Chapter 11 -> Membrane Structure

Question 1

What are the 3 functions of the Cell Membrane?

Answer 1

1) Receiving information
2) Importing and Exporting small molecules
3) Ability to move and expand

Question 2

Bacteria have a _____ membrane while eukaryotic cells have a membrane as well as ______ membranes

Answer 2

Single, Multiple

Question 3

Give some examples of organelles within a eukaryotic cell that have their own membrane

Answer 3

Mitochondria, Golgi apparatus, ER

Question 4

All cell membranes are composed of _____ and _______ and share the general structure of lipids that form a lipid bilayer (about _ nm thick)

Answer 4

Proteins, Lipids, 5

Question 5

Lipids bilayer consists of phospholipids that have a _____ head and a _______ tail

Answer 5

Hydrophilic, Hydrophobic

Question 6

The most abundant lipids in cell membranes are _____ which can be further categorized into ________, one of the most abundant phospholipids in the membranes of animals and plants

Answer 6

Phospholipids, Phosphatidylcholine

Question 7

Give two examples of membrane lipids that are amphipathic

Answer 7

Glycolipids and Cholesterol

Question 8

The closer and more regular the packing of tails in the cell membrane, the ____ fluid the bilayer will be

Answer 8

Less

Question 9

What are the two major properties of hydrocarbon tails that affect how tightly they pack in the bilayer?

Answer 9

Their length and the number of double bonds they contain

Question 10

Lipid bilayers that contain a large proportion of unsaturated hydrocarbon tails are _____ fluid than those with lower proportions

Answer 10

MORE

Question 11

What are the three types of movement that the membrane can do and which one rarely occurs?

Answer 11

Rotation, Flexion, and Flip-flop which rarely occurs

Question 12

In animal cells, around _____ % of the membrane lipids are cholesterol, which tends to _______ the bilayer

Answer 12

20, stiffen

Question 13

The cell membrane is ____ and ____ and is therefore strengthened and supported by a framework of _______ which constitute around _____ % of the mass of most plasma membranes

Answer 13

thin, fragile, proteins, 50

Question 14

What proteins attach other proteins to the membrane

Answer 14

Transmembrane proteins

Question 15

What is the cell cortex?

Answer 15

Meshwork of fibrous proteins attached to the cytosolic surface of the membrane which determines the shape of the cell and mechanical properties of plasma membrane

Question 16

What is the main component of the RBCs cortex that forms the meshwork and provides support and gives it that distinct biconcave shape?

Answer 16

Spectrin

Question 17

What are the 5 Functional categories of proteins?

Answer 17

Transporters, Ion Channels, Anchors, Receptors, and Enzymes

Question 18

What does Transporter proteins do? (Functional Category)
Give an Example

Answer 18

Transport particular nutrients, metabolites, and ions
Na+ PUMP

Question 19

What do Anchor Proteins do? (Functional Category)
Give an Example

Answer 19

Anchor the membrane to macromolecules on either side
Integrins in the cell membrane

Question 20

What do Receptor Proteins do? (Functional Category)
Give an Example

Answer 20

Detect chemical signals in the cell’s environment and relays them to interior
PDGF

Question 21

What do Ion Channel Proteins do? (Functional Category)
Give an example

Answer 21

Allows for movement of molecules in and out of cell
K+ Leak channel

Question 22

What do Enzyme Proteins do? (Functional Category)
Give an Example

Answer 22

Catalyze specific reactions
Adenylyl cyclase

Question 23

What are the four Structural Categories of proteins?

Answer 23

Transmembrane, Monolayer Associated, Lipid-linked, Protein Attached

Question 24

Of the four Structural Categories of proteins, which is amphipathic?

Answer 24

Transmembrane

Question 25

How are glycolipids attached to the membrane and where are they attached?

Answer 25

They are attached by their sugar part on the non cytosolic side of lipid bilayer

Question 26

What is a proteoglycan

Answer 26

Protein that has one or more long polysaccharide chains attached to it

Question 27

What three molecule form carbohydrate layer of cell membrane?

Answer 27

Glycolipids, Glycoproteins, and Proteoglycans

Question 28

The many functions of the Carbohydrate layer
- Holds ______, creating slimy surface
- Helps cell not stick to one another
- Involved in ______ response

Answer 28

Water, Inflammatory

Question 29

In the early stages of bacterial infection, carbohydrates on the surface of white blood cells are recognized by ______ on cells lining blood vessels at site of infection, causing WBC to adhere to vessel wall and migrate to infected site

Answer 29

Lectins

Question 30

In epithelial cells lining the gut, _____ proteins are close to the surface facing the gut to get the nutrients

Answer 30

transport

Question 31

_______ junction barrier maintains distribution of membrane proteins

Answer 31

Tight