Chapter 5 - Lipids

Question 1

tricglyceride

Answer 1

• most common lipid in food & body
• major storage form of fat in the body
• composed of 3 fatty acids attached to a glycerol

Question 2

What’s the difference between triglycerides & phospholipids?

Answer 2

triglycerides are stored fats (plant oils from seeds, fruits, fish oil, solid fats, butter, meat fats, tested for in blood

phospholipids - structural fats; plant and animal cell membranes

Question 3

fat vs. fatty acid

Answer 3

fatty acids are a chain of carbon & hydrogen atoms w/an acid group (COOH) at one end & a methyl group (CH3) at the other.
- differ in the length of carbon chains & # & location of their double bonds

fats = triglycerides, phospholipids

Question 4

chemical make up of fatty acids

Answer 4

same basic structure - chain of carbon & hydrogen atoms w/an acid group (COOH) at one end and a methyl group (CH3) at the other end

• can differ:
  
  • in length of carbon chains
  • # & location of double bonds

Question 5

monounsaturated fatty acid

Answer 5

one double bond

- olive & canola oil

Question 6

polyunsaturated fatty acid

Answer 6

• has two or more double bonds

- sunflower & soybean oils

Question 7

saturated fats

Answer 7

• most animal fats

- no double bonds

Question 8

omega number

Answer 8

indicates the position of the first double bond away from the methyl end
omega-3 fatty acid - double bond is 3 carbons away from end

Question 9

what are the individual components of

1. triglycerides
2. phospholipids

Answer 9

1. triglycerides - a lipid composed of 3 fatty acids attached to a glycerol
2. phospholipids - a glycerol with 2 fatty acids & a phosphate group & a molecule of choline

Question 10

saturated fatty acids

Answer 10

• firm at room temp
• chains of fatty acids are straight so lay flat & stays firm
• animal fats, some oils

Question 11

unsaturated fatty acids

Answer 11

• tend to be liquid at room temp
• fatty acids are bent due to the double carbon bonds
• most abundant in seeds, nuts, some fruits (olive, avocado), marine animals

Question 12

What’s difference between saturated & unsaturated fatty acids?

Answer 12

saturated - no double bonds, so straight

• none are essential (our bodies can make them)
• solid at room temp

unsaturated - double bonds make them curve

• some are essential (need from food)
• liquid at room temp

Question 13

How can unsaturated fatty acids aid organisms to adapt to cold weather?

Answer 13

B/c unsaturated fatty acids are bent, they tend to keep things more fluid and store more of them in their tissues to keep them from freezing/becoming solid.

Question 14

Explain: omega-3 fatty acid

Answer 14

• means the first carbon double bond is 3 carbons from the methyl bond/end
• is found in flax seed, walnuts, soybean, hemp seed, fish oil, green plants (ultimately all omega-3 is from green plants)

Question 15

Explain: omega-6 fatty acid

Answer 15

• first carbon double bond is 6 carbons from the methyl group
• linoleum acid
• found in most seeds, germ of grains, walnuts, soybeans

Question 16

Explain: monounsaturated fatty acid

Answer 16

• one of two types of unsaturated fatty acids
• omega-9
• oleic acid - found in olive oil, avocado, cashew, almond, hazelnut, pistachios, macadamia, peanuts

Question 17

Name the two types of unsaturated fatty acids

Answer 17

1. monounsaturated - one double bond
   
   • omega-9
2. polyunsaturated - many double bonds
   
   • some are essential
   • omega-3
   • omega-6

Question 18

What are trans fatty acids?

Answer 18

• result from the conversion of omega-6 fatty acids to saturated fatty acids.
• are rich in highly processed foods

Question 19

point of unsaturation

Answer 19

the double bond of a fatty acid; where hydrogen atoms can easily be added

Question 20

hydrogenation

Answer 20

• some or all of the points of unsaturation (no H) are saturated by adding H molecules
• protects against oxidation (rancidity)
• process produces trans-fatty acids
• total hydrogenation rarely takes place - usually a fat is partially hydrogenated

Question 21

cis-fatty acid

trans-fatty acid

Answer 21

cis = H on the same side, causing a bend

trans = H on opposite sides causing fatty acid to straighten

Question 22

How are trans-fatty acids generated?

Answer 22

Oil is heated in the presence of hydrogen gas & a catalyst like nickel

Question 23

Why are trans-fatty acids used in food processing?

Answer 23

the hydrogenation process:

• extends shelf life of items
• makes oils more firm; affects texture of foods

Question 24

Why to trans-fatty acids place your health at risk?

Answer 24

In the body, they act more like saturated fats:

• increase blood cholesterol
• increase risk of heart disease

Question 25

phospholipids

Answer 25

- have a hydrophilic (water loving) head - the glycerol & phosphate group & choline end - have a hydrophobic (water fearing) region - the fatty acid part

Question 26

roles of phospholipids

Answer 26

- B/c are both water & fat soluble, they help fat soluble vitamins & hormones pass easily in & out of cells. - used as emulsifiers - help keep fats suspended in the blood & bodily fluids

Question 27

lecithin

Answer 27

best-known phospholipid

Question 28

sterols

Answer 28

a form of lipid | - includes: bile acids, sex hormones, adrenal hormones, Vit D & cholesterol

Question 29

cholesterol

Answer 29

endogenous - that is made in the body - body makes 800-1500 mg/day exogenous - from outside the body harmful effects occur when it accumulates in the artery walls -- contributes to plaque

Question 30

cholecystokinin (CCK)

Answer 30

- release is triggered by fat entering the small intestine | - triggers gall bladder to release bile

Question 31

lipoprotein

Answer 31

- a spherical particle in the blood that consists of phospholipids, protein, triglycerides, & cholesterol - transport fats through blood

Question 32

LDL

Answer 32

- low density lipoprotein (bad cholesterol) - derived from VLDL as triglycerides are broken down & removed - composed primarily of cholesterol - LDL receptors in liver responsible for removal of LDL from circulation

Question 33

chylomicrons

Answer 33

- largest and least dense of lipoproteins - transport diet-derived lipids (mostly triglycerides from small intestine (via lymph system) to the rest of the body - as pass thru the body, triglycerides are removed by cells - once depleted, liver removes the remnants from blood

Question 34

VLDL

Answer 34

very low density lipoproteins - made by liver cells to transport lipids to various tissues in body - composed primarily of triglycerides - as triglycerides are removed, mostly cholesterol is left

Question 35

HDL

Answer 35

high density lipoproteins - transports cholesterol back to the liver from the cells - composed primarily of protein - has a protective effect

Question 36

What are some important functions of cholesterol?

Answer 36

- builds and repairs cell membranes - precursor to: * vitamin D * bile formation * steroid hormones (cortisol, aldosterone, estrogen, progesterone, testosterone (sex hormones)

Question 37

essential fatty acids

Answer 37

- the fatty acids the body cannot make & must get from food - Omega-6 (linoleic acid) and -3 (linolenic) - obtained from vegetable oils, seeds, nuts, fish & seafood

Question 38

What's the difference between "good" and "bad" cholesterol?

Answer 38

- HDL (good) carries cholesterol from the tissues back to the liver for excretion (protective) - HDL is comprised of 1/2 protein - LDL (bad) is comprised of 1/2 cholesterol - LDL carries triglycerides, cholesterol, & phospholipids to cells for energy

Question 39

What foods are rich in cholesterol?

Answer 39

eggs milk & milk products meat, poultry & shellfish

Question 40

DRI & dietary guidelines for fat

Answer 40

20-35% of energy intake