Membrane Transport

Question 1

Passive Transport

Answer 1

Requires no input of energy

Question 2

What are the types of passive transport?

Answer 2

Diffusion and Osmosis

Question 3

Diffusion

Answer 3

Movement of molecules from high to low concentration

Question 4

What are factors that effect the rate of diffusion?

Answer 4

• Temperature = warmer temps molecules move faster
• Pressure = higher pressure makes molecules since there is less space
  -Size of Molecule = smaller molecules move faster
• Concentration gradient = The greater the difference the faster the rate of diffusion

Question 5

Osmosis

Answer 5

Diffusion of water
The movement of water molecules from high to low concentration

Question 6

How many osmotic conditions are there and what are they?

Answer 6

3 osmotic conditions
Isotonic, Hypertonic, Hypotonic

Question 7

Isotonic

Answer 7

The concentration of dissolved solutes is equal in and out of the cell. The water concentration is the same. The cell stays the same size

Question 8

example of an isotonic solution

Answer 8

The saline solution given to patients. 0.7% NaCl is isotonic to cells

Question 9

Hypertonic

Answer 9

The concentration of solutes is greater outside the cell than inside. There is a greater concentration of water in the cell.

Question 10

What does Crenation mean?

Answer 10

When the cell lose water and shrink

Question 11

Give an example of a Hypertonic situation

Answer 11

The salting of food for preservation. When vegetation is killed due to the salting of roads.

Question 12

Hypotonic

Answer 12

The concentration of solutes is less outside the cell than inside. The concentration of water is less inside the cell. Water will enter the cell, the cell will increase in size.

Question 13

What does cytolysis mean?

Answer 13

When a cell bursts because it is left as hypotonic for too long. When red blood cells are burst its called hemolysis.

Question 14

Give an example of a hypotonic solution.

Answer 14

misting produce in markets so the plant vacuoles fill with water and push against the cell wall - turgor pressure.

Question 15

Facilitated Diffusion

Answer 15

The movement of molecules that are charged or too large to fit through the plasma membrane - must be transported using carrier proteins (integral proteins)

Question 16

Example of facilitated Diffusion

Answer 16

water through aquaporins; glucose

Question 17

What molecules can pass through the plasma membrane easily?

Answer 17

Lipids, Oxygen, and Carbon Dioxide

Question 18

Active Transport

Answer 18

Process of materials passing through the plasma membrane but requires energy. Two types are solute pumping and bulk transport.

Question 19

Solute Pumping

Answer 19

Moves molecules against the concentration gradient (high to low)

Question 20

Examples of solute pumping

Answer 20

ex. sodium/potassium pump - important in carrying nerve impulses
- sodium is pumped out of the cell from low to high concentration using energy provided by ATP while K+ is pumped into the cells against the concentration gradient
- electrical gradient formed by the difference of charges from the inside and outside of the cell is created by what carries nerve impulses

Ex. stores extra glucose as glycogen
-the glucose must be brought into the liver against concentration gradient

Question 21

Bulk Transport

Answer 21

Molecules too large to fit in the cell are moved in and out. There are two major types: Endocytosis and Exocytosis

Question 22

Exocytosis

Answer 22

a vesicle containing substances moves to the cell membrane and joins it to release the contents

Question 23

Endocytosis

Answer 23

Brings materials into the cell. There are two types which are pinocytosis and phagocytosis

Question 24

Pinocytosis

Answer 24

Cell drinking, when cells take in liquids, anything that has a charge

Question 25

Phagocytosis

Answer 25

Cell eating, when cells take in solids (white blood cells)

Question 26

Receptor-Mediated Endocytosis

Answer 26

• Controls menstrual cycle and allergies
• In this process, there are receptor proteins on the surface of the membrane
• There are specific molecules that can attach to these receptors
• When these receptors attach to the molecules the reaction is triggered
• Endocytosis is controlled by receptors

Question 27

Examples of Receptor-Mediated Endocytosis

Answer 27

Ex. Addiction to drugs
Ex. Allergens = things that cause allergic reactions
- people who have allergies have receptors for the allergen
- The allergen attaches to the receptors on mast cells. This causes the release of histamines (causes runny nose, eye irritation, and trouble breathing)