Chapter 5- Lipid Structure and Function Flashcards Preview

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Flashcards in Chapter 5- Lipid Structure and Function Deck (40)
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1

lipid characterization

insolubility in water and solubility in nonpolar organic solvents

2

2 structural building blocks of lipids and what they make up

Phospholipids and sterols. They make up vesicles, liposomes, and membranes

3

Amphipathic

A molecule that has both hydrophobic and hydrophilic regions

4

what happens when membrane lipids are placed in an aqueous solution?

they form one of three structures to maximize hydrophilic interactions and to minimize hydrophobic interactions.
1. liposome (two layer ball with inside)
2. micelle (one layer like a ball)
3. phospholipid bilayer

5

phospholipid

1. polar head (phosphate and alcohol)
2. hydrophoblic fatty acid tail (connected to (1) by phosphodiester linkage)

6

glycerol

three-carbon alcohol

7

saturated fatty acid

only have single bonds, carbon is considered saturated when it is bonded to 4 other atoms with no pi bonds. (greater van der waals forces and more stability)

8

unsaturated fatty acid

has 1 or more double bonds, introduce kinks making it hard to stack/bond/solidify

9

glycerophospholipids (aka. phosphoglycerides)

phospholipid subtype that contain a glycerol backbone bound by ester linkages to two fatty acids and by a phosphodiester linkage to a highly polar head group (named according to the polar head group)

10

sphingolipids

have a sphingosine/sphingoid backbone. have glycosidic linkage to sugar (glycolipid)--- used in ABO blood typing system

11

4 types of sphingolipids

1. ceramide- single hydrogen atom as head group
2. sphingomyelins
3. glycosphingolipids
4. gangliosides

12

glycosphingolipids

2 types, mainly found on outer surface of plasma membranes
1. cerebrosides- have a single sugar
2. globosides- have 2 or more sugars

13

gangliosides

"gangly" sphingolipids with the most complex structure and functional groups (oligosaccharides and NANA: sialic acid) in all directions

14

functions of wax

-protection
-in animals: waxes are secreted to prevent dehydration, as a water-repellant to keep skin and feathers dry, and as a lubricant

15

3 categories of signaling lipids and an important precursor to lipids

1. steroids
2. prostaglandins
3. fat-soluble vitamins

1. terpenes

16

terpenes

have odor. metabolic precursor to lipid signaling molecules. built from isoprene (C5H8)

17

monoterpenes

single terpene unit = 2 isoprene units (C10H16)-- essential oils

18

sesquiterpenes

3 isoprene units

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diterpenes

4 isoprene units. vitamin A is a diterpene from which retinal is derived (necessary for sight)

20

triterpenes

6 isoprene units. can be converted to cholesterol and other steroids.

21

tetraterpenes

8 isoprene units.

22

structural characterization of steroids

4 cycloalkane rings (3 cyclohexane and 1 cyclopentane)
function: depends on oxidation status of these rings.
steroids are nonpolar due to large number of C and H

23

cholesterol

1. steroid
2. major component of phospholipid bilayer (responsible for mediating membrane fluidity)
3. precursor to steroid hormones, bile acids, and vitamin D

24

prostaglandins

1. produced by almost all cells in the body (paracrine/autocrine hormones)
2. 20-carbon molecules of unsaturated carboxylic acids derived from arachidonic acid, contain one five carbon ring.

25

biological function of prostaglandins

act as paracrine or autocrine hormones. regulate synthesis of cyclic adenosine monophosphate (cAMP)- intracellular messenger.
downstream effects: powerful effects on smooth muscle, influence over sleep-wake cycle, elevation of body temp. associated with fever and pain.

26

how do nonsteroidal anti-inflammatory drugs (NSAIDs) work?

(ex: asprin) they inhibit the enzyme cyclooxygenase (COX), which aids in the production of prostaglandins

27

vitamin

essential nutrient that cannot be adequately synthesized by the body, so it must be consumed in the diet.

28

Vitamin A

aka: carotene (CARROTS HIGH IN VITAMIN A- good for vision). unsaturated hydrocarbon. important for vision, growth, development, and immune function. (ex: retinal, retinol- storage form of vitamin A is oxidized to retinoic acid- a hormone that regulates gene expression during epithelial development)

29

Vitamin D

aka: cholecalciferol. can be consumed or formed through sun interaction. converted to calcitriol (biologically active form of vitamin D) in the liver and kidneys. increases calcium and phosphate uptake in intestines (promoting bone production).

lack of vitamin D: rickets- condition seen in children with underdeveloped/curved long bones as well as impeded growth.

30

Vitamin E

tocopherols and tocotrienols.
characterized by a substituted aromatic ring with a long isoprenoid side chain. hydrophobic.
biological antioxidants (ring destroys free radicals)