Click on a lesson name to select. Cellular Energy Section 1: How Organisms Obtain Energy Section 2: Photosynthesis Section 3: Cellular Respiration

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Cellular Energy

Section 1: How Organisms Obtain Energy

Section 2: Photosynthesis

Section 3: Cellular Respiration

Transformation of Energy

Energy is the ability to do work.

How Organisms Obtain Energy

Cellular Energy

Thermodynamics is the study of the flow and transformation of energy in the universe.

Section 1

Laws of Thermodynamics

First law—energy can be converted from one form to another, but it cannot be created nor destroyed.


Cellular Energy

Second law—energy cannot be converted without the loss of usable energy.

Section 1

Autotrophs and Heterotrophs

Autotrophs are organisms that make their own food.


Cellular Energy

Heterotrophs are organisms that need to ingest food to obtain energy.

Section 1

Metabolism

All of the chemical reactions in a cell


Cellular Energy

Photosynthesis—light energy from the Sun is converted to chemical energy for use by the cell

Cellular respiration—organic molecules are broken down to release energy for use by the cell

Section 1

ATP: The Unit of Cellular Energy

ATP releases energy when the bond between the second and third phosphate groups is broken, forming a molecule called adenosine diphosphate (ADP) and a free phosphate group.


Cellular EnergySection 1

ATP

Overview of Photosynthesis

Photosynthesis occurs in two phases.

Cellular Energy

Light-dependent reactions

Light-independent reactions – Dark Rxns

Photosynthesis

Section 2

Phase One: Light Reactions

The absorption of light is the first step in photosynthesis.

Cellular Energy

Chloroplasts capture light energy.

Photosynthesis

Section 2

What’s Going on in a Chloroplast?

Electron Transport

Step 1 Light energy excites electrons in photosystem II and also causes a water molecule to split, releasing an electron into the electron transport system, H+ into the thylakoid space, and O2 as a waste product.

Cellular Energy

Photosynthesis

Section 2

Step 2 The excited electrons move from photosystem II to an electron-acceptor molecule in the thylakoid membrane.

Step 3 The electron-acceptor molecule transfers the electrons along a series of electron-carriers to photosystem I.

Cellular Energy

Photosynthesis

Section 2

Cellular Energy

Photosynthesis

Step 4 Photosystem I transfers the electrons to a protein called ferrodoxin.

Step 5 Ferrodoxin transfers the electrons to the electron carrier NADP+, forming the energy-storing molecule NADPHNADPH.

Section 2

Metabolic Pathways

Catabolic Pathway•Releases Energy

•Breaks Down Molecules

Anabolic Pathway•Stores (Uses) Energy

•Makes Molecules

Light Dependent RXN Long Version

• Go to 4:50

https://www.youtube.com/watch?v=joZ1EsA5_NY


Short Version

Cellular Energy

Photosynthesis

Phase Two: The Calvin Cycle

In the second phase of photosynthesis, called the Calvin cycle, energy is stored in organic molecules such as glucose.

Section 2


Cellular Energy

Photosynthesis

Step 1 Six CO2 molecules combine with six 5-carbon compounds to form twelve 3-carbon molecules called 3-PGA.

Step 2 The chemical energy stored in ATP and NADPH is transferred to the 3-PGA molecules to form high-energy molecules called G3P.

Section 2

Cellular Energy

Photosynthesis

Step 3 Two G3P molecules leave the cycle to be used for the production of glucose and other organic compounds.

Step 4 An enzyme called rubisco converts the remaining ten G3P molecules into 5-carbon molecules called RuBP.

These molecules combine with new carbon dioxide molecules to continue the cycle.

Section 2

Cellular Energy

Photosynthesis

Alternative Pathways

C4 plantsFix carbon dioxide into 4 carbon compounds instead of 3.Keep their stomata closed during hot days.Sugar cane and corn

CAM plantsCrassulacean acid metabolismOnly allow CO2 to enter leaves at night when its cooler and humidPineapple plant, cacti, orchids

Section 2

Overview of Cellular Respiration

Organisms obtain energy in a process called cellular respiration.

