topic 6

Question 1

what is homeostatsis

Answer 1

the maintainencace of a stable environment

Question 2

what happens if the temperature is too high in the body

Answer 2

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

Question 3

what happens if the temperature of the bidy is too low

Answer 3

enzyme activity is reduced
slowerrs metabolic reactions

Question 4

what is the optimum temperature of enzymes

Answer 4

37 degrees

Question 5

what happens if the blood pH is too high or low

Answer 5

enzymes are denatured. hydrogen bonds in the tertiary structure is broken
so shape of active site changes
- so cant work together as a catalyst

Question 6

what happens if the blood glucose is too high

Answer 6

the water potential of the blood is reduced
water moves out the cell by osmosis
cells shrivel and die

Question 7

what happens if the blood glucose oncentraation is too low

Answer 7

there isnt enough glucose for aerobic respiration

Question 8

what are thee two hormones that control blood glucose concentration

Answer 8

insulin
glucagon

Question 9

what cells secrete insulin

Answer 9

beta cells

Question 10

what cells secrete glucagon

Answer 10

alpha cells

Question 11

what is a sacroplasm

Answer 11

the cytoplasm of muscle cells

Question 12

what does trpomyosin cover

Answer 12

the binding sites for myosin to bind onto the actin

Question 13

what is the role of calcium ions in the sliding filameent theory

Answer 13

calcium bind to troponin
causes tropmyosin to move

exposing tthe binding sites

Question 14

what is a ccross bridge

Answer 14

when myosin and actin are binded together `

Question 15

what does the pancreas detect

Answer 15

change in blood glucose levels

Question 16

what cells are contained in the pancreas

Answer 16

endocrine cells

Question 17

where are the endocrine cells found in the pancreas

Answer 17

islets of langherhans

Question 18

where is adrenaline released

Answer 18

the adrenal gland

Question 19

what detects an increase in blood glucose concentrations

Answer 19

beta cells

Question 20

what is the role of insulin

Answer 20

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

Question 21

what cells detect a decrrease in blood glucose levels

Answer 21

alpha cells

Question 22

what do alpha cells releasea

Answer 22

glucagon

Question 23

what do alpha cells allow

Answer 23

it allowss glycogen to be hydrolysed to glucose and moree glucose is released back nto the blood

Question 24

what is glycogenesis

Answer 24

when excess glucose is converted to glycogen when blood glucose is higher than normal

Question 25

what is glycogenolysis

Answer 25

the hydrolysis of glycogen back into glucose in the liver. when blood blucose levels are too low

Question 26

what is gluconeogenesis

Answer 26

creating glucose from non carbohydrate stores

Question 27

how does insulin decrease blood glucose

Answer 27

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

Question 28

what is the action of alpha cells

Answer 28

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