Plant Nutrition and Transport

Question 1

What is the word equation for photosynthesis?

Answer 1

Carbon Dioxide + Water (+ light) -> Glucose + Oxygen (+ ATP)

Question 2

What is the symbol equation for photosynthesis?

Answer 2

6CO2 + 6H2O -> C6H12O6 + 6O2

Question 3

List the structure of a leaf, from top layer to bottom layer

Answer 3

Waxy cuticle
Upper epidermis
Palisade mesophyll
Spongy mesophyll
Lower epidermis
Guard cell/stomata

Question 4

What is a limiting factor?

Answer 4

Something that stops photosynthesis from happening any faster

Question 5

How does light intensity affect the rate of photosynthesis?

Answer 5

Chlorophyll uses light intensity to perform photosynthesis.

If light in plentiful supply, CO2/temperature will be the LF

Question 6

How does CO2 affect the rate of photosynthesis?

Answer 6

One of the raw materials needed for photosynthesis

If CO2 in plentiful supply, light/temperature will be the LF

Question 7

How does temperature affect the rate of photosynthesis?

Answer 7

Affects the enzymes involved.
If temperature is too low, rate is slow.
If temperature too high, enzymes denature

Question 8

How to test a leaf for starch

Answer 8

1. Dunk the leaf in boiling water (stops any chemical reactions)
2. Heat leaf in boiling tube with ethanol (gets rid of any chlorophyll and makes it white in colour)
3. Rinse the leaf and add iodine solution. If it turns blue-black, starch is present

Question 9

Why are phosphates needed for plant growth?

Answer 9

Contains phosphorus which is needed to make DNA and cell membranes.
Also needed for respiration and growth

Question 10

What must be used to heat the ethanol, and why?

Answer 10

A water bath, as ethanol cannot be near an open flame because it is highly flammable

Question 11

Why are nitrates needed for plant growth?

Answer 11

Contains nitrogen which is needed for making amino acids and proteins

Question 12

What does a plant look like if it doesn’t have enough nitrates?

Answer 12

It will be stunted and older leaves will turn yellow

Question 13

What does a plant look like if it doesn’t have enough phosphates?

Answer 13

Poor root growth and older leaves look purple

Question 14

Why is potassium needed for plant growth?

Answer 14

To help the enzymes needed for photosynthesis/respiration

Question 15

What does a plant look like if it doesn’t have enough potassium?

Answer 15

Poor root and flower growth and discoloured leaved

Question 16

Why is magnesium needed for plant growth?

Answer 16

Required to make chlorophyll

Plants only need in small amounts

Question 17

What does a plant look like if it doesn’t have enough magnesium?

Answer 17

They have yellow leaves

Question 18

What do the xylem transport?

Answer 18

Water and minerals from the root to the leaves in a transpiration stream

Question 19

What do the phloem transport?

Answer 19

Sugars (e.g. sucrose) and amino acids from the leaves to the rest of the plant

Movement known as translocation

Question 20

How does the root hair transport water into its cell?

Answer 20

Through osmosis.

This happens because the soil water has a higher water potential than the root hair cell cytoplasm

Question 21

How does the root hair transport water into its cell?

Answer 21

Through osmosis.

This happens because the soil water has a higher water potential than the root hair cell cytoplasm

Question 22

How does the root hair transport water into its cell?

Answer 22

Through osmosis.

This happens because the soil water has a higher water potential than the root hair cell cytoplasm

Question 23

How does the root hair cell transport mineral ions into the cell, and why does it do this?

Answer 23

Through active transport

To maintain the concentration gradient and so the constant movement of water into the root hair cell by osmosis

Question 24

What causes transpiration?

Answer 24

The evaporation and diffusion of water from a plant’s surface

Question 25

What are the three steps in a transpiration stream.

Answer 25

1. Water evaporates and diffuses from the surface of the leaf
2. This creates a slight shortage of water in the leaf, so more water is drawn up from the xylem
3. This means more water is drawn up from the roots

Question 26

What four factors affect the rate of transpiration?

Answer 26

1. Light intensity
2. Humidity levels
3. Temperature
4. Wind speed

Question 27

How does light intensity affect the rate of transpiration?

Answer 27

The brighter the light, the greater the transpiration rate.

Stomata close at night when there’s no light, which means little water can escape from the cell

Question 28

How does temperature affect the rate of transpiration?

Answer 28

The warmer it is, the faster transpiration happens

When it’s warmer, the water particles have more energy to evaporate and diffuse

Question 29

How does wind speed affect the rate of transpiration?

Answer 29

The higher the wind speed, the greater the rate of transpiration

Low wind speeds mean that the water evaporated from the leaf collects around it, leading to a higher concentration of water outside. This means the rate of diffusion is lower

Question 30

How does humidity levels affect the rate of transpiration?

Answer 30

The drier the air is, the faster transpiration happens

If the air is very humid, there’s a lot of water in the air already, so there’s no difference in the outside or inside of the leaf

Question 31

What is a potometer?

Answer 31

An apparatus that estimates transpiration rates by measuring the water uptake of a plant

Question 32

What are the steps when carrying out a potometer experiment?

Answer 32

1. Cut the shoot and insert it into the potometer underwater so air doesn’t go up xylem
2. Ensure the apparatus is water/air tight and remove the end of the capillary tube from the water until one air bubble forms
3. Record the starting position of the air bubble
4. Start a stopwatch and record the distance moved by the bubble/hour