lipids

Question 1

Functions

Answer 1

-energy source
-energy storage
-insulation/protection
-cell membrane structure
-transport of fat-soluble vitamins
-hormones and signal molecules
-vitamin D, bile, sex, pros
-regulators of appetite and satiety

Question 2

Triglycerides

Answer 2

95% of what we consume
-energy source and storage
(9cal/g and fuel source is secondary to glucose)
-fat as fuel is preferred by heart, liver, and resting muscle
-spares glucose for use by nervous and RBC
-stored in adipocytes

Question 3

adipose tissue

Answer 3

subcutaneous= tissue for thermoregulation
visceral= surrounds and protects organs

Question 4

Not enough fat

Answer 4

skin issues, depression, compromised immune, infections, slow wound, anemia, diarrhea

Question 5

Fatty acids

Answer 5

long carbon chains with a carboxyl and a methyl group
-building bloxk of nutritional lipid
n= any even number from 2-24

Question 6

FA vary by

Answer 6

-length of chain, degree of satuartion, shape

Question 7

Length of chain

Answer 7

Acetic acid (C2:0)
Palmitic Acid (C14:0)
Stearic Acid (C18:0)
-short chain <8 C
Medium chain 8-14 C
Long 16 or more
very long >22C

Question 8

Saturation

Answer 8

saturated=no double bonds
ex: stearic acid
unsaturated= one or more double bond
Ex: Monosaturated=oleic acid (c18:1)
-Polyunsaturated= Linoleic (C18:2) or Linolenic (C18:3)

Question 9

Omegas

Answer 9

Omega number: position of the double bond closest to the methyl end
-MUFA: Omega-9=oleic acid
-PUFA(2): Omega-6= linoleic
-PUFA (3): Omega-3=Linolenic

Question 10

Essential FA

Answer 10

Unsaturated, essential to human health and cannot be manufactured in the body
-linolenic omega 3
-linoleic omega 6

Question 11

Firmness

Answer 11

PUFA are oils, SFA are solids
-shorter chains are softer at room temperature
-some shorter saturated chains are oils

Question 12

Stability of FA

Answer 12

Rancidity- spoiling of fats through oxidation (oils go bad faster)
-double bonds are less stable than single bonds
can prevent by: add antioxidants, limit oxygen, heat, and light, and hydrogenation

Question 13

hydrogenation

Answer 13

adding H atoms to double bonds to make saturated fatty acids
-can cause trans FA (behave like saturated FA and increase cholesterol)

Question 14

Triglycerides

Answer 14

FAs attached to OH groups, gives off H2O
-ester bond

Question 15

Phospholipids

Answer 15

one fatty acid gets replaced with choline
-used as emulsifiers

Question 16

average cell membrane

Answer 16

50% lipids, 75% phospholipids, 20% cholesterol, and 5% glycolipids

Question 17

Sterols

Answer 17

four fused C rings
-cholesterol is most well known
-plant sterols interfere with cholesterol absorption and can lower blood cholesterol
*starting material for : Vit D3, Estrogen, testosterone, bile, cholesterol

Question 18

Digestion mouth

Answer 18

chewing breaks down fat
-some hard fats melt at body temp
-food mixes with saliva and lingual lipase
-hydrolyzes the medium-chain FA

Question 19

Digestion Stomach

Answer 19

strong muscular contractions (grinds solid pieces, disperses fat
-gastrin stimulates release of gastric juices, rich in gastric lipase
-gastric lipase hydrolyzes one fatty acid from tri, and makes a diglycerides

Question 20

Digestion SI

Answer 20

fat in the duodenum stimulates the release of Cholecystokinin (CCK)- stimulates gallbladder to release bile
Bile-made from cholesterol and amino acid
-bile emulsifies fat droplets into smaller fat droplets
-pancreatic lipase digest the lipids
-monoglycerides and FAs are emulsified by bile to form micelles

Question 21

Absorption

Answer 21

-glycerol and short and medium chain FA are directly absorbed by diffusion
-monoglycerides and long-chain FA merge into micelles
-once inside the intestinal cells, micelles diffuse and mono and FA are reassembled into TG

Question 22

Chylomicrons facilitate lipid absorption

Answer 22

long chain fatty acids combine with phospholipids and cholesterol to form chylomicrons
-transport triglycerides from SI through lymph into blood and body cells which remove the lipids
-travel through lymph system, exit lymph and enter bloodstream near the heart
-as chylomicrons move through the the body they pick up TG

Question 23

bile

Answer 23

most bile is reabsorbed and sent back to liver, but some is excreted because its trapped by soluble fibers (reduces blood choledterol)

Question 24

Lipoporteins

Answer 24

lipid transport structures
-blood is 55% water
-lipids and proteins help transport lipids through the blood and tissues

Question 25

Liver

Answer 25

-site of lipid synthesis
-removes remnants of the chylomicrons from the blood and reassembles them into new triglycerides
-new lipids go into a lipoprotein to be transported

Question 26

VLDL

Answer 26

very low density lipoprotein
-made in liver about 50% of transport
-travel through body and cells remove TGs from them
-as they lose TGs they become more dense

Question 27

LDL (not bad)

Answer 27

low density lipoprotein- mostly cholesterol
-circulate through body and release TGs, cholesterol and phospholipids to cells
-liver removes LDL from circulation
-delivers lipids to tissue cells

Question 28

HDL

Answer 28

High density lipoprotein
-transports cholesterol from cells back to liver for disposal