topic 6 Flashcards
what is homeostatsis
the maintainencace of a stable environment
what happens if the temperature is too high in the body
enzymes may denature. breaks the hydrogen bonds in the tertiary structure.
active site of enzyme is changed no longer works as a catalyst.
metabolic reactions are less efficient
what happens if the temperature of the bidy is too low
enzyme activity is reduced
slowerrs metabolic reactions
what is the optimum temperature of enzymes
37 degrees
what happens if the blood pH is too high or low
enzymes are denatured. hydrogen bonds in the tertiary structure is broken
so shape of active site changes
- so cant work together as a catalyst
what happens if the blood glucose is too high
the water potential of the blood is reduced
water moves out the cell by osmosis
cells shrivel and die
what happens if the blood glucose oncentraation is too low
there isnt enough glucose for aerobic respiration
what are thee two hormones that control blood glucose concentration
insulin
glucagon
what cells secrete insulin
beta cells
what cells secrete glucagon
alpha cells
what is a sacroplasm
the cytoplasm of muscle cells
what does trpomyosin cover
the binding sites for myosin to bind onto the actin
what is the role of calcium ions in the sliding filameent theory
calcium bind to troponin
causes tropmyosin to move
exposing tthe binding sites
what is a ccross bridge
when myosin and actin are binded together `
what does the pancreas detect
change in blood glucose levels
what cells are contained in the pancreas
endocrine cells
where are the endocrine cells found in the pancreas
islets of langherhans
where is adrenaline released
the adrenal gland
what detects an increase in blood glucose concentrations
beta cells
what is the role of insulin
makes liver cells more permeable to glucose
and enzymes are used to convert glucose to glycogen
which results glucose being removeed ffrom the blood
so that it is stored glycogen
what cells detect a decrrease in blood glucose levels
alpha cells
what do alpha cells releasea
glucagon
what do alpha cells allow
it allowss glycogen to be hydrolysed to glucose and moree glucose is released back nto the blood
what is glycogenesis
when excess glucose is converted to glycogen when blood glucose is higher than normal
what is glycogenolysis
the hydrolysis of glycogen back into glucose in the liver. when blood blucose levels are too low
what is gluconeogenesis
creating glucose from non carbohydrate stores
how does insulin decrease blood glucose
attach to receptors on the surface of liver cells
- changes the tertiary structuee of the protein
- so more glucose is absorbed by facilitated diffusuion. by creating larger surface area
- more protein channels are incorporated into the cell membrane so more glucose is absorbedd
- it activates enzymes involved in the conversion of glucose to glycogen
what is the action of alpha cells
glucagon is released
and attaches to the receptors on liver cells
causes a protein to be activatedd into adenylate cyclase
and to convert ATP into cyclic AMP
which activates the enzyme protein kinase
so that glycogen is hydrolysed into glucose
activates enzymes invloved in the conversion of glycerol and amino acids into glucose
