Cell Energy

Photosynthesis

and

Respiration

Section 1

1.Thermodynamics

2.Metabolism

3.Photosynthesis

4.cellular respiration

5.Adenosine Triphosphate

Crash course photosynthesis

• http://www.youtube.com/watch?v=sQK3Yr4Sc_k&feature=fvwrel&nomobile=1

Energy objectives:

1. Explain that living things need energy to fight entropy, grow, develop, maintain

homeostasis,and move etc.

The 2nd Law of Thermodynamics states that all things move toward disorder (entropy) spontaneously! Livings things maintain order! This requires lots of energy!

The ultimate source of this energy is…

The

Metabolism

• Living things break down things, which often releases energy.: catabolism

• Living things build up things, which often requires energy: anabolism

• Together these processes are known as metabolism.

Photosynthesis captures this energy of the sun and transfers it to

Form bonds in organic molecules like glucose.

Be able to:

Write the equation for photosynthesis:

6CO2 + 6H2O light C6H12O6 + 6O2

During photosynthesis:

• energy produced by splitting water in the light dependent reactions is used to bond Carbon dioxide into glucose (sugar) in the light independent reactions

Energy is transferred from the bonds of glucose to…

• The bonds of ATP

Explain that energy is stored in an ATP molecule in the phosphate to phosphate bonds and how it can be released when those bonds are broken producing ADP + P + energy.

This can be accomplished by Respiration

• Which transfers the energy in the chemical bonds of organic molecules like glucose and stores it in the bonds of molecules like ATP where it is more easily released when needed by the cell for other chemical reactions.

• Glucose + oxygen yields carbon dioxide + water plus ATP

Respiration

Write the equation for respiration:

C6H12O6 + 6O2 6CO2 + 6H2O

Respiration starts in the cytoplasm and finishes in the mitochondrion

Know that when oxygen is present it is called aerobic respiration and is much more efficient at producing ATP

and that when oxygen is not present

it is called anaerobic when no oxygen is used and it is less efficient at producing ATP.

ATP is the molecule that stores energy for easy use within the cell.

ATP is formed when a phosphate group is added to ADP.

When ATP is broken down, ADP and phosphate are formed and energy is released.

Photosynthesis

Green organisms trap the energy in sun light and store it in the bonds of certain molecules for later use. They are called Autotrophs.

Organisms that can not use sunlight directly obtain energy by consuming plants or other organisms that have consumed plants.

They are called Heterotrophs!!!

Photosynthesis is the process by which cells use light energy to make simple sugars.

• Chlorophyll in the chloroplast of plant cells “traps” light energy needed for photosynthesis.

• The light reactions of photosynthesis produce ATP and NADPH and result in the splitting of water molecules.

• The reactions of the carbon cycle make carbohydrates using CO2 along with ATP and NADPH from the light reactions.

Respiration

• In cellular respiration, cells break down carbohydrates to release energy.

• The first stage of cellular respiration, Glycolysis, takes place in the cytoplasm and does not require oxygen.

• The citric acid cycle takes place in mitochondria and requires oxygen.

ATP 3 parts

1. sugar: ribose2. nitrogen base: adenine3. 3 Phosphate groups

MAKING ATP:

AMP + P = ADP

ADP + P = ATP

ATP = ADP + ENERGY

• ATP SYNTHASE is the enzyme that attaches the third phosphate to the molecule. This enzyme is located in the thylakoid membrane and is like a rotary engine. The movement of H+ ions through it spins the enzyme, providing the energy to bond a P on to the ADP.

ATP Synthase

Autotroph or Heterotroph?

• Do they “make” their own energy source?

Autotrophs/producers

• Autotrophs, such as plants, use photosynthesis to convert light energy from the Sun into Chemical energy, which is stored in Carbohydrates and other Organic Compounds.

Heterotrophs

• Both Autotrophs and Heterotrophs depend on these Organic Compounds for the energy to Power Cellular Activities

SC. 912.L.18.10 Connect the role of adenosine triphosphate (ATP) to energy

transfers within the cell

What are the three parts of ATP?

