Topic 4 (all)

Question 1

The name of the surface of gas exchange for plant

Answer 1

Spongy mesophyll cells

Question 2

How is the leaf adapted for gas exchange (3)

Answer 2

1)Big surface area
2)Short diffusion distance between stomata and spongy mesophyll cells
3)Ventilation around leaves to maintain concentration gradient

Question 3

What makes up a stomata

Answer 3

Two guard cells

Question 4

How does a stomata open (4)

Answer 4

1)Potassium ions enter via active transport
2)which lowers solute potential
3)Water move down concentration gradient into the cell
4)Cells become turgid and bend

Question 5

Where are lenticles found

Answer 5

On impermeable surfaces on truck

Question 6

What are lenticles and how are they adapted to gas exchange (2)

Answer 6

1)Loosly packed cells
2)Contains air space

Question 7

The function of xylem (2)

Answer 7

1)Transport water
2)Transport mineral ions

Question 8

The function of phloem (2)

Answer 8

1)Transport sucrose
2)Transport amino acid

Question 9

How does the structure of xylem adapts to its function (3)

Answer 9

1)Cell walls lignified with rings and spirals
-prevents vessels from collapsing under tension
-increase flexibility
2)Made up of dead cells with no organelles
-Wide lumen for unrestricted water flow
3)End walls break down
-continuous tube for water transport

Question 10

How does the structure of phloem adapts to its function (3)

Answer 10

1)Sieve tube cells with limited organelles
-Create space for sugar transport
2)Each sieve tube cells are connected via sieve plates with pores
-Form direct connections from one sieve tube cell
to the next
3)Compaion cells are connected to sieve tube cells via plasmodesmata
-Companion cells with dense organelle including
mitochondria used in respiration to produce ATP
for sugar transport

Question 11

What is apoplast pathway

Answer 11

Transport of water via fully permeable cell wall

Question 12

What is symplast pathway

Answer 12

Transport of water via plasmodesmata

Question 13

What stops apoplast pathway from transporting water

Answer 13

Casparian strip in the cell wall which is impermeable to water

Question 14

What is transporation

Answer 14

The loss of water through stomata via diffusion

Question 15

Factors affecting rate of transpiration (4)

Answer 15

1)Temperature
2)Air movement
3)Humidity
4)Light intensity

Question 16

How does temperature affect the rate of transpiration

Answer 16

Water molecules gain kinetic energy

Question 17

How does air movement affect the rate of transpiration (2)

Answer 17

1)Moves water molecules around leaf
2)Maintains deep concentration gradient

Question 18

How does humidity affect the rate of transpiration

Answer 18

High humidity means small concentration gradient

Question 19

How does light intensity affect the rate of transpiration (3)

Answer 19

1)Plants needs CO2 to photosynthesize
2)Stomata opens to absorb CO2 under the presence of light
3)High light intensity means more stomata open

Question 20

What is translocation

Answer 20

The movement of water between the xylem and the phloem that moves sugar from source to sink

Question 21

What are the two stages of photosynthesis (2)

Answer 21

1)Light dependent stage
2)Light independent stage

Question 22

Where does the light dependent stage of photosynthesis

Answer 22

The grana (Stack of thylakoid membrane)

Question 23

Where does the light independent stage take place

Answer 23

The stroma

Question 24

What are the two types of reactions in light dependent stage (2)

Answer 24

1)Cyclic
2)Non-cyclic

Question 25

The stages of cyclic reaction (3)

Answer 25

1)Light energy excites electrons from photosystem I
2)Losses energy and return back to photosystem I via electron transport chain
3)Energy lost carries out chemiosmosis

Question 26

The process of chemiosmosis (4)

Answer 26

1)Energy lost from electron exicitation pumps protons into the thylakoid membrane
2)Creates an electro-chemical gradient
3)Electrons diffuse down their electro-chemical gradient via ATP sythase
4)Phosphorylate ADP to ATP

Question 27

The process of non-cyclic reaction (5)

Answer 27

1)Light energy promotes electrolysis at photosystem I, photosystem II and water (photolysis)
2)Electrons lost from photolysis due to excitation travel down the electron carrier to photosystem II and those from photosystem II to photosystem I.
3)Electrons lost from photosystem I reduces NADP into NADPH2 (reduced NADP)
4)Water is left as O2
5)Electrons lost from photosystem II carry out chemiosmosis which phosphorylate ADP into ATP

Question 28

What are the stages of light dependent reaction (calvin cycle) (2)

Answer 28

1)Co2 fixed by RUBP into GP (catalysed by Rubisco)
2)NADPH2 and ATP produced from light dependent stage reduces GP to TP (GALP) or regenerate RUBP

Question 29

What is GALP (TP) (2)

Answer 29

1)Raw molecule for the production of monosaccharides
2)amino acids

Question 30

What are the limiting factors of photosynthesis (3)

Answer 30

1)Temperature
-affect enzyme activity
2)CO2
-affect rate of calvin cycle
3)Light intensity
-affect production of NADPH2 and ATP hence also
the calvin cycle (Both the light dependent and
independent stage)

Question 31

Which ion is needed to make cholorophll

Answer 31

Magnesium ion

Question 32

Why does plant has a variety of different photosynthetic pigment (4)

Answer 32

1)Each pigment absorbs light of different wavelength
2)Able to absorb light of different wavelength
3)Absorb more light
4)More photosynthesis/ higher rate