B8 Photosynthesis

Question 1

Is photosynthesis an endothermic or exothermic reaction?

Answer 1

Endothermic

Question 2

What is Photosynthesis?

Answer 2

Photosynthesis is a chemical reaction that takes place inside a plant, producing food for the plant to survive.

Question 3

What is needed for Photosynthesis?

Answer 3

Carbon dioxide, water and light are all needed for photosynthesis to take place.

Question 4

What is the word equation for photosynthesis?

Answer 4

Carbon Dioxide + Water + (light over the arrow) -> glucose +oxygen

Question 5

What is the symbol equation for Photosynthesis?

Answer 5

6CO2 + 6H20 +(light over the arrow)-> C6H12O6 + 6O2

Question 6

How can you see oxygen being produced when a plant is photosynthesising?

Answer 6

If you use Water plants such as Pom weed or Elodea you can see and collect the bubbles of gas they give of when photosynthesising.

Question 7

How are leaves of plants adapted for photosynthesising?

Answer 7

• Most leaves have a big surface area for light to fall on.
• Most leaves are thin so diffusion distance for the gases are short
• Contain chlorophyll in the chloroplasts to absorb light
• They have veins , which bring plenty of water in the xylem to the cells of the leaves and remove products of photosynthesis in the pholem.
• Air spaces that allow Carbon dioxide to get to the cells, and oxygen to leave by diffusion
• They have guard cells that open and close the stomata to regulate gas exchange.

Question 8

What happens during photosynthesis?

Answer 8

_During photosynthesis energy is transferred from the environment to the chloroplast by light.

• It is used to convert carbon dioxide and water into sugar (glucose).
• Oxygen is also formed and released as by product

Question 9

What are the limiting factors for photosynthesis?

Answer 9

• Temperature
• Light
• Carbon dioxide concentration
• Chlorophyll levels in the leaf

Question 10

How is temperature a limiting factor for photosynthesis?

Answer 10

As temperature rises, the rate of photosynthesis increases as the reaction speeds up. However enzymes are denatured once the temperature rises around 40-50°C.

Question 11

What happens to the rate of photosynthesis if the temperature gets too high?

Answer 11

if the temperature gets to high , the enzymes controlling photosynthesis are denatured and the rate of photosynthesis will fall.

Question 12

How is light a limiting factor for photosynthesis?

Answer 12

If there is plenty of light , lots of photosynthesis can take place. If there is little or no light , photosynthesis will stop.

Question 13

What is the correlation for light and photosynthesis?

Answer 13

For most plants, the brighter the light, the faster the rate of photosynthesis.

Question 14

how is Carbon Dioxide limiting factors for photosynthesis?

Answer 14

At lower carbon dioxide concentrations carbon dioxide is the limiting factor because an increase in carbon dioxide causes an increase in photosynthesis.

Question 15

What is the correlation for Carbon Dioxide and photosynthesis?

Answer 15

As carbon dioxide concentrations increase, so too does the rate of photosynthesis until a certain point where the graph levels off

Question 16

How is chlorophyll levels in the leaf a limiting factor for photosynthesis?

Answer 16

If the amount of chlorophyll in a leaf is limited in any way less photosynthesis will take place

Question 17

What are the control variables the light intensity and rate of photosynthesis practical

Answer 17

The control variables are:

• the same Piece of pondweed
• temperature using beaker of water

Question 18

What are the safety considerations for the light intensity and rate of photosynthesis practical?

Answer 18

• Keep electrical equipment dry
• Heat from lamp
• Careful with glass

Question 19

What is light intensity and the inverse square law?

Answer 19

The light energy at twice the distance away is spread over four times the area. The light energy at three times the distance away and is spread over nine times the area and so on. The light intensity is inversely proportional to the square of the distance this is the inverse square law.

Question 20

What is the equation for Light intensity?

Answer 20

Light intensity (inverse symbol) 1/d^2

Question 21

How do plants use glucose?

Answer 21

The glucose is broken down using oxygen to provide energy for the cells.

• For cell walls
• To be stored

Question 22

What are the waste products of photosynthesis?

Answer 22

Carbon dioxide and Water

Question 23

Why do plants build up glucose?

Answer 23

Plant build up glucose into complex carbohydrates such as cellulose. they use this strengthens the cell walls.

Question 24

What happens if glucose was stored in plant cells?

Answer 24

If it was stored in plant cells it could affect the way water moves into and out of the cells by osmosis.

Question 25

Is Glucose soluble or insoluble in water?

Answer 25

Glucose is soluble in water. Lots of glucose is stored in plant cells could affect the water balance of the whole plant.

Question 26

Is Starch insoluble or soluble in water?

Answer 26

Starch is insoluble in water. It has no effect on the water balance of the plant so plants can store large amount of starch in their cell walls.

Question 27

Why is starch stored in the cells of the leaves?

Answer 27

Starch is stored in the cells of the leaves.It provides an energy store for when it is dark or when Light levels are low.

Question 28

Where else is starch stored?

Answer 28

Starch is also kept in special storage areas of the a plant.
For example many plants produce tubers and bulbs that are full of stored starch to help them survive for the winter

Question 29

How are amino acids made and used

Answer 29

Glucose is used to make amino acids to build up proteins to be used in plant cells in many ways including enzymes. the energy is used for respiration

Question 30

How are lipids made and used?

Answer 30

Glucose is used to make lipids to use as energy stores.

• energy is used for respiration
• used in cells to make stronger
• and seeds are created to provide new food for new plants

Question 31

How do you plant and algal cells use glucose?

Answer 31

Plant and Agal cells use the Glucose produced during photosynthesis respiration to:

• convert into insoluble starch for storage
• to produce fat or oils for storage
• to produce cellulose to strengthen cell walls
• and to produce Amino acid for protein synthesis

Question 32

Why do plants and algal cells need nitrate ions?

Answer 32

Plants and alcohol cells also need nitrate ions absorbed from the soil or water to make the amino acids used to make proteins

Question 33

Why are limiting factors important in greenhouses?

Answer 33

Limiting factors are important in the economics of enhancing the conditions in the greenhouses to gain the maximum rate of photosynthesis whilst still maintaining profit.

Question 34

Why is a greenhouse a good storage facility to increase light intensity for crops?

Answer 34

Maximising the light transmission which can speed up the rate of photosynthesis

Question 35

What process do the fungi do to increase the concentration of carbon dioxide in the greenhouse?

Answer 35

Fungi respire and release carbon dioxide into the environment

Question 36

In what layer of the leaf does photosynthesis take place?

Answer 36

Palisade layer

Question 37

Which organelle in plant cells produce chlorophyll?

Answer 37

Chloroplasts

Question 38

In what layer of the leaf does most photosynthesis take place?

Answer 38

Palisade mesophyll layer

Question 39

How are water levels controlled in the plant?

Answer 39

By the guard cells that open and close the stomata

Question 40

Why are there air spaces in the spongy mesophyll layer?

Answer 40

For faster exchange of gases