Section 3 Plant Nutrition and Transport

Question 1

what is the equation for photosynthesis?

Answer 1

Carbon dioxide + water ➡️ glucose + oxygen

6CO2 + 6H2O ➡️ C6 H12 O6 + 6O2

Question 2

when is the chemical energy from photosynthesis released?

Answer 2

when glucose is broken down in respiration

Question 3

what is needed for photosynthesis?

Answer 3

chlorophyll to absorb sunlight

Question 4

what does the waxy cuticle do?

Answer 4

reduce water loss

Question 5

why is the upper epidermis transparent?

Answer 5

so light can pass to the palisade layer

Question 6

where are most of the chloroplasts?

Answer 6

in the palisade layer

Question 7

what are the 3 factors affecting the rate of photosynthesis?

Answer 7

light intensity
cardon dioxide
temperature.

Question 8

what happens to the rate of photosynthesis over 45 degrees in temperature?

Answer 8

the enzymes denature - rate is very slow

Question 9

how do you test a leaf for starch?

Answer 9

kill the leaf by placing it in boiling water
put in ethanol - to get rid of chloroplasts
rinse in cold water
add few drops of iodine solution
If starch present, will turn blue/black.

Question 10

how can you show chlorophyll is needed for photosynthesis?

Answer 10

Use variegated leafs
Record which bits on it are green
test for starch
only green bits have starch as they are only parts that turn blue / black
So only parts that contain chlorophyll can photosynthesise and produce starch

Question 11

how can you show co2 is needed for photosynthesis?

Answer 11

Use: sealed bell jar, lights source, soda lime, a plant
soda lime will absorb co2 from air in jar
if you leave plant in the jar with soda lime no starch will be made (prove by testing it for starch)
Shows no starch is made, so co2 needed for photosynthesis

Question 12

how do you show light is needed for photosynthesis?

Answer 12

put a plant in the dark
test a leaf from it for starch
Leaf won’t turn bluey black
Shows light is needed for photosynthesis to produce starch

Question 13

what plant can be used to show the effect of light intensity on rate of photosynthesis?

Answer 13

Canadian pondweed

Question 14

how can pond weed be used to test light on rate of photosynthesis?

Answer 14

Place source of white light at specific distance from pondweed
Leave for set time for oxygen to collect in a gas syringe
Use a ruler to measure length of oxygen gas bubbles in tube (this is proportional to volume of O2 produced)
Repeat moving the light closer and further away at different distances

Question 15

what are the 3 main mineral ions needed for plant growth?

Answer 15

nitrates
phosphates
potassium

Question 16

what happens to a plant deficient in nitrates?

Answer 16

stunted

yellow older leaves

Question 17

what do phosphates contain?

Answer 17

phosphorus for DNA making
cell membranes

Needed for: respiration and growth

Question 18

what happens to a plant deficient in phosphates?

Answer 18

poor root growth

purple older leaves

Question 19

what happens to a plant deficient in potassium?

Answer 19

poor flower and fruit growth

discoloured leaves

Question 20

why does a plant need magnesium ions?

Answer 20

Needed in small amounts

to make chlorophyll

Question 21

………………………… organisms need transport systems

Why?

Answer 21

multicelluar

To move substances to and from individual cells quickly.

Question 22

what carries water and mineral salts from the roots to the leaves in the transpiration stream / the other parts of the plant?

Answer 22

The xylem.

Question 23

what does the phloem do?

Answer 23

Transport sugars (sucrose and amino acids) between leaves and other parts of the plant.
This is translocation.

Question 24

what is translocation?

Answer 24

the movement of food substances around the plant.

Question 25

What do root hair cells do?

Answer 25

Absorb water for the plant by osmosis.

Question 26

what is transpiration caused by?

Answer 26

the evaporation and diffusion of water from a plants surface

Question 27

What is transpiration? | What happens in transpiration?

Answer 27

When water is lost from the surface of a plant. When the water evaporates, more water is drawn up through the xylem vessels to replace it. So, more water is drawn up through the roots in turn, making a constant transpiration stream.

Question 28

What is transpiration rate affected by?

Answer 28

``` Light intensity (brighter = greater) Temperature (warmer = faster) Wind speed (faster = greater) Changes in humidity. (drier = faster) ```

Question 29

what can be used to measure the rate of transpiration?

Answer 29

a petometer

Question 30

Describe the experiment to measure the rate of transpiration from a leafy shoot.

Answer 30

1. Cut a shoot underwater at a slant to prevent air entering xylem and to increase surface area for water intake. 2. Assemble petometer in water and insert shoot under water so no air can enter. 3. Remove apparatus from water but keep end of capillary tube submerged in beaker of water. 4. Check apparatus is water and airtight. 5. Dry the leaves, allow time for shoot to acclimatise and then shut the tap. 6. Remove end of capillary tube from beaker of water until one air bubble has formed, then put end of tube back into water. 7. Record starting position of air bubble. 8. Start stopwatch and record distance moved by bubble per unit time. 9. Keep conditions constant throughout e.g. temperature and air humidity.

Question 31

What is photosynthesis?

Answer 31

Photosynthesis is the process that produces 'food' (glucose) in plants.

Question 32

Describe the structure of a leaf and explain how it is adapted for photosynthesis.

Answer 32

- Broad - so large surface area exposed to light. - Most chloroplasts in palisade layer to get most sunlight. - Upper epidermis is transparent so light can pass through to palisade. layer. - network of vascular bundles called xylem and phloem which deliver water and nutrients to leaf - Waxy cuticle reduces water loss by evaporation.

Question 33

What do plants need nitrate ions needed for?

Answer 33

Making Amino acids and proteins

Question 34

Describe the structure of a leaf from top to bottom.

Answer 34

``` Waxy cuticle Upper epidermis Paliside Mesophyll Spongy Mesophyll including the xylem and phloem Lower epidermis ```

Question 35

How is the structure of a leaf adapted for gas exchange?

Answer 35

Broad structure: large surface area for diffusion Thin: short distance for gases to travel Air spaces inside: gases move around easily, increases sa for gas exchange

Question 36

Describe the role of the stomata in gas exchange.

Answer 36

Let gases diffuse in and out Allow water to escape, transpiration Close when dark, want can't escape, doesn't dry out

Question 37

Why do plants need potassium ions?

Answer 37

To help enzymes needed for photosynthesis and respiration

Question 38

What happens to a plant deficient in magnesium?

Answer 38

Yellow leaves