Photosynthesis + Plants

Question 1

What is the symbol equation for photosynthesis?

Answer 1

6CO2 + 6H2O -> C6H12O6 + 6O2

Note: you must put light energy and chlorophyll on the arrow

Question 2

What is the simplest way to test for whether photosynthesis has taken place?

Answer 2

Test for starch. (as it is a product of photosynthesis) However this is said to be a qualitative test as it only shows whether photosynthesis has or hasn’t taken place.

Question 3

What’s the best way to test how much photosynthesis has taken place?

Answer 3

You can measure the amounts (volumes) of oxygen, so the production of oxygen can be used as a quantitive test for photosynthesis.

Question 4

What is photosynthesis?

Answer 4

Photosynthesis is the fundamental process by which plants manufacture carbohydrates from raw materials using energy from light

Question 5

What is chlorophyll?

Answer 5

A green pigment in plants that is responsible for the absorption of light to provide energy.

Question 6

What is the waxy cuticle for on a leaf?

Answer 6

It reduces water loss

Question 7

What is that the epidermis on a leaf?

Answer 7

A covering which is usually one cell thick. It is transparent And allows light to pass and has the major function of preventing entry of disease-causing organisms.

Question 8

What is the Palisade mesophyll on a leaf?

Answer 8

Tall, thin cells that are tightly packed near the upper layer of a leaf. They have many chloroplasts which allows the maximum absorption of light energy.

Question 9

What is the vein in a leaf?

Answer 9

The transport system in and out of the leaf. Xylem vessels deliver water and mineral salts, and the phloem tubes carry away the organic products of photosynthesis such as glucose

Question 10

What is the spongy mesophyll layer in a leaf?

Answer 10

Cells which are rather loosely pack allowing airspaces between them to aid diffusion of gases through the leaf.

Question 11

What is a limiting factor?

Answer 11

Something present in the environment in such short supply that it restricts life processes

Question 12

How do plants obtain the CO2 needed for photosynthesis?

Answer 12

CO2 diffuses into the leaves through this stomata on the underside of the leaf.

Question 13

How do plants obtain the water for photosynthesis?

Answer 13

The water is carried to the leaves from the soil through root hairs and xylem vessels.

Question 14

What is the glucose produced in photosynthesis used for?

Answer 14

Respiration, stored as starch, used to make cellulose, combines with mineral ions to make proteins, fats and vitamins for growth.

Question 15

What happens to the oxygen produced in photosynthesis?

Answer 15

It is a waste product, and diffuses out of the leaf via stomata

Question 16

Chlorophyll absorbs light energy. What is this light energy used for?

Answer 16

It is used along with enzymes to combine CO2 and H2O to make glucose.

Question 17

What are the four steps for testing a leaf for starch?

Answer 17

1. The leaf is putt in boiling water.
2. The leaf is warmed in Ethanol until the leaf turns colourless.
3. The leaf is dipped into warm water again briefly.
4. The Leaf is placed on a white tile and iodine solution is added. Blue/black is a positive result.

Question 18

What is the purpose of putting the leaf into boiling water?

Answer 18

To break down cell walls and stop action of enzymes. It allows easier penetration by ethanol.

Question 19

What is the purpose of warming the leaf in ethanol?

Answer 19

To extract chlorophyll, which would mask observations later.

Question 20

What is the purpose of dipping the leaf into water again briefly.

Answer 20

To soften he now brittle leaf to allow penetration of iodine solution.

Question 21

Define the term limiting factor.

Answer 21

A limiting factor is something present in the environment in such short supply that it could restrict lights processes.

Question 22

What are the three ways photosynthesis can be increased in greenhouses?

Answer 22

I burning hydrocarbons, paraffin heaters or manure.

Question 23

How does burning hydrocarbons in greenhouses increase the rate of photosynthesis?

Answer 23

When you burn hydrocarbons (combustion) you produce CO2, H2O and heat.

Question 24

How does using the manure in greenhouses increase the rate of photosynthesis?

Answer 24

The microbes in manure respire producing CO2 and heat.

Question 25

What are nitrate ions used for in plants?

Answer 25

Protein synthesis

Question 26

What are magnesium ions used for in plants?

Answer 26

Chlorophyll synthesis

Question 27

What is the main danger of overuse of nitrogen fertilisers?

Answer 27

Eutrophication

Question 28

Describe the eight stages of eutrophication.

Answer 28

1. Farmers spray crops with fertilisers to help it grow.
2. Fertilisers (containing nitrates) spread into the water.
3. Water plants and algae arrive on the nutrients.
4. Algae on the surface blocks out light to the plants below.
5. The plants die due to lack of light.
6. Microorganisms (e.g. bacteria) feed on the dead plants.
7. Microorganisms rapidly multiplying and use up oxygen in respiration.
8. Fish and other aquatic animals die due to lack of oxygen.

Question 29

What is the deficiencies symptoms for a plant that does not get enough magnesium ions?

Answer 29

Yellow leaves, magnesium is responsible for the green chlorophyll.

Question 30

What are the deficiency symptoms of a plant that does not get enough nitrate ions?

Answer 30

Poor growth and yellow leaves, as nitrogen is responsible for the amino acids that are responsible for growth.

Question 31

What is the path taken by water through a plant?

Answer 31

Root hair, root cortex cells, xylem, mesophyll cells.

Question 32

What is transpiration?

Answer 32

Transpiration is the evaporation of water at the surfaces of the mesophyll cells followed by loss of water vapour from plant leaves, through the stomata.

Question 33

Describe how increased temperature effects transpiration rate.

Answer 33

Transpiration is faster, as evaporation and diffusion is faster at higher temperatures.

Question 34

Describe how we increased humidity effects transpiration rate.

Answer 34

Transpiration is slower, as the leaf is already surrounded by moist hair so the concentration gradient for the diffusion is shallower.

Question 35

Describe how increased light intensity effects transpiration rate.

Answer 35

Transpiration is faster, because the stomata open wider allowing more diffusion out of the leaf.

Question 36

Describe how increased wind effects transpiration rate.

Answer 36

Transpiration is speeded up as wind causes diffusion to be quicker

Question 37

Describe how wilting occurs.

Answer 37

Most plant cells are turgid at all times. This supports the weight of the plant. If the plant looses water faster than it can be absorbed the cells loose turgor pressure and become flaccid. This causes the plant to wilt.

Question 38

What tissue is responsible for transpiration?

Answer 38

Xylem

Question 39

What tissue is responsible for translocation?

Answer 39

Phloem

Question 40

What is translocation?

Answer 40

Translocation is the movement of soluble materials such as Sugars in the form of sucrose and amino acids in the phloem, from regions of production to regions of storage or to regions of utilisation in respiration and growth.

Question 41

How do plants create the low water potential in their roots so that they can uptake water?

Answer 41

Transpiration in their leaves produces attention (pull) from above, creating a water potential gradient in the xylem, drawing cohesive water molecules up the plant.