lipids 1

Question 1

general features

Answer 1

1- heterogenous
2-water insoluble
3-soluble in organic solvent

Question 2

functions

Answer 2

1-structure membrane
2-energy storage
3-hormones
4-vitamines
5-co-factors
6-signalling molecules

Question 3

fatty acid nomenclature

Answer 3

depends on number of carbon atoms, number of double bonds and where bonds are.
numbering starts from carboxyl group

Question 4

different types of fatty acid

Answer 4

bad-saturated
good-polyunsaturated
very bad-trans fatty acids
essential-linoleic and linolenic fatty acids derived from plant. fatty acids with double bond past 9th carbon cannot be produced in human body. linoleum acid synthesises production of omega-3 and omega-5 and arachidonic acid.

Question 5

unsaturated/saturated fatty acids

Answer 5

unsaturated-kink due to double bend. have low melting point

saturated-no double tend-solid

Question 6

deficiencies

Answer 6

depression
adhd
skin lesions, neurological disorders, kidney problems
chronic intestinal problems

Question 7

triglycerides

Answer 7

esters made up of 3 fatty acid chains and glycerol
water insoluble
form lipid droplets in adipose tissue
uncharged

Question 8

phospholipids, steroids and glycolipids

Answer 8

phospholipids: 2 fatty acid chains +glycerol. amphipathic
glycolipids: carbohydrate +lipid. important function in membrane structure and blood group antigens
steroids: ring shaped lipids

Question 9

how does the absorption and digestion of lipids occur?

Answer 9

1- products of TAG, PL and cholesterol esters are mixed up with bile salts in the stomach to produce micelles
2-miscelles move towards enterocytes along with small FAs and diffuse across membrane
3-in SI the micelles are resynthesises into TAG, PL and cholesterol esters
4- they are mixed with a solubilising protein -APOB-48- to form a chylomicron
5-chylomicron transports the lipid out the SI, into the lymph and then the blood
6-TAG is hydrolysed into FA and glycerol by LIPOPROTEIN. LIPASE ( found in skeletal and adipose tissue)
7- chylomicron remnants return to liver.

Question 10

what happens to the products of the TAG?

Answer 10

1- glycerol is transported to liver where it is used in gluconeogenesis
2-free FA is used for energy or re-esterified into TAG for storage

Question 11

what are bile salts

Answer 11

derivates of cholesterol.

promotes emulsification with peristalsis to produce micelles.

Question 12

what are the products of TAG, PL, and cholesterol esters hydrolysis by pancreatic ligases?

Answer 12

1-TAG–> glycerol+fatty acid
2- PL–> fatty acid+ LYSOPHOSPHOLIPID
3- cholesterol ester–> cholesterol+ FA

Question 13

what happens in the stomach?

Answer 13

small FA are digested by ligases.

Question 14

how are Fatty acids transported in the blood?

Answer 14

They are transported in lipoproteins ( FA and serum albumin)

Question 15

what are lipoproteins made of

Answer 15

serum albumin- most abundant plasma protein in the blood with 2-7 binding sites for FA
they have a hydrophilic surface-PL, apolipoproteins and a hydrophobic core-TAG

Question 16

When is the storage TAG released from cells?

Answer 16

in response to adrenaline or epinephrine which triggers the hormone sensitive lipase to be released.

Question 17

what are the different classes off lipoproteins?

Answer 17

from least dense to most dense
1- chylomicrons
2-VLDL- from liver to tissues
3-LDL-extra hepatic tissue
4HDL- from tissue to liver

Question 18

what is Steattorhea?

Answer 18

Lipid Malabsorption
XS fat in stools
Gallbladder secretes bile- removal can lead problems