1. Ribose, sugar, 2 phosphates

2. Sugar, 1 phosphate and a nitrogen base

3. Adenine, sugar and 3 phosphates

4. Adenine, deoxyribose and 3 phosphates.

What is the molecule that most often used as a source of energy for chemical reactions in the cell?

1. Glucose

2. ATP

3. ADP

4. NADPH

5. Starch

What is the original source of energy for all living things on earth?

1. Fossil fuels

2. Uranium

3. Sunlight

4. Wind

5. Hydroelectric

1. Why do living things need energy?

1. To make new cells.

2. To break down

3. To stay organized

4. All of these are ways to fight entropy and are correct.

What does the 2nd law of thermodynamics say about

entropy?

1. It takes energy to maintain entropy

2. All things move toward entropy spontaneously.

3. Living things have lots of entropy.

What kind of organisms can use sunlight to make food for

themselves? 1. Heterotrophs

2. Autotrophs

3. Consumers

4. Decomposers

What are the catabolic and anabolic reactions of the cell together known

as?

1. Catabolism

2. Anabolism

3. Metabolism

What is required to fight the entropy that the 2nd law says will spontaneously occur?

1. ATP

2. Catabolism

3. Anabolism

4. Photosynthesis

5. All of these might work

• SC. 912.L.18.10 Connect the role of adenosine triphosphate (ATP) to energy transfers within the cell

• 1. Why do living things need energy? __________________________________________________

• 2. What does the 2nd law of thermodynamics say about entropy? __________________________________________________

• 3. What is the original source of energy for all living things on earth? __________________________________________

• What kind of organisms can use the sun to make energy? ______________________________

• What kind of organisms need to eat other things? ________________________________

• 4. What are the catabolic and anabolic reactions of the cell together known as? __________________________________

• 5. What is required to fight the entropy that the 2nd law says will spontaneously occur? ____________________________

• 6. What is the molecule that most often used as a source of energy for chemical reactions in the cell? ________________

• What are the three parts of ATP? _________________________ __________________________ and three ___________________________________

• SC. 912.L.18.10 Connect the role of adenosine triphosphate (ATP) to energy transfers within the cell

• 1. Why do living things need energy? To fight entropy

• 2. What does the 2nd law of thermodynamics say about entropy? All things move spontaneously toward disorder (entropy)

• 3. What is the original source of energy for all living things on earth? The sun

• What kind of organisms can use the sun to make energy? Autotrophs

• What kind of organisms need to eat other things? Heterotrophs

• 4. What are the catabolic and anabolic reactions of the cell together known as? Metabolism

• 5. What is required to fight the entropy that the 2nd law says will spontaneously occur? Energy, ATP

• 6. What is the molecule that most often used as a source of energy for chemical reactions in the cell? ATP

• What are the three parts of ATP? Ribose ( sugar) , Adenine ( nitrogen base) and 3 Phosphates

7. What does ATP become when it loses a phosphate group? _______8. Where in the ATP molecule is the energy stored?

_______________________________________________________9. How does ATP release energy?

_____________________________________________________________________

10. Write the equation that shows the release of energy from ATP. ___________________________________________ ________________________________________

11. What is the main role that ATP plays within a cell? ____________________________________________________________________________________________________

12. Why are the processes of photosynthesis and cellular respiration considered a cycle? ___________________________

_________________________________________________________________________________________________

7. What does ATP become when it loses a phosphate group? ADP

8. Where in the ATP molecule is the energy stored? In the chemical bonds

9. How does ATP release energy? Energy is released when the bonds between the phosphates are broken.

10. Write the equation that shows the release of energy from ATP. ATP ADP + P

11. What is the main role that ATP plays within a cell? When coupled with other chemical reactions, it supplies energy for activation for many chemical reactions.

