Section 6- Plant Structures And Their Functions Flashcards
How are plants able to make their own food
Plants make their own food by photosynthesis
What happens during photosynthesis
During photosynthesis, photosynthetic organisms use energy from the sun to make glucose.
Photosynthetic organisms
Green plants and algae
How are some of the glucose used.
Some of the glucose is used to make larger, complex molecules that the plants or algae need to grow. These make up the organisms biomass
Biomass
The mass of living tissue.
Where does photosynthesis occur
Photosynthesis happens inside chloroplasts as they contain chlorophyll which absorbs light. Energy is transferred to the chloroplasts by light.
Equation for photosynthesis
Carbon dioxide + water = glucose + oxygen
6CO_2 + H_2_O = C_6_H_12O_6 + 6O_2
Is photosynthesis endothermic or exothernic
Endothermic, energy is taken in during the reaction
What is the rate of photosynthesis affected by
3 limiting factors which stops photosynthesis from happening any faster
- light intensity
- concentration of carbon dioxide
- temperature
How to investigate the effect of light intensity on the rate of photosynthesis
Pondweed can be used to measure the effect of light intensity on the rate of photosynthesis. The rate at which pondweed produces oxygen corresponds to the rate at which it is photosynthesising.
The faster the rate of oxygen production, the faster the rate of photosynthesis.
1. The apparatus is set up. Light source is pointing to the conical flask, the conical flash contains water and sodium hydrogen carbonate with water and Canadian pondweed. Gas syringe is joint with the with the conical flask.
2. A source of white light is placed at a specific distance from the pondweed
3. The pondweed is left to photosynthesise for a set amount of time
4. As it photosynthesises, the oxygen released will collect in the gas syringe.
5. the whole experiment is repeated with the light source at different distances from the pondweed. the rate of oxygen production at each distance can then be produced.
6. this can be calculated by: volume produced/time taken.
7. Any variables that could affect the results should be controlled.
e.g. temperature- controlled by putting the conical flask in a water bath.
Carbon dioxide concentration- adding a set amount of sodium hydrogencarbon to a set volume of water
what does sodium carbonate do
released carbon dioxide in the solution
what does the gas syringe do
allows you to measure the volume of oxygen produced
what are the limiting factors of photosynthesis
- temperature
- carbon dioxide concentration
- light intensity
how does light intensity affect the rate of photosynthesis
Not enough light slows down the rate of photosynthesis. This is because light transfers energy needed for photosynthesis.
how is the graph for light intensity and how is it described
at first, as the light level is raised, the rate of photosynthesis increases steadily as the rate is directionally proportional to light intensity. however this is only up to a certain point.
beyond this certain point it plateus so it wont make a difference meaning itll either be temperature or the concentration of carbon dioxide being the limiting factor
how do you investigate light intensity in a lab
by moving a lamp closer to or further away from the plant.
how to work out light intensity
light intensity∝ 1/(distance)^2
how does carbon dioxide affect the rate of photosynthesis
too little carbon dioxide slows down the rate of photosynthesis. carbon dioxide is one of the raw materials needed. So increasing the carbon dioxide concentration, increases the rate of of photosynthesis up to a point.
how is the graph of carbon dioxide affecting he rate of photosynthesis described
as the concentration of carbon dioxide increases the rate of photosynthesis increases up to a point. after this the graph plateaus showing that carbon dioxide is no longer the limiting factor and either temperature and light intensity are
how does temperature affect the rate of photosynthesis?
if the temperature is a limiting factor, its because its too low, the enzymes needed for photosynthesis work more slowly at low temperatures, if the plant gets too hot, the enzymes it needs for photosynthesis will denature
types of transport vessels that flowering plants have
- xylem
- phloem