Biology 1.4

Question 1

What is photosynthesis word equation

Answer 1

Carbon dioxide + water —> Oxygen + glucose

Question 2

What is photosynthesis symbol equation (balanced)

Answer 2

6CO2 + 6H2O —> C6H12O6 + 6O2

Question 3

Where does photosynthesis occur

Answer 3

In the chlorophyll

Question 4

What is stage 1 of photosynthesis

Answer 4

Energy transferred from light splits water molecules into oxygen gas and hydrogen atoms

Question 5

What is stage 2 of photosynthesis

Answer 5

Carbon dioxide gas combines with the hydrogen ions to make glucose

Question 6

What are the ways a plant uses glucose

Answer 6

Respiration, made into other sugar like fructose and sucrose, converted to starch,

Question 7

How do you test for starch

Answer 7

Boil the leaf for 1 minute, then put it into a tube of boiling ethanol for a minute to remove chlorophyll, wash with water to remove ethanol, add iodine,if it turns blue-black it has starch present.

Question 8

How do you destarch a plant?

Answer 8

Keep it in dark for a minimum of 24 hrs

Question 9

How do you prove chlorophyll is needed for photosynthesis?

Answer 9

Place a destarched, variegated plant in sunlight for several hours, then test a leaf for presence of starch

Question 10

How can you prove light is needed for photosynthesis?

Answer 10

Take a destarched plant and cover half a leaf with black card or tinfoil. After several hours test the leaf for starch.

Question 11

How can you prove carbon dioxide is needed for photosynthesis

Answer 11

Put a destarched plant inside a polythene bag, add a pot of soda lime, before sealing the bag, place in sunlight for several hours, then test a leaf for starch.

Question 12

How can you prove oxygen is given off during photosynthesis

Answer 12

Place an upside down test tube above an aquatic plant like pondweed, after a while, take the tube and put a glowing splint inside of it, where it will then relight because of the oxygen produced during photosynthesis by the pondweed.

Question 13

What does testing for starch do?

Answer 13

It proves that photosynthesis has happened if starch is present because it means glucose has been produced to make starch and the glucose comes from photosynthesis as it is a product.

Question 14

What factors can affect photosynthesis?

Answer 14

Light intensity, carbon dioxide and temperature.

Question 15

What is a limiting factor

Answer 15

anything that constrains somethings rate of reaction, size, etc.

Question 16

How do you measure the rate of photosynthesis

Answer 16

Measure how much oxygen or glucose a plant makes in a given time, or how much the biomass increases due to glucose being used to make new cells.

Question 17

What is the formula for rate of photosynthesis?

Answer 17

Rate = 1/t where t is the time it takes for the measurement to occur. Units can be s^-1 m^-1 and h^-1 meaning per second, per minute, and per hour respectively.

Question 18

How does light intensity affect the rate of photosynthesis?

Answer 18

The higher the light intensity, the faster the rate of photosynthesis. This
continues until photosynthesis reaches its maximum rate. In
very low light levels or if there is no light, photosynthesis stops.

Question 19

How does carbon dioxide affect the rate of photosynthesis

Answer 19

Carbon dioxide is one of the reactants for photosynthesis. The greater the
carbon dioxide concentration, the faster the rate of reaction.
However, the atmosphere only contains about 0.04% carbon dioxide. This
means that carbon dioxide is most commonly the limitinq factor.
Farmers artificially increase the levels of carbon dioxide in greenhouses.
This increases the rate of photosynthesis.

Question 20

How does temperature affect the rate of photosynthesis

Answer 20

Photosynthesis is a series of enzyme-controlled reactions. Therefore, the
higher the temperature the faster the reactions occur. However, if the
temperature is too high the enzymes will denature the reactions will stop.

Question 21

What does light intensity graph look like

Answer 21

Gradual increase as light intensity goes up but levels out once it is no longer the limiting factor

Question 22

What does carbon dioxide graph look like

Answer 22

Gradual increase as carbon dioxide goes up but levels out once it is no longer the limiting factor

Question 23

What does temperature graph look like

Answer 23

Gradual increase as temperature goes up but levels out once it is no longer the limiting factor. Then goes down sharply as enzymes denature

Question 24

What is the inverse square law

Answer 24

Relative light intensity = 1/ distance from light source^2

Question 25

How do you change light intensity

Answer 25

Change the distance of the light source to the subject

Question 26

How do you change carbon dioxide concentration

Answer 26

Add different masses of potassium hydrogen carbonate powder to the water.

Question 27

How do you change the Temperature

Answer 27

Place the apparatus in a water bath at different temperatures