1.5. Lipids

Question 1

groups of lipids

Answer 1

1) triglycerides (fats & oils)
2) phospholipids
3) steroids

Question 2

triglyceride (neutral fat) is composed of:

Answer 2

1 glycerol molecule and 3 fatty (hydrophobic) acid molecules (chains)

Question 3

group characteristic for alcohols is…

Answer 3

hydroxyl group (-OH)

Question 4

group characteristic for organic acids is…

Answer 4

carboxyl group (COOH) - carboxyl acids

Question 5

the more C an alcohol has in it (methane, ethane, propane…) the ___ soluble in water (polar) it is.

Answer 5

less

Question 6

how many carbons are in a fatty acid chain?

Answer 6

16-18

Question 7

glycerol has the same structure as ___ except it has…

Answer 7

propane, 3 OH instead of 1 (triyglyceride -> 3 dehydration reactions)

Question 8

saturated fatty acid chains are ___ and connected by ___, and unsaturated f.a. are ___ and connected by ___.

Answer 8

straight (best-fit line), single covalent bonds, broken up (bent), double or triple covalent bond(s)

Question 9

The more rounded a triglyceride is (more bends)…

Answer 9

…the less associated it is with other trigl. mol. - consistency is more liquid (oil).

Question 10

Why is fat solid at room temp.?

Answer 10

Because hydrophobic forces keep together their completely straight (saturated) f.a. chains.

Question 11

fatty acids

Answer 11

long hydrocarbon chains (hydrophobic) + carboxyl group

Question 12

A f.a. is ____ when there is only 1 double c.b., and ____ when there is more than 1.

Answer 12

monounsaturated, polyunsaturated

Question 13

Glycogen stores E for only 24 h, then it is turned into __ and stored in…

Answer 13

fat, …adipose tissue, or inside of the liver cells.

Question 14

functions of triglycerides

Answer 14

1) long-term E storage
- insoluble in H2O (not osmotically active; cells that store lipids - no change in osmotic pressure)
- form pure droplets without H2O so body can be lighter (unlike c-h associated with water)
2) more efficient E storage (than c-h)
- more chem. complex than c-h - more covalent bonds=more potential E to be stored (store 2x more than c-h - birds, lighter)

Question 15

draw a triglyceride

Answer 15

…

Question 16

What are phospholipids composed of?

Answer 16

glycerol molecule, 2 fatty acid chains (can be both saturated or unsaturated), and a PO4^3- group

Question 17

which part of phospholipid molecule is hydrophilic and which hydrophobic?

Answer 17

PO4^3- is hydrophilic (charged), the rest hydrophobic; hydrophilic head and hydrophobic tail - amphiphatic molecule

Question 18

Phospoholipids are _____ parts of _____.

Answer 18

major, constituent, plasma membrane

Question 19

Cholesterol is a type of ___ which is a ___ of ____ and recognisable by its _ ____ of _ atoms.

Answer 19

sterol, subgroup, steroids, 4 fused rings, carbon

Question 20

where is cholesterol found

Answer 20

only in animal cells (component of cell membrane)

Question 21

Cholesterol is a precursor for…

Answer 21

…all steroid hormones (estrogen, progesterone, testosterone), vitamin D, and bile.

Question 22

bile
vitamin D

Answer 22

• produced in liver, deposited in gallbladder, released in intestines to digest fats and oils
• enables calcium absorption into blood (strong bones)

Question 23

steroids are associated with ___(___) in order to be able to be…
they pass ___ through the _____

Answer 23

proteins, lipoproteins, transported through blood
easily, cell membrane (most of the membrane is hydrophobic)

Question 24

phospholipids have a ___ function,a nd steroids (cholesterol) has a ___ function.

Answer 24

structural, regulatory