Chapter 6 - Plant Structures and Functions

Question 1

Photosynthesis

Answer 1

• Occurs in plants where the sun is used to produce glucose for energy
• Some lf the glucose is used to make larger and more complex molecules that the plants or algae need to grow (biomass)
• Biomass works its way through the food chain
• Occurs inside cholroplasts where there is chlorophyll to absorb light

Question 2

Limiting factors of photosynthesis - Light

Answer 2

• Light transfers energy needed for photosynthesis
• If light level is increased, the rate increases steadily. This is only true up to a certain point
• Beyond that, it will be another factor
• This can be investigated by moving a light closer and further away from a plant

Question 3

Light intensity

Answer 3

1
—————
Distance squared
Inverse

Question 4

Limiting factors of photosynthesis- Carbon Dioxide

Answer 4

• Carbon dioxide is a raw material needed for photosynthesis
• ## Carbon dioxide concentration increases the rate of photosynthesis.

Question 5

Limiting factors of photosynthesis - Temperature

Answer 5

• The temperature needs to be just right or enzymes will not work - If its too low, enzymes will work slower and photosynthesis will be slower
• If its too hot, they will denature and will not work at all
• This is about 45 degrees

Question 6

Root Hair cells

Answer 6

• Take in minerals and water for plants
• Have hairs and a large surface area to increase efficiency
• The concentration of minerals is usually higher in the cells, so mineral ions are absorbed by active transport and water by osmosis

Question 7

Phloem

Answer 7

• Made up of elongated living cells with small pores in the end walls to allow stuff to flow through
• Transport food substances made in the leaves for immediate use or storage
• This is translocation and requires energy from respiration

Question 8

Xylem tubes

Answer 8

• Made up of dead cells
• Carry water and mineral ions from the roots to the stem and leaves
• This is called the transportation system

Question 9

Transpiration

Answer 9

• Caused by evaporationand diffusion of water from a plants surface, happens at leaves
• Creates a slight shortage, so more water is drawn from the rest of the plant to replace it
• This means there is a constant transpirations stream through the plant
• Also carries mineral ions