Photosynthesis

Question 1

In which plant organ does photosynthesis occur?

Answer 1

The leaf

Question 2

Why are plants green?

Answer 2

They contain chlorophyll

Question 3

What is the word equation for photosynthesis?

Answer 3

Water + carbon dioxide (+light) ——> glucose + oxygen

Question 4

What is the symbol equation for photosynthesis?

Answer 4

6H2O + 6CO2 ——> C6H12O6 + 6O2

Question 5

Where is light absorbed?

Answer 5

In the chlorophyll pigments locates in the chloroplasts

Question 6

Is photosynthesis an endothermic or exothermic reaction?

Answer 6

ENDOTHERMIC

Energy is transferred from the environment to the chloroplasts by light

Question 7

How does water get to the leaves?

Answer 7

Water absorbed by OSMOSIS from soil to roots

Absorbed from roots to XYLEM by osmosis

Water driven by EVAPORATION from leaves, up the stem

Osmosis from xylem to PALISADE cells

Question 8

How does carbon dioxide get to the leaves?

Answer 8

DIFFUSE through STOMATA into air spaces in leaves

Dissolved on surface of SPONGY MESOPHYLL

Diffuses to PALISADE CELLS from spongy mesophyll

Question 9

Uses of Glucose used in a plant?

Answer 9

Building plant cells

Some stores as starch

Releases energy through respiration for :
Repair
Metabolic processes
Growth

Used to make:
Amino acids
Fats
Cellulose for plant walls

Question 10

What is the function of the waxy cuticle?

Answer 10

Waxy later which prevents water loss but allows light through

Question 11

What are the characteristics of the upper epidermis?

Answer 11

Narrow layer

Few chloroplasts

Sunlight passes by through

Question 12

What is the function of the palisade layer?

Answer 12

Contains many chloroplasts so is where most photosynthesis happens

Question 13

Characteristics of the spongy mesophyll?

Answer 13

Contains few chloroplasts

Walls are saturated with water

Question 14

Characteristics of the lowers epidermis?

Answer 14

Thin

Few chloroplasts

Many stomata and guard cells

Question 15

What happens in the air spaces in leaves?

Answer 15

Gases diffuse freely here

Question 16

What is the function of the guard cells?

Answer 16

Open and close the stomata pores

Question 17

What is the function of the phloem?

Answer 17

Takes soluble food from the leaf to the rest of the plant where it is needed

Question 18

What is the function of the xylem?

Answer 18

Brings back water and dissolved minerals to the leaf from the root

Question 19

What is the function is the stoma?

Answer 19

Allow gases to diffuse in and out

Mainly on the LOWER SURFACE

Question 20

What enters the leaf through the stomata?

Answer 20

Carbon dioxide

Question 21

What exits the leaves through the stomata?

Answer 21

Oxygen

Water vapour

Question 22

Why does glucose need to be converted into starch?

Answer 22

For storage to provide energy to the plant when it is dark so photosynthesis can’t happen

Question 23

Adaptations of a leaf?

Answer 23

LARGE SURFACE AREA

WAXY CUTICLE prevent too much water loss

CHLOROPLASTS on top of leaf

chloroplasts contain CHLOROPHYLL

leaves are THIN less diffusion distance

STOMATA ON BOTTOM of leaf to reduce water loss from transpiration

XYLEM

GUARD CELLS

SPNGY MESOPHYLL is not tightly packed to provide large surface area

Question 24

Main factors that affect photosynthesis?

Answer 24

Carbon dioxide concentration

Light intensity

Temperature

Question 25

What is a limiting factor?

Answer 25

A variable which, of increased, will increase the rate of the process it affects

Question 26

Why does temperature affect the rate of photosynthesis?

Answer 26

It gives the particles more KINETIC ENERGY so they collide more

Question 27

LIGHT INTENSITY =

Answer 27

1 ————————— Distance squared

Question 28

What are the possible limiting factors for photosynthesis?

Answer 28

Light intensity Temperature Carbon dioxide concentration Chlorophyll levels in the leaf

Question 29

What factors can we control in a green house?

Answer 29

CO2 - burn natural gas Temperature- heat room Water amounts Light intensity- lamps Amount of minerals- nitrate fertilisers Insects - spray pesticides

Question 30

What factors can’t we control in a green house?

Answer 30

High temperature Plant density

Question 31

Why are greenhouses useful?

Answer 31

Can control rate of photosynthesis Refuse amount of limiting factors Produce more food

Question 32

What are the problems of using a greenhouse?

Answer 32

Expensive

Question 33

What is a polytunnel ?

Answer 33

A substitute for giant greenhouses for g owing crops It is made from plastic

Question 34

Why do plants grow faster in polytunnels?

Answer 34

It is hot Carbon dioxide concentration can be controlled

Question 35

What is hydroponics?

Answer 35

Growing plants in water rather than soil so you can control the amount of nutrients in it to maximise the growth rates of the plant

Question 36

Advantages of growing crops in an artificial environment?

Answer 36

Maximised growth rate Plants can grow all of the time Grow lots of food

Question 37

Disadvantages of growing crops in an artificial environment?

Answer 37

Expensive as lots of energy is needed Plants are close to each other so shade each other Diseases can spread easily