lecture 23 redone

Question 1

insulin is secreted in conditions of

Answer 1

high blood glucose

Question 2

insulin lowers

Answer 2

blood glucose

Question 3

glucagon is secreted in conditions of

Answer 3

low blood glucose

Question 4

glucagon increases

Answer 4

blood glucose

Question 5

the cells in the islet of langerhans have a dense capillary network so they can

Answer 5

detect the blood levels and can release the hormones very quickly

Question 6

regulators of insulin release

Answer 6

glucose, amino acids, neural input, gut hormones (GLP1, GIP), adrenaline

Question 7

regulators of glucagon release

Answer 7

glucose, insulin, amino acids, gut hormones

Question 8

insulin production
pre-proinsulin cleaved into

Answer 8

pro insulin in the RER

Question 9

proinsulin is cleave into

Answer 9

insulin and C-peptide in the golgi

Question 10

disulphide bonds form and the residues 31 and 65 are cleaved to separate the

Answer 10

c-peptide and the insulin

Question 11

insulin is stored in a

Answer 11

hexatrimeric form with zinc in the middle

Question 12

insulin is composed of A and B chains connected by

Answer 12

disulphide bridges

Question 13

what can you use c peptide for

Answer 13

to test the concentration as its not degraded and diagnose type 1 diabetes for example as c peptide levels would be low

Question 14

beta cells have a glucose transporter.
inside the cell glucose is converted to

Answer 14

glucose 6-P

Question 15

what is glucose converted to glucose 6-P by

Answer 15

glucokinase

Question 16

glucose 6-P turns to pyruvate due to

Answer 16

glycolysis

Question 17

pyruvate enters the mitochondria and undergoes

Answer 17

krebs cycle and ETC

Question 18

ETC releases ATP.
when there are low levels of glucose not much ATP is released causing what channel to stay open

Answer 18

K-ATP channel

Question 19

therefore potassium ions still move out the cell and membrane potential remains at

Answer 19

-60mV

Question 20

what channel stays shut

Answer 20

voltage gated calcium channel, therfore not calcium enters the cell and no insulin in released

Question 21

whne blood glucose levels are high, glucokinase is more active, more ATP is released causing

Answer 21

potassium ATP channel to close

Question 22

this causes the membrane to depolarise and when membrane potential is -40mV the

Answer 22

calcium channels open, high cytoplasmic calcium, high insulin secretion

Question 23

insulin in muscle
in reponse to insulin the muscle takes up glocose and converts it to

Answer 23

glycogen or oxidises it as a source of energy

Question 24

insulin in adipose tissue
in reposne the adipose tissue takes up glocose and converts it to

Answer 24

fat

Question 25

insulin in the liver liver extracts about 1/3rd of glucose and comverts it to

Answer 25

glycogen

Question 26

surplus of glucose and amino acids are converted to

Answer 26

lipids that can be taken up by adipose cells

Question 27

when liver stores are full krebs cycle only gets as far as

Answer 27

citrate

Question 28

citrate comes out the mitochondria and cirtrate is converted to

Answer 28

acetyl CoA

Question 29

acetyl coA is converted to

Answer 29

malonyl CoA

Question 30

malonyl CoA is converted to

Answer 30

FA

Question 31

FA is conjoined with glycerol to make

Answer 31

triglycerides

Question 32

triglycerides are turned into

Answer 32

VLDL and secreted into the blood

Question 33

fasting state response in muscles proteins converted to

Answer 33

amino acids and released into blood stream

Question 34

fasting state response in adipose triglycerides to FA and glycerol and release

Answer 34

FA into blood stream which muscles can use

Question 35

fasting state response in liver glucagon signals to liver to convert glycogen to glucose and release. tells liver to convert aa release by muscle to glucose. this is knows as

Answer 35

gluconeogenesis - uses other substrate to make glucose

Question 36

liver can take up _______ to convert to energy for itself

Answer 36

fatty acids

Question 37

liver can convert FA to

Answer 37

ketone bodies

Question 38

ketone bodies can fuel the

Answer 38

brain

Question 39

FA cant fuel the brain as they cant cross the

Answer 39

blood brain barrier

Question 40

during fasting glucose is produced by

Answer 40

glycogenolysis and glyconeogenesis

Question 41

when insulin binds to muscle cell it causes translocation of?

Answer 41

GLUT4 to the membrane

Question 42

insulin tells the muscle to increase the formation of glycogen by activating what

Answer 42

glycogen synthase

Question 43

adipose also have the GLUT4 transporter insulin increases the FA synthesis and increases transcription of key enzymes such as

Answer 43

fatty acid synthase and acetyl CoA carboxylase

Question 44

insulin switches of enzymes that

Answer 44

switch triglycerides back to FA (hormone sensitive lipase)

Question 45

glucose transporter in the liver

Answer 45

GLUT2

Question 46

insulin increases the transcription of

Answer 46

glucokinase

Question 47

insulin also stimulates conversion to glucogen by activating

Answer 47

gylcogen synthase

Question 48

inhibits activtity of

Answer 48

glycogen phosphorylase

Question 49

insulin switches off PEPCK and glucose 6-P phosphatase

Answer 49

theyre used in conversion back to glucose (gluconeogenic enzymes)

Question 50

when glycogen synthase is phosphorylated its

Answer 50

inactive

Question 51

when its dephosphorylated its

Answer 51

active

Question 52

insulin (in liver and muscle) activates protein phosphatase 1

Answer 52

this removes phosphate groups and activates glycogen synthase

Question 53

glycogen phosphorylase takes glycogen to G1P then back to glucose

Answer 53

when glycogen phosphorylase is phosphorylated its active

Question 54

insulin causes dephosphorylation of glycogen phosphorylase

Answer 54

making it inactive

Question 55

glucagon can increase the activity of an enzyme that phosphorylates glycogen phosphorylase

Answer 55

glycogen phosphorylase