Cell Membrane Transport UNIT 3 AOS 1

Question 1

What is the structure of the plasma membrane?

Answer 1

phospholipid bilayer with hydrophilic (water loving) heads with hydrophobic tails (water hating). Large proteins are embedded within the phospholipid. e.g cholesterol

Question 2

What is the function of the plasma membrane?

Answer 2

Control the movement of molecules moving in and out of the cell

Question 3

What gets in easily?

Answer 3

• alcohol
• water
• small uncharged molecules
• oxygen, carbon dioxide and other gases
• small hydrophobic (water hating) substances

Question 4

What doesn’t get in easily?

Answer 4

• charged molecules

- large molecules, especially hydrophilic (water loving)

Question 5

Factors that affect the rate of movement across the plasma membrane?

Answer 5

• cell membrane structure and fluidity
• chemical gradient
• electrical gradient
• temperature

Question 6

What is facilitated diffusion?

Answer 6

passive movement of substances from an area of high to low concentration via a membrane protein. passive transport

Question 7

What is osmosis?

Answer 7

Movement across a semi-permeable membrane from a region of high water concentration to low concentration, or from low solute to high solute concentration. passive transport

Question 8

What is ATPase pump?

Answer 8

The process of moving sodium and potasium ions across a cell membrane. Involved the hydrolysis of ATP to provide energy. It involved an enzyme (Na+/K+ pump). active transport

Question 9

What is endocytosis?

Answer 9

Cells engulfing large particles of fluid from the outside of the cell. Vesicle brings it into the cell.

Question 10

What are the three types of endocytosis?

Answer 10

• phagocytosis (large molecules)
• pinocytosis (fluid)
• receptor mediator (small molecules)

Question 11

What is exocytosis?

Answer 11

Vesicles with substances the cell wants to export fuse with the plasma membrane and exit the cell

Question 12

Define isotonic?

Answer 12

A solution when the same solute, solvent concentration

Question 13

Define hypertonic?

Answer 13

Higher salt (solute) concentration compared to the surrounding environment

Question 14

Define hypotonic?

Answer 14

High water (solvent) concentration compared to the surrounding environment

Question 15

Term used for hypotonic (bursting) animal cells?

Answer 15

Lysis

Question 16

Term used for shrinking (hypertonic) animal cell?

Answer 16

Crenate

Question 17

Term used for hypotonic plant cell?

Answer 17

Turgid

Question 18

Term used for hypertonic plant cell?

Answer 18

Plasmolyse

Question 19

What is simple diffusion?

Answer 19

The movement of compounds from high to low concentration. Compounds unable to pass through the membrane will only pass if the membrane channels open. It is driven by the concentration difference and requires no further input of energy

Question 20

how does the concentration gradient effect rate of diffusion?

Answer 20

larger concentration gradient means things will move faster between the two sides. The bigger the concentration gradient the faster the rate of movement.

Question 21

how does kinetic energy effect the rate of diffusion?

Answer 21

more heat equals more energy. Things will move faster at greater temperatures

Question 22

define active transport?

Answer 22

the movement of molecules, from a region of low concentration to a region of high concentration, requiring the use of energy in the form of ATP, via a carrier protein. Goes against the concentration gradient