Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Biochemistry > structure of nucleic acids and synthesis of DNA > Flashcards

structure of nucleic acids and synthesis of DNA Flashcards

1
Q

key difference between proteins / nucleic acids

A

primary sequence for nucleic acids doesn’t dictate secondary/tertiary structure, like it does for proteins

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

N-glycosidic bond

A

-the bond between the sugar and the base -anti-confirmation at physiological ph (allows for H-bonding to form double stranded DNA) -bond formed at anomeric carbon, beta configuration (Be up!)

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

nucleoside

A

base + sugar

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

nucleotide

A

base + sugar + phosphate

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

What is the linkage/bond that holds the sugar phosphate backbone (single strand) together?

A

phosphodiester bond -5’ end (phosphate) to 3’ end (OH)

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

DNA vs. RNA

A

-Anti-parallel, double helix, (B-DNA form dominates in living systems), Thymine (a bit more stable than uracil) -Single stranded, helix, uracil (add destability to RNA), denatures and breaks apart in basic solution (DNA does not), *5’cap, *polyA tail, encodes proteins

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

mRNA

A

*5’cap polyA tail - for stability needs to be transported to a ribosome for protein synthesis

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

ribosomes

A

rRNA + protein **DIFFERENT subunits in Prokaryotes and Eukaryotes

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

tRNA

A

-have the anti-codon that recognizes the codon on mRNA -responsible for bringing the AA being added to the growing polypeptide

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

What is Tm?

A

temperature required for denaturation of DNA -Tm is directly proportional to the number of G-C bonds

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

What will a basic solution do to DNA/RNA

A

-it will only denature DNA (separate strands) -it will BREAK APART (its because of the OH

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

What happens when we cool temp back down?

A

hybridize = anneal = renaturation speed can tell if you have several types of DNA or just 1 type also highly repetitive sequences anneal faster

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

What is chromatin?

A

DNA is too big for free float in cell, so its supercoiled And binds to histones to form chromatin -positively charged histones attract negatively charged DNA

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

What about the human genome

A

each cell has 23 pairs of chromosomes

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

Zidovudine

A

Reverse transcriptase isn’t able to add nucleotide to 3’ end

  • reverse transcriptase inhihbitor
  • for treatment of HIV
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

5-FU

A

-non targeted cancer treatment (injures body cells too!) basically prevents thymine from being synthesized -without one of its precursors DNA can’t be made -this should stop cell division and slow the growth of the cancer

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

Azithromycin

A

-antibiotic -binds to prokaryotic robosomal subunit (50S) -but since mitochondrial ribosomes are similar to bacterial, the drug can affect our mitochondria

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

How many unique DNA molecules are possible for a 5 base pair sample

A

1024 = 4x4x4x4x4 (5 base pairs)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Helicase

A

unwinds DNA strands

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

topoisomerase

A

breaks / rejoins phosphodiester bonds to relieve supercoiling - i.e. cuts strands (single strand - type I or double - type II)

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

single stranded binding proteins

A

binds to DNA as it unwinds to prevent re-association or enzyme degradation

22
Q

DNA polymerase III

A

adds deoxyribonucteotides in the 5’ to 3’ direction (proof reads) -can also proof read in 3’ to 5’ (exonuclease) -makes 2 new strands leading/lagging (semiconservative replication

23
Q

Primase

A

adds RNA primers to the DNA because DNA pol needs a 3’ OH to attach its first nucleotide -eventually primers removed by DNase, DNA pol I

24
Q

Leading vs. Lagging strand

A

continuous synthesis vs. discontinuous synthesis

25
Q

DNA repair

A

DNA ligase DNA pol II

26
Q

Cyclin dependent Kinases (CDK)

A

when cyclin is around it binds to a kinase this binding turns on the phosphorylating ability of the CDK -phosphorylation acts as a switch to turn on replication -cell leaves interphase and enters mitosis?

27
Q

DNA replication differences: prokaryotes vs. eukaryotes

A

eukaryote have larger genomes Histomes / nucleosomes - unique to eukaryote Prokaryotic DNA is circular

28
Q

Why is eukaryote DNA replication faster?

A

Multiple replication forks

29
Q

DNA polymerase delta

A

lagging strand replication (3’ to 5’ exonuclease)

30
Q

DNA polymerase epsilon

A

leading strand replication (3’ to 5’ exonuclease)

31
Q

what is flap endonuclease

A

an enzyme that removes primers

32
Q

Prokaryote DNA Polymerases

A
33
Q

Eukaryote DNA Polymerases

A
34
Q

How do we know if DNA is in the post-transciptional stage?

A

IF DNA is methylated then we are post-transcription

35
Q

WHat is a telomere

A

A G rich sequence/repeats at the end of a chromosome

I guess it prevents shortening of the DNA by elongating the partent strand?

36
Q

What are some example of how DNA can be damaged?

A

cigarettes (benzoapyrene) - binds Gaunine, stoping DNA sythesis

Sun exposure can cause thymines to start to bind together (preventing replication)

X-rays can cause the formation of free radical, which can damage cells

37
Q

How can DNA be repaired?

A

Base Excision Repair

Nucleotide Excision Repair

Mismatched Repair

38
Q

Base excision repair

A
  1. glycosylase - cleaves glycosidic bond, removing base
  2. AP endonuclease - chops/cleaves deoxyribose
  3. exonuclease removes deoxyribose and several (base) residues
  4. DNA pol add the propper bases back to fill gap
  5. DNA ligase - seals the nicks
39
Q

Nucleotide Excision Repair

A

corrects DNA damage after sun exposure

same steps as BER, but cleaves a larger segment of DNA

40
Q

Mismatched Repair

A

fixes errors that proof reading missed

unmatched bases produce a bulge in the DNA

must methylate the parental strand so we know to fix the incorrect base in the newly synthesized strand

41
Q

Transposon

A

could cause or reverse a mutation

DNA jumps (copy and paste or just cut and paste) to a new locatoin in genome

42
Q

Homologous recombination

A

genetic diversity!

exchange of nucleotide sequences between homologs (similar DNA molecules)

43
Q

translocation

A

caused by breaks in two non-homologous chromosomes

can result in CANCER

44
Q

Deamination

A

Thymine/cytosine can synthesized using Uracil

so thymine or cytosine (loses amino group) and forms Uracil (it’s called deamination)

C or T converted to U disrupts base pairing

But its an obvious error since U is not tipically present in DNA and our body can fix this (mismatch repair)

45
Q

How to treat HIV

A

cocktail of reverse transcriptase inhibitors

why a cocktail?

  • because reverse transcriptase can mutate
  • these drugs block the 3’ OH, so reverse transcriptase cant add nucleotides
46
Q

How can we fix a mutation due to smoking?

A

our body will probably use Nucleotide assisted repair (despite being one base guamine is large!)

47
Q

What about a mutation due to sun exposure, how can our body fix that?

-2 adjacent pyrimidines mutate

A

again NER (because large 2 adjacent pyrimidines mutating is a large size)

48
Q

Why dont you need a primase during DNA repair?

A

Because a 3’ OH is already present

49
Q

What is special about cDNA

A

it contains no introns

ONLY extrons (expressed regions of DNA)

50
Q

If you want to label DNA, what could you use?

A

Nitrogen. All bases have it

51
Q

What does 5-FU do?

A

inhibits DNA sythesis due to Uracil

Biochemistry (15 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions