Topic 6- Plant Structures And Their Functions

Question 1

Photosynthesis word equation and then symbol equation

Answer 1

Carbon dioxide + water > glucose + oxygen

6CO2+ 6H2O > C6H12O6 + 6H2O

Question 2

What type of reaction is photosynthesis

Answer 2

Endothermic

Question 3

Bio mass

Answer 3

Mass of living material

Question 4

Where do photosynthetic organisms get their energy from?

What do they store it as?

Answer 4

They get their energy from the sun to form glucose which is stored as starch (larger, complex molecule)

Question 5

Photosynthetic organisms role in the food chain

Answer 5

Main producers of nearly all life on earth as animals eat it and then are eaten.

Question 6

Where does photosynthesis take place?

Answer 6

In the chloroplasts

Containing chlorophyll which absorbs light and so energy

Question 7

What affects the rate of photosynthesis

Answer 7

Water availability
Carbon dioxide availability 
Light intensity
Temperature
Chlorophyll availability

Question 8

How to test for starch

Answer 8

Boil a leave in water for 30 secs.
Then boil in ethanol for a few mins which is heated using a water bath
Dry with distilled water and place on white tile
Add iodine solution from a pipette which will detect starch after a few minutes by turning black.

Question 9

What does boiling the leaf in water do?

Answer 9

Stop chemical reactions from occurring

Question 10

What does boiling in ethanol do?

Answer 10

Decolorisation

Needs water bath as ethanol is flammable

Question 11

How do you distract a plant

Answer 11

Leave in the dark for a few hours

Question 12

How to investigate the effects of light intensity on rate of photosynthesis

Answer 12

1. ) set up apparatus (including gas syringe, ruler, conical flask w water in and light source) and put sodium hydrogencarbonate into water.
2. ) place light source at specific distance away from the plant
3. ) leave to photosynthesise for a set time
4. ) as it photosynthesises, released oxygen will collect in the gas syringe to accurately measure volume of gas produced
5. ) repeat w different distances away from light

Question 13

Why is sodium hydrogen-carbonate added to the water?

Answer 13

To provide it with CO2.

Is a control variable that can be controlled by set amount of sodium hydrogen-carbonate mixed with set amount of water.

Question 14

Rate of oxygen produced

Answer 14

Volume produced/ time taken

Question 15

Control variables in investigation into effect of light intensities on rate of photosynthesis

Answer 15

Carbon dioxide concentration (sodium hydrogencarbonate amount)
Temperature (putting in water bath)

Question 16

Law of limiting factors

Answer 16

When a process depends on 2 or more factors, the rate of that process is limited by the factor which is in short supply.

Question 17

Light intensity’s effect on photosynthesis graph

Answer 17

At first, no gas is released as rate of photosynthesis= rate of respiration (compensation point)
Then the (as light intensity increases), rate of photosynthesis steadily increases up to a certain point in which it plateaus as another factor limits the rate.

Question 18

Light intensity

Answer 18

Proportional to 1/ distance squared

Question 19

Relationship between light distance and intensity of light

Answer 19

Inversely proportional

Question 20

Carbon dioxide’s effect on photosynthesis rate graph

Answer 20

As CO2 concentration increases, so does rate of photosynthesis until plateaus as other factor limits rate.
This is because CO2 is a raw material needed for photosynthesis.

Question 21

Temperature ‘s effect on photosynthesis rate graph

Answer 21

As temp increases, rate increases (as it gives more kinetic energy to enzymes to carry out photosynthesis) until it reaches an optimum temperature in which it then begins to steadily decrease (enzymes are becoming denatured by the too hot temp)

Question 22

Temp in which all photosynthesis enzymes are denatured

Answer 22

45 degrees Celsius

Question 23

2 types of plant transport vessel

Answer 23

Xylem and phloem (go to every part of plant totally separate)

Question 24

What do root hairs take in and how?

Advantages of a root hair cell?

Answer 24

Minerals and water.
active transport for minerals
Diffusion for water
They have a large surface area

Question 25

What do phloem tubes transport and how?

Answer 25

Food (ph vs f) - mainly sucrose which is made in leaves Uses TRANSLOCATION and requires energy from respiration to transport food in both directions to rest of plant for immediate use/ storage.

Question 26

What are phloem tubes made up of?

Answer 26

Elongated living cells w pores in end walls for stuff to get through.

