Exam 2: Lipids, Digestion and Absorption, Energy Metabolism

Question 1

Fatty acids that are most common in foods and most noteworthy in nutrition have how many carbons?

Answer 1

18

Question 2

What type of foods contain monounsaturated fats?

Answer 2

Olive and canola oil

Everywhere

Question 3

Long chain saturated fatty acids have how many carbons? What form do they take at room temperature?

Answer 3

> 12

Solid

Question 4

Short chain saturated fatty acids have how many carbons? What form do they take at room temperature?

Answer 4

<6

Liquid

Question 5

How many carbons do medium chain saturated fatty acids have? What form do they take at room temperature?

Answer 5

6-10

They go between solid and liquid

Question 6

Why are unsaturated fats generally liquids?

Answer 6

Double bonds create kinks in the chain, not allowing them to pack as easily as the straight chain saturated fatty acids

Question 7

What kind of fatty acid is oleic acid? How many carbons does it have?

Answer 7

Monounsaturated

18

Question 8

Where is the first double bond in oleic acid?

Answer 8

C9

omega-9 acid

Question 9

What kind of fatty acid is stearic acid? How many carbons does it have?

Answer 9

Saturated

18

Question 10

Why do fatty acids produce more energy than carbohydrates?

Answer 10

Because of the large amount of carbons and almost no oxygen

Question 11

What kind of fatty acid is linoleic acid? How many carbons does it have?

Answer 11

Polyunsaturated

18

Question 12

How many double bonds does linoeic acid have? On which carbon is the first one?

Answer 12

2 double bonds

omega-6

Question 13

What kind of fatty acid is alpha-linolenic acid? How many carbons does it have?

Answer 13

Polyunsaturated

18

Question 14

How many double bonds does alpha-linolenic acid have? On which carbon is the first one?

Answer 14

3 double bonds

omega-3

Question 15

Why are omega-3 and omega-6 fatty acids essential?

Answer 15

The body does not have enzymes that can unsaturate (add double bonds) saturated fats before C9, therefore we must consume them - although in small amounts

Question 16

Why do we need omega-3 and omega-6 fatty acids?

Answer 16

Functions: 
Cell membranes
Immune function
Vision
Eicosanoid production
Structural molecules

Question 17

What kind of fatty acids are eicosanoids?

Answer 17

20C polyunsaturated

Question 18

What do eicosanoids do?

Answer 18

Function like hormones (act locally); regulate blood pressure, clotting, immune response, inflammatory response, GI secretions

Question 19

What pathway does aspirin block?

Answer 19

Stops Arachidonic acid (omega-6) from being turned into a Group 2 series eicosanoid, which then decreases blood clotting, vasoconstriction - why it is recommended to be taken during a heart attack or those at risk

Question 20

What series of eicosanoids to omega-6 acids make? What are their function and name one.

Answer 20

Series 1 and 2
Stimulates blood clotting and vasoconstriction
Thromboxane A2 (TXA2)

Question 21

What is thromboxane A2 (TXA2)? When is it advantageous? When is it dangerous?

Answer 21

Series 1/2 eicosanoid that is made by platelets and stimulates blood clotting and vasoconstriction
Hemorrhage
Heart disease

Question 22

Describe the eicosanoid pathway that omega-3 fatty acids take.

Answer 22

Docosahexonic acid (DHA)
Eicosapentanoic acid (EPA)
Group 3 series eicosanoids

Question 23

What functions do group 3 eicosanoids have?

Answer 23

Inhibits making of group 2 series eicosanoids and therefore decrease blood clotting and risk of heart attack; could lead to hemorrhagic stroke

Question 24

What are the symptoms of essential fatty acid deficiency?

Answer 24

Flaking itchy skin
Diarrhea
Reduced wound healing
Anemia

Question 25

What are sources of omega-3 fatty acids?

Answer 25

Canola, soybean, flax seed oil | Fatty fish

Question 26

What are sources of omega-6 fatty acids?

Answer 26

Everywhere, especially vegetable oil

Question 27

What are sources of monounsaturated fatty acids?

Answer 27

Everywhere, especially olive oil

Question 28

What are sources of saturated fat?

Answer 28

Animal fat Coconut oil Palm oil

Question 29

What are sources of cholesterol?