12. Why are the processes of photosynthesis and cellular respiration considered a cycle? The products of one are the reactants of the other, they supply each other with what is needed!

Section 2 Photosynthesis

• Vocabulary:

• 1. Thylakoid

• 2. Granum

• 3. Stroma

• 4. Pigment

• 5. NADP

• 6. Calvin cycle

• 7. Light Reactions

• 1. Thylakoid 2. Granum

3. Stroma 4. Pigment

• 7. Light Reactions 6. Calvin cycle

•5. NADP

Photosynthesis

• the process by which plants make sugar from sunlight, water, and carbon dioxide):

• Sunlight shines through the top of the leaf and reaches the next layer of cells. 

• The light energy is trapped by the chlorophyll in the chloroplasts. 

• In the chloroplasts, a process that uses water changes the light energy into a kind of chemical energy. This chemical energy is stored in the chloroplasts. The electrons in chlorophyll are excited and travel down electron transport chains!

• Air enters the leaf through the stomata and moves into tiny spaces around the food-making cells in the leaf.

• Carbon dioxide from the air passes through the cell walls and membranes of the cells. 

• Carbon dioxide enters the chloroplasts where the previously stored chemical energy converts the carbon dioxide into sugar.

• Phloem tubes in the plant carry sugar from the leaf cells to other parts of the plant, such as roots, stems, and fruits.  

• Cells in these parts of the tree store some of the sugar

chloroplast

Draw a diagram of this chloroplast

STAGE 1 - CALLED THE LIGHT DEPENDENT REACTIONS.

• Energy is Captured from Sunlight.

• Water is Split into Hydrogen Ions, Electrons, and Oxygen (O2).

• The O2 Diffuses out of the Chloroplasts (Byproduct).

Light is Captured by Pigments in Chloroplasts

Chlorophyll - absorbs violet, blue and red light (reflects green) –

The TWO most common Types of Chlorophylls are designated Chlorophyll a and Chlorophyll b.

Chlorophyll F

A new kind of chlorophyll that catches sunlight from just beyond the red end of the visible light spectrum has been discovered. The new pigment extends the known range of light that is usable by most photosynthetic organisms. Harnessing this pigment’s power could lead to biofuel-generating algae that are super-efficient, using a greater spread of sunlight than thought possible.

Why are plants green?

• http://www.nsf.gov/news/mmg/mmg_disp.cfm?med_id=70873

Carotenoids - absorb blue and green light (reflect yellow, orange, or red). Carotenoids are visible in the fall, when plants stop producing chlorophyll, leaves take on a yellow/red colorPhycocyanins - absorb green and yellow light (reflect blue or purple)Xanthophyll - type of carotenoid that reflects yellow light (seen in the autumn)

STAGE 2

• - The Light Energy is Converted to Chemical Energy, which is Temporarily Stored in ATP and NADPH.

STAGE 3 - CALLED THE CALVIN CYCLE.

• . The Chemical Energy Stored in ATP and NADPH powers the formation of Organic Compounds (Sugars),

• Using Carbon Dioxide, CO2.

Light Independent Reaction (The Calvin Cycle)

What is the end result?

• Oxygen

• Carbohydrates

Required Notes

• The following is a summary of the required notes from this section on photosynthesis.

Write the equation for Photosynthesis:

LIGHT

• 6 CO2 + 6 H2O C6H12O6 + 6 O2

Write the equation for respiration:

• C6H12O6 + 6 O2 6 CO2 + 6 H2O

PHOTOSYNTHESIS:

• PLANTS CONVERT THE ENERGY OF SUNLIGHT INTO THE ENERGY OF CHEMICAL BONDS IN CARBOHYDRATES.

LIGHT REACTIONS:

• LIGHT STRIKES PIGMENTS, WATER IS SPLIT INTO HYDROGEN AND OXYGEN, ATP AND NADPH ARE PRODUCED.

CARBON FIXATION:

• HYDROGEN IS COMBINED WITH CARBON DIOXIDE TO FORM CARBOHYDRATES.

