1. Energy for Living Systems

2. Energy Ability to do work Types of energy Potential Energy
Energy of position  
For living organisms, potential energy is stored in chemical bonds  
Kinetic Energy 
Energy of motion  
Breaking of chemical bonds in various life processes.  
Activation Energy  
Energy necessary to trigger a chemical reaction  
Lighted match held to a piece of paper

3. Energy All living things require energy.
Necessary for carrying out all life processes - building, repairing, growing, and reproducing.  
Energy comes from food (glucose)  
Energy is stored in glucose bonds - potential energy  
No organism can make energy - comes from the sun.  
Law of Conservation of Energy -
Energy can be neither created nor destroyed, but can only be changed from one form to another.  

4. Energy
Organisms divided into 2 groups according to the way they get their food.  
Autotrophs –
organisms that can combine inorganic molecules into organic molecules for use as food; make their own food  
Heterotrophs -
organisms that don't make their own food but depend directly on other organisms for food.  

5. Energy Energy is not recycled, matter is recycled
Energy available for use decreases with each transformation  
Some of the energy used to break bonds and some is lost as heat.  
New energy must be constantly supplied - must come from sunlight.  
Materials used in producing new molecules can be reused.  

6. Energy Energy processes of living organisms Photosynthesis
Process in which carbon dioxide and water is used to form glucose.  
Requires light energy from the sun.  
Takes place in the presence of chlorophyll.  
Respiration  
Process in which glucose molecule is broken down and chemical energy it contains is released.  
Carbon dioxide and water released.  
Performed by all cells - releases energy of food

7. Adenosine Triphosphate
Usable energy from by one reaction may be stored by another molecule and used in a later reaction.  
Many times the storage molecule for the released energy is ATP.  

8. Adenosine Triphosphate
Composed of 3 parts  
Adenine - a nitrogen base  
Ribose - a 5-carbon sugar  
Three (3) phosphate groups  
Adenine joins with ribose to form adenosine
Phosphate groups attach in sequence to adenosine  
Adenosine monophosphate - AMP - 1 phosphate group  
Adenosine diphosphate - ADP - 2 phosphate groups  
Adenosine triphosphate - ATP - 3 phosphate groups

9. Adenosine Triphosphate

10. Adenosine Triphosphate
High energy bonds form between the phosphate groups - indicated by a wavy line (~)  
Requires a great deal of energy to form bond.
Energy is released when bond is broken.  
ATP - A - P ~ P ~ P  
ADP - A - P ~ P  

11. Adenosine Triphosphate
Normally reaction is cyclic - moves between ADP and ATP Controls the cell's production through cycle of energy storage and release. ADP + P + energy ---> ATP - energy is stored ATP ---> ADP + P + energy - energy is released Normally cell does not use ADP as energy source; ADP not converted to AMP

12. Photosynthesis
Process by which green plants convert the sun's light energy into chemical energy stored as food in the form of glucose.  
Photo - means "light"  
Synthesis - means "to build a complex substance from simple substances"  

13. Photosynthesis Raw materials - the reactants of the reaction
Carbon dioxide - CO2  
Water - H2O  
Light energy

14. Photosynthesis
Products
Glucose - C6H12O6  
Oxygen - O2  
Water - H2O

15. Photosynthesis Chlorophyll is necessary
Acts as a catalyst - causes the reaction to move forward.
Pigment in green plants that gives them their color  
Primary light absorbing pigment of green plants.  

16. Photosynthesis
Represented by the following reaction: chlorophyll 6 CO H2O + light > C6H12O6 + 6 O2 + 6 H2O

17. Photosynthesis
Process is series of reactions that change reactants to the products - divided into 2 main reactions  
Light Reactions - require light energy  
Dark Reactions - Do not require light energy

18. Light
Sunlight is white light; mixture of different wavelengths of light  
Each wavelength of light has a characteristic color -  
Colors that make up white light can be separated by prism to produce the visible part of the spectrum
- ROYGBIV –
Red, Orange, Yellow, Green, Blue, Indigo, Violet  
Shorter the wavelength of light, the more energy it has
Blue – shorter wavelengths; more energy
Red – longer wavelengths; less energy

19. Light

20. Light
Objects appear to be a certain color because they transmit or reflect light of that color.  
Colors absorbed by an object are not seen  
Color of object is the wavelength of light that is reflected or transmitted by the object.  
Plants appear green because they reflect green light and absorb other colors of light.  

