Biochemistry Flashcards
what cells make up the pancreatic islet?
alpha cells
beta cells
delta cells
PP cells
what does it secrete:
alpha cells
insulin
what does it secrete:
beta cells
glucagon
what does it secrete:
delta cells
somatostatin
what does it secrete:
PP cells
pancreatic polypeptide
the insulin peptide structure has _ polypeptide chains linked by what type of bond?
the insulin peptide structure has 2 polypeptide chains linked by DISULFIDE BONDS
name the type of insulin that is…
ultra fast/ultra short acting
lispro
name the type of insulin that is…
short-acting
regular
name the type of insulin that is…
intermediate acting
NPH/lente
name the type of insulin that is…
long acting
ultralente
name the type of insulin that is…
ultra long acting
glargine
insulin lispro is ____meric
insulin lispro is MONOmeric
glargine is administered at what time of the day?
bedtime
glucose enters _ cells through the _____ glucose transporter and is phosphorylated by ___________
glucose enters BETA cells through the GLUT2 glucose transporter and is phosphorylated by GLUCOKINASE
Increased metabolism of glucose leads to an increase in intracellular ___ concentration
Increased metabolism of glucose leads to an increase in intracellular ATP concentration
how many ATP are produced per glucose?
36
glucose-6-P -> __________ -> acetyl-CoA -> ___ cycle
glucose-6-P -> GLYCOLYSIS -> acetyl-CoA -> TCA cycle
ATP inhibits what channel?
K+ channel
inhibition of the K+ channel leads to hyper/depolarisation of the cell membrane
inhibition of the K+ channel leads to DEPOLARISATION of the cell membrane
depolarisation of the cell membrane results in opening of what channel?
voltage gated Ca2+ channel
increase in internal Ca2+ concentration leads to release of what?
insulin
insulin should only be secreted in response to blood glucose rising above what?
5mM
in T1DM, beta cells are….
lost
release of insulin is __phasic
release of insulin is BIphasic
sulphonylurea drugs mimic the action of ___ to depolarise ____ cells
sulphonylurea drugs mimic the action of ATP to depolarise BETA cells
Kir6 and SUR1 are 2 proteins that make up what channel?
Katp channel
Kir6.2 mutations can lead to _________ diabetes
Kir6.2 mutations can lead to NEONATAL diabetes
some Kir6.2 or SUR1 mutations lead to congenital _________________
some Kir6.2 or SUR1 mutations lead to congenital HYPERINSULINISM
monogenic diabetes with genetic defect in b cell function
familial form of early-onset type II diabetes, primary defects in insulin secretion
mutations in at least 6 different genes (150 different mutations) can cause
diagnosis?
MODY
activity of what is impaired in MODY2?
glucokinase activity
MODY is treated with ______________ whereas T1DM is treated with _______
MODY is treated with SULPHONYLUREA whereas T1DM is treated with INSULIN
loss of insulin secreting beta cells
diagnosis?
T1DM
defective glucose sensing in the pancreas and/or loss of insulin secretion
diagnosis?
MODY
initially hyperglycemia with hyperinsulinemia so primary problem is reduced insulin sensitivity in tissues
diagnosis?
T2DM
biological effect of insulin:
- Amino acid uptake in muscle
- Lipolysis
- DNA synthesis
- Protein synthesis
- Growth responses
- Glucose uptake in muscle and adipose tissue
- Gluconeogenesis in liver
- Lipogenesis in adipose tissue and liver
- Glycogen synthesis in liver and muscle
what’s turned on and whats turned off?
- Amino acid uptake in muscle - ON
- Lipolysis - OFF
- DNA synthesis - ON
- Protein synthesis - ON
- Growth responses - ON
- Glucose uptake in muscle and adipose tissue - ON
- Gluconeogenesis in liver - OFF
- Lipogenesis in adipose tissue and liver - ON
- Glycogen synthesis in liver and muscle - ON
name the type of receptor that insulin binds to
receptor tyrosine kinase
rare autosomal recessive genetic trait
mutations in the gene for the insulin receptor
severe insulin resistance
developmental abnormalities:
- elfin facial appearance
- growth retardation
- absence of subcutaneous fat, decreased muscle mass
caused by defects in insulin binding or insulin receptor signalling
diagnosis?
leprechaunism – Donohue syndrome
rare autosomal recessive genetic trait
severe insulin resistance, hyperglycemia and compensatory hyperinsulinemia
developmental abnormalities
acanthosis nigricans (hyperpigmentation)
fasting hypoglycaemia (due to hyperinsulinemia)
diabetic ketoacidosis
Ssevere cases linked to mutations in the insulin receptor that reduce sensitivity
diagnosis?
Rabson Mendenhall syndrome
vomiting
dehydration
increased heart rate
distinctive smell on breath
diagnosis?
diabetic ketoacidosis - DKA
where are ketone bodies formed?
liver mitochondria
in T1DM, DKA is a danger is insulin supplementation is ______
in T1DM, DKA is a danger is insulin supplementation is MISSED
DKA is more rare in T_DM
DKA is more rare in T2DM
if supply of ____________ is limited (eg no glycolysis) the Acetyl CoA diverted to ketones
if supply of OXALOACETATE is limited (eg no glycolysis) the Acetyl CoA diverted to ketones
when glucose is not available, what are oxidised to provide energy?
fatty acids
accumulation of ketone bodies leads to what?
acidosis
