DNA, RNA, Proteins Flashcards
illustrate transcription
initiation - TATA box binding protein bind to DNA, TFII + RNA polymerase II bind, transcription factors at enhancers trigger elongation
elongation - 5’ to 3’ with template strand, free nucleotides line up by comp base pairing -> pre-mRNA
illustrate splicing
in nucleus
capping at 5’ end for stabilisation , add polyA to 3’
splicing - removal of introns by spliceosome
alternative splicing - combination of diff exons give diff mature RNAs + proteins;one gene -> diff proteins
mature mRNA produced
illustrate translation
mature mRNA transported to ribosomes in cytoplasm
tRNA carries amino acid to ribosome, bind from A -> p -> E
rRNA catalyse formation of peptide bond between amino acid
what is the central dogma
DNA —transcription—> RNA —translation—> protein
<—reverses trans—
DNA undergo replication
diseases related to transcription + translation
anaemia - variation in HBB sequence (7th protein) A to T -> fibre formed + cell shape distorted -> cannot carry oxygen (hetero adv: carriers have 10-fold decreased chance of malaria)
thalassaemia - reduced alpha/beta-globin, lack of haemoglobin production
cystic fibrosis - salty skin, deletion of 3bp at 508 -> loss of Phe
nucleotide and nucleic acid structure
nucleotide - monomers of nucleic acid
consists of phoshpate, pentose, purine ( 2 carbon nitrogen rings, A/G), pyramidines (1 carbon nitrogen ring, C/T)
difference between dna and rna structure and function
2’ carbon of pentose - DNA = H, RNA = OH
DNA - T, RNA - U
DNA - double helix, anti parallel, major + minor grooves, phosphate + pentose backbone , bases inside
RNA - varied structure (>=2 nucleotides link tgt)
illustrate packaging of DNA by histones into nucleosomes
histone - protein providing structural support for chromosomes, DNA wrap around for compact shape
nucleosome - 8 core histone protein, spool-like for DNA to wrap around
DNA < nucleosome < beads-on-a-string chromatin
regulation of gene expression + importance
- transcription factors = bind to activator proteins -> form protein complex that binds to gene promoter -> for RNA polymerase to attach
- splicing
- histone modification - which DNA exposed to polymerase to turn on or off the histones
important for detecting expression of gene. to diagnose cancer progression
examples of genomic science and digital health in precision medicine
function of CRISPR-Cas9
a CAS9 protein bounded with sgRNA - identify + cut specific sections of DNA
for deactivating gene by cutting DNA + error prone repair of cell -> mutations disable gene
also add new genes / change specific base
important roles of protein in biomedicine
enzymes
nucleic acid interactions
receptors
provide structure to cells and tissues
antibodies in immune system
insulin + receptor interaction
insulin bind to outside part of receptor -> protein parts inside cell unwind + make contact for activation -> more glucose transporters inserted into cell membrane for increased glucose uptake
enantiomeric nature of amino acids
proteins made up of L-a amino acids
a - chiral molecule, diff mirror image
L - with H towards me, CORN in clockwise (D- CORN anticlockwise)
difference between 4 levels of protein structure
primary - amino acid sequence, read from nitrogen to carbon terminal
secondary - conformation of backbone, alpha helix + beta sheet
tertiary - 3D structure due to h-bond, vdw, electrostatic attractions
quaternary - >1 polypeptide chain forming final functional structure (eg haemoglobin)
