plant exam questions

Question 1

Explain why large multicellular plants need a transport system.

Answer 1

• Contain small SA : Vol ratio.
• Long distance from external surfaces to cells.
• Sucrose needs to be transported.
• Diffusion happens over long period of time.

Question 2

Explain the benefit to plants of internal transport systems.

Answer 2

• Allows high metabolic rate.
• Ensures nutrients can reach all tissues.

Question 3

Where are the guard cell, companion cell and root hair cell located?

Answer 3

Guard cell - Stomata.
Companion cell - phloem.
root hair cell - Roots

Question 4

What is example of substance transported by guard cell, companion cell and root hair cell?

Answer 4

Guard cell - CO2
Companion cell - Sucrose
Root hair cell - nitrate ions.

Question 5

What type of cell makes up meristem tissue?

Answer 5

meristem.

Question 6

For which macromolecule does a plant need both nitrogen and phosphorus?

Answer 6

DNA/RNA/ nucleic acid

Question 7

How does flooding affect soil water potential?

Answer 7

Lowers.

Question 8

Explain how the casparian strip prevents these ions from reaching the xylem of the plant by the apoplast pathway.

Answer 8

• Casparian strip is impervious to water.
• Forces water to pass through cell surface membrane.
• Phospholipid repels ions.

Question 9

Explain why water molecules can form hydrogen bonds with nitrate ions.

Answer 9

• Water is a polar molecule.
• NO3- is charged.
• Hydrogen bonds form between H on water and O on nitrate.

Question 10

Explain how the events cause water to enter the endodermis.

Answer 10

• Ions enter against concentration gradient by active transport.
• Reduces water potential of endodermal cells.
• Water moves by osmosis down water potential gradient.

Question 11

A group of students wanted to observe the position of xylem vessel in the leaf stalks of celery.
Describe a procedure.

Answer 11

• put leaf stalks in stain
• then cut cross section

Question 12

What’s one similarity and two differences of phloem and xylem?

Answer 12

similarity - Both made of cells joined end to end.
Differences -Xylem contains lignin. Phloem does not contain lignin only cellulose.
- Xylem has a wide lumen. Phloem has a small lumen.

Question 13

Moses are small plants. Why do moses not need structures such as roots or xylem to survive?

Answer 13

• Large surface area to volume ratio.
• the distance water need to travel is short

Question 14

State the function of the pits in the xylem tissue.

Answer 14

Lateral movement of water.

Question 15

Explain one practical precaution that should be taken when using a potometer.

Answer 15

Do not allow air to enter shoots, ensures continues column of water.

Question 16

Plan an investigation into the rate of transpiration in two species of plant that allow valid data to be collected.

Answer 16

• pick up two plant species you would like to compare.
• Set up the potometer and measure the rate of transpiration by measuring the distance the bubble has moved at regular intervals.
• Repeat the experiment at least 3 times. This will allow you to identify anomalies and take a mean. Perhaps plot a graph so results can be compared.
• Make sure experiment is carried out at the same temperature.
• Make sure light intensity is the same, perhaps buy a lamp w the same power.

Question 17

Describe how a potometer can be used to calculate a more accurate rate of transpiration.

Answer 17

• Potometer must be airtight.
• Dry leaves
• Cut shoots under water.
• Measure distance air bubble travels per time interval.
• Calculate volume of water uptake.
• Maintain constant conditions such as temperature.

Question 18

Name and describe two pathways that water takes to reach the xylem vessels at the base of the stem.

Answer 18

• Symplast pathway passing through cytoplasm.
• Apoplast pathway passing along the cell walls.