Photosynthesis

Question 1

What is the word equation for photosynthesis?

Answer 1

carbon dioxide + water —> oxygen + glucose

Question 2

Photosynthesis converts light energy into…

Answer 2

chemical energy

Question 3

What is glucose used for in plants?

Answer 3

DNA, amino acids, lipids, chlorophyll, carbohydrates (cellulose cell wall, starch for storage, sucrose for transport)

Question 4

What factors affect the rate of photosynthesis?

Answer 4

CO2 concentration, light intensity, temperature

Question 5

What happens to rate of photosynthesis when you increase temperature?

Answer 5

increase rate - enzymes + substrates have more kinetic energy, up to optimum temp (before enzyme denatures)

Question 6

The factor in the shortest supply is called the…

Answer 6

limiting factor

Question 7

What happens to rate of photosynthesis when you add more CO2?

Answer 7

increase rate - more molecules to collide with enzymes

Question 8

What happens to rate of photosynthesis when you increase light intensity?

Answer 8

increases rate - more energy for reaction to occur

Question 9

How is a leaf adapted for photosynthesis?

Answer 9

large SA and thin

Question 10

Why does a leaf having a large SA and being thin increase rate of photosynthesis?

Answer 10

maximises absorption of sunlight, increases number of stomata so CO2 can diffuse quicker

Question 11

How is the upper epidermis specialised for photosynthesis?

Answer 11

transparent - allows light to penetrate to the mesophyll

Question 12

How are the palisade cells specialised for photosynthesis?

Answer 12

long + thin, tightly packed, contain many chloroplasts - maximises absorption of sunlight energy

Question 13

What part of the leaf is the main sight of photosynthesis?

Answer 13

palisade mesophyll

Question 14

How is the stomata specialised for photosynthesis?

Answer 14

allows gases to diffuse into air spaces in leaf - short diffusion distance for CO2

Question 15

The xylem transports…

Answer 15

water into leaf - short diffusion distance to photosynthesising cells

Question 16

The phloem vessels transport…

Answer 16

sugars made in photosynthesis

Question 17

What mineral ions do plants require?

Answer 17

nitrates, magnesium, phosphates

Question 18

Why do plants need nitrates?

Answer 18

make amino acids and nucleic acids (DNA)

Question 19

Why do plants need magnesium?

Answer 19

makes chlorophyll

Question 20

What are the symptoms of deficiency of nitrates in plants?

Answer 20

stunted growth

Question 21

What are the symptoms of deficiency of magnesium in plants?

Answer 21

yellow leaves

Question 22

How can you test leaves for starch?

Answer 22

using iodine solution on a leaf that has had it’s chlorophyll removed (by boiling in ethanol)

Question 23

If starch is present on a leaf, iodine will turn…

Answer 23

black

Question 24

How can you show that light is required for photosynthesis?

Answer 24

cover leaf in foil

Question 25

How can you show that carbon dioxide is required for photosynthesis?

Answer 25

put a leaf in an enclosed conical flask containing SODA LIME (absorbs CO2)

Question 26

How can you show that chlorophyll is required for photosynthesis?

Answer 26

use a variegated leaf - white parts of leaf lack chlorophyll

Question 27

How can you investigate how light affects the rate of photosynthesis?

Answer 27

pondweed in a beaker of water - move lamp closer and further away, count number of bubbles produced in 15 seconds