• The CO2 goes into making the carbohydrate

• The H2O provides the Oxygen that is given off and the Hydrogen used to make the carbohydrate.

• The reactants must be in constant supply and the temperature must be in favorable ranges for photosynthesis to occur. If they are not, the rate of photosynthesis will be affected.

PIGMENTS:

• found in plastids, such as the chloroplast.

• Molecules that absorb light and reflect unused light.

• Chlorophyll a and b

• Carotenoids

• Xanthophylls

• Water is used in the light reaction, split, provides electrons and H+ ions, and provides the oxygen that is released from plants.

• Carbon dioxide is used in the Calvin cycle to produce carbohydrate (PGAL) by adding H+ ions to the carbon.

• The original source of energy for this is the SUN

1. What is the equation of photosynthesis? 6CO2 +  6H2O + LIGHT ENERGY    C6H12O6  + 6O2

2. What are the reactants of photosynthesis? 6CO2 +  6H2O

3. What are the products of photosynthesis? C6H12O6  + 6O2

4. What is the main purpose of photosynthesis? To use sunlight as an energy source to make organic molecules from inorganic molecules.

5. What happens in the light dependent reactions? Sunlight is converted into ATP and NADPH bonds and water is split producing oxygen

6. What happens in the Calvin cycle? Carbon dioxide is bonded together with hydrogens using the APAT and NADPH as energy from the light reactions to make glucose.

• 7. Where in the cell does photosynthesis occur? Chloroplast

• 8. What pigment is responsible for capturing most of the sunlight energy for the process of photosynthesis? Chlorophyll_Are there other pigments in plants? yes What is the advantage of having different pigments? different wavelengths of light can be used for photosynthesis.

• 9. Where does the oxygen that is released in photosynthesis come from? When water is split in the light reaction

• 10. What 2 energy storing molecules are made after the light reactions? ATP and NADPH

• 11. What is the source of carbon for the glucose in the equation for photosynthesis? carbon dioxide

• 12. In the chemical reaction

6CO2 + 6H2O + sunlight C6H12O6 + 6O2 , where does the energy from the sun go at the end of the chemical reaction? into the bonds of the glucose molecules

• 13. The ability to transfer the energy of the sun into chemical bond energy is completed by a process known as what? photosynthesis

• http://www.youtube.com/watch?v=hj_WKgnL6MI&feature=youtube_gdata_player

The process:

• Fill in the blanks below to show what occurs during the light reactions: • Light causes _________________ in photosystem II to go into a high

energy state.• __________________ is split, releasing an

_______________________ into the electron transport system, a ______________________ into the thylakoid, and _________________ as a waste product.

• _______________________ are moved from photosystem II to photosystem I, which absorbs the light and moves excited electrons along electron carriers again and finally to ________________, forming NADPH.

• _____________________ is made when protons from water build up inside the thylakoid and then diffuse through ATP synthases channels.

• The ____________________ and ___________________ produced during the light reactions are used to produce organic molecules during the Calvin cycle.

The process:

Fill in the blanks below to show what occurs during the light reactions:

Light causes electrons in photosystem II to go into a high energy state.

water is split, releasing an electron into the electron transport system, a hydrogen ion into the thylakoid, and oxygen as a waste product.

electrons are moved from photosystem II to photosystem I, which absorbs the light and moves excited electrons along electron carriers again and finally to NADP, forming NADPH.

ATP is made when protons from water build up inside the thylakoid and then diffuse through ATP synthase channels.

The ATP and NADPH produced during the light reactions are used to produce organic molecules during the Calvin cycle.

1. Why is the Calvin cycle referred to as the light-independent reaction?

• Fill in the blanks below to show what occurs during the Calvin cycle. See page 226 – ____________ combines with six 5-carbon compounds

to make twelve 3-carbon molecules.– The chemical energy in __________________ and

___________________ is passed to the 3-carbon molecules.

– Two of the 3-carbon molecules are used to make ___________________ and other organic compounds.

