Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Ellie's Medical Cell Biology And Genetics > Sesh 2: DNA Structure and Replication > Flashcards

Sesh 2: DNA Structure and Replication Flashcards

1
Q

What is the central dogma?

A

DNA–> RNA–> Protein

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

What is a histone?

A

An octameric protein that forms the core of a nucleosome. 147 base pairs of DNA wrap around a histone to –> nucleosome.

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

What type of chromatin is more in the solenoid form?

A

Heterochromatin. More tightly coiled, so is a way of controlling gene expression.

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

__________ are further coiled to form chromatin fibres.

A

Nucleosomes

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

What is the effect of the main mutation leading to CF?

A

It is a 3 bp deletion, leading to deletion of 1 amino acid. CFTR misfolds and does not reach the plasma membrane, so you don’t get Cl- conductance.

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

How many chromosomes are in the human genome?

A

24- (22 autosomes + X and Y)

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

What is the genome?

A

The entire DNA sequence.

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

Nucleic acids are _________________.

A

Polynucleotides= linear polymers of nucleic acids

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

What 3 components make up a nucleotide?

A
  1. Base
  2. Sugar
  3. Phosphate
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is a nucleoSide composed of?

A

A base and a sugar….no phosphate group.

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

What is the difference between ribose and 2-deoxyribose?

A

Ribose has an OH group on C2, but 2-deoxyribose only has a H on C2.
Ribose forms RNA, and 2-deoxyribose forms DNA.

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

What carbon of 2-deoxyribose does the nitrogenous base attach to?

A

C1

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

The phosphate group of a deoxyribonucleotide connects to carbon ____.

A

5

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

How many rings do purines and pyrimidines have?

A

Purines-2 rings

Pyrimidines- 1 ring

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

Which bases are purines and which are pyrimidines?

A 
Purines= adenine and guanine
Pyrimidines= cytosine, thymine and uracil
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Nucleotides are connected by __________ bonds.

A

Phosphodiester

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

At the 5’ end of DNA there is a ________, and a _________ at the 3’ end.

A
  1. Phosphate

2. Hydroxyl

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

__ hydrogen bonds form between C and G bases, and __ hydrogen bonds form between A and T/U bases.

A
  1. 3
  2. 2

Due to the bases’ chemical structure, get secondary structure of DNA.

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

In the duplex DNA structure, the strands are _____________ and run ___________.

A
  1. Complimentary

2. Anti-parallel

20
Q

By convention, DNA is written ___ to ____.

A

5’ to 3’.

21
Q

What occurs in each stage of the cell cycle listed below?

  1. G1
  2. S
  3. G2
  4. M
A
  1. G1= cell contents replicated
  2. S= DNA replication
  3. G2= check and repair
  4. M= cell division- mitosis/meiosis
22
Q

Where do the cell cycle checkpoints occur?

A

After G1 and G2.

23
Q

Which enzyme catalyses the formation of phosphodiester bonds in DNA replication?

A

DNA polymerase

24
Q

What direction is chain growth in DNA replication?

A

From 5’ to 3’- DNA polymerase adds nucleotides to the 3’ end.

25
What drives the reaction of DNA replication?
Pyrophosphate hydrolysis.
26
What is the structure of DNA in prokaryotes?
It is in the form of a naked circular chromosome.
27
Sine DNA polymerase can only EXTEND from a 3' end, a ________ is required to 'kick start' DNA replication.
Primase
28
What direction does DNA polymerase read the template strand?
3' to 5' (to make in 5' to 3')
29
The leading strand is made _________, but the lagging strand is made in ________ ___________.
1. Continuously 2. Okazaki 3. Fragments
30
Which enzyme joins the Okazaki fragments of the lagging strand?
DNA ligase.
31
Which enzyme unwinds the DNA double helix, for DNA replication?
DNA helicase.
32
Apart from catalysing DNA replication, what can DNA polymerase do?
Can proofread- corrects 99.9% of its errors.
33
When does DNA replication terminate in prokaryotes?
When the 2 facing replication forks meet and DNA ligase joins the final fragments.
34
How many molecules of DNA does replication of 1 chromosome produce?
2 molecules of DNA (chromatids held together by a centromere)- 1 REPLICATED chromosome.
35
What are the 2 major functions of DNA?
1. To replicate itself | 2. To store genetic information
36
What is the definition of a gene?
A stretch of DNA at a specific locus on a specific chromosome, that carries the code for a protein.
37
Histones can be methylated or acetylated to regulate gene expression. This is termed_________.
Epigenetics.
38
Phosphodiester bonds are a type of ________ bond.
Covalent.
39
What is chromatin?
DNA+histone, that allows DNA to be tightly packaged into a small volume.
40
Why are nucleoSide analogues used instead of nucleoTide analogues, as antiviral and anti cancer drugs?
Nucleosides lack a phosphate group, making it easier for them to pass through the cell membrane. Once in the right place, nucleosides are phosphorylated by kinases--> nucleotides
41
What is the difference between an exo- and endonuclease?
Exonucleases cleave the end of DNA at the 5'/3' end. | Endonucleases cleave DNA within the nucleotide chain.
42
What is the function of an exonuclease domain in DNA polymerase?
Proofreading...detects base pair mismatches, helps remove the incorrect base for it to be replaced with the correct one. Mutations in this domain can-->errors in DNA replication-->mutations-->cancer
43
How can nucleoside analogue drugs be used to treat HIV/AIDS?
They act as substrates for DNA polymerase, but when incorporated into the newly-synthesised strand, cannot form phosphodiester bonds, so cause termination of the nucleotide chain...preventing DNA replication. -In high doses can have adverse effects on continually dividing cells e.g. Skin, GIT
44
Define precision medicine
An emerging approach for disease treatment and prevention that takes into account individual variability in genes, environment and lifestyle.
45
What is pharmacogenomics?
The study of how genes affect individual's response to specific drugs.

Ellie's Medical Cell Biology And Genetics (12 decks)

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