1. Unit 4: Bioenergetics
BIO.A.3.1 Identify and describe the cell structures involved in
processing energy.
BIO.A Describe the fundamental roles of plastids (e.g., chloroplasts)
and mitochondria in energy transformations.
BIO.A.3.2 Identify and describe how organisms obtain and transform
energy for their life processes.
BIO.A Compare the basic transformation of energy during
photosynthesis and cellular respiration.
BIO.A Describe the role of ATP in biochemical reactions.

2. KEY CONCEPT All cells need chemical energy (ATP).

3. Molecules in food store chemical energy in their bonds.
The chemical energy used for most cell processes (photosynthesis and cellular respiration) is carried by ATP (Adenosine Triphosphate).
Molecules in food store chemical energy in their bonds.
Starch molecule
Glucose molecule

4. ADP is changed into ATP when a phosphate group is added.
The energy in ATP is created from the breakdown of food molecules and used to perform other cell functions.
Energy is released when a phosphate group is removed (ATP is changed to ADP).
ADP is changed into ATP when a phosphate group is added.
phosphate removed

5. Click on the link above to view an animation of ATP Formation!
Organisms break down carbon-based molecules (proteins, lipids, and carbohydrates) to produce ATP.
Carbohydrates are the molecules most commonly broken down to make ATP.
not stored in large amounts
up to 36 ATP from one glucose molecule
TRIphosphate
adenosine
DIphosphate
Carbohydrates, lipids and proteins help to convert ADP into ATP (ENERGY)!
Click on the link above to view an animation of ATP Formation!

6. Fats store the most energy.
80 percent of the energy in your body
about 146 ATP from a triglyceride
Proteins are least likely to be broken down to make ATP.
amino acids not usually needed for energy
about the same amount of energy as a carbohydrate

7. A few types of organisms do not need sunlight and photosynthesis as a source of energy.
Some organisms live in places that never get sunlight.
In chemosynthesis, chemical energy is used to build carbon-based molecules.
similar to photosynthesis
uses chemical energy instead of light energy

8. KEY CONCEPT The overall process of photosynthesis captures energy from sunlight to produce sugars (glucose) that store chemical energy (ATP).

9. Photosynthetic organisms are producers.
Producers, or autotrophs, make their own source of chemical energy.
Plants use photosynthesis to make their own food; therefore they are producers.
Photosynthesis captures energy from sunlight to make glucose (sugar).

10. Chlorophyll is a molecule that absorbs light energy.
chloroplast
leaf cell
leaf
In plants, chlorophyll is found in organelles called chloroplasts.

11. The majority of chloroplasts are located within the mesophyll of the leaf. The stomata (stoma = singular) allow for gas exchange during photosynthesis, while the waxy cuticle is essential in the prevention of water loss.

12. Photosynthesis in plants occurs in chloroplasts.
Photosynthesis takes place in two parts of chloroplasts.
grana (stacks of thylakoids)
stroma (fluid outside the thylakoid)
chloroplast
stroma
grana (thylakoids)

13. The light-dependent reactions (A. K. A
The light-dependent reactions (A.K.A. – Light Reactions) capture energy from sunlight.
take place in thylakoids
water and sunlight are needed (reactants)
chlorophyll absorbs energy
energy is transferred along the thylakoid membrane then to light-independent reactions
oxygen is released (product)

14. The light-independent reactions (A. K. A
The light-independent reactions (A.K. A. – Dark Reactions) make sugars (glucose).
takes place in stroma (fluid outside the thylakoid)
needs carbon dioxide from atmosphere
use solar energy to build a sugar (glucose)

15. The equation for the overall process is:
6CO2 + 6H2O  C6H12O6 + 6O2
C6H12O6
granum (stack of thylakoids)
thylakoid
sunlight
1 six-carbon sugar
6H2O
6CO2
6O2
chloroplast 1 2 4 3
energy
stroma (fluid outside the thylakoids)

16. There are two steps to photosynthesis:
Light-Dependent Reactions
Also known as Light Reactions
Occurs in the thylakoids of chloroplasts
Uses (Reactant): Water
Produces (Product): Oxygen
Light-Independent Reactions
Also known as Dark Reactions or Calvin Cycle
Occurs in the stroma of chloroplasts
Uses (Reactant): Carbon Dioxide
Produces (Product): Glucose
In order for these two types of reactions to take place the following is needed:
Sunlight
Chlorophyll
Energy (solar)
Both of these reactions take place in the CHLOROPLASTS of plant cells!

