IAS01,02
visualize transcription, splicing and translation mechanisms central to molecular biology
The Central Dogma: transcription, translation (DNA → RNA → protein) More recently: reverse transcription (RNA → DNA), enzymes that add epigenetic marks (protein → DNA), replication of RNA (in virus), etc.
most common conformation
right-handed helix (clockwise as it goes forward)
major groove (long gap), minor groove (short gap)
ribose & phosphate along outside
bases in the middle
Chargaff's Rule: amount of A = T, G = C
purines: A, G; pyrimidines: T, C
from 5' to 3'
Initiation
TATA-box binding protein bind to DNA
other components of TFII, RNA polymerase II bind
transcription factors at cis-acting enhancers can trigger elongation
Elongation
Termination
pre-mRNA before splicing
removes introns by using spliceosome (set of proteins)
Spinal muscular atrophy is an inherited disease caused by splicing problems
sequence that tRNA binds at ribosome: A site → P site → E site
illustrate how problems in transcription and translation can lead to disease through specific examples
caused by defects in haemoglobin
Haemoglobin
tetramer (4 subunits), α2β2 structure
α protein subunit HBA2 coded by HBA1, HBA2 genes
β protein subunit HBB1 coded by HBB gene (human genes--italic caps, protein--non italic)
sickle cell HBB gene: glutamic acid (hydrophilic side chain) → valine (hydrophobic side chain) → sickle cell haemoglobin tends to form fibres due to interactions between beta chains → distortion of cell shape → disrupted function
persistence of sickle cell anaemia: heterozygous advantage → selection pressure for HbS to be maintained in population
other examples: Thalassaemia cystic fibrosis mutation in CFTR
visualize transcription, splicing and translation mechanisms central to molecular biology
The Central Dogma: transcription, translation (DNA → RNA → protein) More recently: reverse transcription (RNA → DNA), enzymes that add epigenetic marks (protein → DNA), replication of RNA (in virus), etc.
most common conformation
right-handed helix (clockwise as it goes forward)
major groove (long gap), minor groove (short gap)
ribose & phosphate along outside
bases in the middle
Chargaff's Rule: amount of A = T, G = C
purines: A, G; pyrimidines: T, C
from 5' to 3'
Initiation
TATA-box binding protein bind to DNA
other components of TFII, RNA polymerase II bind
transcription factors at cis-acting enhancers can trigger elongation
Elongation
Termination
pre-mRNA before splicing
removes introns by using spliceosome (set of proteins)
Spinal muscular atrophy is an inherited disease caused by splicing problems
sequence that tRNA binds at ribosome: A site → P site → E site
illustrate how problems in transcription and translation can lead to disease through specific examples
caused by defects in haemoglobin
Haemoglobin
tetramer (4 subunits), α2β2 structure
α protein subunit HBA2 coded by HBA1, HBA2 genes
β protein subunit HBB1 coded by HBB gene (human genes--italic caps, protein--non italic)
sickle cell HBB gene: glutamic acid (hydrophilic side chain) → valine (hydrophobic side chain) → sickle cell haemoglobin tends to form fibres due to interactions between beta chains → distortion of cell shape → disrupted function
persistence of sickle cell anaemia: heterozygous advantage → selection pressure for HbS to be maintained in population
other examples: Thalassaemia cystic fibrosis mutation in CFTR
