases viscosity

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

outline dna uv absorption

A

nitro-bases strongly absorb uv light 260nm

ssDNA more absorb as double helix shields the bases

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

outline dna denaturation

A

h bonds are broken by increase in temp or pH extremes

decrease in viscosity

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

what is a melting curve

A
  • show absorption due to melting a substance.
  • Tm represents where 50% of substance has melted
  • steeper curve = narrower melting range and lower complexity (more repetition of bases)
  • Tm depends on size, GC content, pH and ionic strength
  • AT rich denature faster to ss
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

outline renaturation

A
  • also called annealing

- produce dsDNA from ssDNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is a probe

A

labelled DNA or RNA fragment used to detect specific sequence by hybridisation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

outline gel electrophoresis

A
  • separates DNA through electric field
  • +ve at bottom so -ve DNA moves down
  • smaller fragments move faster
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

outline DNA replication mechanism

A

DNA helicase unwinds and ss binding proteins keep strands apart
primase produces RNA primers to start growing strand
DNA polymerase adds nucleotides to growing strands
okazaki fragments of primer are added to lagging strand and polymerase fills gaps
RNase H removes primers
Ligase fills nicks

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

why is DNA replication semi conservative

A

1 strand of the original is in each new copy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

outline the sliding ring

A

clamp loader sits next to 3’ end of growing strand
sliding ring attached to polymerase
clamp loader dissociates
holds polymerase in place

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

types of DNA replication errors

A
  • changes in geometry allows 2 h bonds form between T and G

- rare tautomeric forms (less affinity to polymerase) of bases where c can pair with a

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

DNA polymerase checking for errors

A

enzyme undergoes conformation change
fingers tighten around active site
allows double checking of nucleotide errors at covalent addition

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

exonuclease proofreading

Study These Flashcards
A

unpaired 3’-OH ends are detected
the 3’ to 5’ reading exonuclease cuts this off
DNA polymerase fixes mistake

25
Must detecting mismatch
detects mismatched read back until it finds nick triggers degradation of strand all the way back to the nick
26
DNA organisation
chromatin wrapped around histone proteins (H2A, H2B, H3 and H4) forming nucleosomes H1 binds an october of histones compacting it into chromosomes
27
what is the centromere
centre 1/chromosome directs chromosome segregation during mitosis/meiosis highly repetitive sequences of 170bp 2,000-3,000 repeats
28
what are telomeres
the ends of chromosomes and form protective caps telomerase add repeating sequences an overhang of where a primer was removed needed as telomerase shorten during division
29
Virus genome
ds or ss RNA or DNA very large and diverse genome
30
bacteria genome
``` classified by types of chromosome the bacteria has single circular 2 circular linear circular and linear ```
31
bacterial genetic elements
main chromosome (genes needed for all conditions) plasmids (extrachromosomal, genes not essential for all conditions) bacteriophages (viruses that infect bacteria) transposable elements (mobile DNA in/out of chromosome)
32
outline plasmids
autonomously replicating pieces of DNA multiple copies per cell plasmid copy number: average # of plasmid in cell
33
outline vertical transfer
parent to daughter chromosomes (chromosomes, mobile DNA, bacteriophage) plasmids
34
types of horizontal transfer
cell to unrelated cell transformation conjugation transduction
35
outline transformation
uptake of free DNA gets integrated into chromosome or if its plasmid just normal lab: membrane made permeable and using electroporation to make membrane pores
36
outline conjugation
direct transfer of DNA from cell to cell | bacteria must have DNA to encode the 'sex pilus', proteins for dna transfer
37
outline F plasmid
``` has all factors needed for transfer plus of F+ cell binds to F- cell retraction brings cells together form a bridge and opening 1 strand of DNA is passed to F- cell plasmids synthesised again both cells are F+ ```
38
Outline transduction
transfer via a bacteriophage follows lytic or lysogenic cycle by integrating into genome new genes only stable if integrated into chromosome generalised transduction: incorrectly packages normal bacterial DNA which cannot act as a proper phage
39
prokaryote replication initiation
fully methylated origin | sufficient resources to complete replication
40
eukaryote replication initiation
occurs in G1 phase | prereplicative complex forms from ORC and mcm helicase
41
What is PCR used for
to amplify a specific DNA sequence
42
Describe the method of PCR
denaturation to produce ssDNA primer marks a specific sequence Polymerase replicates from the primer
43
PCR in gene testing
design a primer that will only work if gene is present | test if successful pcr with gel elec
44
PCR in paternity testing
many short repeated sequences inherited from parents pcr amplifies these short repeated sequences comparison of gel elec to parents
45
PCR in forensic science
each individual has a variable # of tandem repeats (VNTR) 1 VNTR for each chromosome and unlikely unrelated individuals have same VNTR pair on chromosome primers that bracket the VNTR will provide different sized fragments comparison of gel elec to crime scene
46
Bacterial artificial chromsomes genome
BACs with F plasmids are used to hold DNA fragments to make up a genome produces a genomic DNA library but also contains non-coding DNA
47
cDNA library
mRNA corresponds to coding DNA mRNA is used to synthesise the initial coding strand (cDNA). polymerase produces dscDNA from the sscDNA This produces a cDNA library
48
shearing produces...
random fragmentation
49
outline restriction endonucleases
restriction enzymes that cut DNA at a specific site. | Type 2 has its cleavage site within/close to the recognition site
50
what is enzymatic ligation
where a plasmid and insert digested with the same restriction enzymes with DNA ligase to stick them together.
51
altered genes into mammal cells
transfection micro conjugation virus
52
altered genes into plants
agrobacterium tumefacias | particle bombardment
53
altered genes into bacteria
electroporation heat shock chemical transformation
54
dideoxy chain method, also called sanger method:
dideoxyribonucleoside triphosphate is used (lacks 3'-OH) and therefore doesn't allow for chain elongation 1 ddNTP added to mixture of dNTP of same base ddNTP will be used as the DNA is sequenced and will stop elongation. these fragments can be pieced together to sequence the strand.
55
what is sequencing DNA
working out the sequence in the DNA
56
what is shotgun sequencing
used for short strands | computer reads overlaps of fragments to work out the total strand
57
outline the Meselson-Stahl experiment
heavy nitrogen was used to grow DNA in e.coli then switched to lighter nitrogen DNA progressively became lighter due to hybrids of heavy and light and then fully light nitrogen bases. supported semi conservative method of replication
58
Meselson-Stahl results
noticed that after one division a dna molecule was 50% light and heavy = not in line with conservative which would produce a 100% light and 100% heavy molecule each after two divisions a dna molecule was either 50% light and heavy or 100% light = not in line with dispersive as this would produce a constant hybrid molecule not a 100% light molecule

eBMS1062 (7 decks)

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