21. Light Absorption by Green Plants

22. Plant Pigments
Primary pigment in plants that absorbs light energy is chlorophyll  
Green in color - reflects green wavelengths  
Absorbs mainly red and blue wavelengths of light  
Act as catalysts to speed the reaction of photosynthesis.  
Types  
Chlorophyll a
Chlorophyll b
Chlorophyll c
Chlorophyll d
Bacteriochlorophyll  

23. Plant Pigments
Accessory Pigments - may be used to transfer some energy to chlorophyll
Types
Carotenoids - yellow, brown and orange pigments of plants
Carotene
Xanthophyll
Phycobilins - accessory pigments of red algae and blue-green bacteria
Not normally visible in tree leaves - masked by chlorophyll; appear when chlorophyll production ceases  

24. Chloroplasts Organelle in plant cells where photosynthesis occurs.
Contain the Chlorophyll pigment.  
Structure  
Grana - tiny stacked structures in the chloroplasts  
Contains the chlorophyll  
Also contains the accessory pigments.  
Site of light reactions  
Stroma - protein-rich solution around the grana  
Site of dark reaction  

25. Chloroplasts

26. Light Reactions Chlorophyll traps the light energy
Causes chlorophyll molecules to become energized; electrons released from molecule  
Two different photosystems active in photosynthesis  
Photosystem I  
Photosystem II  
Water molecules are split and oxygen is released.  
Energy is stored in ATP and NADPH2 (electron acceptor)  
Both used in the Dark Reactions  
Supply the energy for the Dark Reactions  

27. Light Reactions

28. Dark Reactions
Light is not required; energy comes from ATP and NADPH2; Called the Calvin cycle
Carbon dioxide bonds to 5-carbon sugar called ribulose diphosphate, RuDP - forms unstable 6-carbon compound
6-carbon compound immediately breaks down into two 3-carbon molecule of phosphoglyceric acid, PGA.
Each PGA reacts with hydrogen atoms in NADPH2 to produce 3-carbon molecule of phosphoglyceraldehyde, PGAL, water reformed
Two molecules of PGAL combine to produce glucose molecule.
Some PGAL used to reform RuDP.

29. Dark Reactions

30. Respiration
Process in which cells take energy, stored in chemical bonds of food and incorporates it into chemical bonds of ATP
Occurs in the mitochondria  
Series of chemical reactions  

31. Respiration
Reactants
Glucose - C6H12O6  
Oxygen - O2

32. Respiration Products Carbon dioxide - CO2 Water - H2O
Carbon dioxide - CO2  
Water - H2O  
ATP - adenosine triphosphate  

33. Respiration
Overall equation of cellular respiration (aerobic) enzymes C6H12O6 + 6 O > 6 CO2 + 6 H2O + 36 ATP

34. Respiration Types Anaerobic Respiration - doesn't require oxygen
Anaerobic Respiration - doesn't require oxygen  
Aerobic Respiration - requires oxygen  

35. Stages of Aerobic Respiration
Glycolysis - Anaerobic
Kreb’s (Citric Acid)Cycle - Aerobic
Electron Transport Chain - Aerobic

36. Glycolysis First stage of respiration; occurs outside the mitochondria
Does not require oxygen.
Glucose breaks down into two 3-carbon molecules of pyruvic acid
Requires 2 molecules of ATP to supply activation energy
Produces 4 molecules of ATP; net gain of 2 ATP's
Pyruvic acid can go in two directions - depends on of organism type and oxygen availability
Aerobic respiration - oxygen required
Anaerobic respiration - oxygen not needed

37. Glycolysis

38. Transition to Aerobic Respiration

39. Aerobic Phases Divided into two major reactions
Citric acid cycle (Krebs Cycle)  
Electron Transport Chain

40. Citric Acid Cycle
Pyruvic acid loses a carbon dioxide forms 2-carbon molecule that enters cycle.  
Process takes place in the mitochondria  
Hydrogen atoms released during the cycle - will carry electrons to the next reactions
2 molecules of ATP are produced  

41. Citric Acid Cycle

42. Electron Transport Chain
Involves a series of electron acceptors  
Accepts electrons and H ions from NADH &FADH 
24 hydrogen atoms produce 24 electrons and 24 hydrogen ions form 12 pairs of hydrogen ions and 12 pairs of electrons  
Near end of chain 12 molecules of hydrogen bond with 6 oxygen molecules to produce 12 molecules of water.  
32 molecules of ATP produced  

43. Electron Transport Chain

44. Summary of ATP Production In Aerobic Respiration
Glycolysis ATP  
Citric Acid Cycle ATP  
Electron Transport 32 ATP
Total ATP  

45. Anaerobic Repiration
Occurs when cell obtains energy from breakdown of food molecules in the absence of oxygen  
Also known as Fermentation
First step similar to aerobic respiration - glucose converted to pyruvic acid - glycolysis  
Types of Fermentation  
Alcoholic Fermentation  
Lactic Acid Fermentation

46. Alcoholic Fermentation
Pyruvic acid is converted to ethyl alcohol
Most of the energy is still stored in the alcohol.
Summary equation:
enzymes
C6H12O > 2 C2H5OH + 2 CO2 + 2 ATP
Industries that depend on alcoholic fermentation  
Baking - carbon dioxide; makes bread rise.  
Brewing - ethyl alcohol in alcoholic beverages

47. Alcoholic Fermentation

48. Lactic Acid Fermentation
Occurs in muscle tissue especially during heavy exercise  
Blood can't bring oxygen fast enough; lactic acid builds up causing soreness (cramps); muscles go into oxygen debt.  
Summary equation:  
enzymes  
C6H12O > 2 CH3CHOHCOOH + 2 ATP  

49. Lactic Acid Fermentation