– The enzyme ____________________ changes ten 3-carbon molecules into six 5-carbon molecules to continue the cycle.

1. Why is the Calvin cycle referred to as the light-independent reaction? No light is needed for this process to

occur.– 6 carbon dioxide molecules combine with six 5-

carbon compounds to make twelve 3-carbon molecules.

– The chemical energy in ATP and NADPH is passed to the 3-carbon molecules.

– Two of the 3-carbon molecules are used to make glucose and other organic compounds.

– The enzyme rubisco changes ten 3-carbon molecules into six 5-carbon molecules to continue the cycle.

Cellular respiration

• Takes place in the mitochondria

Glucose song!

• http://www.youtube.com/watch?v=jJvAL-iiLnQ&feature=youtube_gdata_player

Vocabulary:

• 1. Anaerobic

• 2. Aerobic respiration

• 3. Glycolysis

• 4. Krebs cycle

• 5. Fermentation

• 6. Electron Transport Chain

CELLULAR RESPIRATION

• . CELLULAR RESPIRATION:

• Releases the energy stored in glucose into ATP, a useable form of energy.

Energy to do work!

• By Breaking Down Organic Molecules into simpler molecules, CELLS RELEASE ENERGY.

ATP is the Main Energy Currency of Cells.

• Some of the energy is used to make ATP from ADP and Phosphate. 

STAGE 1

• - Cellular Respiration BEGINS with a Biochemical Pathway called GLYCOLYSIS, that takes place in the Cells Cytosol or cytoplasm,

• This yields a relatively Small amount of ATP and does not require oxygen.

GLYCOLYSIS notes:

• GLYCOLYSIS: The first part of respiration occurs with out oxygen.

• • This changes glucose in several steps

to form Pyruvic Acid and 2 ATP• The energy needed to start this

reaction is two ATP; it makes 4 ATP so the net gain is 2 ATP. It also produces 2 molecules of NADH

glycolysis

• http://www.youtube.com/watch?v=3GTjQTqUuOw&feature=youtube_gdata_player

STAGE 2• The Second Stage of Cellular Respiration is

called OXIDATIVE RESPIRATION, and follows Glycolysis. 

• Oxidative because it uses oxygen!!

• Oxidative Respiration takes place within the Mitochondria.  This is far more effective than Glycolysis at recovering energy from food molecules.

AEROBIC PHASE:(required)

• Uses the pyruvic acid and OXYGEN

• Krebs Cycle: Pyruvic acid breaks into carbon dioxide and a 2 carbon molecule called acetyl a

• Coenzyme A bonds to the acetyl group ----- acetyl co A

• Acetyl Co a enter the Krebs cycle, 9 steps change it.

Krebs

• http://www.youtube.com/watch?v=KAjUsiZWywk&feature=youtube_gdata_player

2 CO2 are released,3 molecules of NADH 1 molecule of FADH21 molecule of GTP/ ATP

• OXIDATIVE RESPIRATION IS THE METHOD BY WHICH PLANT AND ANIMAL CELLS GET THE MAJORITY OF THEIR ENERGY.

ELECTRON TRANSPORT: The real energy producer!!!! The last electron acceptor in the electron transport chain is OXYGEN.

It combines with hydrogen and forms water that is released.

(Required)

Electron transport animation

• http://www.youtube.com/watch?v=kN5MtqAB_Yc&feature=youtube_gdata_player

• Each pair of electrons from

NADH can produce 3 ATP,

from FADH2 produce 2 ATP

and 1 GTP equals 1 ATP.

• This means that a total of 38 ATP can be made from one molecule of GLUCOSE.

THERE ARE TWO TYPES OF CELLULAR RESPIRATION:

•   AEROBIC (PRESENCE OF OXYGEN) AND

• ANAEROBIC (ABSENCE OF OXYGEN) RESPIRATION OR FERMENTATION.

