Topic 6: Plants

Question 1

Xylem Adaptations

Answer 1

No end walls (continuous tube)
Lignified walls (strength)
Dead cells (no organelles)

Question 2

Phloem Adaptations

Answer 2

Sieve tube/cell (allow sugar transport)
Living cells

Question 3

Xylem Function

Answer 3

Transports water and mineral ions from roots to leaves (one direction)

Question 4

Phloem Function

Answer 4

Transports sugars (sucrose) and amino acids from leaves to other parts (bidirectional)

Question 5

Transpiration

Answer 5

Loss of water vapour from the leaves through the stomata, by evaporation/diffusion.
Causes capillary action (cohesion) ‘pulling’ water

Question 6

Translocation

Answer 6

• Movement of sugars and amino acids from leaves to sinks

Question 7

Sink

Answer 7

Parts of the plant where sugars and amino acids are used/stored (roots, flowers etc)

Question 8

Osmosis

Answer 8

Movement of water from an area of high concentration to an area of low concentric through a semi-permeable membrane

Question 9

Diffusion

Answer 9

Movement of particles from an area of high concentration to an area of low concentration

Question 10

Active Transport

Answer 10

Movement of substances against a concentration gradient requiring energy

Question 11

Photosynthesis Word Equation

Answer 11

Carbon Dioxide + Water → Glucose + Oxygen (Light, chlorophyll)

Question 12

Photosynthesis Symbol Equation

Answer 12

6CO₂ + 6H₂O → C₆H₁₂O₆ + O₂

Question 13

Auxin Uses

Answer 13

Selective weed killer (broad leaved plants)
Rooting powder for cuttings

Question 14

Leaf Structure

Answer 14

Upper Epidermis
Waxy Cuticle
Palisade Mesophyll
Spongy Mesophyll (Air Space)
Lower Epidermis (Guard Cells, Stomata)

Question 15

Stomata

Answer 15

Small pores on the leaf surface for gas exchange

Question 16

Guard Cells

Answer 16

When turgid (full of water) open stomata
When flaccid (lacking water) closing stomata

Question 17

Light Intensity Formula

Answer 17

Light Intensity = 1 ÷ distance² (inverse square law)

Question 18

Gibberellin Uses

Answer 18

Stimulating germination and flowering
Seedless, larger fruit

Question 19

Ethene

Answer 19

• Fruit ripening

Question 20

Plant adaptations in extreme environments to reduce water loss

Answer 20

Thick waxy cuticle
Stomata in pits/less stomata
Spines, small leaves, curled leaves
Thick, fleshy stem

Question 21

Plant adaptations in extreme environments for survival

Answer 21

Spines: protection
Extensive roots/thin leaves: reduce wind damage

Question 22

Factors affecting Transpiration

Answer 22

Light intensity
Humidity
Temperature
Wind speed

Question 23

Factors affecting Photosynthesis

Answer 23

Light intensity
Temperature
Amount of Carbon Dioxide
Amount of Water (not usually considered)

Question 24

Phototropism

Answer 24

• Growth towards light: shoots positive, roots negative

Question 25

Gravitropism

Answer 25

- Growth in response to gravity: shoots negative, roots positive

Question 26

Transpiration Practical

Answer 26

- Potometer used to measure transpiration rate

Question 27

Photosynthesis Practical

Answer 27

Pondweed in test tube of water Sodium hydrogen carbonate added to water (carbon dioxide supply) Bubbles produced in water counted (dependant variable)

Question 28

Auxin effect in shoots vs roots

Answer 28

Shoots: causes cell elongation Roots: inhibits cell growth