Chapter 6

Question 1

Define photosynthesis

Answer 1

the process by which plants synthesise carbohydrates from raw
materials using energy from light

Question 2

State the word and chemical equation for photosynthesis process

Answer 2

carbon dioxide + water → glucose + oxygen
in the presence of light and chlorophyll
6CO2 + 6H2O → C6H12O6 + 6O2

Question 3

What is chlorophyll?

Answer 3

A green pigment that is found in chloroplasts

Question 4

What is the function of chlorophyll?

Answer 4

It transfers energy from light into energy in chemicals, for the synthesis of
carbohydrates

Question 5

Describe how the products of photosynthesis are used?

Answer 5

STARCH - stored as energy source
CELLULOSE - to build cell wall
GLUCOSE - used in respiration to provide energy
SUCROSE - for transport in phloem
NECTAR - to attract pollinators
FATS & OILS - stored in seeds
AMINO ACIDS - combined with nitrates in soil to form protein

Question 6

Explain the function of the nitrate ion and its signs of deficiency.

Answer 6

Function:
Source of nitrogen to make amino acids
Signs:
Causing stunted growth and yellowing of leaves

Question 7

Explain the function of magnesium ion and its signs of deficiency

Answer 7

Function:
Needed to make chlorophyll
Signs:
Yellowing between veins of leaves

Question 8

Identify the structures in the leaf of a dicot plant cell

Answer 8

waxy cuticle
upper epidermis
palisade mesophyll
spongy mesophyll
lower epidermis
guard cells
stomata
xylem
phloem

Question 9

Describe the functions of the structures in the leaf

Answer 9

waxy cuticle - made of wax, waterproofing, prevent transpiration
upper epidermis - thin and transparent, no chloroplast, acts as barrier to disease organisms
palisade mesophyll- packed with chloroplasts, receives carbon dioxide by diffusion from air spaces in spongy mesophyll
spongy mesophyll - spherical and loosely packed, contain some chloroplast, air spaces between cells to allow gas exchange
lower epidermis - acts as protective layer, guards cells present to regulate transpiration, site of gas exchange in and out of leaf
guard cells - controls opening and closing of stomata, contain chloroplast
stomata - each is surrounded by guard cell that controls whether stomata opens or closes, water vapour passes out during transpiration
xylem - transports water and mineral ions
phloem - transports sucrose and amino acids

Question 10

what are the functions and characteristics of upper epidermis

Answer 10

thin and transparent
no chloroplast
acts as barrier to disease organisms

Question 11

what are the functions and characteristics of palisade mesophyll

Answer 11

packed with chloroplasts
cells are columnar
receives carbon dioxide by diffusion from air spaces in spongy mesophyll

Question 12

what are the functions and characteristics of spongy mesophyll

Answer 12

spherical and loosely packed
contain some chloroplast
air spaces between cells to allow gas exchange

Question 13

what are the functions and characteristics of lower epidermis

Answer 13

acts as protective layer
guards cells present to regulate transpiration
site of gas exchange in and out of leaf

Question 14

what are the functions and characteristics of guard cell

Answer 14

controls opening and closing of stomata
contain chloroplast

Question 15

what are the functions and characteristics of stomata

Answer 15

each is surrounded by guard cell that controls whether stomata opens or closes
water vapour passes out during transpiration

Question 16

What are the features of the leaf structure?

Answer 16

1. LARGE SURFACE AREA
2. THIN
3. CHLOROPHYLL
4. NETWORK OF VEINS
5. STOMATA
6. EPIDERMIS IS THIN AND TRANSPARENT
7. THIN CUTICLE MADE OF WAX
8. PALISADE CELL LAYER AT TOP OF LEAF
9. SPONGY LAYER
10. VASCULAR BUNDLE

Question 17

What are the adaptations of the leaf structure

Answer 17

1. LARGE SURFACE AREA ( increases SA for diffusion of CO2 and absorption of light for photosynthesis )
2. THIN ( Allows CO2 to diffuse to palisade cell quickly )
3. CHLOROPHYLL ( absorbs light energy so that photosynthesis takes place )
4. NETWORK OF VEINS ( allows water to be transported to cells of leaf, and transport of carbohydrates from the leaf for photosynthesis )
5. STOMATA ( Allows diffusion of carbon dioxide and oxygen in and out of cell )
6. EPIDERMIS IS THIN AND TRANSPARENT ( allows more light to reach palisade cell )
7. THIN CUTICLE MADE OF WAX ( to protect the leaf without blocking sunlight )
8. PALISADE CELL LAYER AT TOP OF LEAF ( maximise light absorption as it will hit chloroplast in cells directly )
9. SPONGY LAYER ( air spaces allow carbon dioxide to diffuse through the leaf, increasing surface area )
10. VASCULAR BUNDLE ( thick cell walls of tissue in the bundle help to support stem and leaf )