Photosynthesis

Question 1

what part of the plant has no chloroplasts? why?

Answer 1

roots - becuase it doenst get any sunlight

Question 2

what part of the plant has lots of chloplasts Why?

Answer 2

leaf becasue its easily exposed to sunlgiht - palisade cells

Question 3

WHEN does photosynthesis occur?

Answer 3

daytime - needs sunlight

Question 4

How does photosythesis differ from respiration

Answer 4

• only in plants
• mitochondria
• relases ATP ( uses glucose).
• happens all the time.

Chloroplasts

• Make glucose
• only light

Question 5

At night…..

Answer 5

• rate of respiration will be greater than the rate of photosynthesis
• no light for photosynthesis
• more CO2 released. - it can’t be absorbed

Question 6

No noon….

Answer 6

• rate of photosynthesis will be greater than the rate of respiration
• lots of light for photosynthesis
• more CO2 absorbed

Question 7

leaf adaptations

Answer 7

thin - short diffusion distance - to maximise light absorption

large surface area - absorbs as much light as possible

Lots of Chloroplasts - access as much light as possible & lots of photosythesis can occur

Question 8

waxy cuticle

Answer 8

• reduce water loss by evaporation by waterproofing the leaves
• wax secreted by cells of upper epidermis
• barrier to disease causing microrganisms e.g. bacteria and fungi

Question 9

Upper Epidermis

Answer 9

• thin and relatively transparent

to allow sunlight to reach the palisade mesophyll to photosynthesis

Question 10

palisade mesophyll

Answer 10

• column shaped, thin and arranged close together
• contains many chloroplasts and densely packed so that as much light energy can be absorbed as possible for efficient photosynthesis

absorb light efficiently

Question 11

Vascular Bundles

Answer 11

• Contains the xylem which transports water and mineral salts from the roots to the leaves
• contains phloem which carry organic products of photosythsis around the plant e.g. Sucrose and amino acids
• cannot transport starch becasue it is too big. and insoluble

Question 12

Spongy Mesophylll

Answer 12

• Have fewer chloroplasts compared to Palisade but can still photosynthesis.
• They are the main gas exchange surface absorbed CO2 and realises O2 and H20
• loosely packed with a large space, helps with diffusion of gases through the leaves
• Saturated with water vapour, helps in absorption of gases

Question 13

Lower Epidermis

Answer 13

-Acts as protective layer,

contains more stomata compared to upper Epidermis to reduce water loss

site of gaseous exchange into and out of the cell

Question 14

Stomata

Answer 14

• Regulates water loss ( transpiration)

- site of gaseous exchange in the leaf

Question 15

Guard cells

Answer 15

• controls the opening and closing of stomata

Question 16

water is needed for photosynthesis in the leaf. Describe how water is carried from the soil to the leaf.

Answer 16

• absorbed from root hair cell
• xylem transports it to the leaves
• through stem to the leaf

Question 17

Phloem

Answer 17

transports sucrose and amino acids —> translocation

Question 18

In what tissue is sugar transported in a leaf?

Answer 18

Phloem

Question 19

How do leaves capture light energy from the sun?

Answer 19

Lots of chloroplasts –> contains chlorophyll

Question 20

In what form do plants such as potatoes store sugar?

Answer 20

Starch

Question 21

Which process releases energy in a plant?

Answer 21

respiration

Question 22

measuring the rate of photosynthesis using pond weed>

Answer 22

inde- light intensity
depen- number of bubbles

control - temp

         - amount of pond weed 
         - same brightness of the bulb

Question 23

How is glucose carried from the leaves to every part of the plant?

Answer 23

transports glucose through the phloem

Question 24

Why are palisade cells near the surface?

Answer 24

So they can absorb light energy efficiently - near to the sun

Question 25

3 factors that limit the rate of photosynthesis?

Answer 25

• light
• CO2
• Temperature