Lecture 1 Flashcards
Why is the central dogma of biology?
The flow of genetic information within a biological system
What acids are DNA/RNA?
DNA/RNA are nucleic acids.
DNA – deoxyribonucleic acid
RNA – ribonucleic acid
What is the basic unit of DNA?
The basic unit of DNA is a nucleotide.
Nitrogenous Bases of RNA and the bonds between them?
RNA:
Uracil
= 2 Bonds
Adenine
Cytosine
3 bonds
Guanine
Nitrogenous Bases of DNA and the bonds between them?
Thymine
= 2 Bonds
Adenine
Cytosine
3 bonds
Guanine
What is the bonding between nitrogenous bases ?
Hydrogen bonding between nitrogenous bases.
What is joined by a glycosidic bond?
Base and Sugar are joined by a glycosidic bond.
What type of bonds are in the backbone?
Phosphodiester bonds - in the backbone
What type of bonds between bases?
Hydrogen bonds – between bases
Why is DNA negatively charged? and why is this significant in the lab?
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.
What is a purine?
heterocyclic aromatic organic compound, consisting of a pyrimidine ring fused to an imidazole ring.
2 ring structure
Adenine and guanine
What is a pyrimidine?
heterocyclic aromatic organic compound, consisting of 2 nitrogen atoms at positions 1/ 3 of the six member ring.
Thymine uracil and cytosine
How many protein encoding genes in the human genome?
20,000 protein encoding genes
Describe the Packing of DNA: 4 steps
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.
How many chromosomes in each diploid cell in our body?
46 chromosomes
22 autosome pairs
1 pair of sex chromosomes
The importance of the double Helix in Clinical Practice:
Precision Medicine, Pharmacogenomics,
Cancer Genetics, Infectious Disease Diagnosis, Reproductive Medicine, Ethical and Counselling Considerations
Why should clinicians be interested in DNA structure?
Vast majority of syndromes and diseases are genetic even though they are not hereditary.
why is hydrogen-bonding and base-pairing important in defining nucleic acid secondary structure?
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.
Describe polarity of a DNA chain
-> 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)
Describe polarity of a RNA chain
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.