Answer 29

Animals and animal byproducts Lard Butter

Question 30

What is esterification? When does it happen?

Answer 30

A condensation reaction (water removed) forming an ester bond Occurs when fatty acids are bound to glycerol

Question 31

What components of fatty acids can cross cell membranes?

Answer 31

Free fatty acids Monoglycerides Glycerol

Question 32

What are the functions of triglycerides?

Answer 32

``` Provide energy (9 kcal/g) Energy storage Insulation Protection Transport of fat soluble vitamins ```

Question 33

What is the main phospholipid?

Answer 33

Phosphatidyl choline (lecithins)

Question 34

What makes up a phospholipid?

Answer 34

1 glycerol + 2 fatty acids + 1 phosphorus containing fatty acid

Question 35

What are the functions of phospholipids?

Answer 35

Emulsifiers (micelles) Cell membranes Metabolism is important in regulating cell function

Question 36

Which part of the phospholipid (lecithin) is hydrophilic?

Answer 36

Head

Question 37

Where can lecithins be found?

Answer 37

Egg yolks

Question 38

What are the function of micelles?

Answer 38

Lipid digestion/transport | Food prep, cooking

Question 39

How much cholesterol do we consume per day? (range)

Answer 39

200-400 mg/day

Question 40

Name examples of sterols.

Answer 40

Steroid hormones: corticosteroids (stress), estrogen, testosterone, Vitamin D, bile acids, embedded in cell membranes

Question 41

What is the function of vitamin D?

Answer 41

Steroid hormone that is needed for the absorption of calcium

Question 42

What makes up a lipoprotein?

Answer 42

Micelle + Apolipoproteins Free cholesterol Triglycerides (inside), some bound to cholesterol

Question 43

Name the lipoproteins, in descending order of lipid content.

Answer 43

Chylomicrons VLDL LDL HDL

Question 44

What are the functions of chylomicrons?

Answer 44

Transport diet derived lipids from the small intestine to the lymphatics, then blood Delivers diet derived lipids to tissues for use and storage Whatever is left goes to the liver

Question 45

Where are chylomicrons made?

Answer 45

Epithelial cells lining the intestine

Question 46

What are the functions of very low density lipoproteins?

Answer 46

Made in liver from dietary and newly made lipids | Carries newly made lipids and cholesterol to tissues

Question 47

Where are VLDLs made?

Answer 47

Made of leftover chylomicrons in liver

Question 48

What are the functions of low density lipoproteins?

Answer 48

Receptor pathways: supplies cholesterol for growth and development of tissues mainly in the liver, and some other cells Scavenged: WBCs attach to blood vessels and oxidize the lipids = plaque = atherosclerosis

Question 49

Where are LDLs made?

Answer 49

From VLDLs that have lost their TGs to cells

Question 50

What are the functions of HDLs?

Answer 50

Picks up cholesterol from dying cells and transfers it to other lipoproteins and takes it to the liver for excretion

Question 51

Where are HDLs made?

Answer 51

Liver, intestine

Question 52

How do lipids get to cells (adipose, muscle) from the blood vessels?

Answer 52

Lipoprotein lipase, an enzyme attached to the vessel wall hydrolyzes TGs (from chylomicrons and VLDLs) - recognized by certain apolipoproteins

Question 53

What hormone induces lipoprotein lipase?

Answer 53

Insulin

Question 54

What do you want in a blood lipid profile?

Answer 54

Total to be low as possible HDL to be high as possible ratio should be less than 4:1

Question 55

``` What do you want to see in your blood lipid profile, in mg/dl, for: Total cholesterol LDL HDL TGs ```

Answer 55

Total: less than 200 LDL: less than 130 HDL: more than 40 TG: less than 150

Question 56

During the fed state, how long does the clearance of blood lipids take?

Answer 56

10-14 hrs

Question 57

How many kcal/lb does adipose tissue contain?

Answer 57

3,500 kcal/lb

Question 58

During fasting, what delivers free fatty acids to the liver and muscle?

Answer 58

Albumin protein in blood

Question 59

How can you improve your lipid profile?

Answer 59

Aerobic exercise (can increase HDL) Soluble fiber Statins (drugs)