1. Chapter 4
Cells and Energy

2. 4.1 Chemical Energy and ATP

3. ATP All cells need chemical energy.
Molecules in food store chemical energy in their bonds.
When bonds in food you consume are broken, the energy released is used to make ATP.
ATP is the chemical energy used by cells.
Starch molecule
Glucose molecule

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

5.
What special kind of chemical is used by cells to store and transport ENERGY???
ATP
Image by: Riedell

6. How Cells Obtain Energy
Stop to 3:20

7. PHOTOSYNTHESIS EQUATION
Plants make their own food through the process of photosynthesis.
PHOTOSYNTHESIS EQUATION
6 CO2 + 6 H2O+ sunlight  C6H12O6 + 6 O2
6 carbon dioxide + 6 water + sunlight  glucose + 6 oxygen

8. Photosynthesis vs. Chemosynthesis
In photosynthesis, light energy is used to make sugars.
In chemosynthesis, chemical energy is used to make sugars.
Due to no sunlight
Without it, there would be no life at the bottom of the sea.

9. 4.2 Overview of Photosynthesis

10. Producers/Autotrophs
Producers make their own food (sugars).
Plants use photosynthesis.
Photosynthesis captures energy from sunlight to make sugars.

11. Consumers/heterotrophs
Consumers cannot make their own food.
Obtain food by feeding on other organisms.

12. Photosynthesis
chloroplast
stroma
grana (thylakoids)
Photosynthesis takes place in two parts of chloroplasts.
1) Thylakoid: disk-shaped sac
- grana (a stack of thylakoids)
2) Stroma: thick fluid inside the chloroplast

13. PHOTOSYNTHESIS EQUATION
6 CO2 + 6 H2O+ sunlight  C6H12O6 + 6 O2
6 carbon dioxide + 6 water + sunlight  glucose + 6 oxygen
Occurs in two main stages:
1. Light reactions (Light-Dependent)
2. Calvin cycle (Light-Independent)

14. Stage 1: The light-dependent reactions
Where? Thylakoid membrane
Reactants: water & sunlight
Water (H2O) broken apart  Oxygen (released)& H+
Products: Oxygen, H+, & ATP
Oxygen
Light & Water
1. Light-Dependent Reaction
(thylakoid membrane)
ATP H+

15. Stage 2: The light-independent reactions (AKA Calvin cycle)
Where? stroma
Reactants: carbon dioxide, ATP, & H+
Products: sugars (Glucose)
ATP H+
C6H12O6
Carbon Dioxide
2.Light-Independent Reactions
Calvin Cycle
(stroma)

16. 6 CO2 + 6 H2O+ sunlight  C6H12O6 + 6 O2
6 carbon dioxide + 6 water + sunlight  glucose + 6 oxygen
C6H12O6
granum (stack
of thylakoids)
thylakoid
sunlight
1 six-carbon
sugar
6H2 O
6CO2
6O2
chloroplast 1 2 4 3
energy
stroma (fluid outside
the thylakoids)
Light-dependent reactions
Light-independent reactions

17. 2.Light-Independent Reactions
PHOTOSYNTHESIS
Oxygen
Light & Water
1. Light-Dependent Reaction
(thylakoid membrane)
ATP
& H+
Carbon Dioxide
C6H12O6
2.Light-Independent Reactions
Calvin Cycle
(stroma)

18. The simple story of photosynthesis and food

19. Photosynthesis

20. Detailed Photosynthesis Video
Watch it, if interested

21. What you need to know about the light reactions
Stage ONE
Gets energy from light & makes Oxygen
Occur on thylakoid membranes
Reactants: H2O, light
End products: O2, H+ ions, ATP
Oxygen
Light & Water
1. Light-Dependent Reaction
(thylakoid membrane)
ATP H+

22. What you need to know about the light reactions
Destination of end products:
ATP and H+ ions go to stroma (Calvin cycle)
O2 released into the atmosphere as waste product
Oxygen
Light & Water
1. Light-Dependent Reaction
(thylakoid membrane)
ATP H+

