5/6 markers Flashcards
(12 cards)
5 properties that make water important for organisms (5)
high specific heat capacity- buffers change in temperatures
high specific latent heat- provides a cooling effect
cohesion- so supports columns of water OR produces surface tension supporting small organisms
solvent- so metabolic reactions can occur
metabolite- in condensation or hydrolysis
Role of enzymes in the digestion of proteins in a mammal (4)
hydrolysis of peptide bonds
endopeptidase- break bonds in the middle to make smaller chains
exopeptidase- remove amino acids at the end of the chain
dipeptidase- split dipeptides
D&E cell fractionation and ultracentrifugation are used to isolate mitochondria (6)
cells homogenised to break open cells
filter to remove large debris
isotonic solution to prevent cells bursting
cold, buffered to prevent enzyme action so denatured
centrifuge at low speed to remove large organelles
re-spin at higher speed to for mitochondria pellets
Describe antibody production from viral infection (5)
viral antigen presented by host cell (APC)
specific B-lymphocytes activated
B-lymphocyte undergoes mitosis
plasma and memory cells produced
plasma cells can produce antibodies
Describe the structure of proteins (7)
polymer of amino acids
joined by peptide bonds in a condensation reaction
primary- sequence of amino acids
secondary- folding by hydrogen bonds into b-pleated sheet or a-helix
tertiary- dissulfide bridges, ionic, hydrogen bonds form the 3D structure
quaternary- multiple tertiary structures
Explain how epithelial tissues in the small intestine are adapted for glucose absorption (6)
lots of carrier proteins- for active transport
microvilli- large surface area
many mitochondria-for ATP production
channel/carrier proteins- for facilitated diffusion
co-transport (carrier) proteins- for sodium and glucose
membrane bounds enzymes- digest disaccharides
Describe how membrane structure affects movement of substances (8)
phospholipid bilayer- allows movement of lipid-soluble substances OR prevents movement of polar substances
carrier proteins- for active transport
channel + carrier proteins- for facilitated diffusion
shape of carrier affects which substances move
number of transport proteins determine how much movement
surface area- how much movement
cholesterol- affects fluidity
Describe polypeptide formation by translation of mRNA (7)
mRNA attaches to ribosome
codons complementary to anticodons
tRNA brings specific amino acid
amino acids joined by peptide bonds
with use of ATP
tRNA released
ribosome moves along mRNA to form polypeptide
Explain why maltase only breaks down maltose and why the enzyme allows the reaction to take place at body temperature (5)
tertiary structure of enzyme
has an active site that is only complementary to maltose
and becomes more complementary when maltose enters (induced fit)
activation energy lowered
when enzyme substrate complex is formed
Explain how nitrates might cause the death of fish in fresh water (5)
increase algal bloom
plants can’t access light so can’t photosynthesise so die
microbial saprobiants break down dead plants releasing more nitrates and phosphates
microbial saprobiants respire aerobically so remove oxygen from the water
fish don’t have enough oxygen for aerobic respiration so die
DNA replication during S phase, PCR in vitro
DNA used helicase to break H bonds, PCR uses 95’
DNA occurs to whole DNA molecule, PCR to fragment only
DNA doesn’t need primers, PCR needs primers
DNA uses cell’s own DNA polymerase, PCR uses taq polymerase
DNA occurs once a cell cycle PCR can take place many times
Cholinergic synapse (8)
Ca++ enter axon
vesicles move to and fuse with membrane
acetylcholine released
diffuses across synaptic cleft
binds with receptors on membrane
Na+ enter
they depolarise the membrane
if above threshold, nerve impulse produced
