Topic 6 Plant structures and photosynthesis

Question 1

Describe the role of photosynthetic organisms

Answer 1

• main producers of food
• biomass

Question 2

Is photosynthesis endothermic or exothermic

Answer 2

endothermic

Question 3

What is the structure and function of the stomata

Answer 3

They are responsible for allowing oxygen in and carbon dioxide out

Has guard cells on either end to control opening and closing of the cell

Question 4

When will the stomata be open/close

Answer 4

Open at day and closed at night

Question 5

Name 3 factors that affect the rate of photosynthesis

Answer 5

• temperature
• light intensity
• carbon dioxide

Question 6

When drawing graphs why does light intensity and carbon dioxide plateau?

Answer 6

Due to some other limiting factor

Question 7

What is the relationship between the distance of light source and photosynthesis

What is the the equation for inverse square law

Answer 7

It is an inverse relationship
1/distance^2

Question 8

How are root hair cells adapted to absorb water and mineral ions?

Answer 8

• Large surface are for increased rate of absorption
  -Lots of mitochondria for energy for active transport

Question 9

How are the xylem adapted to their function ?

Answer 9

• made of dead cells
• their cell walls are made of lignin, which supports and strengthens the plant

Question 10

How are the phloem adapted to their function?

Answer 10

• made of living cells that are supported by companion cells
• cells are joined end to end to allow sugar to flow freely
• few subcellular structures to aid flow of material

Question 11

How are water and mineral ions transported

Answer 11

• By transpiration
• The water travels up the xylem towards the leaf in a transpiration stream
• in one direction

Question 12

How is sucrose and amino acids transported?

Answer 12

• By translocation
• source to sink
• moves in both directions

Question 13

Name the 4 factors affecting the rate of transpiration

Answer 13

• air movement
• humidity
• light intensity
• temperature

Question 14

How does air flow affect rate of transpiration

Answer 14

Increased air flow leads to more transpiration

Question 15

How does humidity affect rate of transpiration

Answer 15

Increased humidity leads to less transpiration

Question 15

How does light intensity affect rate of transpiration

Answer 15

Increased light intensity leads to more transpiration

Question 16

How does temperature affect rate of transpiration

Answer 16

Increased temperature leads to more transpiration

Question 17

How to calculate the rate of transpiration?

Answer 17

distance moved by air bubble(m)
/ time (min)

Question 18

What is the adaptation of the waxy cuticle?

Answer 18

prevents water loss

Question 19

What is the adaptation of the upper epidermis?

Answer 19

thin and transparent to allow light to enter palisade mesophyll layer

contains lots of chloroplasts for maximal photosynthesis

Question 20

What is the adaptation of the spongy mesophyll?

Answer 20

Contains internal space to increase SA:V for diffusion

Question 21

What is the adaptation of the lower epidermis?

Answer 21

contains guard cells and stomata

Question 22

What is the adaptation of the stomata?

Answer 22

Lots of stomata on the underside of the leaf to reduce water loss

Question 23

A type of plant living in extreme conditions is xerophytic plant. What are their adaptions

Answer 23

• live in areas of lots of freshwater supply
  -short diffusion distance in stomata and large spaces in spongy mesophyll area leaving risk of water loss
• Few stomata
• Waxy cuticle

Question 24

A type of plant living in extreme conditions is cacti. What are their adaptions

Answer 24

- Spines that do not photosynthesise - Thick cuticle to store water - roots are shallow and deep meaning all water available can be reached