1. PHOTOSYNTHESIS AND CELLULAR RESPIRATION
Chap 5
Section 1

2. ENERGY AND LIVING THINGS
Metabolism involves either using energy to build molecules or breaking down molecules in which energy is stored
PHOTOSYNTHESIS - the process by which light energy is converted to chemical energy of carbohydrates
- sugar and starches

3. AUTOTROPHS – organisms that use energy from sunlight or from chemical bonds inorganic substances to make organic compounds (food)

4. Some prokaryotes use chemosynthesis to produce organic compounds

5. HETEROTROPHS – organisms that must get energy from food instead of directly from sunlight or inorganic substances

6. CELLULAR RESPIRATION – a metabolic process similar to burning fuel, but it converts food energy to ATP
ATP provides cells with the energy needed to carry out the activities of life

7. Chemical energy stored in food is released gradually
The product of one chemical reaction becomes a reactant in the next reaction
Some of the energy is released as heat, but the remaining energy is stored as ATP – portable form of energy
Adenosine triphosphate

8. Flow of Energy
Energy flows from sunlight or inorganic substances to autotrophs, such as grasses, and then to heterotrophs, such as rabbits and foxes

9. Energy Storage in Organisms
Plants store energy in the form of starch
Animals store energy in the form of glycogen

10. Complete sentences
P.96 section review 1-6
P a,6,12

11. PHOTOSYNTHESIS section 2
Using the Energy in Sunlight

12. Requirements for Photosynthesis
Sunlight – nearly all organisms on Earth depend on sun for energy
Pigments – colored substance that absorb or reflect light

13. Energy-Storing Compounds – stored in the bonds of compounds
Most important compound – one used by every living cell – ATP
Adenosine triphosphate
Inorganic substances – Water and Carbon Dioxide

14. White Light – perceived as ”colorless”
Actually a mixture of different wavelengths of light
Visible spectrum – wavelengths visible to our eyes
Infrared and ultraviolet – not visible to our eyes

15. About 1 % of the energy in the sunlight is converted to chemical energy
Three stages of Photosynthesis
Stage 1: Energy is captured from sunlight.
Stage 2: Conversion of Light Energy
Stage 3: Storage of Energy

16. Stage 1 Absorption of Light Energy
First & second stages are sometimes called “light reactions”
Light is a form of radiation – energy in the form of waves
Pigments absorb only certain wavelengths and reflect all the others
Chlorophyll absorbs mostly blue & red lights

17. Plants contain two types of chlorophyll, a and b, a being the most important
Carotenoids – pigments that produce yellow & orange colors – absorb wavelengths of light different from chlorophyll
Most of the pigments reflect the color green, making the leaves appear green

19. Production of Oxygen
Thylakoids-located in the chloroplasts & contain the pigments necessary for photosynthesis
Light energy is transferred to electrons causing them to be “excited”

20. Electrons jump to other molecules where they are used to power the second stage
Replacement electrons come from water molecules
Water molecules are split by enzymes, leaving H+ ions, and O atoms, forming Oxygen gas,

21. Stage Two: Conversion of Light Energy
Electron Transport Chains (2)- series of molecules through which excited electrons are passed along a thylakoid membrane
First, provides the energy needed to change ADP to ATP – needed by dark reaction

22. A second electron transport chain provides energy used to make NADPH- which is needed by the dark reaction
NADPH – electron carrier that provides the high-energy electrons needed to make carbon-hydrogen bonds in the third stage
Excited electrons combine with hydrogen ions & NADP+ to form NADPH

23. Animated Light Reaction

24. Photosynthesis Problem

25. Dark Reaction (Light Independent Reaction)
Dark reactions generally take place in sunlight; light does not play a role in the dark reactions
The simple inorganic molecule carbon dioxide is used to make a complex organic molecule
Melvin Calvin, American, worked out cycle

