Air & gases
Which gas makes up the largest percentage of air?
Nitrogen
What green substance in leaves converts light energy?
Chlorophyll
What process releases energy from food?
Respiration
In a food chain, what do we call plants?
Producers
What chemical tests for starch?
Iodine solution
Which gas turns limewater milky?
Carbon dioxide
Name two reactants needed for photosynthesis.
Carbon dioxide and water
Which gas is needed for the respiration process?
Oxygen
In grass → rabbit → fox, what role does the rabbit play in this food chain?
consumer / Primary consumer
Name two controlled variables about "investigating whether light is necessary for photosynthesis".
supply of carbon dioxide
supply of oxygen
supply of water
presence of chlorophyll
temperature
Which gas relights a glowing splint but does not turn limewater milky?
Oxygen
Write the word equation for photosynthesis
Carbon dioxide + water → glucose + oxygen
Write the word equation for respiration.
Glucose + oxygen → carbon dioxide + water
What flows along a food chain?
Energy
Predict iodine test results for covered vs uncovered leaf during the " whether light is necessary for photosynthesis."
Uncovered turns blue-black; covered remains brown.
Why is nitrogen used to fill potato chip packets instead of oxygen?
Nitrogen is unreactive and prevents oxidation, keeping chips fresh.
Why do only the green parts of a leaf turn blue-black in an iodine test?
They contain chlorophyll and produce starch.
Why do plants carry out both photosynthesis and respiration day and night, but photosynthesize only in daytime?
Respiration does not require light; photosynthesis does.
What happens if producers disappear?
Consumers eventually die due to a lack of an energy source.
Investigate whether chlorophyll is necessary for photosynthesis
Name the independent variable
Name the dependent variable
Name two controlled variables
Independent variable: presence of chlorophyll
Dependent variable: presence of starch
Controlled variables: supply of carbon dioxide, supply of oxygen, supply of water, supply of light, temperature
What color is the hydrogencarbonate indicator when the carbon dioxide concentration is lower? And what color is it when the carbon dioxide concentration is higher?
Lower - purple
Normal - red
Higher - yellow
Why must plants be destarched before experiments?
Use up all the previous starch, and to ensure starch detected is made during the experiment.
Give one similarity and one difference between photosynthesis and respiration
Both involve energy; respiration releases energy, photosynthesis stores it.
Why is energy not completely transferred?
Energy is lost as heat and used for life processes.
Some parts can't be eaten or digested by the next level.
What is the purpose of setting up tubes B and D?
They are control set-ups. They make sure the results in tubes A and C are caused by the presence of green leaves.