1. Photosynthesis
Ms. Hughes
Bio I

2. Energy in Living Systems
Living things also need energy in order to stay in good repair or maintain homeostasis.
Homeostasis is the process of maintaining the internal order and balance even when the environment changes.
Organisms require a constant source of energy (ATP).

3. Chemical Energy
Organisms use and store energy in the chemical bonds of organic (carbon) compounds.
Almost all of the energy in organic compounds comes from the sun.
Solar energy enters living systems when plants and etc. use sunlight to make organic compounds from CO2 and H2O through the process of photosynthesis.

5. DOODLE DEFINTION
Complete a doodle definition of photosynthesis.

6. Autotrophs
Autotroph – make organic compounds that serve as food for them and for almost all of the other organisms on Earth.
Most autotrophs have a supply of food as long as sunlight is available.

7. Auto vs. Hetero

8. Heterotrophs
Organisms that cannot make their own food must absorb molecules made by autotrophs.
The cells of these organisms break down the energy stored in the autotroph to fuel life processes.

9. Metabolism and the Carbon Cycle
Metabolism is either using energy to build organic molecules or breaking down organic molecules in which energy is stored.
Organic molecules contain carbon.
Therefore an organism’s metabolism is part of the Earth’s Carbon Cycle.

10. Carbon Cycle

12. Photosynthesis
Energy enters an ecosystem when an organism uses sunlight during photosynthesis to convert stable carbon dioxide molecules into glucose.
In plants this takes place in chloroplasts

13. Cellular Respiration Respiratory – oxygen involved
Organisms extract energy stored in glucose molecules. This is called cellular respiration.
Read Cellular respiration on page 198.

15. Transferring energy
During chemical reactions energy can be absorbed and released during the breaking and forming of bonds.
In cells chemical energy is gradually released in chemical reactions that are assisted by enzyme.

16. ATP
When cells break down food molecules some of the energy in the molecules is released as heat the rest is used to make ATP.
ATP can be made in one place and then sent to another place to be used.
ADP + P = ATP

17. ATP synthase
An enzyme that catalyzes the synthesis of ATP, recycles ADP by bonding a third phosphate group to the molecule.
ATP synthase catalyzes a reaction in which a phosphate group is added to a molecule of ADP to make ATP.

18. ATP synthesis VIDEO
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19. Hydrogen Ion Pump
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20. DLE the carbon cycle and how it relates to metabolism and atp
Activity
DLE the carbon cycle and how it relates to metabolism and atp

21. Over View
Plants, algae and prokaryotes capture about 1% of the energy in the sunlight that reaches Earth and convert it into chemical energy through the process of photosynthesis.

22. Harvesting Light Energy
The cells o f many photosynthetic organisms have chloroplasts, organelles that convert light energy into chemical energy.
A chloroplast has an outer membrane and an inner membrane.
The inner membrane is much more selectively permeable than the outer membrane.
Both membranes allow light to pass through.
The space inside the inner membrane is the stroma.

23. Chloroplast

24. Harvesting Light Energy
Within the stroma is a membrane called the thylakoid membrane.
This membrane is folded in a way that produces flat, disc-like sacs called thylakoids.
These sacs, which contain molecules that absorb light energy for photosynthesis are arranged in stacks.
The first phase of photosynthesis begins when light hits these stacks.

25. Activity
Create a diagram for photosynthesis within a chloroplast using these words: thylakoid, stroma, stacks, sacs, selectively permeable, ETC, chloroplast, plant, inner, outer, light energy, chemical energy

27. Pigments Cells in the back of the eye contain pigments.
Pigment- a substance that absorbs certain wavelengths (colors) of light and commonly reflects all of the others.
In plants, light energy is harvested by pigments that are located in the thylakoid membrane of chloroplasts.

28. Pigment
Chlorophyll is a green pigment in chloroplasts that absorbs light energy to start photosynthesis.
It absorbs mostly blue and red light and reflects green and yellow light, which makes plants appear green.
Plants have pigments called carotenoids.
Carotenoids absorb blue and green light and they reflect yellow, orange and red light.
When chlorophyll fades away in the fall the colors of carotenoids are exposed.

29. Electron Carriers
When light hits a thylakoid, energy is absorbed by many pigments.
They all funnel the energy to a special chlorophyll molecule in a region called the reaction center, where the energy causes the electrons to become “excited” and to move to a higher energy level.

