Topic 6 - Plants

Question 1

What is the role of respiration in leaves?

Answer 1

Respiration produces carbon dioxide as metabolic waste.

Question 2

What does photosynthesis produce as a metabolic waste?

Answer 2

Photosynthesis produces oxygen as metabolic waste.

Question 3

What is gas exchange in leaves?

Answer 3

Gas exchange involves carbon dioxide entering the leaf and oxygen exiting through stomata by diffusion.

Question 4

What is the function of the upper epidermis in leaves?

Answer 4

The upper epidermis is a transparent layer of cells that allows light to pass through.

Question 5

What is the palisade mesophyll layer composed of?

Answer 5

The palisade mesophyll layer is densely packed with chloroplasts for light absorption.

Question 6

What is the spongy mesophyll layer’s function?

Answer 6

The spongy mesophyll layer contains air spaces to increase the surface area for the diffusion of carbon dioxide.

Question 7

What structures increase carbon dioxide diffusion in leaves?

Answer 7

The underside of the leaf has lots of stomata and guard cells that open the stomata.

Question 8

What is the role of the vascular bundles in leaves?

Answer 8

Vascular bundles contain xylem to transport water to the leaf.

Question 9

Why does a leaf have a waterproof layer?

Answer 9

The waterproof layer prevents water loss.

Question 10

How does leaf structure support photosynthesis?

Answer 10

Leaves are broad and thin to increase surface area for light absorption and reduce diffusion distance for carbon dioxide.

Question 11

What factors affect the rate of photosynthesis?

Answer 11

Light intensity, carbon dioxide concentration, and temperature are all limiting factors affecting the rate of photosynthesis.

Question 12

What indicates a limiting factor on a graph of photosynthesis?

Answer 12

If the rate is still increasing, the variable on the x-axis is limiting. When it plateaus, another factor is limiting.

Question 13

How can starch be tested in leaves?

Answer 13

The presence of starch can be tested by adding iodine, which turns from orange-brown to blue-black if starch is present.

Question 14

What is a safety precaution when testing leaves for starch?

Answer 14

Wear safety glasses when using iodine.

Question 15

What does de-starching a plant involve?

Answer 15

De-starching involves keeping a plant in the dark to use up all starch before testing.

Question 16

What is the function of nitrates in plants?

Answer 16

Nitrates are needed to make amino acids, which are essential for growth.

Question 17

What happens to a plant that is deficient in phosphates?

Answer 17

A phosphate deficient plant will have purple leaves and short roots.

Question 18

What is the role of potassium in plants?

Answer 18

Potassium is needed for enzymes of respiration and photosynthesis to work.

Question 19

What adaptation do xylem vessels have?

Answer 19

Xylem vessels have hollow, dead cells that form tubes for water transport.

Question 20

What is a characteristic of phloem vessels?

Answer 20

Phloem vessels have companion cells that provide ATP for the phloem sieve tube cells.

Question 21

What does the term ‘sieve plate’ refer to in phloem?

Answer 21

The sieve plate allows sucrose to be transported from cell to cell through pores.

Question 22

What gas do plants take in during photosynthesis?

Answer 22

Plants take in carbon dioxide during photosynthesis.

Question 23

What gas do plants release during photosynthesis?

Answer 23

Plants release oxygen during photosynthesis.

Question 24

How is water transported in plants?

Answer 24

Water is transported from the roots to the leaves through the xylem.

Question 25

What is the main function of the phloem?

Answer 25

The phloem transports sugar solution and amino acids from leaves to other parts of the plant.

Question 26

What happens to a leaf kept in the dark regarding photosynthesis?

Answer 26

It will not have photosynthesized and therefore will likely not have starch present.

Question 27

What plant feature prevents excessive evaporation of water?

Answer 27

No stomata are located where evaporation is highest.

Question 28

What must a leaf be treated with to test for starch?

Answer 28

A leaf must be boiled to stop all chemical reactions before testing for starch.

Question 29

What is the result of boiling a leaf before testing for starch?

Answer 29

Boiling stops all chemical reactions, allowing accurate testing for starch.

Question 30

What does the presence of chlorophyll indicate?

Answer 30

It indicates a leaf can photosynthesize and thus may have starch.

Question 31

What occurs if a leaf or part of it is white?

Answer 31

If a leaf is white, it does not have chlorophyll and cannot photosynthesize.

Question 32

What do variegated leaves contain?

Answer 32

Variegated leaves are part white and part green.

Question 33

What type of transport do root hair cells use for mineral ion absorption?

Answer 33

Root hair cells often use active transport to absorb mineral ions.

Question 34

How does a plant with a nitrate deficiency appear?

Answer 34

A nitrate deficient plant may be smaller than expected and have yellow older leaves.

Question 35

How can temperature influence photosynthesis?

Answer 35

Temperature can be a limiting factor affecting the rate of photosynthesis.

Question 36

What happens when a graph of photosynthesis shows a plateau?

Answer 36

When it plateaus, it indicates that another factor, not shown on the x-axis, is the limiting factor.

Question 37

What is the function of magnesium in plants?

Answer 37

Magnesium is needed for the production of chlorophyll.

Question 38

What indicates a potassium deficient plant?

Answer 38

A potassium deficient plant may have dead spots and yellow leaves.

Question 39

How is glucose related to starch in leaves?

Answer 39

Glucose is converted into starch in leaves, indicating photosynthesis.