GCSE 2 (section B)

Question 1

How do you calculate the rate of osmosis?

Answer 1

Change in weight/time

Question 2

How do you calculate the rate of diffusion?

Answer 2

Surface area x concentration difference / distance

Question 3

How do you calculate percentage change?

Answer 3

Change in weight / starting weight

Question 4

What is diffusion?

Answer 4

The movement of molecules from a religion of high concentration to low concentration

Question 5

What is osmosis?

Answer 5

The movement of solvent molecules through a semi-permeable membrane into a region of higher solute concentration

Question 6

What is active transport?

Answer 6

The movement of ions and molecules across a cell membrane into a region of higher concentration, assisted by enzymes and requiring energy

Question 7

What does hypertonic mean?

Answer 7

There is a higher solute concentration than the fluid inside the cell

Question 8

What does hypotonic mean?

Answer 8

There is a lower solute concentration than the fluid inside the cell

Question 9

What does isotonic mean?

Answer 9

The osmotic pressure inside the cell is the same as the osmotic pressure outside the cell

Question 10

What does turgid mean?

Answer 10

(Relating to hypotonic)

when a cell is swollen - there is more liquid inside a cell then outside

Question 11

What does flaccid mean?

Answer 11

(Relating to hypertonic)

The state of which the cell is lacking in water - the plasma membrane is not tightly in touch with the cell wall

Question 12

What are three factors that could affect active transport?

Answer 12

• temperature
• oxygen concentration
• pH

Question 13

What are four factors that could affect diffusion?

Answer 13

• density
• temperature
• distance
• concentration difference

Question 14

What are four factors that could affect osmosis?

Answer 14

• temperature
• surface area
• pressure
• concentration gradient

Question 15

How does density affect diffusion?

Answer 15

Heavier particles will travel slower than light ones; light particles are more mobile and are smaller

Question 16

How does temperature affect diffusion?

Answer 16

Heat gives energy to particles, so increasing the temperature will increase the rate of diffusion and vice versa

Question 17

How does concentration difference affect diffusion?

Answer 17

If there is already a near-equal amount of a particle on either side the rate of diffusion will be slower as the particles have to move to make it equal and vice versa

Question 18

How does distance affect diffusion?

Answer 18

Particles will take a shorter time to travel shorter distances, so the rate of diffusion will be faster

+ gas will diffuse faster through a thin wall than a thick one

Question 19

How does the surface area affect osmosis?

Answer 19

The larger the surface area, the easier the particles can cross the membrane

Question 20

How does the temperature affect osmosis?

Answer 20

Energy is expended to permeate the membrane to allow water to flow through, the higher the temperature the more energy is produced

Question 21

How does pressure affect osmosis?

Answer 21

The higher the pressure on one side of the membrane the higher the rate of osmosis on the other

Question 22

How does the concentration gradient affect osmosis?

Answer 22

The lower the concentration of solute in water, the faster it moves through the water as there are no particles interrupting the flow

Question 23

How does temperature affect active transport?

Answer 23

Enzymes work best at an optimum temperature and denature after a certain temperature is reached. The rate of chemical reaction will increase at an enzymes optimum temperature.

Question 24

How does oxygen concentration affect active transport?

Answer 24

Oxygen produces energy when it breaks down food. When the oxygen concentration is low less energy is produced which slows down the rate of active transport.

Question 25

How does pH affect active transport?

Answer 25

Enzymes only work at specific pH’s. When a ph is altered the enzyme activity will be slowed or stopped which will stop all chemical reactions

Question 26

What is photosynthesis?

Answer 26

The process in which plants absorb visible light and carbon dioxide and produce glucose and oxygen

Question 27

What is the word equation for the reaction that occurs in photosynthesis?

Answer 27

(6) water + (6) carbon dioxide —> glucose + (6) oxygen

Question 28

What is the symbol equation for the reaction that occurs in photosynthesis?

Answer 28

6 CO2 + 6 H2O —> C6H12O6 + 6 O2

Question 29

What nutrients are needed in photosynthesis and why?

Answer 29

Nitrates ; used in making amino acids

Magnesium ; part of the chlorophyll molecule

Phosphate ; making DNA

Potassium ; needed for enzymes of respiration

Question 30

Why is photosynthesis important?

Answer 30

• converts light energy into usable chemical energy
• produces oxygen
• produces food
• removes carbon dioxide from the air

Question 31

What can affect photosynthesis?

Answer 31

If a plant gets more light, carbon dioxide; water or a higher temperature (and no other factors increase) then it will not be able to photosynthesize

Question 32

Where in a leaf do the most chloroplasts occur?

Answer 32

The palisade layer

Question 33

What are the two top layers of a leaf?

Answer 33

The waxy cuticle and upper epidermis