SAFOLO — 2e.1 — Nutrition in plants

Question 1

Photosynthesis?

Answer 1

The production of Glucose and oxygen in cells using light energy, carbon dioxide and water.

Question 2

Light energy to chemical energy in photosynthesis?

Answer 2

Light energy from the sun is absorbed by Chlorophyll to produce Glucose (chemical energy) and is stored as starch for growth while Oxygen is a waste product.
Chloroplasts are responsible for changing light energy to chemical energy

Question 3

Equation for photosynthesis?

Answer 3

Carbon dioxide + Water —> Glucose + Oxygen
6CO2 + 6H2O —> C6H12O6 + 6O2

Question 4

Limiting factors of photosynthesis?

Answer 4

• Carbon dioxide
• Temperature
• Light Intensity

Question 5

How does Carbon dioxide affect the rate of photosynthesis?

Answer 5

• As conc. of CO2 increases, rate of Photosynthesis will increase
• However, as conc. of CO2 increases beyond a certain point, rate of Photosynthesis will plateau (something else is limiting the rate of carbon dioxide)

Question 6

How does temperature affect the rate of photosynthesis?

Answer 6

• As temperature increases towards optimum, rate of Photosynthesis will increase
• However as temperature increases above optimum, enzymes involved in Photosynthesis will denature, causing rate of Photosynthesis to decrease

Question 7

How does light intensity affect the rate of photosynthesis?

Answer 7

• As light intensity increases, rate of photosynthesis will increase
• However, as light intensity increases beyond a certain point, rate of photosynthesis will plateau (something else is limiting the rate of photosynthesis)

Question 8

Waxy cuticle?

Answer 8

Outer protective layer that prevents water loss via evaporation

Question 9

Upper epidermis?

Answer 9

Thin and transparent layer of cells that allow light to enter Palisade Mesophyll

Question 10

Palisade mesophyll?

Answer 10

Layer tightly packed with chloroplasts to maximise light absorption for photosynthesis

Question 11

Spongy mesophyll?

Answer 11

Layer containing air spaces to increase SA:V ratio for more efficient diffusion of gases (mainly CO2)

Question 12

Lower epidermis?

Answer 12

Contains:
- Guard cells which control the opening and closing of the stomata by absorbing and losing water to regulate gas exchange and prevent water loss
- Stomata: opening controlled by guard cells to regulate gas exchange (CO2 in, O2 out) and prevent water loss

Question 13

How is a leaf adapted for photosynthesis?

Answer 13

• Large surface area: increases SA:V ratio for diffusion of CO2 and absorption of light
• Thin: Short diffusion length
• Chlorophyll
• Vascular bundles
• Stomata

Question 14

Chlorophyll?

Answer 14

Found in the chloroplasts, responsible for the green colour, absorb light energy

Question 15

Vascular bundles?

Answer 15

Support the leaf
Transport water for photosynthesis from roots to stems and leaves - Xylem
Carbohydrates produced by photosynthesis transported from leaves to roots - Phloem

Question 16

Why do plants require magnesium ions?

Answer 16

• To build Chlorophyll for growth
• Deficiency: Leaves turn yellow

Question 17

Why do plants require nitrate ions?

Answer 17

• To produce Amino acids to build protein and DNA
• Deficiency: Leaves turn yellow and stunted growth

Question 18

Experiment: effect of light intensity on Photosynthesis

Answer 18

Independent variable: distance of lamp from pondweed or light intensity
Dependent variable: amount of oxygen bubbles produced
Control: Temperature of water, length of pondweed, species of plant, colour of light

Question 19

How do plants store all of the glucose produced during photosynthesis?

Answer 19

They convert glucose into larger starch molecules. They are insoluble, cannot move between cells and are stored in the leaves.

Question 20

Testing a leaf for starch: Heat the leaf?

Answer 20

Because it destroys the enzymes, and if that isn’t done then the enzymes in the leaf may interfere with the experiment. The heat will also break down the waxy layer of the leaf.

Question 21

Testing a leaf for starch: Put in ethanol?

Answer 21

To dissolve the chlorophyll and the leaf get decolourised (because of the loss of the chlorophyll pigment). It will be plain yellow in colour.

Question 22

Testing a leaf for starch: Iodine to leaf?

Answer 22

Because iodine is an indicator to show if starch is present- if it is, the leaf will turn blue-black.

Question 23

Chloroplast

Answer 23

Converts light energy into relatively stable chemical energy via the photosynthetic process.

Question 24

What is glucose used for in a plant?

Answer 24

Glucose is used by plants for energy and to make other substances like cellulose, starch, proteins and amino acids

Question 25

Where do plants get minerals from?

Answer 25

Plants get water through their roots. This is how they get minerals, too. From the roots, the minerals travel to the stems.