Aerobic is best!!!

• Aerobic Respiration produces a much Larger Amount of ATP, UP TO 20 TIMES MORE ATP PRODUCED.  

required

• When oxygen is not available:

Fermentation occurs. ANAEROBIC

Lactic Acid forms when oxygen is not available.

Not very efficient!! 2 ATP

Anaerobic is not as good.

• There are TWO TYPES of Anaerobic Respiration or Fermentation:

• LACTIC ACID FERMENTATION

AND

• ALCOHOLIC FERMENTATION.

Anaerobic explained…

• http://www.youtube.com/watch?v=FPXOKHkLJI4&feature=youtube_gdata_player

Lactic acid hurts!!!

• DURING EXERCISE, BREATHING CANNOT PROVIDE YOUR BODY WITH ALL THE OXYGEN IT NEEDS FOR AEROBIC RESPIRATION. 

• WHEN MUSCLES RUN OUT OF OXYGEN, THE CELLS SWITCH TO LACTIC ACID FERMENTATION

• The side effects of Lactic Acid Fermentation is Muscle Fatigue, Pain, Cramps, and you feel Soreness

Alcoholic fermentation

• Bakers use Alcoholic Fermentation of YEAST to make Bread.

• Alcoholic Fermentation is used to make wine, beer, and the ethanol added to gasoline to make gasohol

• Alcoholic fermentation: ANAEROBIC

• Bacteria and yeast can convert the pyruvic acid into alcohol and carbon dioxide.

Oxygen!!!!!

• Oxygen SERVES as the FINAL Acceptor of Electrons. 

• By Accepting Electrons from the last molecule in the Electron Transport Chain, Oxygen allows additional electrons to pass along the chain.  Allowing ATP to continue to be synthesized.

CELLULAR RESPIRATION EQUATION:

• C6H12O6 + 6O2  6CO2+ 6H2O +  (ATP)

• ENERGY RELEASED

Section 3 Cellular Respiration1. What is the equation for aerobic respiration?_ C6H12O6 + 6O2  6CO2+ 6H2O +  (ATP) 2. What are the reactants for aerobic respiration?

C6H12O6 + 6O2 3. What are the products of aerobic respiration?

6CO2+ 6H2O 4. What are the products of anaerobic respiration?

CO2 alcohol or lactic acid 5. What is the main purpose of cellular respiration? To

convert the energy stored in the chemical bonds of molecules such as glucose into a more useable form such as ATP.

6.Where in the cell does respiration occur? Glycolysis in the cytoplasm, then it finishes in the membrane of the mitochondrion

7. Is the process with or without oxygen more efficient at producing ATP? It is most efficient with oxygen, 38 ATP with, only 2 without.

8. Which part of the process makes the most ATP? Electron transport

9. Large molecules contain energy in the chemical bonds. The cell must break these bonds in an orderly manner in order to retrieve the energy in the form of ATP. What process is used in the cell to convert these organic molecules into ATP molecules? Cellular respiration

• Specific Process questions:

1. During glycolysis, what is glucose broken down into?

2 pyruvic acid molecules.

2. How is NADH produced during glycolysis? When hydrogen ions combine with NAD as glucose is split into two 3 carbon molecules

3. What is the net ATP gain during glycolysis? 2ATP

4. Where in the cell does pyruvate go after glycolysis is complete? Into the mitochondria

5. Before pyruvate enters the Krebs cycle, __carbon dioxide____ is released and NADH is produced. __

6. When acetyl CoA combines with a 4-carbon compound, citric acid is produced.

7. As citric acid is broken down, 2 molecules of CO2 are released and 1 ATP, 3 _NADH, and 1 _FADH2_ are made.

8. For each glucose molecule, how many turns of the Krebs cycle happen? 2 _

9. Which energy carriers are used during electron transport? NADH and FADH2

10. What type of energy is produced during electron transport? ATP chemical bond energy

11. How is water produced during electron transport?when oxygen accepts the last electron, protons and electrons transfer to form water.

