L2 Medical Genetics Flashcards
what are the 2 types of grooves in the DNA double helix and which is important in transcription?
major and minor.
bases are easier to bind to at a major groove, site for transcription factor binding
what are the differences between DNA and RNA?
DNA- thymine, double helix, large , stable, fixed, Information store
RNA- uracil, single stranded, mass produced, disposable, translation of DNA, regulatory roles
how Does DNA replicate?
double helix is unwound, new bases are paired to each strand, double helix reforms and is checked for errors
DNA helices function?
unwinds DNA
DNa primase?
adds RNA primers, initiate the Okazaki fragments on the lagging strand
what is DNA polymerase and what direction does it move in?
catalyses synths of new DNA strand, moves in 5’to3’ direction
how is the lead strand synthesised?
one continues strand
how is the lagging strand syntheised.
discontinuously
what is DNA ligase
seals gaps between the Okazaki fragments in the lagging strand.
what happens to the RNA primers in the Okazaki fragments
they are removed
describe the structure of nucleosome
DNa complexed with 8 histones to form a nucleosome
what is karpytping and what are the light and dark bands
light areas are where the chromosome is less tight wound
what are telomeres
the end of chromosomes, lose some each time we replicate
what is the P arm?
shorter arm of chromosome
what is the Q arm?
the longer arm of the chromosome
