Lipids

Question 1

What are lipids?

Answer 1

A compound that is souble in a ORGANIC solvent, but insoluble in water or hydrophobic.

Question 2

What is the function of lipids?

Answer 2

Provision of energy, structure and cell signaling.

Question 3

Function of lipids .2

Answer 3

Provide calories needed to meet the body’s energy needs.

Question 4

Function of lipids .3

Answer 4

Source of essential fatty acids needed for cell membranes, skin, cardiovascular and brain health.

Question 5

Why is phospholipids important?

Answer 5

Phospholipids are essential for the structure of cell membranes and form membrane of lipoproteins -> make transport of lipids in the blood possible.

Question 6

Functions of lipids:

Answer 6

Maintain body temperature, absorption of fat-soluble vitamins (A,D,E,K),

Question 7

What is Adipose tissue?

Answer 7

The site of fat storage in the body –> excess triglycerides are stored –> needed for energy during fasting.

Question 8

What is cholesterol?

Answer 8

Used to produce steroid hormones (oestrogens & androgens), bile acids, vitamin D and glucocorticoids (cortisol)

Question 9

Types of Lipids?

Answer 9

Triglycerides, phospholipids, sterols.

Question 10

What is triglycerides?

Answer 10

Composed of three fatty acids eterified to a glycerol backbone.

Question 11

Fatty acid is a chain of..

Answer 11

methyl (CH3-) and carboxyl (-COOH) end

Question 12

How are fatty acids characterized?

Answer 12

By their degree of saturation and length of the carbon chain.

Question 13

Short chain?

Answer 13

2-6 carbons

Question 14

Medium-chain?

Answer 14

7-14 carbons

Question 15

Long-chain

Answer 15

> 14 carbons

Question 16

Longer-chain

Answer 16

20-26 carbons

Question 17

Example of organic solvent

Answer 17

Oil, alcohol and etanol.

Question 18

DIffer in: Chain length (no.of carbons)

Answer 18

Higher melting point

Question 19

Differ in: unsaturation (no. of double bonds)

Answer 19

Lower melting point

Question 20

Differ in: position and geometry (cis or trans) of double bonds.

Answer 20

All health effects.

Question 21

What does it mean when a fatty acid is saturated?

Answer 21

All the carbons in the chain have hydrogen atoms for each available bond –> no double bonds

Question 22

What does it mean when a fatty acid is unsaturated?

Answer 22

Has at least ONE carbon missing a hydrogen atom –> causing a double bond to form.

Question 23

What is essential fatty acid?

Answer 23

Fatty acids that cannot be synthesized by the body and must be consumed in the diet.

Question 24

Example of essential fatty acid?

Answer 24

Linoleic acid (18:2;w-6) and a-linolenic acid (18:3;w-3)

Question 25

What does phospholipid have?

Answer 25

Two fatty acids & phosphate group.

Question 26

What does phospholipids form?

Answer 26

Form a lipid bilayer --> key for the structure of cell memebranes

Question 27

The phospholipid head is...

Answer 27

Hydrophilic

Question 28

The 2 fatty acids are..

Answer 28

Hydrophobic

Question 29

Structure of sterols:

Answer 29

Four-membered ring

Question 30

The sterol in humans is?

Answer 30

Cholesterol

Question 31

Foods high in unsaturated fat:

Answer 31

Nuts, seeds, olives/olive oil and avocados

Question 32

Foods high in monounsaturated fat

Answer 32

Olive oil, almond, avocados

Question 33

Foods high in polyunsaturated fat

Answer 33

Nuts, seeds, vegetable oils, oily fish

Question 34

Where do we find TRANS unsaturated fatty acids?

Answer 34

Present in very small amount in dairy products

Question 35

How is trans fat created?

Answer 35

Hydrogenation --> double bonds in unsaturated fatty acids are changed from the cis to trans --> making vegetable oil into solid fat.

Question 36

Where do we find trans fat?

Answer 36

Margarines, snack foods and prepared desserts.

Question 37

How many percent of dietary fat is absorbed

Answer 37

90-95%

Question 38

What is absorbed direcly into the blood?

Answer 38

Glycerol and small-& medium - chain fatty acids.

Question 39

What is absorbed into the enterocytes?

Answer 39

Long-chain fatty acids, cholesterol and monoglycerides.

Question 40

What is not soluble in water?

Answer 40

Fat

Question 41

Lipid transport: how is triglycerides packaged?

Answer 41

Packed along with cholestrol and phospholipids into CHYLOMICRONS.

Question 42

How does chylomicrons transport triglycerides?

Answer 42

From the enterocyte to the muscle and adipose tissues.

Question 43

Lipid transport: What happens if the body is at rest?

Answer 43

Triglycerides are taken up by adipose tissue for storage.

Question 44

Lipid transport: What happens if the body is active?

Answer 44

Muscle tissue will oxidize fatty acids to provide energy --> Beta-oxidation

Question 45

How is lipoproteins classified?

Answer 45

By their density

Question 46

The density names:

Answer 46

VLDL (very low-density lipoproteins), LDL (low-density lipoproteins) and HDL (high-density lipoproteins)

Question 47

VLDL transport:

Answer 47

Triglycerides from the liver to the muscle & adipose tissue.

Question 48

LDL transport:

Answer 48

Cholestrol from the liver to body tissues.

Question 49

HDL transport:

Answer 49

Cholestrol from the tissues back to the liver.

Question 50

What is essential fatty- acid deficiency:

Answer 50

A issue that can arise from a severe restriction of fat intake.

Question 51

What cannot be synthesized by the human body?

Answer 51

The long-chain omega-3 and omega-6 fatty acids.

Question 52

What are the symptoms of deficiency?

Answer 52

Poor wound healing, visual problems, neuropathy, susceptibility to infection, decreased growth in children.

Question 53

The most prevalent outcome of excess caloric intake from fat

Answer 53

Obesity

Question 54

High fat intake and high saturated fat intake can cause:

Answer 54

various cancers (colorectal & breast cancer)

Question 55

Reduction in saturated fat intake can result in?

Answer 55

14% reduction in cardiovascular risk.