Chapter 4- Cell Membrane

Question 1

What is the accepted theory of the structure of the cell membrane?

Answer 1

The fluid mosaic model

Question 2

What is the fluid mosaic theory?

Answer 2

There is a double layer of phospholipids but the proteins are scattered through the membrane. The proteins float among the semi-fluid phospholipids.

Question 3

What does a Glycoprotein consist of?

Answer 3

Protein + carbohydrate chain

Question 4

What does a Glycolipid consist of?

Answer 4

Phospholipid + carbohydrate chain

Question 5

What will happen if a cell has the wrong markers?

Answer 5

The body will attack these cells

Question 6

What does impermeable mean?

Answer 6

Nothing passes through

Question 7

What does permeable mean?

Answer 7

Most things pass through

Question 8

What does semi-permeable mean?

Answer 8

Smaller molecules pass through but not larger ones

Question 9

What does selectively permeable mean?

Answer 9

Only certain molecules can pass, no matter what the size. Cell membranes are selectively permeable

Question 10

What is diffusion?

Answer 10

Movement of a solute from an area of high concentration to an area of low concentration. No membrane, carrier, or ATP required

Question 11

What is osmosis?

Answer 11

Water moves from an area of high water concentration to an area of low concentration across a membrane. No carrier or ATP required

Question 12

What is a hypertonic solution?

Answer 12

A solution with the greatest amount of solute compared to another solution.

Question 13

What is a hypotonic solution?

Answer 13

A solution with the least amount of solute compared to another solution

Question 14

What is an isotonic solution?

Answer 14

Two solutions with equal concentrations of solute to solvent

Question 15

True or False; water will always move from a hypotonic solution to a hypertonic solution

Answer 15

True

Question 16

What is tonicity

Answer 16

Refers to the concentration of a solute in a solvent

Question 17

What is facilitated transport?

Answer 17

Solutes move from an area of [high solute] to an area of [low solute] with the help of a carrier molecule. No ATP is required

Question 18

What is active transport?

Answer 18

Solutes moving from an area of [low solute] to an area of [high solute] across a membrane with the aid of a protein carrier molecule and ATP. Moves against the concentration gradient

Question 19

What factors affect diffusion?

Answer 19

• Temperature
• Concentration gradient
• Size
• Surface area
• Volume
• Diffusion medium(solid, liquid, gas)

Question 20

What is endocytosis?

Answer 20

The process in which large materials enter a cell

Question 21

What are the two different types of endocytosis and what do they do?

Answer 21

• Phagocytosis: whole cells, or bacteria, or cell fragments are taken in (cell eating)
• Pinocytosis: molecules like protein, are taken in (cell drinking)

Question 22

What is exocytosis?

Answer 22

The process by which products or wastes exit the cell. Reverse of endocytosis