Lecture 15 + 16, Membrane (Ford)

Question 1

T or F: Lipids are amphipathic.

Answer 1

True.

Question 2

What does amiphipathic mean?

Answer 2

Having hydrophilic and hydrophobic parts

Question 3

What is the basic structure of a general fatty acid?

Answer 3

Hydrocarbon + carboxyl

Question 4

What is the primary hydrophobic determinant of a fatty acid?

Answer 4

Hydrocarbon + carboxyl

Question 5

How does the melting point of saturated vs. unsaturated fatty acids compare?

Answer 5

Saturated = higher
Unsaturated = lower

Question 6

How does the flexibility of saturated vs. unsaturated fatty acids compare?

Answer 6

Saturated = high
Unsaturated = low

Question 7

What makes a fatty acid saturated or unsaturated?

Answer 7

Presence of a double bond (unsaturated)

Question 8

How does the shape of the hydrocarbon of saturated vs. unsaturated fatty acids compare?

Answer 8

Saturated = linear
Unsaturated = bent more or less

Question 9

What is the dietary source of saturated vs. unsaturated fatty acids?

Answer 9

Saturated = animal fats
Unsaturated = plant oils, processed fats

Question 10

T or F: Longer fatty acids melt at lower temperatures than shorter fatty acids.

Answer 10

False. Shorter fatty acids melt at lower temperatures than longer fatty acids.

Question 11

List examples of saturated fatty acids.

Answer 11

Lauric, myristic, palmitic, stearic, arachidic, behenic, lignoceric

Question 12

List examples of unsaturated fatty acids.

Answer 12

Palmitoleic, oleic, linoleic, linolenic, arachidonic; EPA, DHA; Partially hydrogenated oils

Question 13

Fatty acids form ___.

Answer 13

Micelles

Question 14

How are fatty acid carbons numbered?

Answer 14

From carboxyl end to methyl end

Question 15

Which part of the fatty acid name indicates the fatty acid is unsaturated?

Answer 15

cis- or trans-

Question 16

Which part of the fatty acid name indicates where the double bond is located on an unsaturated fatty acid?

Answer 16

Delta#

Question 17

What would indicate 4 double bonds in an unsaturated fatty acid?

Answer 17

tetra-en

Question 18

What nomenclature would indicate a protonated/acid fatty acid?

Answer 18

-oic acid

Question 19

What nomenclature would indicate a deprotonated/conjugate base fatty acid?

Answer 19

-oate

Question 20

Which part of the fatty acid name indicates the fatty acid is saturated?

Answer 20

n-

Question 21

What does the number in parentheses of a fatty acid name indicate?

Answer 21

Total number of carbons : Total number of double bonds

Question 22

How are omega fatty acids named?

Answer 22

For the position of the double bond closest to the methyl end of the fatty acid

Question 23

Which omega fatty acids can’t be synthesized by humans?

Answer 23

Linoleic acid and linolenic acid

Question 24

What is ALA converted into? Is this an efficient process?

Answer 24

EPA and DHA; No, it is an inefficient process

Question 25

Why are omega fatty acids important?

Answer 25

Used in cell membrane and other important lipids, common energy source, promote good health by improving cardiovascular health

Question 26

What are the 2 parts of triacylglycerols?

Answer 26

Polar head = glycerol | Hydrophobic tails = 3 fatty acid chains

Question 27

Describe the structure of waxes.

Answer 27

Similar to triacylglycerols, but have an alcohol head with fatty acid chains

Question 28

Archaeal lipid membranes contain ___ fatty acids.

Answer 28

Branches

Question 29

What are the 3 categories of cell membrane lipids?

Answer 29

Phospholipids, glycolipids, cholesterol

Question 30

What is the majority component of cell membranes?

Answer 30

Glycerophospholipids

Question 31

What are all the components of a glycerophospholipids?

Answer 31

Hydrophilic group, phosphate, glycerol, fatty acid chains

Question 32

What are some common alcohols added to glycerophospholipids?

Answer 32

Amino acids (serine), sugar alcohols (inositol, glycerol), organics (ethanolamine, choline)

Question 33

What attaches a fatty acid to an amine?

Answer 33

Sphingomyelin

Question 34

What are glycosphingolipids important for?

Answer 34

ABO blood type antigens, cell signaling

Question 35

T or F: Glycoglycerolipids are usually found in animals, but rarely in plants or bacteria.

Answer 35

False. Glycoglycerolipids are found in plants or bacteria, and rarely in animals.

Question 36

What does cholesterol do for cell membranes?

Answer 36

Adds rigidity

Question 37

How is a bilayer formed?

Answer 37

When multiple hydrocarbon tails are present

Question 38

What is the dual role of a lipid bilayer?

Answer 38

2D liquid that allows the lateral movement of proteins and lipids, permeability barrier

Question 39

Describe the Fluid Mosaic Model.

Answer 39

Cell membranes are made up of several different types of structures (lipids, proteins, carbohydrates) that allow for their flexible nature

Question 40

What is the base component of the Fluid Mosaic Model?

Answer 40

Lipid bilayer

Question 41

Where are carbohydrates presented on the cell membrane?

Answer 41

Not in contact with cytosol

Question 42

T or F: Integral membrane proteins span the entire width of the lipid bilayer.

Answer 42

True.

Question 43

Why is having membrane proteins with lots of hydrophobic amino acids displayed on their surfaces good and bad?

Answer 43

``` Good = feature of living in a hydrophobic environment Bad = if cytoplasm of cell is aqueous ```

Question 44

What is a solution to the issue of integral membrane protein insertion?

Answer 44

Contralateral insertion

Question 45

T or F: Membrane anchors are hydrophilic.

Answer 45

False. Membrane anchors are hydrophobic.

Question 46

How much of the proteome do membrane proteins constitute?

Answer 46

30%

Question 47

List some functions of membrane proteins.

Answer 47

Receive external signals, transmit signals to cytoplasm, transmit signals to another cell, allow solutes through membrane, help to determine membrane thickness and rigidity

Question 48

What does it mean that lipids are 2D fluids?

Answer 48

Allow only lateral movement of components

Question 49

In bacteria, what is the rigidity of the membrane determined by?

Answer 49

Fatty acid composition

Question 50

In humans, what is the rigidity of the membrane determined by?

Answer 50

Cholesterol content

Question 51

T or F: Membranes are asymmetrical.

Answer 51

True.