12. Which part of cellular respiration is anaerobic? Glycolysis is anaerobic because it does not require oxygen. Which is aerobic? The krebs and electron transport chain are aerobic because of the oxygen at the end of the transport chain.

13. How many total ATP are produced per glucose?38 If oxygen is not available for aerobic respiration, what happens? Anaerobic respiration occurs or fermentation. Lactic acid or alcohol are the end products.

1. What is true about the products of photosynthesis and the reactants of respiration? They are the same

2. Which process, photosynthesis or respiration stores energy?_photosynthesis

3. Which process, photosynthesis or respiration releases energy? Respiration

4. How are the equations for photosynthesis and respiration related? They are the reverse except for the light needed in photosynthesis.

5. What method of making ATP do both Photosynthesis and respiration processes have in common? ( think membranes) electron transport chains in the membranes.

SC.912.L.18.6 Discuss the role of anaerobic respiration in living things and in human society.

1. When does lactic acid form in humans? Muscles when overworked and anaerobic processes take over.

2. What is a commercial use for an anaerobic byproduct? Alcohol and cheese products.

3. Yeast and some bacteria use another anaerobic pathway besides the lactic acid one. What is it and how can the products be used in society? Fermentation to produce alcohol

PHOTOSYNTHESIS EQUATION: 6CO2 +  6H2O + LIGHT ENERGY    C6H12O6  + 6O2

 

CELLULAR RESPIRATION EQUATION:

C6H12O6 + 6O2    6CO2 +  6H2O +  ENERGY RELEASED

(ATP)

Photosystems I & II• Photosystem II - photons split water molecules

(producing O2), electrons produced from the split travel down electron transport chain. Energy provided in the transport chain is used to make ATP from ADP

• Photosystem I - photons boost electrons to a higher energy state, electrons travel down electron transport chain, energy is used to make NADPH from NADP.

• The ATP and the NADPH are used for the next main step, the Calvin cycle, or "Light independent reactions" - also called the Dark Reaction

Quiz• 1. Draw a molecule of ATP• 2. Where is energy stored in an ATP molecule?• 3. What does ATP become when it loses a

phosphate?• 4. What is the formula for glucose?• 5. where does photosynthesis occur in a cell?• 6. Where does respiration occur in a cell?• 7. List 2 reasons living things need energy?• 8. Do plants use both photosynthesis and respiration?• 9. Do animals use both photosynthesis and

respiration?• 10. Write the equation for photosynthesis.

Energy and Living Things

• Energy from sunlight flows through living systems, from

• autotrophs to heterotrophs.• Photosynthesis and cellular respiration

form a cycle• because one process uses the products of

the other.• ATP supplies cells with energy needed for

metabolism.

Photosynthesis

• Photosynthesis has three stages. First, energy is captured

• from sunlight. Second, energy is temporarily stored in ATP

• and NADPH. Third, organic compounds are made using

• ATP, NADPH, and carbon dioxide.• Pigments absorb light energy during photosynthesis.• Electrons excited by light travel through electron

transport• chains, in which ATP and NADPH are produced.•

• Through carbon dioxide fixation, often by the Calvin cycle,

• carbon dioxide in the atmosphere is used to make organic compounds, which store energy.

• Photosynthesis is directly affected by environmental factors such as the intensity of light, the concentration of carbon dioxide, and temperature.

Cellular Respiration

• Cellular respiration has two stages. First, glucose is broken down to pyruvate during glycolysis, making some ATP.

• Second, a large amount of ATP is made during aerobic

respiration. When oxygen is not present, NAD+ is recycled

during the anaerobic process of fermentation.

•

• The Krebs cycle is a series of reactions that produce energy-storing molecules during aerobic respiration.

• During aerobic respiration, large amounts of ATP are made in an electron transport chain.

• When oxygen is not present, fermentation follows glycolysis, regenerating NAD+ needed for glycolysis to continue.