Photosynthesis

Question 1

What is photosynthesis?

Answer 1

an endothermic reaction where energy is transferred from the environment to the chloroplasts by light from the sun and glucose is produced

Question 2

What is a stomata?

Answer 2

holes on the underside of the leach which open and close to allow for gas exchange

Question 3

What is spongy mesophyll?

Answer 3

a tissue found in plant leaves that is specialised for gas exchange by having air spaces that allow diffusion of gases to happen quicker

Question 4

What are stomata?

Answer 4

small holes found in the lower epidermis that open and close because of guard cells. they control water loss by closing at night and allow diffusion of CO2 and O2.

Question 5

What is the job of the waxy cuticle?

Answer 5

reduces evaporation of water but allows light to pass through because it is transparent

Question 6

Where is the waxy cuticle?

Answer 6

on top of the upper epidermis that is insoluble, so the waxy cuticle waterproofs the leaf

Question 7

What is the palisade mesophyll?

Answer 7

a tissue found in plant leaves carry out photosynthesis

Question 8

How are the palisade mesophylls specialised to carry out photosynthesis?

Answer 8

vertically packed to capture more sunlight and store more chloroplasts

Question 9

How might a leaf be specialised for photosynthesis?

Answer 9

large surface area and being thin to absorb maximum sunlight. by increasing the number of stomata, carbon dioxide can diffuse quicker for photosynthesis

Question 10

What feature of the upper epidermis means the leaf is specialised for photosynthesis?

Answer 10

the upper epidermis is transparent so light is allowed to penetrate the mesophyll

Question 11

What is the function of the xylem?

Answer 11

the xylem transports water absorbed by roots into the leaves.

Question 12

How are stomata specialised for photosynthesis?

Answer 12

allow gases to diffuse into air spaces of leaf, this provides a short diffusion distance for carbon dioxide

Question 13

What is the function of the phloem?

Answer 13

phloem vessels transport sugars made in photosynthesis to other parts of the plant

Question 14

What are the uses of glucose in plants?

Answer 14

makes other biological molecules
- used to make cellulose (cell walls)
- used to make nucleotides (DNA)
- used to make protein (enzymes)
OR make chlorophyll

Question 15

Photosynthesis transfers light energy into what?

Answer 15

chemical energy which is then used for respiration and making other biological molecules

Question 16

What does the plant require to make these biological molecules?

Answer 16

mineral ions

Question 17

What is the use of nitrates in the plant?

Answer 17

making amino acids (CHON), and nucleic acids (CHONP) and therefore proteins/DNA/RNA

Question 18

What is the deficiency of nitrates in plants?

Answer 18

stunted growth

Question 19

What is the use of magnesium ions in the plant?

Answer 19

make chlorophyll

Question 20

What is the deficiency of magnesium in plants?

Answer 20

yellow leaves

Question 21

What is the use of phosphate ions in the plant?

Answer 21

make nucleic acid, part of cell membrane

Question 22

What is the deficiency of phosphate ions in the plant?

Answer 22

poor root growth, purple younger leaves

Question 23

What are the factors affecting rate of photosynthesis?

Answer 23

carbon dioxide - substrates
light intensity - energy
temperature - kinetic energy - enzymes

Question 24

What is STEP 1 when testing for starch in a leaf?

Answer 24

heat boiling water in a beaker then turn off bunsen

Question 25

What is STEP 3 when testing for starch in a leaf?

Answer 25

place the leaf on a white tile and cover in iodine solution

Question 25

What is STEP 2 when testing for starch in a leaf?

Answer 25

transfer leaf in test tube in ethanol (flammable) into the beaker and soften the leaf

Question 25

What is STEP 4 when testing for starch in a leaf?

Answer 25

the leave must be destarched for 24 hours in the dark because it means any starch was produced from the glucose made in photosynthesis during your experiment

Question 25

What is SHOWN when testing for starch in a leaf?

Answer 25

light is required - one leaf is covered with foil
chlorophyll is required - a variegated leaf is used and starch is only produced in certain places
carbon dioxide is required - one leaf is in an enclosed plastic bag with soda lime which absorbs carbon dioxide

Question 26

How can you investigate the factors affecting the rate of photosynthesis?

Answer 26

a length of pondweed is added to a beaker and the number of bubbles released is counted for one minute.
- distance between bench and lamp changed to vary light intensity
- collecting gas in an inverted measuring cylinder and measuring the volume of oxygen is more accurate