Lipids

Question 1

Properties of Lipids

Answer 1

• Made up primarily of carbon, hydrogen and oxygen
• Lipids are hydrophobic

Question 2

Why are lipids hydrophobic?

Answer 2

• They contain more relatively non-polar C-H bonds in comparison to O-H bonds which tend to be more polar

Question 3

Functions of Lipids

Answer 3

• Energy storage in organisms
• Make up membrane structures
• They are chemical messengers

Question 4

Classification of Lipids

Answer 4

1. Fats
2. Phospholipids
3. Steroids
4. Waxes

Question 5

What are fats main function?

Answer 5

• Major storage depot for energy in the form of adipose tissues in many heterotrophs

Question 6

What are fats made up of?

Answer 6

• Glycerol
• one, two, or three fatty acids

Question 7

What is kJ?

Answer 7

Units for energy

Question 8

How much energy storage does 1 gram of fat have?

Answer 8

38 kJ energy storage capacity in bonds

Question 9

Saturated Fatty Acid

Answer 9

• number of carbons varies
• max number of hydrogens in the structure

Question 10

Unsaturated Fatty Acid

Answer 10

• number of carbons varies
• hydrogen numbers are not maximized
• double bonds are made between carbon

Question 11

What type of fat is healthier saturated or unsaturated?

Answer 11

Unsaturated fats

Question 12

What is the linkage between a glycerol and a saturated fatty acid called?

Answer 12

An “ester linkage”

Question 13

Reality of unsaturated fatty acids..

Answer 13

The molecule would appear bent wherever there are double bonds

Question 14

Application of saturated fatty acids

Answer 14

• They contain many van Der Waals attractions between molecules
• This accounts for a straight condensed shape which allows saturated fatty acids to be solid at room temp

Question 15

Example of a saturated fat

Answer 15

• animal fats such as lard

Question 16

Application of unsaturated & polyunsaturated fatty acids

Answer 16

• Contain many double bonds which cause the molecules to fold up, therefore allowing fewer van Der Waals forces
• Accounts for the fact that unsaturated fats are usually liquid at room temp

Question 17

Example of an unsaturated fat

Answer 17

vegetable oils

Question 18

What is industrial hydrogenation

Answer 18

• Unsaturated fats can be covered into saturated or partially saturated fats by this process

Question 19

What do phospholipids consist of?

Answer 19

• one glycerol
• 2 fatty acids
• one phosphate group
• made up of a polar head and two non-polar tails

Question 20

What does amphipathic mean?

Answer 20

Polar and non-polar

Question 21

What does the amphipathic nature of phospholipids cause?

Answer 21

It forms a bilayer or a single-layer micelle spontaneously in water

Question 22

Phospholipid bilayers

Answer 22

• Phospholipids group together to form doubled-up sheets of phospholipids

Question 23

Example of phospholipid bilayers

Answer 23

• The cell membrane and membrane-bound cell organelles
• These are semi-permeable structures that allow some substance to travel through them

Question 24

Micelles

Answer 24

• single layers of phospholipids
• ex: soap bubbles

Question 25

Vesicles

Answer 25

• made up of phospholipid bilayers
• Tiny transport bubbles found in cells

Question 26

Steroid Functions

Answer 26

• Chemical messengers
• Important component of cell membranes

Question 27

What are steroids?

Answer 27

• Compact hydrophobic molecules
• Made up of 4 hydrocarbon rings joined together, along with variable functional groups

Question 28

Steroid molecular shape

Answer 28

• 3 hexagons
• 1 pentagon
• variable side groups

Question 29

Cholesterol (steroid)

Answer 29

• Responsible for cell membrane structural integrity
• Too much in body is associated with atherosclerosis (caused by liver imbalance)

Question 30

Male Hormone

Answer 30

testosterone (steroids)

Question 31

Female Hormone

Answer 31

Estrogen (steroids)

Question 32

Progesterone (steroids)

Answer 32

Androgenous hormone

Question 33

Waxes molecular shape

Answer 33

• Lipids with long fatty acids attached with alcohols or carbon rings

Question 34

Functions of waxes

Answer 34

• Used by plants as a waxy, protective coating on leaves and stems
• Ear wax in mammals

Question 35

How to determine a trans fat by its molecular appearance?

Answer 35

• When the H’s are on opposite sides of an unsaturated fat they become a trans fat