[Bi] - Topic 7

Question 1

What is photosynthesis?

Answer 1

Photosynthesis is the process by which use sunlight to synthesize foods with the help of chlorophyll.

Question 2

Write the word equation for photosynthesis.

Answer 2

Carbon dioxide + Water → Glucose + Oxygen

Question 3

Write the balanced chemical equation for photosynthesis.

Answer 3

6 CO₂ + 6 H₂O → C₆H₁₂O₆ + 6 O₂

Question 4

Where in the plant cell does photosynthesis take place?

Answer 4

Photosynthesis takes place in the chloroplasts of plant cells.

Question 5

What is the function of the stomata in leaves?

Answer 5

Stomata are pores on the leaf surface that allow gas exchange; they let carbon dioxide in and oxygen out.

Question 6

How do guard cells function in the opening and closing of stomata?

Answer 6

Guard cells control the opening and closing of stomata by changing shape due to the uptake or loss of water.

Question 7

What is transpiration?

Answer 7

Transpiration is the process of water movement through a plant and its evaporation from aerial parts, especially from the leaves.

Question 8

What is the equation for the rate of transpiration?

Answer 8

Rate of transpiration = Volume of water lost / Time

Question 9

What is the role of xylem in plants?

Answer 9

Xylem transports water and minerals (dissolved potassium, nitrates etc) from the roots to the rest of the plant.

Question 10

Describe the structure of xylem.

Answer 10

Xylem vessels are long, tube-like structures formed from dead cells. They have no organelles present (because cells are dead), there’s no barrier between cells and they’re surrounded by lignin which is hard and a water barrier (water cannot escape).

Question 11

What is the role of phloem in plants?

Answer 11

Phloem transports dissolved sugars - called Translocation

Question 12

Describe the structure of phloem.

Answer 12

Phloem consists of living cells arranged end to end, forming sieve tubes. Phloem also have companion cells at the sides that keep them alive. Direction of travel is 2 way (up and down the plant).

Question 13

What is phototropism?

Answer 13

Phototropism is the growth of a plant in response to light direction.

Question 14

What hormone is primarily involved in phototropism?

Answer 14

Auxin.

Question 15

Define “tropism.”

Answer 15

Tropism is the growth response of a plant toward or away from a stimulus.

Question 16

What is geotropism (or gravitropism)?

Answer 16

Geotropism is the growth of a plant in response to gravity.

Question 17

What is the role of gibberellins in plant growth?

Answer 17

Gibberellins promote seed germination, stem elongation, and flowering.

Question 18

What is the function of the cuticle on a leaf?

Answer 18

The cuticle is a waxy layer that reduces water loss from the surface of the leaf.

Question 19

What are meristems?

Answer 19

Meristems are regions of undifferentiated cells in plants where active cell division occurs, allowing for growth.

Question 20

What are the different types of meristem and where are they found?

Answer 20

Shoot (found at the tip of the shoots), root (found at the tip of the roots) and lateral (found at the side of branches).

Question 21

What is the role of roots in a plant?

Answer 21

Roots anchor the plant, absorb water and minerals from the soil, and sometimes store food.

Question 22

What is greenhouse economics?

Answer 22

Greenhouse economics involves optimizing the conditions inside a greenhouse to maximize plant growth and yield, balancing factors like light, temperature, and carbon dioxide levels against costs to achieve profitable crop production.

Question 23

How do plants use glucose produced in photosynthesis? (Hint: 5 things)

Answer 23

Respiration
Make cellulose
Store as starch
Make amino acids
Make lipids

Question 24

What are the limiting factors of photosynthesis?

Answer 24

The limiting factors of photosynthesis are light intensity, carbon dioxide concentration, temperature and water.

Question 25

Briefly describe the required practical on investigating the effect of light intensity on the rate of photosynthesis using pond weed.

Answer 25

This practical involves placing pond weed in water with sodium hydrogen carbonate to provide CO₂, then varying the distance of a light source and counting the oxygen bubbles produced over a fixed period to measure the rate of photosynthesis.

Question 26

Briefly describe the required practical on investigating the effect of a factor on the rate of transpiration using a potometer.

Answer 26

This practical uses a potometer to measure water uptake by a plant cutting. By altering environmental conditions like humidity, wind, light, or temperature, the effect on the rate of transpiration can be observed and recorded.