Lecture 1

Question 1

Why is the central dogma of biology?

Answer 1

The flow of genetic information within a biological system

Question 2

What acids are DNA/RNA?

Answer 2

DNA/RNA are nucleic acids.
DNA – deoxyribonucleic acid
RNA – ribonucleic acid

Question 3

What is the basic unit of DNA?

Answer 3

The basic unit of DNA is a nucleotide.

Question 4

Nitrogenous Bases of RNA and the bonds between them?

Answer 4

RNA:
Uracil
= 2 Bonds
Adenine

Cytosine
3 bonds
Guanine

Question 5

Nitrogenous Bases of DNA and the bonds between them?

Answer 5

Thymine
= 2 Bonds
Adenine

Cytosine
3 bonds
Guanine

Question 6

What is the bonding between nitrogenous bases ?

Answer 6

Hydrogen bonding between nitrogenous bases.

Question 7

What is joined by a glycosidic bond?

Answer 7

Base and Sugar are joined by a glycosidic bond.

Question 8

What type of bonds are in the backbone?

Answer 8

Phosphodiester bonds - in the backbone

Question 9

What type of bonds between bases?

Answer 9

Hydrogen bonds – between bases

Question 10

Why is DNA negatively charged? and why is this significant in the lab?

Answer 10

Due to the bonds between the phosphorus and oxygen atoms

-> performing gel electrophoresis which is a laboratory method used to separate mixtures of DNA, RNA, or proteins according to molecular size.

Question 11

What is a purine?

Answer 11

heterocyclic aromatic organic compound, consisting of a pyrimidine ring fused to an imidazole ring.
2 ring structure
Adenine and guanine

Question 12

What is a pyrimidine?

Answer 12

heterocyclic aromatic organic compound, consisting of 2 nitrogen atoms at positions 1/ 3 of the six member ring.

Thymine uracil and cytosine

Question 13

How many protein encoding genes in the human genome?

Answer 13

20,000 protein encoding genes

Question 14

Describe the Packing of DNA: 4 steps

Answer 14

DNA wraps around histones, this is called a nucleosome.

Nucleosomes are packaged into a thread (supercoiled) like structure known as chromatin.

Nucleosomes can also tightly pack into solenoid structures (chromatin), forming 30nm fibres.
These fibres are compacted into several ‘hierarchical loops’ which is the highly condensed structure known as chromosomes.

Question 15

How many chromosomes in each diploid cell in our body?

Answer 15

46 chromosomes
22 autosome pairs
1 pair of sex chromosomes

Question 16

The importance of the double Helix in Clinical Practice:

Answer 16

Precision Medicine, Pharmacogenomics,
Cancer Genetics, Infectious Disease Diagnosis, Reproductive Medicine, Ethical and Counselling Considerations

Question 17

Why should clinicians be interested in DNA structure?

Answer 17

Vast majority of syndromes and diseases are genetic even though they are not hereditary.

Question 18

why is hydrogen-bonding and base-pairing important in defining nucleic acid secondary structure?

Answer 18

Hydrogen bonding between base pairs - provide stability to the nucleic acid structure.

Base-pairing - complementary base-pairing is essential for maintaining the integrity and fidelity of genetic information.

Stability, specificity, and structural features.

Question 19

Describe polarity of a DNA chain

Answer 19

-> refers to the directionality or orientation of the nucleotides within the chain.

-> polarity is determined by the orientation of the sugar molecules.

->one strand -5’ to 3’ direction, while the other runs in the 3’ to 5’ direction. (helix)

Question 20

Describe polarity of a RNA chain

Answer 20

typically single-stranded: RNA chain runs in the 5’ to 3’ direction, with the 5’ end having a phosphate group and the 3’ end having a hydroxyl group.

-> refers to the directionality or orientation of the nucleotides within the chain.

-> polarity is determined by the orientation of the sugar molecules.