17. KEY CONCEPT The overall process of cellular respiration converts sugar into ATP using oxygen.

18. Cellular respiration makes ATP by breaking down sugars.
Cellular respiration is aerobic which means it requires oxygen.
Aerobic stages of cellular respiration take place in the mitochondria.
mitochondrion
animal cell

19. Mitochondrial Structure
Cellular respiration takes place in the mitochondria. Review the parts of a mitochondria below that are involved in cellular respiration:
Mitochondrial matrix (area inside the inner membrane)
Inner membrane of the mitochondria

20. Glycolysis = initial breakdown of glucose into 2 pyruvates
anaerobic process (does not require oxygen)
takes place in cytoplasm
splits glucose into two three-carbon molecules called pyruvate
produces two ATP molecules

21. Cellular respiration is like a mirror image of photosynthesis.
The 1st step in cellular respiration is the Krebs cycle. It transfers energy to an electron transport chain.
takes place in mitochondrial matrix
breaks down the pyruvate
(three-carbon molecules)
made during glycolysis
Krebs Cycle
6H O 2
6CO 6O
mitochondrion
matrix (area enclosed
by inner membrane)
inner membrane
ATP
energy
energy from glycolysis 1 4 3
and
makes a small amount of ATP
releases carbon dioxide
transfers energy-carrying molecules

22. energy from glycolysis
The 2nd step of cellular respiration is the electron transport chain. It produces a large amount of ATP.
takes place in inner membrane of the mitochondria
Energy is transferred to the electron transport chain from glycolysis and the Krebs Cycle.
oxygen enters process
ATP produced
6H O 2
6CO 6O
mitochondrion
matrix (area enclosed
by inner membrane)
inner membrane
ATP
energy
energy from glycolysis 1 4 3
and
Electron Transport
water released as a waste product

23. There are two steps to cellular respiration:
Step 1 = Kreb’s Cycle
Occurs in the mitochondrial matrix
Uses (Reactant): Pyruvate (2 molecules of C3H6C3 = glucose split in half)
Produces (Product): Carbon dioxide
Produces a small amount of ATP (2 ATP)
Step 2 = Electron Transfer Chain
Occurs in the inner membrane of the mitochondria
Uses (Reactant): Oxygen
Produces (Product): Water
Produces a large amount of ATP (32-34 ATP)
Cellular respiration takes place in the mitochondria of plants, animals, protists, and fungi!!! Why doesn’t it happen in bacteria???

24. The equation for the overall process is:
C6H12O6 + 6O2  6CO2 + 6H2O + 36 ATP
The reactants in photosynthesis are the same as the products of cellular respiration.

25. KEY CONCEPT Fermentation occurs in place of cellular respiration when oxygen is NOT present.

26. Fermentation allows glycolysis to continue.
Fermentation is an anaerobic process.
occurs when oxygen is not available for cellular respiration
does not produce ATP, but allows glycolysis to continue so it can make a small amount of ATP.

27. There are two types of fermentation: Lactic Acid and Alcoholic
Lactic acid fermentation occurs in muscle cells.
glycolysis splits glucose into two pyruvate molecules
pyruvate is converted into lactic acid
Lactic acid causes soreness in muscles

28. Alcoholic fermentation is similar to lactic acid fermentation.
glycolysis splits glucose into two pyruvate molecules
pyruvate is converted into alcohol and carbon dioxide
alcoholic fermentation takes place in yeast and some plants

29. Fermentation is used in food production.
yogurt
cheese
bread