Chapter 8 Cell Membranes

Question 1

Why is cell size limited?

Answer 1

The cells in the body are microscopic because it’s easier/quicker for cells to diffuse the nutrients in and out the center of the cells. Since they have a greater surface area to volume ratio. This allows the rate of diffusion to be faster and cells to work more efficiently.

Question 2

Membrane Transport: Which types are active?

Answer 2

ACTIVE

• primary active transport
• secondary active transport
• Vesicular bulk transport

Question 3

Membrane Transport: Which types are passive?

Answer 3

PASSIVE

• simple diffusion
• facilitated diffusion
• osmosis

Question 4

Membrane Transport: Which types require ATP?

Answer 4

ACTIVE TRANSPORT

• primary active transport
• Secondary active transport
• vesicular (bulk) transport

Question 5

Membrane Transport: Which types require transport proteins?

Answer 5

Facilitate diffusion (called channels carriers pores)
Active transport

Question 6

Membrane Transport: In which direction do solutes move in each type?
PASSIVE

Answer 6

• simple diffusion: move down w/ concentration gradient
• facilitated diffusion: move with/down a concentration gradient
• osmosis : move from a higher concentration gradient to a lower concentration gradient

Question 7

Membrane Transport:
What types of molecules are transported in each type?
PASSIVE

Answer 7

-simple diffusion:
Oxygen and carbon dioxide and most lipids

-facilitated diffusion :
polar and charged molecules(carbs, amino acids, nucleosides, ions)

-osmosis: movement of water molecules

Question 8

In which direction do solutes move in each type?

ACTIVE

Answer 8

-primary active transport: Solutes move up/against their concentration gradient

-secondary active transport: One molecule diffuses down its concentration gradient.
Second molecule is transported against its
concentration gradient

-Vesicular bulk transport
Phagocytosis: large cells particles transported into the cell
Endocytosis: move particles into a cell

Question 9

What types of molecules are transported in each type? ACTIVE

Answer 9

• primary active transport: metal ions(Na+, K+, Mg2+, and Ca2+)
• secondary active transport: sodium ions
• Vesicular bulk transport: large solid ( phagocytosis ) or liquid ( pinocytosis ) molecules

Question 10

Vesicular (bulk) transport

Answer 10

Types:○Endocytosis – molecules brought into the cell
■Phagocytosis – cellular “eating”
■Pinocytosis – cellular “drinking”

○Exocytosis – molecules sent out of the cell

Question 11

Define osmosis

Answer 11

The movement of water from an area of lower solute concentration to an area of HIGHER solute concentration

Question 12

explain what happens to a cell that is in an isotonic solution and explain why the cell is affected the way it is.

Answer 12

Homeostasis

-Amount of water entering the cell =
amount of water exiting the cell
-No net movement of water
- = stabled

Question 13

explain what happens to a cell that is in a hypertonic solution & explain why the cell is affected the way it is in the hypertonic solution:

Answer 13

The cell will shrivel

When a solution has a
higher solute concentration than
another area
Therefore a net flow of water out of the cell, and the cell will lose volume.

Question 14

explain what happens to a cell that is in a hypotonic solution & why the cell is affected the way it is in the hypotonic solution:

Answer 14

The cell swells and may burst

When a solution has a lower solute concentration than another solution. There will be a net flow of water into the cell, and the cell will gain volume.