Ch. 3 Lipids (Exam 1)

Question 1

What are the 3 major functions of a lipid?

Answer 1

1) Energy storage
2) Membrane function
3) Signaling molecules

Question 2

What are the 5 major classes of lipids discussed in class?

Answer 2

1) Fatty acids
2) Triglycerides
3) Phospholipids
4) Sphingolipids
5) Isoprenoids/steroids

Question 3

What are the 2 distinct regions of a fatty acid?

Answer 3

1) Large hydrocarbon tail

2) Short carboxylic head

Question 4

Which carbon is C1 in delta notation?

Answer 4

The carboxyl

Question 5

What is the lipid number format?

Answer 5

C#1:#2 where #1 represents # of carbons present and #2 represents # of double bonds present

Question 6

Which carbon is C1 in omega notation?

Answer 6

Carbon at end of chain/tail

Question 7

What is the max number of carbon for a monocarboxylic acid?

Answer 7

24

Question 8

Where do most animals get their fatty acids from?

Answer 8

Food/diet

Question 9

Will you mostly find FAs in cis or trans-conformation?

Answer 9

Cis

Question 10

How many double bonds do you notate in omega notation?

Answer 10

Only the first one

Question 11

Which state of matter are saturated fats in a room temperature?

Answer 11

Solid

Question 12

Which state of matter are unsaturated fats in at room temperature?

Answer 12

Liquid

Question 13

What is the general structure of a triglyceride?

Answer 13

Glycerol ester bonded w/ 3 fatty acids

Question 14

How does length of a triglyceride allow for greater energy storage?

Answer 14

Longer, hydrophobic FA = less water in fat cells = greater storage efficiency

Question 15

What do animals use fatty acids for?

Answer 15

Energy storage

Question 16

What do plants use for energy instead of lipids?

Answer 16

Carbs

Question 17

Where are lipids found in plants?

Answer 17

Seeds

Question 18

How do fats and oils differ in saturation and state of matter at room temp?

Answer 18

Fats are usually saturated, so solid at room temp while oils are unsaturated, so liquid at room temp

Question 19

What are phospholipids polar?

Answer 19

B/c of the phosphate group

Question 20

What is the general structure of a phospholipid?

Answer 20

Same as triglycerides but w/ phosphate group at 3rd position (glycerol backbone, FA, FA, phosphate group)

Question 21

Which phosphate pKa is closest to physiological pH?

Answer 21

pK2 at 6.6

Question 22

How many times can a phosphate be esterified?

Answer 22

3

Question 23

Are are two reasons that phospholipids have heterogeneity?

Answer 23

1) FAs in 1st 2 positions can vary

2) Different alcohols can esterify to phosphate

Question 24

What is an example of an amino-alcohol?

Answer 24

Phoshatidylcholine

Question 25

What are 3 important uses of phospholipids?

Answer 25

1) Membrane formation
2) Emulsification
3) Surfactants

Question 26

What 2 interesting structures can phospholipids become?

Answer 26

1) Micelles (pizza)

2) Phospholipid bilayers (french fry)

Question 27

How are steroids structured?

Answer 27

4 flat-ringed systems

Question 28

What are steroids an important component of what part of an animal cell?

Answer 28

Animal cell membranes

Question 29

What are 2 common uses biochemical functions of steroids?

Answer 29

1) Hormones

2) Cholesterol

Question 30

In which organisms can steroids be found?

Answer 30

All eukaryotes and some bacteria

Question 31

What are 2 ways to differentiate steroids?

Answer 31

1) Double bond placement

2) Substituents

Question 32

What is another term for steroid?

Answer 32

Isoprenoid

Question 33

What are 3 common types of steroids?

Answer 33

1) Cholesterol
2) Estradiol
3) Testosterone

Question 34

What are the two conflicting natures of lipids?

Answer 34

1) Water solubility

2) Lipid solubility

Question 35

Which 3 structures can be formed to remedy the conflict between water and lipid solubility?

Answer 35

1) Micelles
2) Liposomes
3) Phospholipid bilayers

Question 36

What are the 3 liposome phases?

Answer 36

1) Exterior water
2) Interior water
3) Nonpolar

Question 37

Under what condition does a bimolecular membrane lipid form?

Answer 37

Low concentrations

Question 38

What does membrane fluidity refer to?

Answer 38

Viscosity of the bilayer

Question 39

What movement is responsible for the normal function of membrane lipids?

Answer 39

Rapid lateral movement

Question 40

What is the consequence of liposomes have two water phases?

Answer 40

2 completely different solutions can be on either side of the membrane

Question 41

What do the channels and transfer proteins transport through lipid membranes?

Answer 41

Sodium ions, glucose, etc.

Question 42

What is diffusion?

Answer 42

The movement of molecules from high concentration to low

Question 43

How does osmosis relate to diffusion?

Answer 43

Osmosis is diffusion with water. Water moves from high concentration to low

Question 44

Describe hypotonic solutions as they relate to red blood cells (HINT: solution in question is distilled water).

Answer 44

Water moves into RBC b/c of RBC’s lower water concentration causing it to burst

Question 45

Describe isotonic solutions as they relate to normal RBCs.

Answer 45

The water concentration outside of the RBC is the same on the inside

Question 46

Describe hypertonic solutions as they relate to RBCs (HINT: solution in question is saltwater).

Answer 46

Water moves out of RBC b/c of lower water concentration outside of cell

Question 47

As it pertains to hypotonic, isotonic, and hypertonic solutions, what is the relationship between water and solute that causes water to move the way it does in osmosis?

Answer 47

Greater solute concentration = less water concentration, so water moves to where there is less water