Lecture 7

Question 1

describe cholesterol

Answer 1

lipid with an -OH group
makes up 30% of all cell membranes
about 1g/a day is synthesised via a 37 step pathway
precurser of steroid hormones

Question 2

what are two properties of steroid hormones

Answer 2

hydrophobic and hydrophilic so abole to enter cell membranes and BBB

Question 3

what are the two classes of steroid hormones

Answer 3

corticosteroids - adrenal cortex

sex steroids - gonads or placenta

Question 4

what does the DNA binding domain encode

Answer 4

Zinc finger
4x crystaline subunits that encapsulate a zinc atom to form a looped structure
able to bind to major groove of double helix

Question 5

what sort of diseases arise from mis-regulation if nuclear receptors

Answer 5

glucocorticoid receptor control cortisol production
addisons disease - too little cortisol
damage to adrenal glands or lack of ACTH
depression, flu like, nausea, weight loss

cushings disease - too much cortisol
benign adenoma in pituitary gland - increased ACTH
or long term steroid abuse
weight gain, raised BP, puffy face. hair growth

Question 6

what are the three main biochemical steps in insulin signalling

Answer 6

1. tyrosine phosphorylation
2. activation of lipid kinase
3. activation of multiple serine/threonine kinases

Question 7

what is the prevalence of type1/2 diabetes

Answer 7

type 1 1:300

type 2 1:17

Question 8

what are the symptoms of type 2

Answer 8

thirsty
passing urine more often
tired
weight loss
slow healing cuts - ulcers
frequent thrush
blurred vision

Question 9

what is the common treatment

Answer 9

metformin
antihyperglycemic agent that resensitises insulin
positively charged - accumulates in mitochondria
inhibits mitochondrial complex 1 -preventing mitochondrial ATP being made - increased cytoplasmic ADP:ATP +AMP:ATP ration
activate AMP - activate protein kinases - enzyme that plays major role in regulation glucose metabolism