Photosynthesis Y9 Flashcards
What conversion of energy occurs in photosynthesis?
Light energy –> Chemical Energy
What is Autotrophism?
plant capable of synthesizing its own food from simple organic substances
Is a plant Autotophic?
Yes
What plant organ does this process of photosynthesis occur in?
Leaf
What organelle does Photosynthesis take place in?
Chloroplast
What pigment does plant require in order to photosynthesise?
Chlorophyll
What is the word equation for photosynthesis?
Water + Carbon Dioxide –> Glucose + Oxygen
What is the Balanced symbol equation for photosynthesis?
6CO2 + 6H2O → C6H12O6 + 6O2
What are the three limiting factors for Photosynthesis?
Temperature, Light Intensity and Co2 concentration.
Explain how Light Intensity affects the rate of Photosynthesis?
Light intensity is the limiting factor. As light intensity increases, the rate of p/s increases 2) Rate of p/s levels off. This is because there is another limiting factor – either temp or CO2 concentration.
Explain how Co2 concentration affecst the rate of photosynthesis?
CO2 concentration is the limiting factor. As CO2 concentration. increases, the rate of p/s increases 2) Rate of p/s levels off. This is because there is another limiting factor – either temp or light intensity.
1
Explain how Temperature affects the rate of Photosynthesis?
Temperature is the limiting factor as the enzymes do not have much kinetic energy. Temp ↑ = K.E ↑= molecules move faster = more E-S complexes formed per second. 2) The rate of p/s will increase until it reaches the optimum temperature. 3) The enzymes denature and E/S complexes can no longer form. Rate of P/S decreases.
Essential practical – what does photosynthesis require?
Plants store glucose as starch. We can test for this using iodine. . The positive result is a colour change from orange/brown to blue/black.
1. We must destarch the leaf. We do this by placing the plant in a dark cupboard for 48 hours. This works because starch is broken down into glucose for use in respiration. 2. Now we can see what conditions are needed for photosynthesis to take place No photosynthesis → No glucose → No starch → Negative iodine test. 3. To safely test for starch we must: a. Boil the leaf in water b. Heat the leaf in ethanol (to remove chlorophyll) c. Using a hot water bath d. Test using iodine
How is the Light factor removed?
Tin foil placed over leaf
How is Carbon Dioxide removed?
Use a variegated leaf
Essential practical – the rate of photosynthesis?
Pond weed is useful, because we can measure the volume of oxygen produced. This allows to determine the rate of
photosynthesis.
Different independent variables we could investigate & how we would do this?
Light intensity – having a lamp at different distances Colour of light – using different coloured filters
CO2 conc. – add different masses of hydrogen carbonate
What are the two ways of measuring Oxygen? (Essential Practical Rate of Photosynthesis?)
1) Counting bubbles produced per minute 2) Gas syringe (more accurate, because bubbles have different sizes)
Where are mineral ions absorbed?
Roots
How are mineral Ions absorbed?
Active Transport against a concentration gradient.
What adaptions does a root have to absorb mineral ions?
Large SA:V
What is the use of Nitrates in plants?
Make amino acids and then proteins for growth
What is the use of Magnesium in Plants?
Making chlorophyll, to absorb light in photosynthesis
What is the use of Potassium in plants?
Helps enzymes needed for photosynthesis and respiration
What is the use of Phosphate in plants?
Used in DNA and cell membranes
What is a mineral ion?
An ion is a mineral or element that has a positive or negative charge.
What happens when there is a deficiency in Nitrates?
Stunted Growth/Yellow older leaves
What happens when there is a deficiency in Magnesium?
Yellow leaves
What happens when there is a deficiency in Potassium?
Poor flower/Fruit Growth/Discoloured Leaves
What happens when there is a deficiency in Phosphates?
Poor root growth/Purple Leaves
Is a leaf an organ, organelle, cell or tissue?
Organ
What is a leaf specialised for?
To increase the rate of photosynthesis
How is a leaf specialised for obtaining light?
Broad Shape gives a large SA
Palisade cells are packed full of chloroplasts These contain chlorophyll which allows them to absorb light The upper epidermis is transparent allowing light through
How is a leaf specialised for Obtaining Carbon Dioxide?
Broad shape gives large SA
Holes called Stomata allow Co2 to diffuse in
Leaf is thin- reducing the diffusion distance
Mesophyll layer contains many air spaces
How is a leaf specialised for obtaining water?
Water comes from the roots in the xylem vessels.
The waxy cuticle prevents water loss Guard cells can close the stomata
