Lipids: Chapter 11

Question 0

How many molecules of membrane lipid are there for each molecule of protein in E. Coli?

Answer 0

200

Question 1

What’s true about sterols in membranes?

Answer 1

Sterol lipids are common in human cell plasma membranes

Question 2

Whats false about the composition of biological membranes?

Answer 2

In a given eukaryotic cell type, all intracellular membranes have essentially the same complement of lipids and proteins

Question 3

Which statement about the composition of mitochondrial membranes is true?

Answer 3

Inner and outer membranes of mitochondria have different protein compositions

Question 4

Characteristics of membrane proteins:

Answer 4

Covalently attached to lipid/carb moities; composed of the same 20 aa’s as soluble proteins; diffuse laterally in the membrane unless they are anchored

Question 5

Peripheral proteins are:

Answer 5

Noncovalently attached to membrane lipids

Question 6

Integral membrane proteins can be extracted with:

Answer 6

Solution containing detergent

Question 7

Shortest alpha helix that can span a membrane bilayer has ____ aa residues

Answer 7

20

Question 8

A hydropathy plot is used to:

Answer 8

Predict whether a given protein sequence contains membrane-spanning segments

Question 9

Whats true of integral membrane proteins:

Answer 9

Hydropathy plot reveals one or more regions with a high hydropathy index

Question 10

General feature of lipid bilayer in all biological membranes:

Answer 10

Individual lipid molecules are free to diffuse laterally in the surface of the bilayer

Question 11

Type of motion least common in biological membranes:

Answer 11

Flip-flop diffusion of phospholipids from one leaflet to another

Question 12

Fluidity of lipid side chains in the interior of a bilayer is generally increased by:

Answer 12

Increase in the number of double bonds in fatty acids

Question 13

Fluidity of a lipid bilayer will be increased by:

Answer 13

Increasing the temperature

Question 14

When a bacterium switches from high growth temp to low growth temp, it compensates by:

Answer 14

Putting more unsaturated fatty acids into its membranes

Question 15

When biological membranes are viewed with an electron microscope after freeze-fracturing, particles of various sizes stand out against a smooth background. Which statement below is correct?

Answer 15

The particles are individual proteins or protein complexes

Question 16

Integrins are:

Answer 16

Membrane proteins that mediate cell adhesion

Question 17

A process not involving the fusion of two membranes or two regions of the same membranes is:

Answer 17

Entry of glucose into cells

Question 18

According to the current HIV model, what is not involved in the process of membrane fusion?

Answer 18

Viral chromosome

Question 19

What is true about facilitated diffusion:

Answer 19

Specific membrane proteins lower the Ea for mvmt of the solute through the membrane

Question 20

Facilitated diffusion through a biological membrane is:

Answer 20

Driven by a difference in solute concentration

Question 21

Glucose transport into erythrocytes is an example of:

Answer 21

Facilitated diffusion

Question 22

For the process of solute transport, the constant Kf is:

Answer 22

Analogous to Km for an enzyme-catalyzed rxn

Question 23

Type of membrane transport that uses ion gradients as the energy source is:

Answer 23

Secondary active transport

Question 24

The free energy change for glucose uptake into the cell is:

Answer 24

About 10 kJ/mol

Question 25

Free-energy change for the transport of K+ across the cell membrane is:

Answer 25

15 kJ/mol

Question 26

An electrogenic Na+ transporter

Answer 26

Transports Na+ w/o concurrent transport of any other charged species

Question 27

Movement of water across the cell membrane is facilitated by proteins called:

Answer 27

Aquaporins

Question 28

Specificity of the potassium channel for K+ over Na+ is mainly the result of the:

Answer 28

Differential interaction with the selectivity filter protein

Question 29

A ligand-gated ion channel (such as nicotinic acetylcholine receptor) is:

Answer 29

Membrane protein that permits an ion to pass through the membrane only when opened by the appropriate ion