Lipids

Question 1

lipid definition

Answer 1

group of water-insoluble (hydrophobic) organic molecules

Question 2

lipid function

Answer 2

major energy source for the body, stored as triacylglycerol (triglycerides)

Question 3

classifications of lipids

Answer 3

FA’s, triglycerides, glycerophospholipids, sterols, sphingolipids, and eicosanoids

Question 4

fatty acids

Answer 4

used as stored energy in living organisms, are carboxylic acids w/ hydrocarbon chains

Question 5

nonesterified vs esterified FA’s

Answer 5

nonesterified: exist freely in the body
esterified: within complex molecules, like triglycerides

Question 6

saturated vs unsaturated FA’s

Answer 6

saturated: contain no carbon-carbon double bonds
unsaturated: contain carbon-carbon double bonds (mono-: 1 double bond, poly-: mult. double bond)

Question 7

FA nomenclature

Answer 7

carboxyl group carbon labeled as #1
- chain length: # of double bonds (location)
- delta sign used for double bonds

Question 8

FA’s characteristics

Answer 8

chain length: longer chains = more hydrophobic and higher melting point
degree of unsaturation: more double bonds = lower melting point, greater degree of fluidity

Question 9

what is more common in FA, double bonds in cis or trans config?

Answer 9

cis configuration

Question 10

omega-3 FA’s

Answer 10

double bond between third and fourth carbon from the end of the chain (omega end)
- good for the eye

Question 11

triglycerides types

Answer 11

simple TAG: 3 of the same kind of FA
mixed TAG: more common- varying chain length/saturation

Question 12

triglyceride general info

Answer 12

mostly found in adipocytes, mainly broken down to form acetyl-coA

Question 13

FA as an energy source

Answer 13

yields more than 2x the energy of carbs, may sustain an individual when dietary intake is low

Question 14

phospholipids definition

Answer 14

lipid class for the formation and maintenance of all forms of cell membranes
-either glycero- or sphingolipids

Question 15

structure of phospholipids

Answer 15

• is amphipathic (both hydrophobic and hydrophilic properties)
• polar head group: face intra/extracellularly
• non polar tail: buried within the cell membrane

Question 16

phosphoglycerides definition

Answer 16

main component of biological membranes, glycerol-based phospholipid
- polar head group: phosphate group + alcohol
- non-polar FA tail

Question 17

sphingolipids

Answer 17

polar head group and two nonpolar tails w/ no glycerol component
-consist of amino alcohol sphingosine

Question 18

sterols definition

Answer 18

steroids w/ 8-10 C’s in the side chain of carbon 17 and a (-OH) group at carbon 3

Question 19

major sterol in tissue

Answer 19

cholesterol

Question 20

sterol function

Answer 20

component of plasma membrane, precursor for synthesis of steroid hormones

Question 21

what’s the precursor for steroid hormones

Answer 21

cholesterol is the precursor of all steroid hormones

Question 22

steroid hormones function

Answer 22

trigger changes in gene expression and metabolism, by traveling through bloodstream from site of synthesis to target organ

Question 23

vitamin general info

Answer 23

• either water soluble or vitamin soluble
• must be obtained through diet
  -required in constant, small amounts because it’s readily eliminated through the urine

Question 24

Vitamin B1 (thiamine)

Answer 24

-coenzyme important for pentose-phosphate rxn and several dehydrogenase complexes

Question 25

vitamin B1 deficiencies

Answer 25

fatal condition, can lead to heart failure - beriberi: typical B1 def syndrome -wernicke-korsakoff: neuro disturbance, assoc w/ alcoholism encephalopathy: ataxia, confusion, EOM paralysis korsakoff's psychosis: amnesia

Question 26

vitamin B2: riboflavin

Answer 26

precursor of flavin mononucleotide (FMN), and flavin adenine dinucleotide (FAD)

Question 27

vitamin B2 deficiency

Answer 27

dermatitis, assoc. w/ other B complex deficiencies

Question 28

vitamin B3: niacin

Answer 28

- active coenzymes forms are NADH and NADPH

Question 29

vitamin B3 deficiency

Answer 29

pellagra (skin, GI tract, CNS)

Question 30

vitamin B9: folic acid

Answer 30

-coenzyme essential for synthesis of certain AA's and nucleotides

Question 31

vitamin B9 deficiencies

Answer 31

most common vitamin deficiency in US, common in pregnant women, and alcoholism - megaloblastic anemia and spina bifida

Question 32

vitamin B12: cobalamin

Answer 32

key role in DNA synthesis and RBC formation, obtained from meat

Question 33

vitamin B12 deficiency

Answer 33

-most common worldwide - causes both neurological and hematological abnormalities - pernicious anemia - sensory neuropathy

Question 34

vitamin C: ascorbic acid

Answer 34

-helps form and repair CT - acts as an antioxidant - important for aqueous and vitreous humor

Question 35

vitamin C deficiency

Answer 35

scurvy

Question 36

Water vs fat soluble vitamins

Answer 36

fat soluble: vitamin C, and B complex water soluble: ADEK

Question 37

vitamin D

Answer 37

- mainly from sunlight - inactive vit D is converted to calcitriol (active Vit D) - regulates Ca2+ intake in the intestine, and Ca2+ levels in kidney/bones

Question 38

vitamin D deficiency & toxicity

Answer 38

deficiency: rickets in children, osteomalacia in adults toxicity: hypercalcemia, band keratopathy

Question 39

vitamin A

Answer 39

- 2 types: 1. retinoids- important for vision transduction 2. carotenoids: green leafy veggies

Question 40

vitamin A deficiency

Answer 40

dry eyes/skin, stunted growth

Question 41

vitamin K

Answer 41

- coenzyme involved in blood clotting cascade - bacteria produces half, other half form plants

Question 42

vitamin K deficiency

Answer 42

excessive bleeding, lack of clotting

Question 43

vitamin E

Answer 43

- antioxidants for membrane of proteins and lipids - reduces the effects of aging - part or AREDS treatment for mac degen

Question 44

minerals

Answer 44

chemical elements needed for normal structure and function of the body - 2 types: macrominerals (ex calcium, sodium, etc.) trace elements (ex iron, copper, etc.)

Question 45

eicosanoids

Answer 45

3 classes: prostaglandins, thromboxanes, leukotrienes - short acting, local hormones

Question 46

micelle

Answer 46

lipid bilayer, looks like a donut

Question 47

liposomes

Answer 47

solvent filled vesicle, looks like donut hole

Question 48

transverse diffusion

Answer 48

is rare because it would have to go across the lipid bilayer

Question 49

lateral diffusion

Answer 49

fast process and highly mobile in this plane