Cellular Respiration

Cellular Energy

The equation for cellular respiration is the opposite of the equation for photosynthesis.

Section 3


Cellular Energy

Cellular respiration occurs in two main parts.

Glycolysis

Aerobic respiration

Section 3

Glycolysis

Glucose is broken down in the cytoplasm through the process of glycolysis.


Cellular Energy

Two molecules of ATP and two molecules of NADH are formed for each molecule of glucose that is broken down.

Section 3

Krebs Cycle

Glycolysis has a net result of two ATP and two pyruvate.


Cellular Energy

Most of the energy from the glucose is still contained in the pyruvate.

The series of reactions in which pyruvate is broken down into carbon dioxide is called the Krebs cycle.

Section 3


Cellular Energy

The net yield from the Krebs cycle is six CO2 molecules, two ATP, eight NADH, and two FADH2.

Section 3



Cellular Energy

Electron Transport

Final step in the breakdown of glucose

Point at which ATP is produced

Produces 24 ATP

Section 3


Cellular Energy

Anaerobic Respiration

The anaerobic pathway that follows glycolysis

Two main types

Lactic acid fermentation

Alcohol fermentation


Section 3

Cellular Energy

Chapter Resource Menu

Chapter Diagnostic Questions

Formative Test Questions

Chapter Assessment Questions

Standardized Test Practice

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Glencoe Biology Transparencies

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Vocabulary

AnimationClick on a hyperlink to view the corresponding feature.

Chapter

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1. A2. B3. C4. D

CDQ 1

A. Energy cannot be converted or destroyed.

B. Energy can be converted and destroyed.

C. Energy can be converted but not destroyed.

D. Energy can be destroyed but not converted.

Which statement describes the law of conservation of energy?

Cellular Energy


Chapter

1. A2. B3. C4. D

CDQ 2

Cellular Energy


Chapter

A. photosynthesis

B. cellular respiration

C. homeostasis

D. fermentation

In which metabolic process are molecules broken down to produce carbon dioxide and water?

1. A2. B3. C4. D

CDQ 3

Cellular Energy


Chapter

A. NADPH

B. ATP

C. chloroplast

D. glucose

At the end of the Calvin cycle, where is energy stored?

1. A

2. B

FQ 1

Cellular EnergyChapter

Which law of thermodynamics explains why the ladybug receives the least amount of usable energy?

A. the first law of thermodynamics

B. the second law of thermodynamics

Section 1 Formative Questions

1. A

2. B

FQ 2



All of the energy from the food you eat comes from the sun.

A. true

B. false

1. A

2. B

3. C

4. D

FQ 3



Why is cellular respiration a catabolic pathway?

A. Energy is used to form glucose and oxygen.

B. Energy is converted from water to carbon

dioxide.

C. Energy that is lost is converted to thermal

energy.

D. Energy is released by the breakdown of

molecules.

1. A

2. B

3. C

4. D

FQ 4



A. It captures light energy from the sun.

B. It is produced in anabolic pathways.

C. It stores and releases chemical energy.

D. It converts mechanical energy to thermal energy.

Why is adenosine triphosphate (ATP) such an important biological molecule?

1. A

2. B

3. C

4. D

FQ 5


A. chloroplasts

B. Golgi apparatus

C. mitochondria

D. vacuoles

Where in the plant cell does photosynthesis take place?


1. A

2. B

3. C

FQ 6



A. 400-500 nm

B. 500-600 nm

C. 600-700 nm

Which range of wavelengths is reflected by chlorophylls a and b?

1. A

2. B

3. C

4. D

FQ 7



A. absorption

B. chemiosmosis

C. electron transport

D. C2 pathway

Which mechanism of photosynthesis uses the movement of hydrogen ions (H+) across a concentration gradient to synthesize ATP?

