Nucleic Acids & Genetic Information

Question 1

State the process of producing mRNA from DNA

Answer 1

Transcription

Question 2

State the process of producing protein from mRNA

Answer 2

Translation

Question 3

State the process of producing DNA from mRNA

Answer 3

Retrotranscription

Question 4

Both DNA and RNA consist of polymers of monomers. What are these monomers called?

Answer 4

Nucleotides

Question 5

What do nucleotides consist of?

Answer 5

A phosphate group
A pentose sugar
A nitrogenous base

Question 6

Nucleoside + Phosphate = ________?

Answer 6

Nucleotide

Question 7

How many rings are in a Purine?

Answer 7

2

Question 8

How many rings are in a Pyrimidine?

Answer 8

1

Question 9

Give all the examples of Purine bases

Answer 9

Adenine, Guanine

Question 10

Give all the examples of Pyrimidine bases

Answer 10

Cytosine, Uracil and Thymine

Question 11

Give 3 examples of other roles of nucleotides (apart from carrying the genetic code) with examples

Answer 11

Energy carrier i.e. ATP
Signalling i.e. cAMP, cGMP
Enzyme cofactors i.e. CoA, FMN, FAD, NAD

Question 12

Who devised the “Double Helix” structure and when?

Answer 12

Watson & Crick, 1953

Question 13

DNA has directionality, what direction is this?

Answer 13

5’ to 3’

Question 14

How many hydrogen bonds pair a C base with a G base in the double helix?

Answer 14

3

Question 15

How many hydrogen bonds pair with an A base and a T base in the double helix?

Answer 15

2

Question 16

What is the name of bonds which bind phosphate groups to sugar groups in DNA?

Answer 16

Phosphodiester bonds

Question 17

What is a phosphodiester bond?

Answer 17

A bond which links phosphate and sugar groups in the backbone of DNA

Question 18

The human genome has roughly how many base pairs?

Answer 18

3 billion

Question 19

Compare how Nuclear DNA is structured with respect to Mitochondrial DNA

Answer 19

Nuclear DNA is linear and packaged into chromosomes, whilst MtDNA is circular

Question 20

What is the basic fundamental unit of chromatin called? What is it comprised of?

Answer 20

A nucleosome, which is comprised of DNA packaged around 8 histones

Question 21

Nucleosomes can be described as beads on a string. What is the string’s technical name in this instance?

Answer 21

DNA linker region

Question 22

What is the difference between “euchromatin” and “heterochromatin”?

Answer 22

Euchromatin - lightly packed chromatin

Heterochromatin - densely packed chromatin

Question 23

Describe what the chromosomal scaffold is..

Answer 23

The chromosomal scaffold is described as a chromatin fibre associated with non-histone proteins

Question 24

What is a centromere?

Answer 24

The centromere is the part of a chromosome that links sister chromatids

Question 25

What is a chromatid?

Answer 25

One copy of the duplicated chromosome

Question 26

What is a telomere? What is its function?

Answer 26

A series of repetitive nucleotide sequences at the ends of chromosomes. They protect chromosomes from deterioration during replication

Question 27

What is the q arm of a chromosome?

Answer 27

The long arm

Question 28

What is the p arm of a chromosome?

Answer 28

The short arm

Question 29

Each somatic human cell contains how many chromosomes?

Answer 29

46

Question 30

How many different autosomal chromosome pairs are there

Answer 30

22

Question 31

What is an allosome?

Answer 31

A sex chromosome

Question 32

What are the two allosomes?

Answer 32

X and Y chromosomes

Question 33

How many homologous chromosome pairs does a human have?

Answer 33

23

Question 34

What is the "karyotype" of a chromosome?

Answer 34

The karyotype is the number and appearance of chromosomes in a eukaryotic cell

Question 35

What is "aneuploidy"?

Answer 35

An abnormal number of chromosomes in a cell

Question 36

What is "trisomy"?

Answer 36

A type of aneuploidy, whereby there is an extra copy of a chromosome

Question 37

Give three examples of Trisomy conditions affecting autosomal chromosomes

Answer 37

Trisomy 21 - Down's Syndrome Trisomy 18 - Edwards Syndrome Trisomy 13 - Patau Syndrome

Question 38

Give two examples of Trisomy conditions affecting allosomal chromosomes

Answer 38

XXX - Triple X syndrome | XXY - Klinefelter syndrome

Question 39

What is "genomic medicine"?

Answer 39

A medical discipline that involves genomic information about an individual as part of their clinical care

Question 40

How long is a typical cell cycle length in mammals?

Answer 40

12-24 hours

Question 41

What is the G0 phase of a cell cycle?

Answer 41

The resting phase, where a cell has not started to divide yet. Once it gets a signal, it can move into the G1 phase

Question 42

What are the three sub-phases of Interphase?

Answer 42

G1, S, G2

Question 43

How long does G1 phase last for and what happens here?

Answer 43

18-30 hours | Cell increases protein synthesis and metabolic activity

Question 44

How long does S phase last for and what happens here?

Answer 44

18-20 hours | Chromosomes containing DNA are duplicated

Question 45

How long does G2 phase last for and what happens here?

Answer 45

2-10 hours | Cell prepares for mitosis and the splitting of the cell

Question 46

How long does M phase last for and briefly state what happens here?

Answer 46

30-60 mins | Cell produces two daughter cells

Question 47

State the subphases of mitosis

Answer 47

``` Prophase (Prometaphase) Metaphase Anaphase Telophase ```

Question 48

Describe the structure of the mitotic spindle

Answer 48

The mitotic spindle is made up of microtubules and originates from the two centrosomes which migrate to opposite ends of the cell

Question 49

The mictotubules of the mitotic spindle attach to which structure on a chrosome?

Answer 49

Kinetochore

Question 50

What occurs during Prophase?

Answer 50

1. The chromosomes condense 2. Nucleoli disperses 3. Centrosomes seperate and form a mitotic spindle

Question 51

What occurs during Prometaphase?

Answer 51

1. Nuclear envelope fragments 2. Spindles attach to centromeres 3. Chromosomes begin to move towards thecell centre

Question 52

What occurs during Metaphase

Answer 52

Chromosome alignment at the metaphase plate

Question 53

What occurs during Anaphase

Answer 53

Chromatids move towards opposite cell poles

Question 54

What occurs during Telophase

Answer 54

1. Chromosomes uncoil into chromatin 2. Nucleoli reappear 3. Disassembly of spindle 4. Nuclear envelope reforms

Question 55

What is the mechanism of action for 5-Fluorouracil as a chemotherapy?

Answer 55

Irreversibly inhibits thymidylate synthase, also a pyrimidine analog

Question 56

What is the mechanism of action for Cyclophosphamide as a chemotherapy drug?

Answer 56

As an alkylating agent, it attaches alkyl groups onto guanines. This interferes with DNA replication and forms crosslinks

Question 57

What is the mechanism of action for Epirubicin as a chemotherapy drug?

Answer 57

Induces intercalation of DNA strands, also triggers DNA cleavage by the topoisomerase II causing cell death