30. Two Electron Transport Chains
Electrons from the electron carrier are used to produce new molecules, including ATP, that temporarily store chemical energy.
During photosynthesis, one ETCs provides energy to make ATP, while the other provides energy to make NADPH.
Both chains use energy from electrons excited by light.

32. Producing ATP
In mitochondria, electron transport chains pump H+ ions through a membrane, which produces a concentration gradient.
This process also happens in chloroplasts.

33. Photosynthesis Steps

34. Step 1 Water Splitting
The excited electrons that leave chlorophyll molecules must be replaced by other electrons.
Plants get these replacement electrons from water molecules.
During photosynthesis, an enzyme splits water molecules inside the thylakoid.
When water molecules are split, chlorophyll molecules take the electrons form the hydrogen atoms, which leaves H ions.
The remaining oxygen atoms from the split water molecules combine to form oxygen gas. This oxygen gas is not used for an later steps of photosynthesis so it is released into the atmosphere.

35. Summary of step 1

36. Step 2 Hydrogen Ion Pump
A protein(2 types: channel & carrier) acts as a membrane pump.
Excited electrons transfer some of their energy to pump H+ ions into the thylakoid.
This process creates a concentration gradient across the thylakoid membrane.

37. Step 3 ATP synthase
Energy from the diffusion of H+ ions through the carrier protein is used to make ATP.
These carrier proteins are unusual because they function both as an ion channel and as the enzyme ATP synthase.
ATP synthase catalyzes a reaction in which a phosphate group is added to a molecule of ADP.
The result of the reaction is ATP, which is used to power the final stage of photosynthesis.

38. Step 3: Producing NADPH
One electron transport chain provides energy used to make ATP, a second electron transport chain receives excited electrons form a chlorophyll molecule and uses them to make NADPH.

39. Step 4: Producing Sugar
Both NADPH and the ATP made during the first stage of photosynthesis will be used to carry out the final stage of photosynthesis.
Final Stage: ATP and NADPH are used to produce energy-storing sugar molecules form the carbon in carbon dioxides.
This forms sugar – glucose
This is also known as the Calvin cycle.

41. Activity
List and explain all steps necessary to produce sugar from a chloroplast in your own words
Ion, selectively permeable, thylakoid, stacks of sacs, stroma, bonds, released, excited, active, pump, synthase, synthesis, concentration gradient, passive, diffusion, NADPH, glucose

42. Factors that Affect Photosynthesis
Light intensity – as light increases the rate of photosynthesis increases typically, until the level that all chloroplasts are being used and then it levels off.
Concentration of CO2 – once a certain concentration of CO2 is present photosynthesis cannot occur any faster.
Temperature – more efficient at certain temperatures. Certain temperature may inactivate enzymes halting photosynthesis.

43. Activity
Place steps for harvesting light energy using the electron transport chain.
Sunlight hits the thylakoid
Electrons get _________ and bonds _______ Energy is _________ and powers the _________ pump.
Finish these steps there are several!
Second ETC gets electrons from _______ and powers the production of _________.
The two products from the ETC (________ and ______) are used to produce _________.
Also need to explain where the hydrogen ion comes from.

49. Cellular Respiration Most foods we eat contain energy.
Energy is stored in proteins, carbohydrates, and fats.
Remember what we learned in our Bio Chem unit!!

50. Glycolysis
Primary fuel for respiration is glucose, which is formed when carbohydrates are available to meet an organism’s energy.
Fats store the most ATP.
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51. Steps of Glycolysis 1,2,3 Pair Share!
1 – read step 1 breaking down glucose
2 – read step 2 NADH Production
3 – read step 3 pyruvate production

52. Aerobic respiration Pyruvate is broken down in the krebs cycle.
Read this paragraph and answer these questions:
One glucose produces how many ATP?
What are the other products of the Krebs cycle?

53. Crash Course!!
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54. Fermentation Lacks oxygen but still breaks down carbohydrates.
Fermentation enables glycolysis to continue supplying a cell with ATP in anaerobic conditions.

55. 1,2 Pair Share 1- lactic acid fermentation 2 – alcoholic fermentation
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56. lactic acid fermentation formula

57. alcoholic fermentation process

59. Photosynthesis Review
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