1. Photosynthesis & Respiration

2. (Photosynthesis and Respiration)
Cell Energy
(Photosynthesis and Respiration)
Energy:
Energy for living things comes from food. Originally, the energy in food comes from the sun.

3. Organisms that use light energy from the sun to produce food—autotrophs (auto = self)
Ex: plants and some microorganisms (some bacteria and protists)

4. Organisms that CANNOT use the sun’s energy to make food—heterotrophs - must eat their food
Ex: animals and most microorganisms

5. Cells usable source of energy is called ATP
Cell Energy:
Cells usable source of energy is called ATP
ATP stands for adenosine triphosphate
Adenine
Ribose
3 Phosphate groups

6. ADP stands for adenosine diphosphate
Adenine
Ribose
2 Phosphate groups

7. All energy is stored in the bonds of compounds—breaking the bond releases the energy
When the cell has energy available it can store this energy by adding a phosphate group to ADP, producing ATP

8. ATP is converted into ADP by breaking the bond between the second and third phosphate groups and releasing energy for cellular processes.

9. Importance of ATP! 1. ALL organisms release ATP from the break down of
glucose during cellular respiration
2. ATP powers the activities of the cell and allows living things to do work
3. ATP/ADP is a cycle that releases/stores energy for cell processes
4. ATP is used to actively transport material across the cell membrane

10. Photosynthesis
Photosynthesis is the process by which the energy of sunlight is converted into the chemical energy of glucose

11. Photosynthesis occurs in the chloroplasts of plants

12. Light absorbing compound is a pigment
pigments absorb some wavelengths of light and reflect others
the color our eyes see is the color that the pigment reflects

13. Chlorophyll is the pigment inside the chloroplast the absorbs light for photosynthesis
As the chlorophyll in leaves decays in the autumn, the green color fades and is replaced by the oranges and reds of carotenoids.

14. General formula for photosynthesis:
sunlight
carbon dioxide + water —> glucose + oxygen
sunlight
6CO H2O —> C6H12O O2

15. Light Reaction Takes place in the thylakoid membrane
(contains chlorophyll)
Reactants needed for the light reaction:
Water, Light, ADP, NADP+
Products made from light reaction and USED in dark
reaction:
ATP energy to make sugar
NADPH supplies e- and H to make C6H12O6
Oxygen is released into the air

16. Dark Reaction (Calvin Cycle)
Takes place in the stroma
Reactants needed for the dark reaction:
CO2, ATP, NADPH
Products made from the dark reaction USED in light reaction are:
ADP returns to the light reaction to make more ATP
NADP returns to the light reaction to pick up more electrons and Hydrogens
Glucose is made in the dark reaction for use throughout the organism.

17. Summary: Light Reaction
H2O is broken down and light energy is stored temporarily in ATP and NADPH.
Oxygen released.
Calvin Cycle (Dark Reaction)
energy is transferred from ATP and NADPH to the organic compound glucose

18. Location
Reactants
Products
Release
Light Reaction
Thylakoid
H2O
Light
ADP and NADP from dark reaction
ATP – energy to make sugar
NADPH – electrons and Hydrogen to make glucose
O2 to the air
Dark Reaction – Calvin Cycle
Stroma
CO2
ATP and NADPH from light reaction
ADP and NADP back to light reaction
GLUCOSE

19. Reactants Products Light H2O CO2 O2 C6H12O6 Glucose Chloroplast
Dependent Reaction
Calvin Cycle
NADP
ADP + P
ATP
NADPH
Diagram

20. Cellular Respiration
Process where energy of glucose is released in the cell to be used for life processes (movement, breathing, blood circulation, etc…)

21. Respiration occurs in ALL cells
Takes place in the mitochondria
Can take place either with or without oxygen present.

22. occurs in the mitochondria
Aerobic Respiration
requires oxygen
occurs in the mitochondria
Net total of 36 ATP produced
Formula
C6H12O O CO H2O + 36 ATP
glucose + oxygen carbon dioxide + water + energy
Human cells contain a specialized structure – the mitochondrion – that generates energy.

23. STEP 1: Glycolysis
First pathway of respiration - ALL organisms perform this (aerobic AND anaerobic)
Takes place in the cytoplasm on enzymes
Splits glucose in half to form 2 pyruvic acid (pyruvate)
Gives off enough energy to make 2 ATP

24. STEP 3: Electron Transport Chain
STEP 2: Krebs Cycle
Also called the Citric Acid Cycle
pyruvic acid is broken down and CO2 is released
Occurs in matrix of mitochondria
STEP 3: Electron Transport Chain
electrons from Krebs Cycle converts ADP into ATP
Occurs along inner membrane (cristae) of mitochondria

25. Electron Transport Chain
Diagram - Cellular Respiration
Glucose
Glycolysis
Electron Transport Chain 2
Krebs Cycle
Mitochondria
In Cytoplasm 32
Electrons carried in NADH
electrons carried in NADH

26. Summary:
3 steps:
1st glycolysis
2nd Krebs cycle
3rd Electron Transport Chain (ETC)

27. Anaerobic Respiration or Fermentation:
pathway organisms use when no oxygen is available to the cell
Mostly unicellular organisms (low energy requirement)
Much less ATP produced than in aerobic respiration
Goes through glycolysis first, which makes 2 ATP
2 kinds: Lactic Acid and Alcoholic
Animals &
some Bacteria
Lactic acid
Glycolysis
2 Pyruvate + 2 ATP
Glucose
Bacteria & Yeast
Ethyl alcohol + CO2

28. Lactic Acid Fermentation
pyruvic acid lactic acid
-Performed by muscle cells (animals)
-Lactic acid is produced in the muscles during rapid exercise, when the body cannot supply enough oxygen to the tissues
-causes a burning sensation in muscles
-Also occurs in some bacteria
-Used to create food products like yogurt and cheese

29. Pyruvic acid ethyl alcohol + carbon dioxide
Alcohol fermentation
Pyruvic acid ethyl alcohol + carbon dioxide
occurs in bacteria and yeast
Process used by baking and brewing industry
yeast produces CO2 gas during fermentation to make dough rise and gives bread its holes

30. Cellular Respiration Diagram
glycolysis
Anaerobic Respiration
Alcoholic fermentation
Bacteria, Yeast 2 ATP
Lactic acid fermentation
Muscle cells ATP
Aerobic Respiration
36 ATP
ETC
Mitochondria
Krebs Cycle
Cytoplasm
C6H12O6
glucose

31. Photosynthesis and Respiration
Products of one reaction are the Reactants of the other (and vice versa)
CYCLE!

32. Cells require a constant source of energy for life processes, but keep only a small amount of ATP on hand. Cells can make more ATP by using the energy stored in foods, like glucose.
The energy stored in glucose by photosynthesis is released by cellular respiration and repackaged into the energy of ATP.

33. Ecological Level
Energy Flow: Producers photosynthesize and provide glucose for consumers
Carbon Cycle: Producers remove CO2 from atmosphere while consumer replaces CO2 during respiration
Water Cycle: Producers take water out of ecosystem and consumers produce water during respiration (also O2 removed by producer and returned by consumer)