Unit 2: Cell Membranes (Bozeman Video 15)

Question 1

Why does soap dissolve the membrane easily

Answer 1

The membrane is made of lipids (fats)

Question 2

What is selective permeability? How does the cell achieve this?

Answer 2

Cells only allow certain things in and certain things out. It achieves this by using the cell membrane.

Question 3

What are the major molecules in the cell membrane?

Answer 3

Phospholipids and Proteins

Question 4

Define Amphipathic. How does this affect transport across the membrane?

Answer 4

Amphipathic- Part of the molecules likes water and there is a part the hates water. It allows small and uncharged particles to move through it.

Question 5

What role do proteins play in transport?

Answer 5

Regulate transport, allow larger and charged particles to move through

Question 6

What kind of cells have cell walls?

Answer 6

Plant cells, Bacteria, Fungi

Question 7

Describe the fluid -mosaic cell membrane model

Answer 7

• The membrane is made of a bilayer (2 layers) of phospholipids with the tails facing inward toward each other and the heads facing to the outside of the membrane.

-Fluid means that the components of the membrane, are always moving (the membrane is not solid)

• “mosaic” explains the many different types of molecules (proteins, phospholipids, glycoproteins, and glycolipids) that make up the membrane

Question 8

What are the roles of cholesterol in the membrane?

Answer 8

a. Connect phospholipids together, keeps them from drifting apart too quickly
b. Keeps phospholipids apart

Question 9

What are glycoproteins made up of, and what is their role in the membrane? Name an important glycoprotein.

Answer 9

(1) made up of proteins and sugar.

(2) antibodies, important in immune response

Question 10

What are glycolipids made up of, what is their role in the membrane?

Answer 10

Fat with sugars attached is a glycolipid. They are important for signaling.

Question 11

Draw and describe the structure of a phospholipid- indicate the charges on the molecule

Answer 11

Head is charged (polar), tails do not have a charge (nonpolar)

Question 12

Is fat = phospholipid? why/why not?

Answer 12

Yes, because it is made up of hydrocarbons

Question 13

Describe the charge distribution of the membrane?

Answer 13

Inside of membrane has no charge, but the lining of it will have a charge.

Question 14

Why can’t water move through the membrane?

Answer 14

Water is charged and there is no charge inside the membrane, preventing the polar water molecule from passing.

Question 15

What protein helps water pass through?

Answer 15

aquaporin

Question 16

What are the characteristics and examples of substances that can move easily through the membrane?

Answer 16

(1) tiny
(2) no charge
(3) hydrophobic

Ex: oxygen and carbon dioxide, ipids and hydrocarbons, and molecules that are lipid-soluble, such as fat-soluble vitamins and several hormones,

Question 17

How do proteins assist in transport?

Answer 17

Allows the things in that the phospholipids can’t allow in.

Question 18

What kinds of particles move through proteins?

Answer 18

(1) large particles
(2) charged particles

Question 19

What kinds of transport do proteins assist with?

Answer 19

Facilitated Diffusion & Active Transport

Question 20

Name 2 characteristics of the cell wall

Answer 20

1. selection of what gets in and out
2. Rigidity, structural support

Question 21

What material makes up the cell wall of
Plants?

Answer 21

Pectin, Cellulose microfibril, hemicellulose, soluble protein

Question 22

What material makes up the cell wall of
bacteria?

Answer 22

Peptidoglycen

Question 23

What material makes up the cell wall of
fungi?

Answer 23

chitin