PLANT NUTRITION Flashcards
What is the definition of photosynthesis?
Process in which plants manufacture carbohydrates from raw materials using energy from light
What is the chemical equation for photosynthesis?
6CO2 + 12H20 = C6H12O6 + 6O2
What are 3 requirements for photosynthesis?
light
chlorophyll
carbon dioxide
What happens if you covered a part of the leaf and added iodine? Why?
Parts that were covered did not turn blue black
In the parts that were covered there wasn’t starch
What happens if there isn’t chlorophyll present and then iodine was added? Why?
White parts turned brown
Green parts turned black/blue
The white part didn’t have chlorophyll and the green part did so that means photosynthesis took place
What does soda lime(sodium hydroxide) do?
Absorbs carbon dioxide
What does sodium hydrogen carbonate do?
Releases carbon dioxide
What happens when soda lime is placed near a plant when iodine is added? Why?
Parts stay brown
starch is not present as there is no carbon dioxide
What happens when sodium hydrogen carbonate is placed near a pant when added iodine? Why?
Parts turn black blue
carbon dioxide is present so it is able to photosynthesis
Where does photosynthesis occur?
It occurs in specialized double- membraned organelles called chloroplasts which contain the light absorbing green pigment called chlorophyll
What does chlorophyll do?
Chlorophyll transfers light energy into chemical energy in molecules for the synthesis of carbohydrates
List the order of the structure of the leaf
Waxy cuticle upper epidermis palisade mesophyll layer spongy mesophyll layer xylem phloem lower epidermis guard cell (stoma)
Where are chloroplasts concentrated? Why?
Chloroplasts are concentrated in the cells near the top of the leaf in order to receive the most sunlight
What are the called?
palisade cells
What are the spongy mesophyll cells?
Layer of loosely packed cells with some chloroplasts that are also able to photosynthesis.
Where are air spaces and what do they do?
Air spaces are in the spongy mesophyll layer and they are in this layer where gases can build up as they enter and leave the leaf.
How is water brought into the leaf?
Water is brought in by veins
What does the cuticle do and where is it found?
upper epidermis
prevents water loss
Where are stomata found?
lower epidermis
What do stomata do?
Control gaseous exchange needed for photosynthesis
When do stomata open?
during the day when there is high carbon dioxide uptale
What is produced by photosynthesis and how does it leave the leaf?
oxygen
by diffusion through the open stomata
How could excessive water loss and wilted plants happen?
Some of the water coming into the leaf via veins also evaporates and diffuses out of the leaf via stomata
What happens if water loss in excessive?
Plants are forced to close their stomata during the day which decreases the rate of photosynthesis.
What are the three factors that affect photosynthesis?
Temperature
Carbon dioxide concentration
light intensity
What is a limiting factor?
If any factors are in short supply the rate of photosynthesis will be less than its maximum possible rate
How can increasing temperature increase photosynthesis?
Increasing molecular collisions due to kinetic energy leads to an increase in the rate of photosynthesis.
What is optimal temperature?
Maximum rate of photosynthesis reached
How can high temperatures decrease the rate of photosyntheis?
Breaking of bonds in enzymes structure leads to a change in shape of the active site( denaturing)
When does the rate of photosynthesis increase due to carbon dioxide concentration?
Rate of photosynthesis increases until all substrate molecules are being used up
How can you increase the rate of concentration if the carbon dioxide concentration has become constant?
increase temperature or light intensity
What causes light intensity to become constant?
a factor becomes a short supply
What 4 conditions can be set up in greenhouses to reduce the effects of limiting factors on the rate of photosynthesis?
Greenhouse to be constructed from glass to enable maximum transmission of light
Artificial lighting systems can be sued to lengthen a plants growing season
Heat is used in greenhouses
Paraffin heaters in small scale to increase concentration of co2
What is the chemical equation for respiration?
6CO2 +C6H12O6 = 6H20 + 6CO2 + energy
What is the compensation point?
Compensation point is the point where teh rate of photosynthesis and respiration point are balanced and there is no net uptake or loss of carbon dioxide or oxygen.
When does photosynthesis not occur? Why?
At night. There is no sunlight
When is the rate of photosynthesis highest?
During the day
What is the indicator that shows carbon dioxide concentration in solution?
hydrogencarbonate indicator
What does orange indicate?
an average amount of co2
What does yellow indicate?
A lot of co2
What does purple indicate?
A little co2
What happens if you boil a leaf?
there are no living cells
What are minerals needed for?
Are needed for healthy growth
How do minerals enter the plant?
They are absorbed through the roots by active transport as mineral ions dissolved in the soil water
What are the 4 most important minerals needed by plants? What are their ions called?
nitrogen nitrates
phosphorus phosphates
potassium potassium ions
magnesium magnesium ions
What is nitrate needed for?
to make proteins
What happens in nitrate deficiency?
The amount of chlorophyll in leaves reduces
This reduces the plant is ability to photosynthesis and grow properly
How can you tell if a plant has a nitrate deficiency?
upper leaves are green but lower leaves are yellow
How can you increase nitrate levels?
add chemicals or natural fertilisers such as manure
What do plants need magnesium ion for?
To make chlorophyll in the leaves
What happens is the plant has magnesium ion deficiency?
the plant is limited in terms of its photosynthetic ability and the plant growth is compromised
How can you tell if a plant has magnesium ion deficiency?
Upper leaves are green lower leaves pale green or yellow
What is eutrophication?
Eutrophication happens when excess nitrate enters rivers or lakes from fields. This can lead to the death of fish and other aquatic animals.
Explain using details how this can heavily affect the ecosystem.
This happens when fertilisers are washed in rivers or lakes. Algae feed off of nutrients and create a green covering of the lake. This is called algae bloom which covers the water source not allowing any light to penetrate. Bacteria then eat the dead matter releasing more nutrients and consume oxygen making the lake anoxic. This causes for plants and animals to die due to lack of oxygen.
How are plants adapted for the process of photosynthesis?
they are broad and thin with many chloroplasts n their cells
What are raw materials of photosynthesis?
water and carbon dioxide
List three uses of carbohydrate in plants
creates the cell walls
stores available energy
primary fuel in cells
Explain how atmospheric carbon dioxide concentrations contribute to global warming.
they contribute as co2 creates a thick blanket around the atmosphere
light and heat cannot escape the atmosphere
co2 is a greenhouse gas contributing to the greenhouse effect
What are energy transducers?
Chloroplasts act as energy transducers converting light energy into chemical energy