26. Stage Three: Storage of Energy
CARBON DIOXIDE FIXATION – transfer of carbon dioxide to organic compounds
Considered light-independent “dark reactions”
Most common method is the Calvin cycle
Calvin cycle- a series of enzyme-assisted chemical reactions that produces a 3-C sugar

27. The reactions are cyclic – they recycle the five-carbon compound needed to begin the cycle again
The energy used in the Calvin cycle is supplied by ATP and NADPH made during the second stage of photosynthesis

29. Calvin Cycle Animated

30. Light and Dark Reactions

31. Factors that Affect Photosynthesis
Light – photosynthesis increases as light intensity increases until all the pigments are being used –limited by Calvin reaction which is the slowest step
Carbon dioxide concentration – once a certain concentration is reached photosynthesis is limited
Temperature- certain range is more efficient

32. Water – the availability of water and the amount of rainfall
Nutrients – how much organic matter that soil contains

33. P. 103
Section 2 review 1-6
P ,2, 5c,8,9, 11
Standardized Test Prep 1-3

34. Cellular Respiration
Food contains usable energy in the form of protein, fat, & carbs (considered organic)
Energy has to be transferred to ATP, which is done through cellular respiration
AEROBIC respiration- metabolic processes that require oxygen, more efficient in making ATP
ANAEROBIC-metabolic processes that do not require O2

35. Stages of Cellular Respiration
Stage I: Breakdown of Glucose
Stage II: Production of ATP

36. Stage I: Breakdown of Glucose
Glycolysis: takes place in the cytoplasm- an enzyme-assisted anaerobic process that breaks down one 6-C molecule of glucose to 2 3-C pyruvic ions
4 Steps in the series on page 105 – you can copy them from the book

37. Glycolysis uses two ATP but produces four ATP

38. Stage 2: Production of ATP
Krebs Cycle enzyme-assisted reactions named for Hans Krebs, 1937
5 steps on p. 106 & 107
Much of the energy that was stored in glucose & pyruvate is now stored in NADH and FADH2

39. Krebs Cycle

41. Electron Transport Chain
The electron transport chain pumps hydrogen ions, H+, out of the inner compartment.
At the end of the chain, electrons & hydrogen ions combine with oxygen, forming water.
ATP is produced as hydrogen ions diffuse into the inner compartment through a channel protein.

42. Respiration in the Absence of Oxygen
Electron transport chain does not function if oxygen is not available as final electron acceptor.
Electrons in NADH are transferred to pyruvate; enables the recycling of NAD+ which is needed to make ATP
Fermentation- recycling of NAD+ using an organic hydrogen acceptor

43. Lactic Acid Fermentation
Pyruvate is converted to lactate
Lactate is the ion of lactic acid
Vigorous exercise –muscles must operate without enough O2 –
ATP produces only while glucose supply lasts
Blood removes excess lactate, but if not quickly-can cause muscle soreness

44. Alcoholic Fermentation
Two step process
Pyruvate is converted to 2-C compound, releasing CO2
Electrons are transferred from NADH to the two-C compound, producing ethanol
Yeast, a fungus, uses alcoholic fermentation. Yeast is used in bread industry and alcoholic beverages
Ethanol (12%) kills yeast

45. Production of ATP
Total of ATP produced from glucose depends on the absence or presence of O2
2 ATP molecules are made during the Krebs cycle
34 ATP are produced by the electron transport chain

47. Types of chemical reactions
An exothermic reaction is a chemical reaction that releases energy in the form of heat..

48. An endothermic reaction is any chemical reaction that absorbs heat from its environment.
These examples could be written as chemical reactions, but are more generally considered to be endothermic or heat-absorbing processes:
melting ice cubes
melting solid salts
evaporating liquid water

49. converting frost to water vapor (melting, boiling, and evaporation in general are endothermic processes)
splitting a gas molecule
cooking an egg

50. Homework Page 110 - section review 1-6
Page 112 – 3,4, 5b, 5d,7,10,13,14,19
Test Part 2 over section 3 Monday 8th
10 true false 14 multiple choice and discussion