10th grade plants

Question 1

What do guard cells do?

• A. make chlorophyll
• B. carry sugar
• C. anchor the roots
• D. open and close the stomata

Question 2

Bubbles per minute from pondweed at different lamp distances: 10 cm: 70 20 cm: 17.5 30 cm: 7.8 40 cm: 4.4 50 cm: 2.8 How many fewer bubbles per minute were counted at 20 cm than at 10 cm?

Answer 

Question 3

Farmers add paraffin heaters to greenhouses in winter. Which two factors does this increase?

• A. water and oxygen
• B. temperature and carbon dioxide
• C. light and oxygen
• D. light and water

Question 4

In a potometer, the air bubble moves 12.5 mm in 5 minutes. What is the rate of water uptake in mm per minute?

Answer mm/min

Question 5

Xylem or phloem? It flow is in one direction only (upwards).

• A. xylem
• B. phloem

Question 6

Light intensity is inversely proportional to the square of the distance from the lamp. A lamp is moved from 20 cm to 60 cm from a plant. The new light intensity is what fraction of the old one? Give a decimal.

Answer 

Question 7

What is transpiration?

• A. moving sugar in the phloem
• B. loss of water vapour from leaves, mainly through stomata
• C. taking in oxygen through roots
• D. making sugar in leaves

Question 8

Bubbles per minute from pondweed at different lamp distances: 10 cm: 53 20 cm: 13.3 30 cm: 5.9 40 cm: 3.3 50 cm: 2.1 How many fewer bubbles per minute were counted at 50 cm than at 40 cm?

Answer 

Question 9

Why does the rate of photosynthesis fall at very high temperatures?

• A. Enzymes are denatured
• B. There is too much light
• C. Chlorophyll becomes blue
• D. Carbon dioxide turns into oxygen

Question 10

In a potometer, the air bubble moves 7 mm in 2 minutes. What is the rate of water uptake in mm per minute?

Answer mm/min

Question 11

Xylem or phloem? It carries water from roots to leaves.

• A. xylem
• B. phloem

Question 12

Light intensity is inversely proportional to the square of the distance from the lamp. A lamp is moved from 20 cm to 40 cm from a plant. The new light intensity is what fraction of the old one? Give a decimal.

Answer 

Question 13

What is transpiration?

• A. taking in oxygen through roots
• B. making sugar in leaves
• C. loss of water vapour from leaves, mainly through stomata
• D. moving sugar in the phloem

Question 14

Bubbles per minute from pondweed at different lamp distances: 10 cm: 64 20 cm: 16 30 cm: 7.1 40 cm: 4 50 cm: 2.6 How many fewer bubbles per minute were counted at 50 cm than at 40 cm?

Answer 

Question 15

Farmers add paraffin heaters to greenhouses in winter. Which two factors does this increase?

• A. temperature and carbon dioxide
• B. light and oxygen
• C. light and water
• D. water and oxygen

Question 16

In a potometer, the air bubble moves 37.5 mm in 5 minutes. What is the rate of water uptake in mm per minute?

Answer mm/min