Movement of substances in and out of cells

Question 2

Movement of substances in and out of cells

Answer 2

In order for cell to carry out the many chemical reactions it needs to substances must enter and leave the cell.
This happens in three ways:
Diffusion
Osmosis
Active transport

Question 3

Diffusion

Answer 3

Is the movement of molecules from a region of its higher concentration to a region of its lower concentration down a concentration gradient as a result of their random movement

Question 4

Concentrate gradient

Answer 4

A difference in concentration between 2 areas is called a concentration gradient

Question 6

Factors affecting rate of diffusion: diffusion distance

Answer 6

The shorter the distance the higher the rate of diffusion

Question 7

Factors affecting rate of diffusion: concentration gradient

Answer 7

The higher the concentration gradient the higher the rate of diffusion

Question 8

Factors affecting rate of diffusion: temperature

Answer 8

The higher the temperature the higher the rate of diffusion. This is because the molecules gain more kinetic energy with higher temperatures so moves faster

Question 9

Factors affecting rate of diffusion: surface area to volume to ratio

Answer 9

The large the surface area in proportion to volume the higher the rate of diffusion. This is because more molecules at a given time will be diffusing

Question 11

Active transport

Answer 11

Is the movement of molecules from a region of low concentration to a region of higher concentration against the concentration gradient using energy of respiration

Question 13

Water potential

Answer 13

The water potential measures the concentration of free water molecules

Question 14

Partially permeable membrane

Answer 14

A partially permeable membrane will allow certain molecules to pass through but not others.
Small molecules can pass through but large molecules cannot

Question 15

Osmosis

Answer 15

Osmosis is the net movement of free water molecules from a region of high water potential to a region of low water potential through a partially permeable membrane until they reach equilibrium

Question 16

Types of solutions: isotonic

Answer 16

An isotonic solution is one that has the same concentration of solutes both inside and outside the cell

Question 17

Types of solutions: hypertonic

Answer 17

A hypertonic solution is one that has a higher solute concentration outside the cell than inside.
Also called as concentrated solution

Question 18

Hypotonic

Answer 18

A hypotonic solution is the one that has a higher solute concentration inside the cell than outside.
Also called dilute solution

Question 19

Osmosis

Answer 19

Endosmosis
Exosmosis

Question 20

Endosmosis

Answer 20

When a substance is placed in a hypertonic solution the solvent molecules move inside the cell and the cell becomes turgid. This is known as endosmosis

Question 21

Exosmosis

Answer 21

When a substance is placed in a hypertonic solution the solvent move outside the cell and the cell becomes flaccid or undergoes plasmolysis. This is known as exosmosis

Question 23

Osmosis in animals: isotonic

Answer 23

Normal red blood cell where concentration of water inside the cell is the same as outside

Question 24

Osmosis in animals: hypertonic

Answer 24

Low water concentration outside cell so water moves out of the cell during osmosis.
Shriveled cell

Question 25

Osmosis in animals: hypotonic

Answer 25

High water concentration outside cell and during osmosis water moves into cell
Cell swell, might burst