1. Chapter 5
Photosynthesis &
Cellular Respiration

2. 5-1 Energy & Living Things
You get energy from the food you eat.
Directly or indirectly, all of the
Energy in living systems needed for
Metabolism comes from the sun.

3. Metabolism involves either using energy To build molecules or breaking
Down molecules in which energy
Is stored.
Photosynthesis is the process by which
Light energy is converted to
Chemical energy.

4. Autotrophs are organisms that use Energy from sunlight or
Inorganic substances to make
Organic compounds.
Like plants use sunlight to
Make glucose.

5. Heterotrphs are organisms that Must get energy from food instead
Of directly from sunlight.
We are heterotrophs because
We can’t make our own food
In our cells.
Instead we use cellular respiration
To “burn” fuel in our bodies.

6. Almost all of the food we eat goes To heat, but some of the energy
Goes into making ATP.
ATP (adenosine triphosphate)
Provides cells with the energy they
Need to carry out life’s processes.

8. 5-2 Photosynthesis

9. In stage 1, light energy is absorbed.
6CO2 + 6H2O + Light C6H12O6 + 6O2
In stage 1, light energy is absorbed.
Structures that will absorb light
Contain pigments.
Chlorophyll is the primary pigment
That absorbs mostly blue and red
Light and reflects green and yellow.

10. That reflection is why plants Are green.
Plants contain 2 types of chlorophyll,
a and b chlorophyll.
Both types of chlorophyll play a
Role in photosynthesis.

11. The pigments that produce yellow And orange colors in fall or
In fruits and vegetables
Are called carotenoids.

12. Pigments involved in plant Photosynthesis are located in the
Chloroplasts of leaf cells.
Clusters of pigments are embedded
In the membranes of disk
Shaped structures called
Thylakoids.

13. When chlorophyll absorbs light this causes 1
pair of chlorophyll electrons to “bounce around”

14. Instead of being “trapped” in a wire they are stored in chemical bonds.

15. These “excited” electrons that leave
The chlorophyll molecules are used
To produce new molecules that
Temporarily store chemical energy,
Including ATP.
The series of molecules through which
Excited electrons are passed along
A thylakoid membrane are called
Electron transport chains.

16. -accepts electrons and is converted to NADPH
NADP+ (in plants)
-accepts electrons and is converted to NADPH
NADPH is an electron carrier that
Provides the high-energy electrons
Needed to make C-H bonds in stage 3.

17. In stage 3, energy is stored in Organic molecules.
In the 1st and 2nd stages of
Photosynthesis, light energy is used
To make ATP and NADPH, which
Temporarily store chemical energy.

18. In the 3rd stage of photosynthesis, Carbon atoms from the CO2 in
The air are used to make
Organic compounds in which
Chemical energy is stored.
This energy is stored in the form
Of sugar…
Glucose.

20. The transfer of carbon dioxide To organic compounds is called
Carbon fixation.
The most common method for
Carbon fixation is the Calvin Cycle.
The Calvin cycle is a series of enzyme
Assisted chemical reactions that
Produce 3 carbon sugars.

22. Photosynthesis is affected by Various types of environmental factors.
The most obvious is light
Then there is CO2 concentration
Also temperature

23. 5-3 Cellular Respiration
Cells transfer the energy in organic
compounds (carbs, proteins, fats)
back to ATP
So for the most part, this is the
Reverse of photosynthesis.

24. Metabolic processes that require Oxygen are called aerobic.
Metabolic processes that can go
On without oxygen are called
Anaerobic.

26. The primary fuel for cellular Respiration is glucose, but fats and
Proteins can also be used.
In the first step of cellular respiration
Glucose is broken down in the
Cytoplasm during a process called
Glycolysis.
Glycolysis is enzyme assisted and
Breaks down a 6 carbon glucose
To 3 carbon sugars of pyruvate.

27. As glucose is broken down, some of Its hydrogens are transferred to
An electron acceptor, NAD+.
This forms the electron carrier
NADH.
For respiration to continue, the
Electrons eventually are donated
To other organic compounds,
This recycles the NAD+.

31. In stage 2, more ATP is made By aerobic respiration.
When oxygen is present, pyruvate
Produced during glycolysis enters a
Mitochondria and is converted to
A 2 chain compound.

32. This reaction produces a carbon Dioxide molecule, 1 NADH
Molecule and a 2 carbon acetyl group.
The acetyl group is attached to a
Molecule called coenzyme A, forming
A compound called acetyl-CoA.
Acetyl-CoA enters a series of enzyme
Assisted reactions called the
Kreps Cycle.

34. After the Krebs cycle, NADH and FADH2 now contain much of the
Energy that was previously stored
In glucose and pyruvate.
When the Krebs cycle is completed,
The 4 carbon compound that began
The cycle is recycled, and
Acetyl-CoA can enter the
Cycle again.

35. In aerobic respiration, electrons Donated by NADH and FADH2
Pass through an electron transport
Chain.
In eukaryotic cells, the electron
Transport chain occurs in the
Inner membranes of the
Mitochondria.

38. Fermentation follows glycolysis In the absence of oxygen.
What happens when there is not
Enough oxygen for aerobic
Respiration?
Then anaerobic respiration occurs.

39. Two important types of fermentation Are lactic acid fermentation
And alcoholic fermentation.
During vigorous exercise, pyruvate
In muscles is converted to
Lactate when there is not
Enough oxygen present.
The lactic acid then created builds
Up and is what causes cramps. 

40. In other organisms, like yeast, The three carbon pyruvate is
Broken down to ethanol, a
2 carbon compound, through a
Process called alcoholic fermentation.
Carbon dioxide is released
During the process.

42. Ethanol is actually toxic to yeast.
Yeast will die with ethanol
Concentrations of about 12%.
So naturally fermented wine and
Beer can only be a maximum
Of 12% alcohol.

45. THE END