Biochemistry Flashcards
describe structure of nucleic acids ( DNA RNA ) and function
Structure :nucleotides are composed of a phosphate group, a pentose sugar ( Ribose - RNA or Deoxyribose - DNA ) and one of four bases ( adenine, thymine, guanine, cytosine, )
DNA and RNA are polymers of nucleotide subunits
DNA : double stranded, helix formation
RNA : single stranded, 3 types, mRNA tRNA and rRNA
Function : storage and replication of genetic material
define adjusted calcium ( laboratory test ) and it`s use
in the blood half of the calcium is ionised and half is bound to albumin
adjusted or corrected calcium adjusts for the amount of albumin which can be relevant in states where it is abnormally high or low and gives a better indication of ionised levels
describe the different classes of hormones
peptide hormones ( large - all pituitary and insulin )
amino acid derived ( adrenaline, dopamine, thyroxine, )
steroid ( end in -one or -ol, testosterone, oestradiol, cortisol )
describe two mechanisms by which hormones work at cellular level
membrane bound eg water soluble
act through receptor on cell surface via a G protein and have various actions eg phosphorylation, activate kinases, open ion channels
intracellular eg pass through cell wall, lipid based hormones
act intracellular eg in cell nucleus
describe structure and function of proteins
primary - sequence of amino acids
secondary - alpha helix, beta pleated sheet create folds or additional groups eg carbolic acids
tertiary - 3 D shape creating sub unit
quaternary - multiple sub units
multiple functions : catalysts, transport, immune protection, cell growth,
which hormones work through neurones rather than blood borne ?
hypothalamic hormones stimulating the posterior pituitary by carrier proteins known as neurophysin granules - this is known as interaxonal transport ( oxytocin and vasopressin transported and released in the posterior pituitary )
