Photosynthesis Flashcards
What substance in the chloroplasts absorbs sunlight
Chlorophyll
What is the photosynthesis equation
(+ light energy)
Carbon dioxide + water —————> glucose + oxygen
What 3 steps are involved in photosynthesis
1) Co2 is taken in by leaves, and water is taken up by the roots
2) The chlorophyll traps the light energy needed for photosynthesis
3) the energy is used to convert the co2 and water into glucose
What is released as a by-product of photosynthesis
Oxygen
What is some of the glucose produced into from photosynthesis
Insoluble starch for storage
How can you identify whether photosynthesis has taken place
Testing leaves with iodine solution should of blue black in the presence of starch
Which parts of a variegated leaf will go blue black with iodine solution
The bits with green patches as they contain the chlorophyll
Why would a lack of light limit photosynthesis
The light provides the energy required for the process to occur
Which organisms can photosynthesise?
Green plants and algae
Why may Coke weather limit photosynthesis
If it’s too cold the enzymes do not work effectively so slow the process down
How will co2 levels affect photosynthesis
Too little co2 will slow photosynthesis down; enclosed spaces eg in a greenhouse have little co2 on a sunny day where there is plenty of light but plants run out of co2
What is a limiting factor
A factor which puts a cap on the rate of photosynthesis
What is an independent variable
The one being controlled eg co2 concentration
What should you take into account when conducting experiments on how factors affect photosynthesis
You need to know which factor is being changed and which is controlled,if you want to investigate the effect of increasing co2 levels then you must be aware that other factors such as light limit the rate of photosynthesis
What is a depending variable
The one you measure, eg volume of oxygen produced
Which variables will need to be controlled if investigation co2 concentration and volume of oxygen produced
Light, temperature and the type of plant
What is the graph for co2 concentration against rate of photosynthesis
As co2 increases ROP increases but eventually another factor becomes the limiting factor
What does a graph of light intensity against ROP look like
As light intensity increases ROP increases
What will a graph of temperature against ROP look like
As temp increases ROP increases until a certain point when the enzymes are destroyed and the reaction stops completely
How may the soluble glucose produced from photosynthesis in plants be used
Converted into insoluble starch for storage
Used for reparation
Converted into fats and oils for storage
Used to produce cellulose which strengthens cell walls
Used to produce proteins
What else do plant and algae cells also need a supply of? And for what?
Mineral ions such as nitrate ions in order to produce protein
Where do plants get nitrate ions from?where do algae get nitrate ions from?
Soil Water they live in
What do farmers have to evaluate when picking the best conditions for their plants to grow in
They have to evaluate the benefits of increased growth and the cost of heating and lighting or providing co2
What can be constructed to grow plants in an enclosed space
Greenhouses and polytunnels
What does a grower have to compare to test a greenhouse or polytunnels
The biomass of plants grown inside and out without the extra factors
What factors must be controlled in a greenhouse to improve plant growth
Co2, temp, light
How may temp affect distribution of organisms
Arctic plants are small which limits the number of plant eaters which can survive in the area
How may availability of nutrients affect distribution
Most plants struggle to grow when mineral ions are in short supply and so few animals can survive in that area
How may amount of light affect distribution of organisms
Few plants live on a forest floor because the light is blocked by the trees shaded plants often have bigger leaves so more chlorophyll
How may availiabitliy of water affect distribution
Water is important for all organisms so few will live in a desert. If it rains in the desert then plant grow, produce flowers and seeds very quickly. There will be more food for animals
How may availability of oxygen affect distribution
Water animals can be affected by lack of oxygen some invertebrates can live at very low oxygen levels, but most fish need high levels of oxygen dissolved in water
How may availability of co2 affect distribution
Lack of co2 will affect plant growth and consequently the food available for animals
How ça quantities data be obtained
Random quanta give sampling with a quadrat
Sampling along a transect
What is a quadrat
A square frame which is subdivided into a grid
When would a quadrat be useful
If you wanted to estimate the number of a certain plant in a whole field
Why is sample size important?
In a large field enough quadrats must be placed to be representative of the whole field and is usually given as a mean per square
When is it good to use a transect
Investigating the distribution between 2 points, physical factors can also be measured at each quadrat point
What is a transect
A line marked between 2 point where a quadrat is placed at regular intervals to measure distribution
What is a valid investigation
An investigation where all possible variables are controlled
She is a measurement considered repeatable
When the same experimanter repeats the investigation using the same method and obtains the same results
Why is it necessary to check that the result are reproducible
Bu using a different person, equipment you can see if you get the same results because an experimenter may make the same mistake over and over but still get the same results
When is an experiment considered reproducible
If the experiment is reoeated by another person, or using different equipment or technique and the same results are obtained
How can you make sure an investigation is valid
Only the independent variable should affect the results all other variables must be controlled
