Plant Nutrition and Transport Flashcards
What is the word equation for photosynthesis?
Carbon Dioxide + Water (+ light) -> Glucose + Oxygen (+ ATP)
What is the symbol equation for photosynthesis?
6CO2 + 6H2O -> C6H12O6 + 6O2
List the structure of a leaf, from top layer to bottom layer
Waxy cuticle
Upper epidermis
Palisade mesophyll
Spongy mesophyll
Lower epidermis
Guard cell/stomata
What is a limiting factor?
Something that stops photosynthesis from happening any faster
How does light intensity affect the rate of photosynthesis?
Chlorophyll uses light intensity to perform photosynthesis.
If light in plentiful supply, CO2/temperature will be the LF
How does CO2 affect the rate of photosynthesis?
One of the raw materials needed for photosynthesis
If CO2 in plentiful supply, light/temperature will be the LF
How does temperature affect the rate of photosynthesis?
Affects the enzymes involved.
If temperature is too low, rate is slow.
If temperature too high, enzymes denature
How to test a leaf for starch
- Dunk the leaf in boiling water (stops any chemical reactions)
- Heat leaf in boiling tube with ethanol (gets rid of any chlorophyll and makes it white in colour)
- Rinse the leaf and add iodine solution. If it turns blue-black, starch is present
Why are phosphates needed for plant growth?
Contains phosphorus which is needed to make DNA and cell membranes.
Also needed for respiration and growth
What must be used to heat the ethanol, and why?
A water bath, as ethanol cannot be near an open flame because it is highly flammable
Why are nitrates needed for plant growth?
Contains nitrogen which is needed for making amino acids and proteins
What does a plant look like if it doesn’t have enough nitrates?
It will be stunted and older leaves will turn yellow
What does a plant look like if it doesn’t have enough phosphates?
Poor root growth and older leaves look purple
Why is potassium needed for plant growth?
To help the enzymes needed for photosynthesis/respiration
What does a plant look like if it doesn’t have enough potassium?
Poor root and flower growth and discoloured leaved
Why is magnesium needed for plant growth?
Required to make chlorophyll
Plants only need in small amounts
What does a plant look like if it doesn’t have enough magnesium?
They have yellow leaves
What do the xylem transport?
Water and minerals from the root to the leaves in a transpiration stream
What do the phloem transport?
Sugars (e.g. sucrose) and amino acids from the leaves to the rest of the plant
Movement known as translocation
How does the root hair transport water into its cell?
Through osmosis.
This happens because the soil water has a higher water potential than the root hair cell cytoplasm
How does the root hair transport water into its cell?
Through osmosis.
This happens because the soil water has a higher water potential than the root hair cell cytoplasm
How does the root hair transport water into its cell?
Through osmosis.
This happens because the soil water has a higher water potential than the root hair cell cytoplasm
How does the root hair cell transport mineral ions into the cell, and why does it do this?
Through active transport
To maintain the concentration gradient and so the constant movement of water into the root hair cell by osmosis
What causes transpiration?
The evaporation and diffusion of water from a plant’s surface
What are the three steps in a transpiration stream.
- Water evaporates and diffuses from the surface of the leaf
- This creates a slight shortage of water in the leaf, so more water is drawn up from the xylem
- This means more water is drawn up from the roots
What four factors affect the rate of transpiration?
- Light intensity
- Humidity levels
- Temperature
- Wind speed
How does light intensity affect the rate of transpiration?
The brighter the light, the greater the transpiration rate.
Stomata close at night when there’s no light, which means little water can escape from the cell
How does temperature affect the rate of transpiration?
The warmer it is, the faster transpiration happens
When it’s warmer, the water particles have more energy to evaporate and diffuse
How does wind speed affect the rate of transpiration?
The higher the wind speed, the greater the rate of transpiration
Low wind speeds mean that the water evaporated from the leaf collects around it, leading to a higher concentration of water outside. This means the rate of diffusion is lower
How does humidity levels affect the rate of transpiration?
The drier the air is, the faster transpiration happens
If the air is very humid, there’s a lot of water in the air already, so there’s no difference in the outside or inside of the leaf
What is a potometer?
An apparatus that estimates transpiration rates by measuring the water uptake of a plant
What are the steps when carrying out a potometer experiment?
- Cut the shoot and insert it into the potometer underwater so air doesn’t go up xylem
- Ensure the apparatus is water/air tight and remove the end of the capillary tube from the water until one air bubble forms
- Record the starting position of the air bubble
- Start a stopwatch and record the distance moved by the bubble/hour
