Lipids

Question 1

What are lipids?

Answer 1

1) essential in diet
2) energy yielding macronutrient (9kcal per gram) <30% energy consumed
3) Organic
3) most do not dissolve in water

Question 2

Lipids in the diet and in the body include:

Answer 2

1) triglycerides/fatty acids -human body stores fat this way
2) phospholipids (how fats interact with water)
3) sterols

Question 3

Functions of Lipids in the body

Answer 3

1) energy
- major source of energy (like carbohydrates)
- stored in adipose tissue
2) protection
- temperature, shock
3) Structural -components of cell membrane
4) Regulation -BP and blood clotting *no limit to how many fat you can store

Question 4

Fatty Acids definition

Answer 4

organic molecules with chains of carbon atoms with attached hydrogen with atoms and a acid group at one end

Question 5

what is this a picture of

Answer 5

fatty acids

Question 6

Classifications of Fatty Acids

definitons

Answer 6

1) saturated
- fully occupied with hydrogen atoms
2) monounsaturated
- one carbon double bond a pair of hydrogens missing
3) polyunsaturated

has two or more carbon double bonds

omega 3 and omega 6

Question 7

Why do we hydrogenerate oils?

*define hydrogenation as well

Answer 7

remember: saturation adds shelf life

Hydrogenation: Chemically adding H for double bonds to add shelf life

Hydrogeneration makes oils less prone to spoilage and makes them remain solid at higher temperatures

Question 8

which is worse: saturated fatty acids or trans fatty acids

Answer 8

trans fatty accid have been linked to similar problems as saturated fats with lesser amount in the diet

Question 9

What are essential fatty acids? why is it essential

Answer 9

Omega 6 fatty acids (plants, animals)

omega 3 fatty acids (fish)

(body cannot produce but needs)

these two types of fatty acids are specific precursors to important regualtory moelcules and therefore consisered essential in the diet

Question 10

Triglycerides

(where, function, %, definition)

Answer 10

the foods we eat contain triglycrides

function: to provide energy; 95%

contains three fatty acids (doesnt have to be all the same) +glycerol molecule

Question 11

What are phospholipids?

Answer 11

phospholipids are like triglyceridesin which one fatty acid is replaced with a phosphate group

this phosphate group is soluble in water (head); hydrophilic

tails are hydrophobic; not soluble in water

Question 12

Primary functions of phospholipds

Answer 12

1) phospholipid bilayer composes cell membrane
2) aids in lipid transport (lipoprotein*)

Question 13

What are sterols?

(eg)

Answer 13

family of molecules consisting of interconnecting carbon rings

the most common sterol in the human body is cholesterol

Question 14

Dietary cholesterol vs blood cholesterol

Answer 14

Cholesteorl in food is referred to dietary choelsterol and is found only in animal products; the human body makes more cholesterol than it needs–so it is not necessary to get choelsterol from food; used to make certain hormones, bile, vitamin D and cell membranes

Blood cholesterol; cholesterol transported in the blood by particles called lipoproteins; mechanism to transfer fats

LDL and HDL

*liver produces both molecule of cholesterol as well as lipoproteins

Question 15

What does the body use cholesterol for, where to find cholesterol

Answer 15

-use to make certain hormones (testosterone and estrogen), bile, vitamin D (cholesterol —> UV light —-> Vitamin D) and cell membranes

*body routinely manufactures choelsterol for its own use

in foods…

plants and animals have sterols

ONLY ANIMAL TISSUE HAVE CHOELSTEROL

(highest in organ meats, egg yolk)

Question 16

Only ____ produce cholesterol

Answer 16

animals

Question 17

Digestion Fat and Lipids

(mouth, stomach, small intestine, colon)

Answer 17

mouth: some fats melt
stomach: fats floar but some mix with water and acid

small intestine: gallbladder secretes bile and fats are emulsified

Pancreatic lipases turn fats –> monoglycerides and fatty acids

absorption takes place

Once absorbed fat, will be transported primarily by lipoproteins

colon: some fat and cholesterol bound to fiber exit in feces

Question 18

Emulsification definition and why is important

Answer 18

substance that suspends fat in liquids; with bile, it breaks down large droplet of fat into much smaller droplets

this makes it easier for fat-digesting enzymes (aka pancreatic lipase) to break down lipids

Question 19

Lipids in Digestive Tract process w/ bile

Answer 19

• bile emulsifies lipids: breaks down larger droplet of fat into much smaller droplets
• fat-digesting enzymes are also released (pancreatic lipase)
• once broken down they form micelles (cluster of fatty acids)
• these fatty acids are absorbed across the lining of the small intestine; then are packaged into Lipoproteins (made of phospholipids) for transport

Question 20

Micelles definition

Answer 20

small droplets of primarily fatty acids and other fat soluble substances

Question 21

Digestion of fat begins with _______

Answer 21

emulsification

Question 22

Lipoproteins definition

list types

Answer 22

lipoproteins: spherical bodies witha phospholid or protein shell that contains differnt types of lipids
1) Chylomicrons
2) VLDL(very low density lipoprotein)
3) LDL (low density lipoprotein)
4) HDL (high density lipoprotein)

Question 23

Lipoproteins from the liver

Answer 23

VLDL, LDL, HDL

Question 24

Chylomicrons

Answer 24

large lipoproteins that carry lipids from the small intestine, first via the lymph system and eventually into the blood stream

82% Triglyceride

8% Phospholipids

8% Cholesterol

2% protein

Question 25

VLDL

definiton and function

Answer 25

formed in the liver from partially spent chylomicrons and function to deliver lipids to body cells

increase triglyceride components

50% triglyceride

Question 26

LDL

aka, function

Answer 26

aka bad choelsterol

are formed in the liver from partially spent VLDLs and again circulate through the body deliveirng lipids

HIGH CHOLESTEROL COMPONENT

Question 27

HDL

aka; function

Answer 27

good cholesterol

circular through the body, removing excess cholesterol from other liporoteins and body cells

Question 28

Negative effects on blood cholesterol

(3)

Answer 28

Saturated fats* —–> increasesTC and LDL

Trans fat—-> increase TC and LDL while decreasing HDL

Dietary Cholesterol —-> increases TC and LDL

greater concern is *

Question 29

Positive Effect on Blood cholesterol

(3)

Answer 29

Polyunsaturated fats —> decreases TC (HDL and LDL)

Monounsaturated fats —> decreases TC and LDL with less effect on HDL

excercise may increase HDL