Nutrition Flowering plants

Question 1

photosynthesis is an ____ reaction

Answer 1

endothermic

Question 2

in photosynthesis, energy from sunlight is transferred to __

Answer 2

the chloroplasts in green plants

Question 3

in photosynthesis, energy from sunlight is absorbed by

Answer 3

chlorophyll

Question 4

green plant use the energy from the sun to make …

Answer 4

the carbohydrate glucose from the raw materials carbon dioxide and water

At the same time, oxygen is made and released as a waste product

Question 5

photosynthesis is

Answer 5

the process by which plants manufacture carbohydrates from raw materials using energy from light

Question 6

word equation for photosynthesis

Answer 6

carbon dioxide + water—— (light, chlorophyll)—– glucose + oxygen

Question 7

symbol equation for photosynthesis

Answer 7

CO2 + H2O —– C6H12O6 + 6O2

Question 8

why is photosynthesis an important process

Answer 8

because it converts light energy into chemical energy which is stored in glucose.

Question 9

what is a limiting factor

Answer 9

something present in the environment that is in such short supply that it restricts life processes

Question 10

main factors that limit rate of photosynthesis (3)

Answer 10

• light intensity
• temperature
• carbon dioxide concentration

Question 11

how does temperature affect the rate of photosynthesis

Answer 11

the temp of the environment affects how much kinetic energy the particles have, so the lower the temperature, the less energy particles have resulting in fewer successful collisions.

Increasing the temp increases kinetic energy of particles, increasing likelihood of successful collisions between reactants and enzymes ( resulting in formation of products)

At higher temperatures, enzymes that control the processes of photosynthesis can be denatured which can reduce rate of photosynthesis

Question 12

how does light intensity affect the rate of photosynthesis

Answer 12

chlorophyll uses light intensity to perform photosynthesis but it can only do it as quickly as the light is arriving

if the light intensity is increased, the rate of reaction also will but only up to a certain point

if it goes beyond that point it won’t make any difference because it will be either TEMP or CO2 level that is the limiting factor

Question 13

if temperature is a limiting factor, is it usually too low or too high and why

Answer 13

too low, things need warming up a bit

Question 14

how does carbon dioxide concentration affect rate of photosynthesis

Answer 14

co2 is pretty scarce in the air, and is one of the raw materials needed for photosynthesis.

more carbon dioxide that is present, the faster the reaction can occur

This trend will continue until some other factor required for photosynthesis prevents the rate from increasing further because it is now in short supply, this factor becomes the limiting factor

Question 15

Waxy cuticle (what does it do)

Answer 15

Protective layer on top of the leaf, prevents water from evaporating

Question 16

upper epidermis (what does it do)

Answer 16

Thin and transparent to allow light to enter palisade mesophyll layer underneath it

Question 17

palisade mesophyll (what does it do)

Answer 17

Column-shaped cells tightly packed with chloroplasts to absorb more light, maximising photosynthesis

Question 18

spongy mesophyll (what does it do)

Answer 18

Contains internal air spaces that increase the surface area to volume ratio for the diffusion of gases (mainly carbon dioxide)

Question 19

lower epidermis (what does it do)

Answer 19

Contains guard cells and stomata

Question 20

guard cell (what does it do)

Answer 20

Absorbs and loses water to open and close the stomata to allow carbon dioxide to diffuse in, oxygen to diffuse out

Question 21

stomata (what does it do)

Answer 21

Where gas exchange takes place: opens during the day, closes during the night. Evaporation of water also takes place from here. In most plants, found in much greater concentration on the underside of the leaf to reduce water loss

Question 22

vascular bundle (what does it do)

Answer 22

Contains xylem and phloem to transport substances to and from the leaf

Question 23

xylem (what does it do)

Answer 23

Transports water into the leaf for mesophyll cells to use in photosynthesis and for transpiration from stomata

Question 24

phloem (what does it do)

Answer 24

Transports sucrose and amino acids around the plant

Question 25

why does the leaf have a lot of stomata

Answer 25

to allow gas exchange to happen faster

Question 26

why does the leaf have air spaces int he spongy mesophyll layer

Answer 26

to allow gas exchange

Question 27

why is the leaf thin

Answer 27

to allow rapid diffusion for gaseous exchange

Question 28

why does the leaf have a broad shape (2)

Answer 28

to increase surface area to catch more light

Question 29

how is the leaf adapted for photosynthesis (6)

Answer 29

• large surface area
• network of veins in the leaf to transport water
• chlorophyll in leaves absorbs light energy
• epidermis is thin
• leaf is thin
• spongy mesophyll layer has air spaces to allow CO2 to diffuse
• waxy cuticle to reduce water loss by evaporation

Question 30

what are two fundamental mineral ions required by plants

Answer 30

magnesium and nitrogen

Question 31

where do plants get mineral ions from

Answer 31

the soil

Question 32

if there isn’t enough of one of the mineral ions, what happens

Answer 32

the plants suffer deficiency symptoms

Question 33

function of mineral ion nitrate

Answer 33

needed to make amino acids/proteins
needed for cell growth

Question 34

deficiency symptoms of nitrate

Answer 34

causes stunted growth and yellowing of leaves

Question 35

magnesium ion function

Answer 35

needed to make chlorophyll

Question 36

deficiency symptom of magnesium

Answer 36

causes yellowing of leaves between the veins

Question 37

what is the yellowing of the leaves called

Answer 37

chlorosis

Question 38

PRACTICAK INVESTIGATING PHOTOSYNTHESIS

Answer 38

Take a bundle of shoots of a type of pondweed

Submerge them in a beaker of water underneath an upturned funnel

Fill a boiling tube with water and place it over the end of the funnel

As oxygen is produced, the bubbles of gas will collect in the boiling tube and displace the water

• Show that the gas collected is oxygen by relighting a glowing splint