Section 3 - Plant Nutrition and Transport Flashcards Preview

Edexcel GCSE Biology > Section 3 - Plant Nutrition and Transport > Flashcards

Flashcards in Section 3 - Plant Nutrition and Transport Deck (46)
Loading flashcards...

Where does photosynthesis take place? (1)



What pigment do chloroplasts contain? (1)



What does chlorophyll do? (2)

- Absorbs sunlight

- Uses its energy for photosyenthesis


Word equation for photosynthesis? (2)

carbon dioxide + water ---> glucose + oxygen


Symbol equation for photosynthesis? (2)

6CO2 + 6H20 ---> C6H12O6 + 6O2


Label the parts {9)

1 - Waxy Cuticle

2 - Upper Epidermis

3 - Palisade

4 - Spongy Mesophyll

5 - Xylem

6 - Phloem

7 - Lower Epidermis

8 - Guard Cells

9 - Stoma


Why are leaves broad? (1)

- Large surface area exposed to light


Where are most chloroplasts found in a leaf and why? (3)

- Palisade layer

- So they are near the top of the leaf

- To get the most light


How is the upper epidermis adapted for efficent photosyenthesis (2)

- It is transparent

- So light can pass through it to the palisade layer


Why do leaves have a network of vascular bundles (4)

- These are the transport vessels xylem and phloem

- They deliver water and other nutriets to every part of the leaf

- They take away the glucose produced by photosyenthesis

- Help to support the leaf structure


What is the role of the waxy cuticle (1)

reduces water loss by evaporation


What are stomata and how do they make gas exchange/photosyenthesis more efficent (2)

- Stomata are little holes

- Let CO2 diffuse directly into the leaf


Name 3 factors affecting a plant's rate of photosyenthesis (3)

- Light

- Amount of CO2

- Temperature of surrondings


Why does not enough light slow down the rate of photosyenthesis (3)

- Chlorophyll uses light energy to perform photosyenthesis

- It can only do it as quickly as the light energy is arriving

- If light intensity is increased, rate of photosyenthesis will steadily increase, up to a point


Why does too little carbon dioxide slow down photosyenthesis (2)

- Because it is a raw material needed for photosyenthesis

- Increasing conc of CO2 will increase rate of photosyenthesis up to a point


Why does this curve flatten out (2)

- Shows the amount of CO2 is not the limiting factor affecting photosyenthesis

- Limiting factor is temperature or light intensity or both


Describe the graph; how temperature affects rate of photosyenthesis (3)

- As the temperature increases, so does the rate of photosyenthesis, up to a point

- If the tempeature goes above roughly 45 degrees, enzymes will denature

- This means the rate of photosyenthesis rapidly decreases


Describe how to test a leaf for Starch? (5)

- Kill it by dunking it in boiling water (hold with tweezers)

- Put leaf in a boiling tube with ethanol 

- Heat the tube in a water bath (gets rid of chlorophyll)

- Rinse the leaf in cold water and add a few drops of iodine

- If starch is present, leaf will go blue-black


Describe an experiement to show chlorophyll is needed for photosyenthesis (5)

- Use a variegated leaf that's been exposed to light 

- Record which parts are green and which aren't (green parts contain chlorophyll)

- Test the leaf for starch (see other flashcard)

- Only the Green parts will turn blue-black

- Shows only parts that contained chlorophyll could photosyenthesise and produce starch


Describe an experiement to show CO2 is needed for photosyenthesis (5)

- Use a soda lime, sealed bell jar, plant and light source

- Soda lime will absorb CO2 out of the air in the jar

- Leave the plant for a day

- Test leaves for starch, won't turn blue/black

- Shows no starch has been made in the leaf, means that CO2 is needed for photosyenthesis 


Describe an experiement to show light is needed for photosyenthesis (4)

- Grow a plant without any light, e.g in a cupboard

- Cut a leaf and test for starch (see other flashcard)

- The leaf won't turn blue/black, no starch present

- Shows light is needed for photosyenthesis, as no starch has been made


If a plant can't photosyenthesise, it can't produce ..... (1)



Describe an experiment to measure the effect of light intensity on the rate of photosyenthesis (7)

- Use canadian pondweed

- Faster it produces oxygen, faster the rate of photosyenthesis

- Source of white light is placed 30cm away from the pondweed

- Leave pondweed to photosyenthesise for 2 minutes

- Count no. of bubbles produced

- Control temperature, time

- Repeat with light source, 40cm, 50cm, 60cm and 70cm


If there aren't enough mineral ions in the soil, plants suffer .............. ............