23. What you need to know about the Calvin cycle
Stage Two
Takes in CO2 and makes Glucose (sugar)
Occurs in the stroma
Reactants: H+ ions, ATP, CO2
Product: glucose (C6H12O6)
ATP H+
C6H12O6
Carbon Dioxide
2. Light-Independent Reactions
Calvin Cycle
(stroma)

24. What you need to know about the Calvin cycle
Where do the reactants come from?
CO2  from atmosphere
H+ ions & ATP  from light reactions
ATP H+
C6H12O6
Carbon Dioxide
2. Light-Independent Reactions
Calvin Cycle
(stroma)

25. 4.4 Overview of Cellular Respiration

26. Photosynthesis & Cellular Respiration
Cellular respiration is like a mirror image of Photosynthesis.
Photosynthesis Equation:
6CO H2O + sunlight  C6H12O O2
6 Carbon Dioxide + 6 Water + sunlight  Glucose Oxygen
Cellular Respiration Equation:
C6H12O O2  6 CO H2O + ATP
Glucose + 6 Oxygen  6 Carbon Dioxide + 6 Water + Energy

27. Cellular respiration
Cellular respiration makes ATP by breaking down sugars
All organisms use cellular respiration for their energy needs
It occurs in 2 places:
cytoplasm
mitochondria
mitochondrion
matrix
inner membrane 1 2 4
cytoplasm

28. 3 stages of Cellular respiration
1) Glycolysis – anaerobic (does not require oxygen)
2) The Krebs cycle – aerobic (requires oxygen)
3) The electron transport chain - aerobic(requires oxygen)

29. Stage 1: Glycolysis anaerobic process (does not require oxygen)
Glucose
anaerobic process (does not require oxygen)
takes place in cytoplasm
requires 2 ATP
splits glucose into two three-carbon molecules
produces 2 ATP molecules
mitochondrion
matrix
inner membrane 1 2 4
cytoplasm

30. Stage 2: The Krebs Cycle aerobic process – requires oxygen
takes place in mitochondrial matrix
breaks down three-carbon molecules from glycolysis
makes 2 ATP molecules
releases CO2
mitochondrion
matrix
inner membrane 1 2 4 O2
ATP & CO2
cytoplasm

31. Stage 3: The Electron Transport Chain
aerobic process – requires oxygen
takes place in inner mitochondrial membrane
34 ATP produced
water released as a waste product
mitochondrion
matrix
inner membrane 1 2 4
cytoplasm O2
H2O & ATP

32. Total: 38 ATP per 1 Glucose molecule
At the end of cellular respiration, the breakdown of one glucose molecule produces up to 38 molecules of ATP.
1) Glycolysis ATP
2) Krebs Cycle 2 ATP
3) ETC ATP
Total: ATP per 1 Glucose molecule

33. Cellular respiration
C6H12O6 + 6O2  6CO2 + 6H2O + ATP
The reactants in photosynthesis are the same as the products of cellular respiration.

34. Cellular respiration 1. Glycolysis Glucose & 2 ATP (cytoplasm) 2 ATP
2 3C-molecule
2 ATP & CO2
Oxygen
2. Krebs Cycle
(mitochondrial matrix)
electrons
34 ATP & water
Oxygen
3. Electron Transport Chain
(Inner mitochondrial membrane)

35. How Cells Obtain Energy
3:20 – 8:22

36. 4.6 Fermentation

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

38. Lactic acid fermentation
Occurs in muscle cells.
Waste product in muscle cells of animals from exercise.
Causes soreness and fatigue in muscles
Glucose
Happens in bacteria, plants, and animals
NO OXYGEN
Lactic Acid

39. Alcoholic Fermentation
Fermenting of sugar
Occurs in microorganisms (yeast) and plants producing ethyl alcohol.
Used to make cheese and yogurt from milk
Used in bread making and alcohol products
Glucose
Happens in yeast
NO OXYGEN
Alcohol + CO2

40. Cellular Respiration Analogy