1. Photosynthesis vs. Respiration

2. Free Energy – ∆𝐺= ∆𝐻 −𝑇∆𝑆
Enthalpy (heat of reaction) is the amount of energy released or absorbed during a chemical reaction
Symbol is ΔH
Think of it as energy needed
Entropy is a measure of randomness, tendency toward disorder
Symbol is ΔS
More disorder = more entropy
If reaction leads to more disorder, the entropy change (ΔS) is positive, if it becomes more ordered, ΔS is negative
Example: melting ice, condensing water, cleaning your room (+,-,-)
Temperature – T measured in K (273 + ºC)
Free Energy – spontaneity of a reaction
Spontaneous - ∆𝐺 is negative
Not spontaneous - ∆𝐺 is positive. Would be spontaneous if reversed.

3. Things in Common Both photosynthesis and respiration make ATP.
Both involve, CO2, oxygen, sugar (C6H12O6), and water (H2O)
Almost all cells go through respiration

4. ATP transfers energy from the breakdown of food molecules to cell functions.
Energy is released when a phosphate group is removed.
ADP is changed into ATP when a phosphate group is added.
phosphate removed

5. Organisms break down carbon-based molecules 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
tri=3
di=2

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. The light-dependent reactions capture energy from sunlight.
take place in thylakoids
water and sunlight are needed
chlorophyll absorbs energy
energy is transferred along thylakoid membrane then to light-independent reactions
oxygen is released

8. The light-independent reactions make sugars.
take place in stroma (fluid outside the thylakoids)
needs carbon dioxide from atmosphere
use energy to build a sugar in a cycle of chemical reactions

9. Photosystem II captures and transfers energy.
chlorophyll absorbs energy from sunlight
energized electrons enter electron transport chain
water molecules are split
oxygen is released as waste
hydrogen ions are transported across thylakoid membrane

10. Photosystem I captures energy and produces energy-carrying molecules.
chlorophyll absorbs energy from sunlight
energized electrons are used to make NADPH
NADPH is transferred to light-independent reactions

11. Summary of Light Dependent Reactions
Energy is captured from the sun.
Energy goes into electrons into the electron transport chain.
Water is broken down
H+ ions are transported and form NADPH
Flow of H+ ions through ATP synthase makes ATP
Electron Transport

12. Summary of Light Independent Reactions (Calvin Cycle)
CO2 enters cycle
ATP and NADPH from light-dependent transfer energy
1 3-carbon molecule made for every 3 CO2
2 3-carbon molecules bonded to make sugar
Products – 6-carbon sugar, NADP+, and ADP

13. A molecule of glucose is formed as it stores some of the energy captured from sunlight.
carbon dioxide molecules enter the Calvin cycle (this is what has sugar as an end product
energy is added and carbon molecules are rearranged
a high-energy three-carbon molecule leaves the cycle

14. two three-carbon molecules bond to form a sugar
A molecule of glucose is formed as it stores some of the energy captured from sunlight.
two three-carbon molecules bond to form a sugar
remaining molecules stay in the cycle

15. Cellular respiration makes ATP by breaking down sugars.
Cellular respiration is aerobic, or requires oxygen.
Aerobic stages take place in mitochondria.
mitochondrion
animal cell

16. Glycolysis must take place first.
anaerobic process (does not require oxygen)
takes place in cytoplasm
splits glucose into two three-carbon molecules
produces two ATP molecules

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

18. energy from glycolysis
The electron transport chain produces a large amount of ATP.
takes place in inner membrane
energy transferred to electron transport chain
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

19. The Krebs cycle is the first main part of cellular respiration.
Pyruvate is broken down before the Krebs cycle.
carbon dioxide released
NADH produced
coenzyme A (CoA) bonds to two-carbon molecule

20. The Krebs cycle produces energy-carrying molecules.

21. The electron transport chain is the second main part of cellular respiration.
The electron transport chain uses NADH and FADH2 to make ATP.
high-energy electrons enter electron transport chain
energy is used to transport hydrogen ions across the inner membrane
hydrogen ions flow through a channel in the membrane

22. The electron transport chain is the second main part of cellular respiration.
The electron transport chain uses NADH and FADH2 to make ATP.
The breakdown of one glucose molecule produces up to 36 molecules of ATP. (2 from glycolysis, 2 from Kreb, 32 from ETC)
ATP synthase produces ATP
oxygen picks up electrons and hydrogen ions
water is released as a waste product

23. ATP Products of Cellular Respiration including glycolysis
Glycolysis – uses 2 ATP and make 4 ATP. Net gain of 2 ATP
Kreb Cycle – 2 ATP, 8 NADH, 2 FADH2
Electron Transport Chain – 32ATP
Net gain – 36 ATP for every glucose molecule.

24. Comparison of Photosynthesis & Cellular Respiration
Organelle for process
Chloroplast
Mitochondrion
Reactants
CO2 and H2O
Sugars (C6H12O6) and O2
Cycle of chemical reactions
Calvin cycle in stroma of chloroplasts builds sugar molecules
Krebs cycle in matrix of mitochondria breaks down carbon-based molecules
Electron Transport Chain
Proteins within thylakoid membrane
Proteins within inner mitochondrial membrane
Products

25. Fermentation allows glycolysis to continue when oxygen is unavailable.
Fermentation is an anaerobic process.
occurs when oxygen is not available for cellular respiration
does not produce ATP

26. Fermentation allows glycolysis to continue making ATP when oxygen is unavailable.
NAD+ is recycled to glycolysis
Lactic acid fermentation occurs in muscle cells.
glycolysis splits glucose into two pyruvate molecules
pyruvate and NADH enter fermentation
energy from NADH converts pyruvate into lactic acid
NADH is changed back into NAD+

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

28. Project
In teams of 2, students will create a visual representation (e.g., poster or PowerPoint) to explain the interdependent relationships of cellular respiration and photosynthesis, and how the processes of cellular respiration and photosynthesis affect a runner in a marathon race.
Students should use few words and focus on using graphics to represent the cyclic processes. Visual representations will be peer and teacher reviewed.