Plants Structures And Their Functions Flashcards
(61 cards)
What is the word equation for photosynthesis?
carbon dioxide + water — light energy —> oxygen + glucose
What is the chemical equation for photosynthesis?
6 CO2 + 6H2O ——> C6H12O6 + 6O2
Where is the main site of photosynthesis in the structure of the leaf?
Palisade mesophyll
What is the order of the structure of the leaf from top to bottom?
Waxy cuticle
Upper epidermis
Pallisade mesophyll
Spongy mesophyll
Lower epidermis
Out of the spongy and pallisade mesophyll, which one has more chloroplasts and why?
Pallisade mesophyll, because it is closer to the light so it needs more chloroplasts, which contains chlorophyll which aids photosynthesis, it also has a vacule which pushes the chloroplasts to the edge of the cell to be even closer to the light.
What is the function of the waxy cuticle?
The waxy layer provides a waterproof layer which provides protection for the leaf.
What is the function of the upper epidermis?
It is transparent, which allows light to pass through to the Pallisade mesophyll to conduct photosynthesis.
What is the function of the Pallisade mesophyll?
Has lots of chloroplasts to conduct lots of photosynthesis, the vacule pushes the chloroplasts to the edge of the cell to reach the light faster.
What is the function of the spongy mesophyll?
It has air pockets for gas exchange to take place.
What is the function of the lower epidermis?
The lower epidermis has guard cells which open and close the stomata to prevent transpiration. The stomata allows gases to diffuse in and out of the leaf.
True or false: the stem, flower, leaf and roots are all organs
True
Where does the water come from for photosynthesis?
It is absorbed through the roots.
Where in the plant does it get carbon dioxide from for photosynthesis?
It diffuses into the leaf via the stomata.
What does the plant do with the glucose produced in photosynthesis?
It is transported around the plant and is:
a) used in respiration to release energy
b) stored as starch in the roots.
What does the plant do with the oxygen produced in photosynthesis?
It is diffused out of the leaf via the stomata.
And uses some of it for respiration
What is a limiting factor?
The factor which doesn’t provide enough for itself, something that stops the process from happening.
Describe a practical which can be used to investigate the effect of light intensity on the rate of photosynthesis.
Add 450 mL of sodium hydrogen carbonate solution to the beaker.
2. Put a sprig of pond weed in the beaker an. sodium hydrogen carbonate solution will provide the Pond weed with the carbon dioxide it needs for photosynthesis.
3. Place the wide end of the funnel over the pond weed as shown in the diagram. The end of the funnel with the small opening should be pointing up.
4. The pond weed and the funnel should be completely under the solution.
5. Fill a test tube with the remaining sodium hydrogen carbonate solution. Place your thumb over the end of the test tube. Turn the test tube upside down, taking care that no air bubbles enter the tube.
6. Look for a stream of bubbles coming from the cut end of the pondweed.
7. Position your lamp 10cm away from your pond weed Leave for 2 minutes and then take count of the number of bubbles produced in one minute.
8. Repeat the count twice more and calculate the mean rate of bubble production.
9. Repeat steps 6 and 7 at 10cm 20 cm 30 cm 40 cm and 50cm.
10. Record your results in a suitable table and plot a graph to illustrate your data.
What can you test to test photosynthesis?
You can test the glucose produced, glucose is found in starch.
What is a practical which can be used to test for the production of photosynthesis?
You test the starch content of a green leaf.
- Add 150cm’ water the beaker and heat to boiling point using the Bunsen, tripod and gauze. Turn off the Bunsen burner and place the boiling tube containing ethanol in the hot water.
- Take a leaf that has been sitting in good light for at least a few days, and soften in the boiling water for ten seconds or so. Then add to the ethanol and allow decolourise for about a minute until all the colour disappears from the leaf.
- Using the forceps remove the leaf from the ethanol and put it back in the hot water to soften for 10 seconds.
- Spread the leaf out on a white tile and use the iodine solution to test for starch; a blue-black colour indicates starch is present.
- This experiment can be repeated with leaves that have been left in the dark. or have been deprived of carbon dioxide.
What is an exothermic reaction?
A reaction which the reaction releases energy so that the products have less energy than the reactants.
What is an endothermic reaction?
A reaction which takes energy out of the environment so the products have more energy than the reactants.
Is photosynthesis an exothermic or endothermic reaction?
An endothermic reaction, takes in energy.
Is respiration an endothermic or exothermic reaction?
Exothermic reaction, releases energy.
What does the xylem do?
Transports water around the plant from roots to the leaf.
