1. Energy in a Cell

2. Terms
Autotroph
creates their own food through photosynthesis or chemosynthesis These organisms are producers.
Heterotroph
depends upon other organisms for nutrition. These organisms are consumers. Some organisms, such as the Euglena, will be photosynthetic in the presence of light and heterotrophic without light.
Chemosynthetic
Organisms that obtain cellular energy by breaking down inorganic chemicals

3. Energy Carriers ATP temporary energy storage molecule in all cells
NADH
H+ and e- carrier molecule
NAD + + H+ + e NADH
FADH2
FAD + 2H+ + e FADH2
Think of NADH and FADH2 as taxi cabs!

4. NADH and FADH2

5. All Cells Need Energy Cells need energy to do a variety of work:
Making new molecules
Building membranes and organelles
Moving molecules in and out of the cell
Movement

6. Where Does A Cell Get Energy?
Food is broken down to a form the cell can use.
Extra energy is stored in an ATP molecule, a nucleotide.

7. What Is ATP?
ATP – adenosine triphosphate is a molecule made up of an adenine, ribose, and 3 phosphate groups.
Adenine
Ribose
phosphate groups

8. A Simple Review
Adenine
Ribose P
What basic unit of what organic compound is pictured to the right?

9. How Does ATP Work?
Energy is stored in the bond between the second and third phosphate group.
When the bond is broken, energy is released and ADP is formed.
Adenine
Ribose

10. ATP – Energy Currency
Within a cell, formation of ATP from ADP and phosphate occurs over and over, storing energy each time.
As the cell uses energy, ATP breaks down repeatedly to release energy and form ADP and phosphate.

11. Making Energy Cells make energy in two ways:
Photosynthesis – takes place in the chloroplasts.
Respiration – takes place in the mitochondria.

12. Photosynthesis
Autotrophs make their own food by trapping light energy and converting it to chemical energy (carbohydrates).

13. Photosynthesis
Using light from the sun, plants combine water and carbon dioxide to make sugar .
General Equation:
6CO2 + 12H2O C6H12O6 + 6O2 + 6 H2O
Reactants Products
light

14. Chemosynthesis
Some autotrophs can convert inorganic substances to energy.
Most are adapted to live in conditions where there is no oxygen.
Marshes
Lake sediments
Digestive tracts of mammals
Deep in the ocean

15. This is a Black Smoker in the Pacific
This is a Black Smoker in the Pacific. A tubular hydrothermal vent that releases hot water,
known as a "black smoker", in the Pacific Ocean.

16. Cellular Respiration
The process of breaking down food molecules to release energy.
Aerobic respiration occurs in the mitochondria.
Two types:
Aerobic – requires oxygen.
Anaerobic – requires an absence of oxygen.

17. Cellular Respiration – Chemical Equation
enzymes
C6H12O O _ CO2 + _ H2O ATP

19. Cellular Respiration Cellular Respiration Steps Glycolysis
Citric Acid Cycle
Electron Transport Chain

20. Glycolysis Chemical Equation
Glucose is split to form pyruvate.
Takes place in the cytoplasm of the cell.
ATP and NADH are byproducts.
Glycolysis Chemical Equation
Glucose + 2 NAD+ + 2 ADP + 2 Pi
2 pyruvate + 2 NADH + 2 ATP + 2 H2O
Enzymes

21. Glycolysis
C6H12O6
NAD+
2 ATP
NADH
C3H3O4 +

22. 2 ATP C6H12O6 (6 carbon molecule) 2 NAD+ (coenzyme) 2 ADP+P
Review
What are the inputs for Glycolysis?
Glucose
2 ATP C6H12O6 (6 carbon molecule) 2 NAD+ (coenzyme) 2 ADP+P
What are the outputs for Glycolysis?
2 pyruvic acid (3 carbon molecules) 2 NADH 2 ATP (makes 4 but 2 are needed in the process)

23. Anaerobic Respiration
Two types of anaerobic respiration:
Fermentation
Occurs when bacteria break down plants (vegetables and fruit) and release alcohol or vinegar.
Lactic Acid Fermentation Occurs in muscles – a buildup of lactic acid causes soreness.

24. Aerobic Respiration 2. Citric Acid Cycle A.K.A. Kreb’s Cycle
Pyruvate is used to build citric acid (a carbon compound), which is broken down to release ATP. (# Net 2 ATP)
Takes place in the cristae (the folded membrane in the mitochondrion)
CO2 is released, and NADH & FADH2 carry electrons and hydrogen ions to the electron transport chain.
Each glucose molecule takes two trips around the cycle!

25. Each glucose molecule takes 2 turns through the cycle!
Inputs
Pyruvate
NAD+
FAD
ADP + Pi
Outputs
4 NADH
1 FADH2
1 ATP
3 CO2
Outputs
8 NADH
2 FADH2
2 ATP
6 CO2

26. 3. Electron Transport Chain
Electrons are reduced, and that energy forms large amounts of ATP. (#32-34 ATP)
Takes place in the inner membrane of the mitochondrion
The used ions are combined with oxygen to form H2O.

27. Electron Transport System
NADH
H2O
NAD+ O2
FADH2
FAD
36-38 ATP

29. Review What are the inputs for the Krebs cycle?
1 Pyruvate (3 carbon molecule)
4 NAD+
1 FAD
1 ADP + Pi
What are the outputs for the Krebs cycle?
(Per 1 pyruvate – 1 glucose yields 2X)
4 NADH
1 FADH2
1 ATP
3 CO2

30. Review What are the inputs for the ETS per one molecule of glucose?
10 NADH: 8 from Krebs, 2 from glycolysis
2 FADH2 : from Krebs cycle O2
What are the outputs for the ETS?
32-24 ATP molecules
H2O

31. Total ATP Production 36 -38 ATP molecules
enzymes
C6H12O O CO2 + 6 H2O ATP

32. Heat O2 ATP H2O CO2 Glucose ATP Pyruvate MITOCHONDRION Electron
Transport
System O2
ATP
H2O
NAD+
FAD
NADH
FADH2
CO2
citric acid
cycle
Glucose
ATP
Pyruvate
ATP
MITOCHONDRION

33. CHLOROPLAST MITOCHONDRION
Sunlight
Heat O2
Photo-
system II
Photo-
System I
Electron
Transport
System
ATP
H2O
ATP
NADH
FADH2
NADP+
ADP
NADPH
NAD+
FAD
CO2
Calvin
Citric
Acid
Cycle
ATP
Glycolysis
Cycle
ATP
Glucose
Pyruvate
CHLOROPLAST
MITOCHONDRION

35. CHLOROPLAST MITOCHONDRION
Sunlight
Photo-
System I
system II
NADP+
ADP
NADPH
ATP
Cycle
Calvin
CO2
H2O O2
NAD+
FAD
NADH
FADH2
Electron
Transport
Heat
CHLOROPLAST
MITOCHONDRION
Glucose
Pyruvate
Glycolysis
Citric
Acid
Cycle

36. Cellular Respiration
C6H12O O CO2 + H2O ATP 6 6 6

37. Oxidation - Reduction
Oxidation is the loss of elecrons from an atom or molecule. It is also the loss (removal) of hydrogen atoms from a molecule. A loss of energy is associated with the loss of electrons or hydrogen atoms.
Reduction is the gain of electrons or the gain of hydrogen atoms. This process stores energy.

38. Oxidation - Reduction
Oxidation and reduction occur together. When a atom or molecule is oxidized, another must be reduced.
Example: Na + Cl ®  Na+Cl-  - The Na is oxidized; the Cl is reduced.