B8 - Photosynthesis Flashcards
What is the word equation for photosynthesis?
Carbon dioxide + water —Light energy—> Glucose + oxygen
What is the symbol equation for photosynthesis?
6CO2 + 6H2O → C6H12O6 + 6O2
What is an endothermic reaction?
a reaction that takes IN heat/ energy. Cold
What type of reaction is photosynthesis?
Endothermic
What is an exothermic reaction?
This reaction gives OUT heat/ energy (Exit-exo). Hot
What are some adaptions leaves have?
air spaces for CO2 to get in and O2 to leave by diffusion.
guard cells to open and close stomata for gas exchange.
chlorophyll in the chloroplasts to absorb light.
Broad for large surface area
thin for diffusion distance for the gases so it’s short
What are the uses of glucose?
Respiration
Starch
Amino Acids
Cellulose
Fats and Oils
Use of Nitrates
Where does respiration occur in a plant cell?
mitochondria
Describe the function of starch to a plant.
Starch is stored in the cells of the leaves. It provides an energy store for when it’s dark or when light levels are low.
Which solution is used to test for the presence of starch?
Iodine
What are amino acids used to form in a plant cell?
proteins
Which solution is used to test for the presence of proteins?
Biuret reagent
In which structure of a plant cell is cellulose found?
cell wall
Why are fats and oils useful to a plant?
used as an energy store
What is a lipid molecule made from?
fatty acids and glycerol
What are nitrates used to make?
amino acids
What is the method for testing for starch?
- Heat a plant leaf in boiling water for 30 seconds.
- Add the leaf to boiling ethanol in a water bath for a few minutes.
- Wash with water to rehydrate and soften the leaf and spread onto a white tile.
- Add iodine solution from a dropping pipette.
When testing for starch, why do you boil the leaf in boiling water for 30 seconds?
to kill the leaf, stopping any chemical reactions.
When testing for starch, why do you add the leaf in boiling ethanol?
the boiling ethanol dissolves the chlorophyll and removes the green colour from the leaf - it should turn white.
If starch is present the leaf should go…
blue/ black
Would a leaf in the dark or light have more starch and colour change?
light
When testing for starch, why did the leaf in the dark stay brown and the iodine didn’t change?
because the leaf couldn’t make anymore starch so it eats itself to create energy #cannibalism
Enzymes are biological ____.
catalysts
Enzymes speed up….
food digestion/ chemical reaction
If it is too hot an enzyme can be ____.
denatured
The ideal temperature for an enzyme is called the ____ _____.
optimum temperature
