1. Photosynthesis and Cellular Respiration
Chapter 5

2. Autotrophs Energy and Living Things I. Energy in Living Systems
Autotrophs make their own food by using energy from sunlight or inorganic substances to build organic compounds.
Many autotrophs make food by the process of photosynthesis.
Autotrophs can use the sun’s energy directly
Euglena

3. Heterotrophs Energy and Living Things I. Energy in Living Systems
C. Breaking Down Food for Energy: Energy from sunlight flows through living systems, from autotrophs to heterotrophs.
D. Heterotrophs release the energy in food through the process of cellular respiration.
E. Heterotrophs are organisms that can NOT make their own food
F. Heterotrophs can NOT directly use the sun’s energy 3 3

4. Energy and Living Things
II. ATP
ATP supplies cells with energy needed for metabolism. Energy is released upon the breakdown of ATP to ADP.
ATP Consists of:
1. Adenine(amino acid)
2. Ribose(sugar)
3. 3 phosphates (Triphosphates)
Adenosine 5

5. It supplies YOU with ENERGY!
What Does ATP Do for You?
It supplies YOU with ENERGY! 5

6. How Do We Get Energy From ATP?
By breaking the high- energy bonds between the last two phosphates in ATP 6

7. Releasing Energy From ATP
A. Adding A Phosphate Group To ADP stores Energy in ATP
B. Removing A Phosphate Group From ATP Releases Energy & forms ADP
Loose
Gain 7 7

8. Photosynthesis
Involves the Use Of light Energy to convert Water (H20) and Carbon Dioxide (CO2) into Oxygen (O2) and High Energy Carbohydrates (sugars, e.g. Glucose) & Starches

9. Photosynthesis: It Begins with Sunlight!9 9

10. Photoautotrophs Absorb Light Energy10 10

11. The Photosynthesis Equation

12. Pigments
In addition to water, carbon dioxide, and light energy, photosynthesis requires Pigments
Chlorophyll is the primary light-absorbing pigment in autotrophs
Chlorophyll is found inside chloroplasts

13. Inside A Chloroplast 13 13

14. Structure of the Chloroplast
Double membrane organelle
Outer membrane smooth
Inner membrane forms stacks of connected sacs called thylakoids
Thylakoid stack is called the granun (grana-plural)
Gel-like material around grana called stroma 14 14

15. Photosynthesis III. Using the Energy in Sunlight
Photosynthesis has three stages:
Energy is captured from sunlight.
Energy is temporarily stored in ATP and NADPH.
3. Organic compounds are made using ATP, NADPH, and carbon dioxide.
6 CO H2OC6H12O6+6O2+6 H2O
Carbon dioxide + water  glucose +oxygen +water 7

16. Photosynthesis
1. Stage One: Absorption of Light Energy
A. Pigments, such as chlorophyll, absorb light energy during photosynthesis.
B. During photosynthesis, water molecules are split to release oxygen by an enzyme inside structures called thylakoids. 8

18. Photosynthesis 2. Stage Two: Conversion of Light Energy
A.Electrons excited by light travel through electron transport chains, in which ATP and NADPH are produced. 9

19. Photosynthesis 3. Stage Three: Storage of Energy
A. Through carbon dioxide fixation, often by the Calvin cycle, carbon dioxide in the atmosphere is used to make organic compounds, which store energy. 10

20. The Calvin Cycle
Step 1: In carbon dioxide fixation, each molecule of carbon dioxide, CO2 is added to a five-carbon compound by an enzyme.
Step 2: The resulting six-carbon compound splits into two three-carbon compounds. Phosphate groups from ATP and electrons from NADPH are added to the three-carbon compounds, forming three-carbon sugars.

21. The Calvin Cycle
Step 3: One of the resulting three-carbon sugars is used to make organic compounds-including starch and sucrose-in which energy is stored for later use by the organism.
Step 4: the other three-carbon sugars are used to regenerate the initial five-carbon compound, thereby completing the cycle.

22. Photosynthesis Overview22 22

23. Photosynthesis Overview23 23

24. Energy and Living Things
IV. Cellular Energy – Cellular Respiration
Cellular respiration releases much of the energy in food to make ATP, the energy “currency” inside cells.
C6H12O6 +6O2 +6 H2O 6 CO2 + 12H2O +36 ATP
Glucose+ oxygen+ water Carbon + water + ATP
gas dioxide 4

25. Cellular Respiration A. Cellular respiration has two stages:
Stage One: Glycolysis in the cytoplasm
Stage Two is either:
1. Aerobic respiration (in the presence of oxygen) - Kreb’s Cycle and Electron Transport Chain in the mitochondria
OR:
2. Anaerobic respiration (in the absence of oxygen). A large amount of ATP is made during aerobic respiration. NAD+ is recycled during the anaerobic process of fermentation. (2 types of fermentation) 12

27. Cellular Respiration 1. Stage One: Breakdown of Glucose
Glycolysis: Glucose is broken down to pyruvate during glycolysis, making some ATP.
Glycolysis produces 2 ATP’s and no oxygen is present for this step.
The Pyruvate then enters the mitochondria where it is broken down into 2 Acetyl-CoA (coenzyme or helper enzymes) 13

28. Cellular Respiration 2. Stage Two: Production of ATP
The Acetyl-CoA enters the Krebs cycle or Citric Acid Cycle. The cycle is a series of reactions that produce energy-storing molecules during aerobic respiration.
The total products of the Kreb’s cycle are:
24 Hydrogen (24H); 6 carbon dioxide (6CO2); 2 ATP’s
b. During aerobic respiration, large amounts of ATP are made in an electron transport chain. The total amount of ATP produced here are 32 ATP’s
A TOTAL of 36 ATP’s for the entire process 14

29. Cellular Respiration: Diagram of the Process
Occurs across Cristae of mitochondria
Occurs in Cytoplasm
Occurs in Matrix of Mitochondria 29

30. Cellular Respiration Fermentation in the Absence of Oxygen
When oxygen is not present, fermentation follows glycolysis, regenerating NAD+ needed for glycolysis to continue.
Two types of Fermentation:
1. lactic acid fermentation
2. alcoholic fermentation 15

31. Cellular Respiration Fermentation in the Absence of Oxygen contd.
In lactic acid fermentation, pyruvate is converted to lactate.
Lactate is what builds up in muscle cells and makes you sore.
Glucose  Lactic Acid Energy 16

32. Cellular Respiration Fermentation in the Absence of Oxygen contd.
In alcoholic fermentation, pyruvate is broken down to ethanol, releasing carbon dioxide.
Ethanol is a type of alcohol and is primarily done by yeast.
2. Although a small amount of ATP is made during fermentation, most of a cell’s ATP is made during aerobic respiration.
Glucose  Ethyl Alcohol +Carbon Dioxide +Energy 16

33. Cellular Respiration 16

34. Comparing: Photosynthesis & Cellular Respiration
Occurs in all cells & goes on with or without light
Releases energy from sugars
CO2 & H20 are products.
Glucose & 02 are raw materials ( reactants)
Photosynthesis
Occurs only in the presence of chlorophyll & light
Stores energy in sugars
CO2 & H2O are raw materials (reactants)
Glucose & O2 are products 16