deficiency symptoms


Name the 4 mineral ions plants need (4)

- Nitrates

- Phosphates

- Potassium

- Magnesium (small amounts)


Why do plants need nitrates and what happens if there is a deficency (3)

- Nitrates contain nitrogen for making amino acids and protein

- These are needed for cell growth

- If a plant can't get enough; it will be stunted and will have yellow older leaves


Why do plants need magnesium and what happens if there is a deficency (3)

- Needed in small amounts

- Required for making chlorophyll, needed for photosyenthesis

- Plants without enough magnesium have yellow leaves


Name the two main transport systems in plants (2)

- Xylem

- Phloem


Why do plants and animals need transport systems to move substances around their bodies but unicellular don't (4)

- Unicellular, substances can diffuse directly in and out across the cell membrane

- Diffusion rate is quick because of the short distances

- Multicellular, direct diffusion is too slow, large distances

- So multicellular need transport systems to move substances quickly


What is the xylem and what does it transport (3)

- Vascular tissue

- Carries water and mineral salts

- From the roots to the leaves in the transpiration stream



What is the phloem and what does it transport (4)

- Vascular tissue

- Transports amino acids, surcrose and other sugars

- From where they are made in the leaves to other parts of the plant

- By translocation


How are root hairs adapted to absorbing water from soil (3)

- Millions of microscropic hairs on each branch of a root

- Gives the plant a big surface area for absorbing water from the soil

- By osmomis


Draw a root hair cell and label it (5)


Outline 2 substances taken in by root hair cells (2)

- Minerals (by active transport)

- Water (by osmosis)


What is transpiration (2)

- Transpiration is the process of water movement through a plant

- Caued by evaporation and diffusion of water from a plant's surface


Explain how transpiration helps a plant lose/obtain water (6)

- Transpiration is caused by the evaporation and diffusion of water from a plant's surface

- Most transpiration happens at the leaves

- Water escaping from the leaves through the stomata by diffusion causes a slight shortage of water in the leaf

- More water is drawn up from the rest of the plant through the xylem to replace it

- Means more water is drawn up from the roots

- Constant transpiraton stream of water through the plant


What 4 factors affects the rate of transpiration (4)

- Light intensity

- Temperature

- Wind Speed 

- Humidity


How does light intensity affect the rate of transpiration (2)

- Brighter the light, greater the transpiration rate

- Stomata begins to close as it gets darker, meaning very little water can escape


How does temperature affect the rate of transpiration (2)

- The warmer it is, the faster transpiration happens

- When it's warm, water particles have more energy to evaporate and diffuse out of the stomata


How does wind speed affect the rate of transpiration (3)

- The higher the wind speed, the greater the transpiration rate

- If it's windy, water vapour is swept away, maintating a low conc of water in the air outside the leaf

- Therefore diffusion happens faster, inreasing the transpiration rate


How does humidity affect the rate of transpiration (4)

- The drier the air around a leaf, the faster transpiration happens

- If the air is humid, diffusion happens slower

- This is because there's a lot of water in the air, making less of a difference between the inside and outside of a leaf

- Diffusion (and therefore transpiration) happens faster with a high conc in one place, and a low conc in the other


Describe an experiment to measure transpiration (9)

- Use a potometer to estimate transpiration rate

- Cut a shoot underwater to prevent air from entering the xylem

- Cut it at a slant to increase surface area for water uptake

- Insert the shoot underwater, so no air can enter

- Remove apparatus from water, but keep the end of a capillary tube submerged in a beaker of water, watertight and airtight

- Dry the leaves, shut the tap

- Remove the end of the capillary tube from the beaker of water until one air bubble has formed, then put it back into water

- Start a stopwatch and measure distance moved by the bubble per hour

- Keep conditions constant, e.g temperature and humidity



Experiement to show how light intensity affects transpiration rate (3)

- Use previous experiment as a control, vary light intensity and compare results

- Use a lamp to increase the intensity of light that hits the plant; this should increase the transpiration rate

- To decrease the light intensity, put the potometer in a cupboard, decreasing transpiration rate


Experiement to show how temperature affects transpiration rate (2)

- Vary temperature by putting the potometer in a room that's warmer or colder than the control experiement room

- An increase in temperature should increase rate of transpiration, a decrease should lower it.


Experiement to show how humdity affects transpiration rate (3)

- Increase humiditiy of air around the plant

- By spraying water in a clear plastic bag before sealing it around the plant

- Should decrease the rate of transpiration


Experiement to show how wind speed affects transpiration rate (3)

- Use a fan

- Increases wind speed

- Increase the transpiration rate