Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Cells and Genes SF1 > DNA Replication > Flashcards

DNA Replication Flashcards

1
Q

What is the function of DNA helicase?

A

Uses ATP to move along the DNA and unwind the double helix

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

What stops DNA from binding to itself

A

Single strand DNA binding protein

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

Function of DNA Topoisomerase

A

Keeps DNA unwound to enzymes can bind easier

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

What is the 1st stage of DNA replication

A

DNA polymerase 3 binds to an RNA primer

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

What is the function of the RNA primer?

A

It is bound to the template strand by DNA primase, and help synthesise individual Okazaki fragments

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

What is the function of DNA polymerase 3

A

Join nucleotides to the RNA primer through a condensation reaction

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

Why is replication different for the different DNA strands

A

The leading strand is in 3’ 5’ direction so rep,Icarian is continuous. The lagging strand is in the 5’ 3’ direction, so replication is discontinuous

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

What is the purpose of Okazaki fragments

A

DNA on the lagging strand is synthesised in these fragments going backwards. It jumps 100/1000 fragments and then synthesised DNA in 5’ 3’ direction. The fragments are small so synthesis doesn’t fall behind so DNA doesn’t bind to itself

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

How does DNA polymerase stay attached to DNA

A

With the sliding clamps

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

What digests the RNA primer

A

RNase

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

What is the function of DNA Polymerase 1

A

Fills in the gaps where the RNA primer was

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

What is the function of DNA ligase

A

Joins fragments together

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

What is the base sequence of the telomeres

A

TTAGGG

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

What is the function of telomerase

A

Replicates the end of the chromosome to form an overhang so the Final Okazaki fragment can be synthesised.

Telomerase get shortened over every replication

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

What is fidelity

A

The ability to avoid mistakes

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

How is replication proofread

A

DNA polymerase proofreads in the 3’ 5’ direction and changes incorrect bases

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

What is Depuration

A

Purine removal

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

What is deamination

A

Cytosine converted to uracil

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

What are the different point mutations?

A

Silent, missence (conservative and radical), nonsense

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

Describe the difference missence mutations

A

Missence is when the incorrect base leads to a different a,ink acid.
Conservative is when the amino acid R groups are similar in size / charge. So protein function is conserved.
Radical is when the R groups are very different, so the 2 3 structure changes

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

What is a nonsense mutation

A

When the incorrect base leads to synthesis of a stop mutation

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

Describe the different frameshift mutations

A

Insertion; nucleotide is added
Deletion; nucleotide is removed
Leads to a completely different amino acid sequence

23
Q

How is DNA repaired?

A

By excision, repaired by exonucleases
DNA polymerase will resynthesise incorrect DNA
Any incorrect DNA will get cut out by enzymes, the DNA ligase will seal the gaps

24
Q

What happens if DNA is broken?

A
  • Broken ends are polished and resealed rapidly by DNA ligase

Or

  • broken sequence gets combined with correct sequence on sister chromatid (gets used as a template). This is a slower process
25
What does polycysteronic mean
When the same mRNA can code for multiple proteins (prokaryotes)
26
How can DNA be damaged?
UV light, ionising radiation, toxic chemicals, oxygen species
27
How do thymine diners arise?
UV light exposure
28
What are introns and extrons?
Introns are non coding DNA Extrons are coding DNA
29
What are control elements?
Promoter, bind to pre initiator complex
30
What are distil control elements?
Enhancers, bind to repress or proteins
31
Name the stages of transcription
Initiation Elongation Processing Termination
32
What is the function of RNA polymerase 1
Makes pre rRNA
33
Describe the 1st step of initiation
RNA polymerase 2 binds to the template strand is the pre initiation complex
34
What is the purpose of chromatin remodelling in the initiation step
Allows chromatin to unwind, exposing the promoter so RNA polymerase can bind to it and initiate transcription
35
What is the TATTA box
The recognition site on the promoter
36
What occurs at the TATTA Box
bind proteins binds to promoter, leading to a chain reaction of recruiting transcription factors. Starting with TBP.. this bundle of transcription factors creates a bundle of proteins that signals RNA polymerase to bind to the promoter. Creates the transcription initiation factor
37
Describe the Elongation step
RNA Polymerase 2 opens the DNA and produces m RNA in the 5’ 3’ direction using the antisense strand as a template ].
38
How is the mRNA processed?
Introns are removed and exons are spliced together The 5’ end is capped with a GTP nucleotide to prevent degradation and promote translation and intron removal (Granyltranferase enzyme) The 3’ end is tailed with an adenine molecule.Polyadenylation ) This indicates that it’s is mature mRNA
39
What removes introns
Spliceosome
40
What allow polyadenylation
Poly-A Polymerase Adds 100-250 adenine to the tail to stabilise it
41
Why do you need to process the mRNA?
Different cells have different needs, so require different genes switched on or off to code for certain proteins
42
What is the mRNA start codon?
AUG Methionine
43
What are the stages of translation?
Initiation: assembly or ribosome, tRNA, mRNA Elongation; addition of amino acids to the chain Termination: Stop codon causes protein complex to dissociate
44
What are the different areas of the ribosome?
Peptidyl-tRNA aminoacyl-tRNA exit
45
What is the purpose of the wobble position?
The 3rd base in the amino acid codon is less critical when binding to the anticodon binding site as the majority of the amino acids are .recognised by the 1st 2 bases
46
What molecules recognises the tRNA molecule with the appropriate amino acid?
Aminoacyl tRNA synthases
47
What are the ribosomal subunits?
30s small 50s large
48
Outline the initiation step of translation
The 30s ribosomal subunit binds to the 5’ cap on the mRNA Ribosome moves in the 3’ direction TRNA binds to the codon at the anticodon binding site 50s subunit aligns next to the tRNA molecule at the P site
49
Outline the elongation stage of translation
The 2nd tRNA molecule pairs with the mRNA codon at the A site The amino acid at the P site forms a peptide bond with the amino acid on the A site The tRNA at the P site is deacylated so the a on the A site carries the polypeptide chain The deacylated tRNA molecule to the E site, and the tRNA at the A moves to the P site and this continues
50
Outline the stages of the termination stage of translation
Once a stop codon is reached the tRNA recruits a release factor. The polypeptide chain is released and the ribosome dissociates into the 2 subunits
51
describe the process of splicing
snRNP proteins bind to the 5' and 3' end of the intron in the preRNA U1, u2, u3, u4, u5 come together to form the lariat structure which cleaves the mRNA. the exons are joined by EJC (exon junction added)
52
what is 5' capping
adding GTP to the 5' end by guanyltransferase to prevent degredation by exonucleases
53
what is 3' capping
the end of the gene has a repeating AAUAAA polyadenylation signals Poly-A-polymerase adds 110 to 250 adenine nucleotides to form a poly A tail to stabalise the transcript

Cells and Genes SF1 (11 decks)

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