Section 6 - Plant Structures and Their Functions

Question 1

What is biomass?

Answer 1

The mass of a living material

Question 2

Give the word equation for photsynthesis.

Answer 2

carbon dioxide + water –> glucose + oxygen

Question 3

Explain why photosynthetic organisms are described as the main producers of food for nearly all life.

Answer 3

The energy stored in the biomass of photosynthetic organisms is passed along the food chain as animals eat the photosynthetic organisms. These animals are food for other animals. So most of the life on Earth is supported by photosynthetic organisms.

Question 4

Give the inverse square law.

Answer 4

light intensity = 1 / distance^2

Question 5

What is translocation? In which tissue does it take place in a plant?

Answer 5

The movement of food substances through phloem tissue

Question 6

Which strengthening material is present in the walls of xylem tubes?

Answer 6

lignin

Question 7

Which type of transport vessel is made up of dead cells?

Answer 7

xylem

Question 8

How are root hair cells adapted for the uptake of water and mineral ions?

Answer 8

they have a large surface area

Question 9

What is the role of xylem tubes in a plant?

Answer 9

xylem tubes carry water and mineral ions from the roots to the stem and the leaves.

Question 10

How does the structure of phloem allow food substances to move between phloem cells?

Answer 10

there are pores in the end walls of phloem cells for the food substances to move through.

Question 11

Explain the constant transpiration stream of water through a plant.

Answer 11

evaporation and diffusion of water from the leaves create a slight shortage of water in the leaf. This means that more water is drawn up from the rest of the plant through the xylem vessels to replace it . This causes more water to be drawn up from the roots.

Question 12

Give three factors that can affect the rate of transpiration.

Answer 12

light intensity, temperature and air flow