Photosynthesis/Respiration Review – Answer Key
Where does most of the energy for life originally come from?
The sun
What is a heterotroph?
An organism that must take in nutrients from an outside
source – in other words, an organism that must eat to get
energy
What is an autotroph?
An organism that produces its own food (i.e. an organism
that can do photosynthesis)
What does ATP do? What happens to an ATP molecule when its energy is
“harvested” in a chemical reaction?
ATP is a molecule that acts as a temporary energy store.
When energy is released or “harvested” from an ATP
molecule, a phosphate is taken off of the molecule and you
end up with ADP.
What is the name of the process in which light energy is converted to
chemical energy in the form of carbohydrates?
Photosynthesis.
Why is chlorophyll green?
It reflects green light – it doesn’t absorb green light
What is the main effect on our atmosphere of photosynthesis?
It produces oxygen gas
What are the products of the light-dependent process of photosynthesis?
Oxygen gas, NADPH and ATP
What are the products of the light-independent (Dark Cycle, Calvin Cycle)
process of photosynthesis?
Glucose, NADP+, and ADP
Where does process of aerobic respiration take place?
In the mitochondria
When is water formed during cellular respiration?
During the Krebs cycle
Fermentation enables glycolysis to continue under what kind of
conditions?
Low or no oxygen
Which produces more ATP, glycolysis or aerobic respiration? How much
is produced by each process?
Aerobic respiration. The net production of glycolysis is 2
ATP. Aerobic respiration in the mitochndria can produce up
to 38 ATP
Why do plants have both chloroplasts and mitochondria?
Because they perform both photosynthesis and cellular
respiration
Where does most of the mass of a tree come from?
From the carbon dioxide in the atmosphere.
What are the inputs of photosynthesis? What are the outputs of
photosynthesis?
CO2 + H2O + sunlight  C6H12O6 + O2
What are the inputs of cellular respiration? What are the outputs?
C6H12O6 + O2  CO2
+ H2O + energy
How are the inputs and outputs of photosynthesis and cellular
respiration related?
The inputs of photosynthesis are the outputs of cellular
respiration and vice versa
Which colors of light would produce the best plant growth? Why?
Blue and orange/red. Because these are the wavelengths
absorbed by the pigments involved in photosynthesis
Could animals exist without plants? Why?
No – because they depend on plants for good and oxygen
Could plants exist without animals? Why?
Yes = plants make their own food and they produce all the
CO2 they need when they do cellular respiration.
Name three different temporary energy storage molecules used in
photosynthesis and respiration:
ATP, NADPH, NADH
Name 2 longer-term organic energy storage molecules produced by plants
Glucose, Starch
A lack of oxygen in muscles of a runner results in the production of
Lactic acid
- from the process of fermentation
The purpose of cellular respiration is
To release energy from glucose molecules
The equation for cellular respiration is
C6H12O6 + O2  CO2 + H2O + energy
The final carbon compound of glycolysis is
Pyruvic Acid
How many carbons are in the final carbon compound of glycolysis?
3
Where does glycolysis take place?
In the cytoplasm
Which compound stores more energy – ATP or ADP?
ATP
What is the first step in cellular respiration to break down glucose?
Glycolysis
Which process makes food, and which breaks it down?
Photosynthesis makes food.
Respiration breaks it down
Do autotrophs perform photosynthesis? Do heterotrophs?
Autotrophs perform photosynthesis.
Heterotrophs do not.