Topic 4 Photosynthesis and Limiting Factors

Question 1

The equation that produces Glucose using light

Answer 1

Carbon dioxide + water –> glucose + oxygen

Question 2

The 5 ways in which plants use Glucose

Answer 2

1. Respiration(transfers energy from Glucose enabling the play to convert the rest of the Glucose to useful substances)
2. Making cellulose (Glucose is converted to cellulose for sting cell walls)
3. Making amino acids (Glucose combined with nitrate ions to make amino acids which are then made into protein)
4. Stored as oils or fats (Glucose is turned into lipids)
5. Stored as starch (Glucose is turned into starch for when there is no photosynthesis is happening e.g. Winter

Question 3

The 4 limiting factors of the rate of photosynthesis

Answer 3

1. intensity of light
2. concentration of CO2
3. temperature
4. chlorophyll

Question 4

How does light limit the rate of photosynthesis

Answer 4

As you increase light the rate of photosynthesis increases until a certain point where it is limited by CO2 or temperature

Question 5

How does CO2 affect rate of photosynthesis

Answer 5

The increase of CO2 also means the increase of rate of photosynthesis until a certain point where it is limited by temperature or light intensity

Question 6

How does temperature affect the rate of photosynthesis

Answer 6

When temperature increases so does the rate of photosynthesis until it gets to hot and the rate goes down and at 45degrees Celsius the enzyme is destroyed

Question 7

How farming can create the ideal conditions for temperature

Answer 7

Greenhouses trap heat so temperature isn’t the limiting factor but in winter they may use heaters and in summer use shades and ventilation to keep the greenhouse cool

Question 8

How farms create ideal light intensity

Answer 8

Often artificial light used when the sun is down so the plant can photosynthesis more

Question 9

How farms creat the ideal level of CO2 concentration

Answer 9

Paraffin heater as when it is burnt it produces a byproduct of CO2 causing the concentration to increase

Question 10

For farms keep crops safe

Answer 10

Kept enclosed in a greenhouse so that it is free from pests and diseases and farmers can also add fertiliser and minerals for better growth

Question 11

Respiration

Answer 11

The process of transferring energy from Glucose which goes on in every cell

Question 12

Is respiration endothermic or exothermic?

Answer 12

Exothermic

Question 13

The 3 things energy is used for

Answer 13

1. to build up larger molecules from smaller ones (proteins from amino acids)
2. In animals it’s used to allow the muscles to contract
3. In mammals and birds the energy is used to regulate their body temperatures

Question 14

What are chemical reactions controlled by?

Answer 14

Enzymes

Question 15

Give examples of larger molecules being broken down into smaller ones

Answer 15

1. Lots of small glucose molecules join together to form starch,glycogen and cellulose
2. lipid molecules are made from one molecule of glycerol and three fatty acids
3. Glucose is combined with nitrate ions to make amino acids which are then made into proteins

Question 16

Examples of larger molecules broken down from larger ones into smaller ones

Answer 16

1. Glucose is broken down in respiration and this transfers energy which powers all the reactions which break down molecules in the body
2. Excess protein is broken down in a reaction to produce urea this is excreted in urine

Question 17

Metabolism

Answer 17

The sum of all the reactions that happen in a cell or the body

Question 18

What does aerobic respiration need lots of

Answer 18

Oxygen

Question 19

Where does aerobic respiration take place?

Answer 19

Mitochondria

Question 20

Equation for Aerobic respiration

Answer 20

Glucose + Oxygen –> carbon dioxide + water

Question 21

When is anaerobic respiration used?

Answer 21

When there isn’t enough oxygen

Question 22

Equation for Anaerobic respiration

Answer 22

Glucose –> lactic acid

Question 23

The usefulness of Anaerobic respiration

Answer 23

Doesn’t transfer as much energy by each molecule of glucose.

Only useful in emergencies such as exercising so you can use your muscles for a little while longer

Question 24

Respiration in plants and yeast

Answer 24

They respire without oxygen and produce ethanol and carbon dioxide not lactic acid

Question 25

The equation for Anaerobic respiration in plant and yeast

Answer 25

Glucose –> ethanol + carbon dioxide

Question 26

Fermentation

Answer 26

Anaerobic respiration in yeast cells

Question 27

The products of fermentation

Answer 27

Bread,beer and wine

Question 28

Oxygen debt

Answer 28

After exercising and using Anaerobic respiration oxygen is needed to react with lactic acid to form CO2 and water

Question 29

The effects of harder exercise

Answer 29

Breathing rate and heart rate increases as the exercises go from sitting to running