1. A

2. B

3. C

4. D

FQ 8



A. They accelerate photosynthesis.B. They release more oxygen.C. They help the plant conserve water.D. They reduce the requirement for ATP.

How are the C4 pathway and the CAM pathway

an adaptive strategy for some plants?

1. A

2. B

3. C

4. D

FQ 9


A. to make ATP

B. to process H2O

C. to store glucose

D. to deliver oxygen

What is the overall purpose of cellular respiration?


1. A

2. B

3. C

4. D

FQ 10


Which represents the general sequence of cellular respiration?

A. TCA cycle chemiosmosis glycolysisB. glycolysis Krebs cycle electron transportC. electron absorption catalysis

phosphorylationD. aerobic pathway anaerobic pathway

fermentation


1. A

2. B

3. C

FQ 11


A. glycolysis

B. Krebs cycle

C. electron transport

Which stage of cellular respiration is the anaerobic process?


1. A

2. B

3. C

4. D

FQ 12


A. CoA

B. CO2

C. FADH2

D. NADH

Which molecule generated by the Krebs cycle is a waste product?


1. A

2. B

3. C

4. D

CAQ 1


Look at the following figure. Which part of the chloroplast is a sac-like membrane arranged in stacks?

A. grana

B. stroma

C. thylakoids

D. Golgi apparatus


1. A

2. B

3. C

4. D

CAQ 2



During the Krebs cycle, pyruvate is broken down into what compound?

A. H2O

B. O2

C. CO

D. CO2

1. A

2. B

3. C

4. D

CAQ 3



Look at the following figure. Which molecule is released when ATP becomes ADP?

A. phosphate group

B. water molecule

C. ribose sugar

D. energy cells

1. A

2. B

STP 1


Which metabolic process is photosynthesis?

A

B


1. A

2. B

3. C

4. D

STP 2



At the beginning of photosynthesis, which molecule is split to produce oxygen (O2) as

a waste product?

A. CO2

B. H2O

C. C6H12O6

D. 3-PGA

1. A

2. B

3. C

4. D

STP 3



Which molecule helps provide the energy that drives this cycle?

A. 3-PGA

B. CO2

C. NADPH

D. rubisco

1. A

2. B

3. C

4. D

STP 4



Which product of the Calvin cycle is used for the production of glucose and other organic compounds?

A. ADP

B. CO2

C. G3P

D. NADP+

1. A

2. B

3. C

4. D

STP 5



What is the final step of cellular respiration?

A. O2 and H+ form H2O.

B. Electrons and H2O generate ATP.

C. C6H12O6 is broken down into CO2.

D. NADH and FADH2 gain electrons.

1. A

2. B

3. C

4. D

STP 6



What prevents pyruvate from entering the Krebs cycle and instead results in this pathway?

A. a buildup of CO2

B. a lack of oxygen

C. an excess of glucose

D. an increased demand for ATP

1. A

2. B

3. C

4. D

STP 7



Which is not a process that occurs in both cellular respiration and glycolysis?

A. chemiosmosis

B. electron transport

C. glycolysis

D. production of G3P

Cellular Energy

Glencoe Biology Transparencies

Chapter

Cellular Energy

Image Bank

Chapter

energy

thermodynamics

metabolism

Photosynthesis

cellular respiration

adenosine triphosphate (ATP)


Vocabulary

Section 1

thylakoid

granum

stroma

pigment

NADP+

Calvin cycle

rubisco


Vocabulary

Section 2

anaerobic process

aerobic respiration

aerobic process

glycolysis

Krebs cycle

fermentation


Vocabulary

Section 3

Cellular Energy

ATP

The Calvin Cycle

Visualizing Electron Transport

The Krebs Cycle (Citric Acid Cycle)

Animation

Chapter




Documents

Click on a lesson name to select. Cellular Energy Section 1: How Organisms Obtain Energy Section 2: Photosynthesis Section 3: Cellular Respiration