Self-Study - Lipids

Question 1

Lipid Functions

Answer 1

metabolic fuel
membrane structure
hormones
digestion
second messengers
vitamins

Question 2

Classes of lipids

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Answer 2

fatty acids
acylglycerols
phosphoglycerides
sphingolipids
steroids
prostagladins, thromboxanes and leukotrienes

Question 3

Fatty acid formula

Answer 3

R-COOH

R = alkyl chain of C and H atoms

Question 4

fatty acid chain lengths

Answer 4

short chain is 2-4 carbons
medium chain is 6-10 carbons
long chain is 12-26 carbons

Question 5

unsaturated fatty acids

Answer 5

1 or 2 double bonds which allow for isomerization b/w cis and trans. Cis- is naturally formation.

Question 6

fatty acid ionization

Answer 6

pKa of fatty acid -COOH group is ~4.8
body pH is 7.35
acids are ionized –> detergent properties

Question 7

fatty acid nomenclature

Answer 7

C atoms numbered from -COOH group or from carbon furthest removed from -COOH group

alpha, beta, gamma, delta… omega

Question 8

branch-chain fatty acids

Answer 8

most fatty acids in mammalian tissue is straight chain

sebaceous gland contains branch-chain

Question 9

hydroxylated fatty acids

Answer 9

fatty acids that contain -OH group attached to alkyl chain

ex: cerebonic acid in CNS

Question 10

what are the 2 main classes of polyunsaturated fatty acids that mammals cannot synthesize?

Answer 10

linoleic (omega-6)
linolenic (omega-3)
used to synthesize biologically active cmpds such as prostaglandin, leukotrienes, lipoxins

Question 11

essential fatty acids

Answer 11

linoleic, linolenic, arachidonic acids

omega 6, omega 3, omega 6

Question 12

acylglyerols (3 types)

Answer 12

fatty acid esters of glycerol
monoglycerides
diglycerides
triglycerides

Question 13

predominant form of acylglycerol & storage form of fat in man

Answer 13

triglycerides

Question 14

phosphoglycerides

Answer 14

acylglycerol containing phosphoric acid esterified at C3-OH group
can form bilayers in aq solutions –> membranes

Question 15

sphingolipids

Answer 15

present in blood and nearly all tissues
highest concentrations found in white matter of CNS
also component of plasma membrane of cells

Question 16

types of sphingolipids

Answer 16

1. sphingomyelin - lipid of membranes of nervous tissue, aka phopholipid
2. glycosphingolipids - derivative with 1 or more carbohydrate residues

Question 17

steroids

Answer 17

members of family include cholesterol, bile acids, and steroid hormones

Question 18

steroid hormones

Answer 18

have same 4 ring structure with shorter side chains than cholesterol or bile salts

mineralcorticoids
glucocorticoids
sex steroids - androgen, estrogen

Question 19

prostaglandins

Answer 19

derivatives of C20, polyunsaturated fatty acids such as arachidonic acid

different from each other by substituents on ring and whether C15 contains an OH or OOH group

Question 20

thromboxanes

Answer 20

derivatives of C20

have an oxgyen incorporated to form six-membered ring

Question 21

leukotrienes

Answer 21

derivatives of C20

substituted derivatives of arachidonic acid in which no internal ring is formed

Question 22

lipid peroxidation

Answer 22

lipids exposed to oxygen may cause tissue damage

effects caused by free radicals

Question 23

amphipathic nature of lipids

Answer 23

membranes, micelles, liposomes

Question 24

fatty acids, phospholipids, sphingolipids, bile salts, and cholesterol contain what?

Answer 24

polar groups

Question 25

amphipathic

Answer 25

both hydrophobic and hydrophilic property

Question 26

which of the following lipids is not an amphipathic molecule? cholesterol ester, phosphatidylcholine, ganglioside, spingomyelin

Answer 26

cholesterol ester