B2a - Plants Flashcards
What are the plant organs?
stems, roots, leaves and petals
Example of plant tissues
- Mesophyll tissue - Where most photosynthesis takes place
- Xylem and Phloem - transports things like water, mineral ions and sucrose around the plant
- Epidermal tissue - covers the whole plant
Equation for photosynthesis
Carbon dioxide + water ———-> glucose + oxygen
Process of photosynthesis
Happens in chloroplasts
Chloroplasts contain green substance called chlorophyll which absorbs sunlight and uses its energy to convert CO2 and water into glucose (O2 also produced)
Happens in the leaves plants
What limits photosynthesis?
Light intensity
Volume of CO2
Temperature
Water supply
How do you check ideal conditions for photosynthesis?
Use pondweed and measure the amount of oxygen produced in a given time to show how fast photosynthesis is happening.
Either count bubbles given off or collect oxygen is a gas syringe.
Equation for photosynthesis
Carbon dioxide + water ———-> glucose + oxygen
Process of photosynthesis
Happens in chloroplasts
Chloroplasts contain green substance called chlorophyll which absorbs sunlight and uses its energy to convert CO2 and water into glucose (O2 also produced)
Happens in the leaves plants
What limits photosynthesis?
Light intensity
Volume of CO2
Temperature
Water supply
How do you check ideal conditions for photosynthesis?
Use pondweed and measure the amount of oxygen produced in a given time to show how fast photosynthesis is happening.
Either count bubbles given off or collect oxygen is a gas syringe.
What do the 3 graphs look like to show the rate of photosynthesis AND WHY
Light - graph increases and then at the optimum levels off. Past optimum it will either be temp or CO2 thats limiting factor
CO2 - graph steadily increases and then at optimum point levels off as either light or temp is the limiting factor
Temp - Increases to optimum and then once it reaches is travels back down to 0. If its too low or high the enzymes cannot work properly and will be damaged/denatured. Only work best at around 45 degrees
How do you control the rate of light intensity, temp and CO2 levels?
Light - don’t block light with anything and use a bench lamp and certain distances to control light
Temp - Keep flask in water bath
CO2 - can’t really do it - just do it very quickly and if using sodium hydrogen-carbonate make sure you change them every time.
How do you control things using a green house?
- They trap the suns heat to keep the temp high.
- Use heaters in the winter to keep it walm and in the summer have shades or ventilation so its not too hot
- Artificial lights
Use paraffin - heaters to produce extra CO2 when they burn - Removes pests or diseases from plants as they are closed in
- Plants grow faster and stronger BUT more expensive
How do plants use Glucose?
- For respiration - needed in respiration as it relates energy that can convert glucose into various other useful substances for plant so they can build new cells and grow.
- Making cell walls - Glucose is converted into cellulose for making strong cell walls
- Making proteins - glucose is combined with nitrate ions (from soil) to make amino acid which is what makes proteins
- Stored in seeds - Glucose is turned into lipids (fats and oils) for storing in seeds.
- Stored as starch - turned into starch and stored in roots, stems and leaves ready for use when photosynthesis isn’t happening. As starch is insoluble its better for storing glucose.
What is a habitat?
Place where organisms live
What environmental factors effect where organisms are found?
- Temperature
- Availability of water
- Availability of oxygen and CO2
- Availability of nutrients
- Availability of light
What ways can you study the distribution of organisms?
- measure how common an organism is in two sample areas using quadrats and compare
- Study how the distribution changes across an area (quadrates along a transect)
How are quadrats used to study the detraction of organisms?
Quadrat is a square frame enclosing a known area.
You have to place quadrat at a random point within the first sample area.
Count the organisms with quadrat
Repeat this and work out a mean or organisms for first area.
Then repeat in another area and compare.
What do you do if your asked to work out the population size?
Work out the mean number of organisms then multiply mean by total surface area.
How are transects used to study the detraction of organisms?
^Make out a line in area you want to study using tape measure
^ Then count number or organisms on/touch that line
^ Or place a quadrat next to each other along the line and count the organisms.
How do you make using quadrates/transects reliable?
^Take a large sample size as they are more representative
^ Use random samples to ensure honest results
How do you make using quadrates/transects valid?
Control the variables
if you have controlled all other variables you will know if this has caused an effect in distribution
