cholest

Question 1

strcuture of cholestrol

Answer 1

cyclic rings with a hydrophobic tail

The steroid ring structure is planar

Question 2

function of cholestrol

Answer 2

is that it can increase and decrease membrane stiffness, depending on the temperature and the nature of the membrane

Question 3

formation of c

Answer 3

liver through de novo synthesis of cholesterol from acetyl-CoA.

Question 4

3 main steps Cholesterol Synthesis

Answer 4

1) Synthesis of isopentenyl pyrophosphate
2) Condensation of 6 moleclies of iso to form squalene
3) Cyclisation and demethylation to get cholestrol

Question 5

how bile salts are formed

Answer 5

major breakdown products of cholesterol

Question 6

what are the primary bile salt

Answer 6

glycocholate and also taurocholate.

Question 7

what makes sterioids

Answer 7

…cholesterol…

Question 8

what does chol generate using demolase

Answer 8

pregnenolone

Question 9

what is pregnenolone

Answer 9

All five classes of steroid hormones come from pregnenolone: Progestagens, glucocorticoids, mineralocorticoids, androgens and oestrogens.

Question 10

what is vitiman d

Answer 10

collective term for a group of steroids which are vital for the intestinal absorption of important ions needed for bone development

Question 11

examples of vitimin d

Answer 11

calcium, phosphate and magnesium.

Question 12

main source of vitimin d

Answer 12

our main source is from the activity of UV light upon 7-dehydrocholesterol in the epdermis of the skin.



Question 13

what is `Calcitriol

Answer 13

most active vitamin D metabolite

Question 14

function

Answer 14

plays a key role in calcium metabolism. It functions as a steroid hormone, binding to vitamin D response elements (VDREs) in the promoter of target genes and inducing key genes involved in bone metabolism

Question 15

lack of calcitrol causes

Answer 15

in childhood leads to rickets

Question 16

is Familial hypercholesterolaemia (FH) dominant

Answer 16

yes

Question 17

what happens if a person is hetrozygotes

Answer 17

have cholesterol levels approximately 2-3 times higher than in normal people and are susceptible to atherosclerosis (hardening of the arteries) in middle age

Question 18

and homozygotes

Answer 18

serum cholesterol levels are five times higher than in healthy individuals and severe atherosclerosis and coronary infarction may be observed in adolescence.

Question 19

severe fh causes

Answer 19

lacked functional LDLRs
LDL receptor (LDLR)
Mutations in several domains of the LDL receptor lead to FH

Question 20

what is hypercholesterolaemia

Answer 20

high cholesterol

Question 21

how to control hypercholesterolaemia

Answer 21

Inhibition of de novo cholesterol synthesis by the liver, or the reduction of dietary cholesterol absorption by the intestines

Question 22

resins method

Answer 22

These bind or sequester bile acid-cholesterol complexes preventing their reabsorption by the intestine

Question 23

HMG-CoA-Reductase inhibitors/

statin

Answer 23

is that of a competitive inhibitor of HMG-CoA Reductase.

Question 24

step 1

Formation of acetoactyl coA

Answer 24

2 acteyl coA to it

Question 25

step 2 to HMG coA

Answer 25

acetoacetyl coa + acetyl coa

Question 26

step 3 form melovonate

Answer 26

uses HMG coA reductase which can be controlled by negative feedback cholestrol bile salts and melavonate