LIPIDS

Question 1

what are the types of lipids?

Answer 1

fats, oil, specific vitamins, some hormones and membrane components

Question 2

what is the structure of fatty acids in general?

Answer 2

hydrocarbon-chain (R) with a carboxyl group

R-COOH

Question 3

what is the nature of fatty acids?

Answer 3

amphipatic - hydrophilic head (COOH) and hydrophobic tail (R) in which the tail is much larger than the head

Question 4

what is the difference between saturated and unsaturated?

Answer 4

fully unsaturated : every carbon in the tail have double bonding
fully saturated : every carbon in the tail have single bonding

Question 5

what effect does increasing the no. of double bond in fatty acids?

Answer 5

decrease mp of fatty acids as C=C bonds cause stiff kinks along the chains and lowers the mp of fat

Question 6

what is the common characteristics of unsaturated fatty acids?

Answer 6

• fatty acids are usually in the even numbered carbon and double bonds in fatty acids are usually in the cis configuration, hence unsaturated fatty acids have have rigid 30 degrees bend

Question 7

fatty acids are more saturated in what organism?

Answer 7

more saturated in animals then plants

Question 8

what is phospholipids?

Answer 8

aka glycerophospholipids are most abundant in cell membrane

Question 9

what is the structure of fatty acids?

Answer 9

1 glycerol + 2 fatty acids + 1 ‘X’ polar phosphate group

Question 10

function of phospholipids?

Answer 10

form membrane and polar vesicle boundaries

Question 11

what is triglycerides?

Answer 11

aka triacylglycerols can be found in fibroblast-like precursor and they are made up of 1 glycerol + 3 fatty acid chains

Question 12

what is the property of lipids?

Answer 12

MICELLES AND BILAYERS

- single tailed lipids tend to form micelles which are aggregate of molecules having both polar and non-polar regions

Question 13

what does phospholipids and sphingolipids form?

Answer 13

tend to form bilayers bc they have 2 tails

- impermeable to ionic and polar substances basically any substance that dissolves in water easily

Question 14

lipid allows for compartmentalization , why is this important?

Answer 14

• nucleus protects DNA
• mitochondria can make ATP
• control of what enters or leaves the cell

Question 15

what are the three functions of lipids?

Answer 15

• energy storage
• formation of biological molecules
• cellular signaling

Question 16

what is energy storage of fats and oils?

Answer 16

• plants and animals have both fat and oils

- cellular oxidation of fatty acids to CO2 and H20 is highly exergonic

Question 17

what are the advantages of lipids over carbohydrates?

Answer 17

1 . carbon atoms of fatty acids are more reduced hence oxidation of it gives twice more energy
2 . triglycerides are hydrophobic and unhydrated unlike carbohydrates which requires 2-3 mg of H2O per gm of carbohydrates

Question 18

what is formation of biological molecules in membrane components?

Answer 18

phospholipids are the major components in cell membranes
- hydrophobic effect drives phospholipid bilayer formation in which H2O and polar molecules attract while non-polar and attract each other

Question 19

how can phospholipid be cleaved?

Answer 19

cobra venom contains phospholipase A2 which can cleave phospholipid at carbon-2 position to generate lysophospholipid which results in powerful detergent which can kill cells and disrupts cell membranes

Question 20

what are some natural phospholipids?

Answer 20

Phospholipase A1, A2, C and D

Question 21

where does cleaved products of the phospholipids go?

Answer 21

cytosal and function as signaling molecules for cell proliferation and apoptosis

Question 22

what is cellular signaling in lipid hormones and specific vitamins?

Answer 22

3 types of hormones :

steroids, AA and polypetides

Question 23

what are steroids?

Answer 23

• have 4 ring structure and are lipid soluble which often bind to receptors inside target cell
• includes cholestrol and sex, stress and waster balancing hormones

Question 24

what are cholestrol?

Answer 24

comprimises 30%-40% of plasma membrance lipids in animals

Question 25

what are sex hormones?

Answer 25

testrogen and estradiol made in the testes and ovaries which regulate the development of male and female sex organs and secondary physical traits

Question 26

what are stress hormones?

Answer 26

cortisol made in the adrenal gland which regulate how we respond to stress and suppress inflammation and immune response

Question 27

what are water balancing hormones?

Answer 27

aldosterone made in the adrenal glands which regulate excretion of salt and water by our kidneys