Fundamentals Of Science > DNA To Gene Expression > Flashcards

DNA To Gene Expression Flashcards

(73 cards)

Start Studying
1
Q

What bases are pyrimidines?

A

C and T

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

What bases are purines?

A

A and G

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

How many hydrogen bonds between bases G andC?

A

3

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

How many hydrogen bonds between bases A and T?

A

2

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

DNA structure

A

-Double helix of 2 complementary strands
- composed of nucleotides : sugar, phosphate group and nitrogenous bases

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

When DNA is replicated what fraction contains the new DNA strand?

A

1/2

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

DNA replication simplified

A
  • Replication fork formation
  • primer binding
  • elongation
  • termination
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Lagging strand is what direction

A

5‘ to 3’ direction

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

Primer binding

A

-A primer (short RNA piece) binds to a 3’ and of leading strand
Primer binds at starting point for replication

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

What enzyme unwinds DNA?

A

DNA helicase

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

Replication progresses in what direction?

A

5’ to 3’ direction

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

Leading strand is in what direction?

A

3’ to 5’ direction

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

Elongation stage for leading strand (replication)

A

DNA polymerase create new strands by adding new base pairs

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

Elongation stage for lagging strand (replication)

A

Begins replication by binding multiple primers

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

Which strand is DNA synthesised continuosly?

A

Leading strand

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

On the lagging strand, DNA is synthesised how?

A

In short fragments (Okazaki)

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

Leading strand synthesised by what enzyme?

A

DNA polymerase

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

Okazaki fragments are joined by what enzymes?

A

DNA ligases

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

What enzyme adds pieces of DNA between primers on lagging strand?

A

Another DNA polymerase

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

In termination what happens to RNA primers?

A

They are removed and replaced with bases

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

Function of telomerase

A

Adds telomeres at DNA 3’ ends

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

Termination stage of DNA replication.

A
  • RNA primers removed and replaced
  • Okazaki fragments joined
    -Telomerase adds telomeres
  • parent and complementary strands coil into double helix
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Function of topoisomerases

A

Unwind and rewind DNA strands to prevent DNA from getting tangled

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

RNA structure

A

Single stranded, composed of nucleotides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
RNA is synthesised in what direction?
5' to 3' direction
26
Transcription steps
1 initiation 2 promoter clearance 3 elongation 4 termination
27
Order of DNA to gone expression
- DNA replication - transcription - mRNA processing - Translation Protein folding
28
Initiation stage of transcription
- RNA polymerase and cofactors unwind and bind to DNA ( at promoter region) Approx 14 base pairs are exposed each time
29
Promoter clearance stage in transcription
- Promoter (DNA sequence) signals which DNA strand is transcribed - RNA polymerase clears the promoter once the first bond has been synthesised
30
Elongation stage of transcription
- When RNA strand gets longer - one DNA strand is template for RNA synthesis
31
Termination stage of transcription
- release of mRNA from the elongation
32
Template strand for DNA is in what direction?
3' to 5' direction
33
Introns
Non-coding regions that interrupt the gene's coding sequence
34
mRNA processing steps
1 capping at 5' end 2 addition of a poly-a tail at 3' end 3 splicing
35
Polyadenylation
addition of a poly-a tail at 3' end
36
Function of capping at 5' (mRNA processing)
Protects 5' end from degradation and helps position mRNA during protein synthesis
37
Name of cap linked at 5’ (mRNA processing)
Methylated-guanosine (7-methyl-G) cap - (modified guanine (G) nucleotide)
38
What happens at polyadenylation?
- a tail of approximately 200 adenine nucleotides is added to 3’
39
Benefit of polyadenylation
Addition of a poly-a-tail (approx.200 adenine nucleotides added at 3’ end) Helps with efficient translation and stability of mRNA
40
Splicing is?
The process of removing introns and rejoining exons of mRNA
41
Exons
Coding regions
42
Polypeptide
Sequence of amino acids
43
Codons
Set of 3 nucleotides for a specific amino acid
44
mRNA vs tRNA
mRNA:contains instructions to make a protein tRNA: responsible for delivering amino acids to ribosomes
45
When tRNA is bound to an amino acid it is called?
Aminoacyl-RNA
46
Stages of translation
1 initiation 2 elongation 3 termination
47
Initiation stage of translation
- Small submit binds to mRNA and scan it (5’ to 3’ direction) until it encounters the start codon (AUG) - when small subunit, mRNA and tRNA are correctly positioned, larger subunit attaches and initiator tRNA binds to ribosome
48
Elongation stage of translation
- Next tRNA with amino acid base, pairs with next codon -Peptide bond formed between the 2 amino acids - ribosome translocates one codon downstream and initiator tRNA is released Cycle repeats until stop codon is reached
49
Start codon for translation
AUG
50
Termination stage of translation
- when ribosome reaches stop codon (UAA, UAG or UGA) - no tRNAs to stop codons - release factors bind and release protein from ribosome -Ribosome subunits dissociate from each other
51
Where does folding /refolding of proteins happen?
Endoplasmic reticulum
52
Packing of proteins into vesicles happens where?
Endoplasmic reticulum further in the Golgi apparatus
53
Glycosylation of proteins happens where?
Endoplasmic reticulum /Golgi apparatus
54
Glycosylation of protein is?
Attachment of carbohydrates to the backbone of a protein through an enzymatic reaction
55
Gene expression is?
Turning on a gene to produce RNA and protein
56
Constitutive genes (describe)
Always active, constantly transcribed
57
Example of constitutive genes
Ribosome genes
58
Inducible genes (describe)
Off unless induced by stimulus
59
Example of inducible genes
Glucose transporter proteins in response to insulin
60
Housekeeping genes (describe)
Maintain basic cellular function, expressed in all cell types, transcribed at constant rate
61
Example of housekeeping genes
Actin
62
Stages of gene expression regulation
1 epigenetic control 2 transcriptional control 3 post-transcriptional control 4 translational control 5 post-translational control
63
What happens at replication fork formation?
H bonds break unwinding the DNA Replication progresses in 5’ to 3’ direction - Leading strand oriented in 3’ to 5’ direction - lagging strand (follows leading) in 5’ to 3’ direction
64
Function of ER ( endoplasmic reticulum):
Folding /folding of proteins Glycosylation of proteins Assembly of multi-subunit proteins Packaging of proteins into vesicles
65
Epigenetic control
DNA tightly packed around histones DNA/histone methylation packs nucleosomes tighter Histone acetylation loosens nucleosome packing
66
Histone methylation
Packs nucleosomes tighter
67
Histone acetylation
Loosens nucleosome packing
68
Post-transcriptional control
mRNA processing+ Transport from nucleus to cytoplasm + binding to ribosomes Includes: alternative splicing and control of RNA stability
69
What is alternative splicing?
Exon splice together in different combinations to generate different mature MRNAs Allows production of many proteins using relatively few genes
70
when can post transcriptional control occur?
mRNA processing Transport from nucleus to the cytoplasm Binding to ribosomes
71
When is translational control regulated?
During mRNA AND RIBOSOME BINDING e.g. ferritin
72
What is ferritin?
Molecule that is only needed when iron levels are high because its main role is to store the iron
73
Post translational control
Modifying protein to affect activity. e.g. reversible, blocking with inhibitors prevents substrate binding

Fundamentals Of Science (37 decks)

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