Chapter 6 - Plant Nutrition

Question 1

Define Photosynthesis

Answer 1

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

Question 2

Mention 3 ways in which organisms can get energy

Answer 2

• living things need biological molecules to make energy
• animals get biological molecules through organic substances they eat
• plants can make some biological molecules from inorganic substances

Question 3

What is the equation for photosynthesis?

Answer 3

6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂

carbondioxide + water → glucose + oxygen

Question 4

Which substance is crucial for photosynthesis?

Answer 4

chlorophyll

Question 5

Can substances react without energy?

Answer 5

no

Question 6

what kind of energy does glucose contain?

Answer 6

energy from the sun

Question 7

What is oxygen used for after photosynthesis?

Answer 7

released into the atmosphere / water

Question 8

What is glucose used for after photosynthesis (8)

Answer 8

• provide energy for active transport
• provide energy for growth
• stored as proteins to use later
• chained together to make sucrose to transport glucose around the leaf
• make cellulose
• make nectar
• create amino acids
• to create other substances if the plant doesn’t have enough or them

Question 9

Where does photosynthesis happen?

Answer 9

leaf, chloroplasts

Question 10

What is inside the leaf stalk?

Answer 10

vascular bundles arranged in parallel tubes which carry substances to and from the leaf

Question 11

Why is chlorophyll spread throughout the leaf?

Answer 11

to absorb as much sunlight as possible

Question 12

How does having a large surface area affect the leaf?

Answer 12

allow for more carbon dioxide to be absorbed into the leaf and allows more sunlight to enter the leaf

Question 13

Which plant is going to photosynthesise faster; one that is thick or one that is thin?

Answer 13

one that is thin

Question 14

How is water brought to the leaf?

Answer 14

in tubes called xylem vessels

Question 15

What is each stomata surrounded with?

Answer 15

guard cells

Question 16

Define stomata

Answer 16

openings in the surface of the leaf, most commonly lower surface. surrounded by pairs of guard cells, which controls wether stomata opens or closes

Question 17

Define guard cells

Answer 17

pair of cells that surround stomata and control its openings. They are the only cells in epidermis that contain chloroplasts

Question 18

What does the stomata do?

Answer 18

allows the diffusion of CO₂ , O₂ and water vapor in and out of the leaf

Question 19

How does sunlight enter the leaf?

Answer 19

By passing through the transparent cuticle and upper epidermis

Question 20

How does water reach the chloroplasts?

Answer 20

It travels from the roots into the xylem vessels. Water gets to the chloroplasts by Osmosis

Question 21

What 4 factors affect photosynthesis?

Answer 21

• supply of raw materials (CO₂ & H₂O)
• quantity and quality of sunlight
• temperature (affects enzyme activity)
• quantity of chlorophyll in leaf

Question 22

Define Destarching

Answer 22

leaving a plant in the dark long enough for it to use up its starch storage

Question 23

Describe a general method for seeing where starch normally is on a leaf

Answer 23

1. put a plant in the darkness for 4 days
2. cover the leaf with a black card that has a shape in it
3. leave the plant in the light for 4 days
4. use ethanol to remove chlorophyll from the leaves
5. use Iodine to see where starch is

Question 24

Why do only some parts of the leaf contain starch?

Answer 24

because there is only glucose in some parts of the leave and that is what starch is made up of

Question 25

What is the key for Hydrogencarbonate indicator?

Answer 25

purple: no CO₂
red: little CO₂ (normal air)
yellow: lots of CO₂

Question 26

Define limiting factor

Answer 26

a factor that is in short supply, which stops an activity happening at a faster rate

Question 27

What are the limiting factors of photosynthesis?

Answer 27

• light intensity
• temperature
• stomata

Question 28

What is the relationship between photosynthesis and light intensity?

Answer 28

as the light intensity increases, the rate of photosynthesis also increases up to the point where the plant is photosynthesising as fast as it can

Question 29

do all plants photosynthesise?

Answer 29

NO

Question 30

What is the relationship between photosynthesis and temperature?

Answer 30

a plant can photosynthesise faster on a warm day (optimum temperature)

Question 31

How does the stomata affect photosynthesis?

Answer 31

• CO₂ diffuses into the leaf through stomata
• if stomata are closed, leaf is lacking raw materials
• on REALLY hot days, photosynthesis will slow down