Question 27

What does xylem transport and how?

Answer 27

water and mineral ions | They use the TRANSPIRATION STREAM in which transported from roots to the stem to the leaves

Question 28

What are xylem tubes made up of?

Answer 28

Dead cells joined end to end (no end walls) and hole down middle. Strengthened with lignin

Question 29

What’s transpiration

Answer 29

loss of water from the plant, caused by evaporation and diffusion of water from plant surface. Mainly happens @ leaves. Creates small shortage of water in leaf, drawing more water up through xylem vessels to replace it. Is constant transpiration stream throughout which carries minerals dissolved in water

Question 30

Stomata | Where are they found?

Answer 30

Tiny pores on the surface of a plant, mostly found underneath leaves.

Question 31

Function of stomata

Answer 31

Allow CO2 and O2 to diffuse directly in and out of a leaf while also allowing water vapour to escape for transpiration. Exchange gases easily.

Question 32

Why does transpiration occur?

Answer 32

Because there’s more water outside the plant than in the air outside so they diffuse via the stomata.

Question 33

What are stomata surrounded by? | What do they do?

Answer 33

2 guard cells | They change shape to control the size of the pore.

Question 34

What happens when the guard cells are turgid?

Answer 34

The stomata open because they have enough water

Question 35

What happens when the stomata are flaccid?

Answer 35

The stomata is closed and so they need more water. | V little water can escape

Question 36

What’s transpiration rate affected by?

Answer 36

Light intensity Temperature Air flow

Question 37

How does light intensity affect transpiration rate?

Answer 37

Brighter light = greater transpiration rate | Stomata begin to close as it gets darker as photosynthesis Cant occur in dark.

Question 38

How does temp affect transpiration rate?

Answer 38

Warmer= faster transpiration | Warm means particles have more energy to evaporate and so diffuse out of stomata

Question 39

How does air flow affect transpiration rate?

Answer 39

Greater airflow= greater transpiration If there’s good airflow (like strong wind), water vapour is swept away, maintaining a low concentration of water in air outside leaf for diffusion.

Question 40

How do you estimate transpiration rate?

Answer 40

1.) set up apparatus (beaker of water with a capillary tube coming from it and a scale that leads to reservoir water tube and a tube with a plant’s head outside and cork around stem) Record the starting position of the air bubble. 2.) start a stopwatch and record distance moved by bubble per unit time . Calculating air bubble movement speed gives an estimate of transpiration rate.

Question 41

Potometer

Answer 41

A piece of apparatus measuring water uptake which correlates to transpiration. Technically is used to estimate transpiration.

Question 42

Top layer of leaf

Answer 42

Waxy cuticle

Question 43

How’s the plant’s surface adapted for photosynthesis?

Answer 43

It has a large surface area for more light needed in photosynthesis and the waxy cuticle helps reduce water loss by evaporation.

Question 44

Cells underneath the waxy cuticle | Adaptations?

Answer 44

Upper epidermis | Transparent so light can get to palisade layer

Question 45

Cells under upper epidermis | Adaptations?

Answer 45

``` Palisade mesophyll (middle) tissue Has many chloroplasts so are near top of leaf for light ```

Question 46

Cells under the palisade mesophyll tissue? Adaptations? What cells are next to this?

Answer 46

Spongy mesophyll tissue Contains air spaces which increase diffusion rate of gases in and out. They are next to xylem/phloem cells

Question 47

Purpose of xylem and phloem

Answer 47

Form network of vascular bundles providing leaf with water for photosynthesis and taking glucose produced. Help to support structure.

Question 48

Cells under spongey mesophyll tissue

Answer 48

Lower epidermis and guard cells w stomata

Question 49

Desert plants adaptations

Answer 49

Small leaves and spines (reduces surface area for water evaporation and prevent animals drinking from it) Curled leaves/ hairs (reducing air flow next to leaf to prevent diffusion) Thick waxy cuticles (reduce evaporation ) Thick, fleshy stem (stores water) Fewer stomata (only open at night sometimes for less evaporation) Sunken stomata (reduces air flow)

Question 50

Translocation

Answer 50

Starch produced via photosynthesis in day and broken down at night, products moved to cytoplasm to make sucrose (soluble) moved via active transport into companion cells w many mitochondria and sieve cells, (no nucleus and v little cytoplasm). Pressure differences move contents up/down.