2. Chapter 8 Cellular Energy
Section 1: How Organisms Obtain Energy
Section 2: Photosynthesis
Section 3: Cellular Respiration

3. Transformation of Energy
Chapter 8
Cellular Energy
8.1 How Organisms Obtain Energy
Transformation of Energy
Energy is the ability to do work.
Thermodynamics is the study of the flow and transformation of energy in the universe.

4. Laws of Thermodynamics
Chapter 8
Cellular Energy
8.1 How Organisms Obtain Energy
Laws of Thermodynamics
First law—energy can be converted from one form to another, but it cannot be created nor destroyed.
Second law—energy cannot be converted without the loss of usable energy.

5. Autotrophs and Heterotrophs
Chapter 8
Cellular Energy
8.1 How Organisms Obtain Energy
Autotrophs and Heterotrophs
Autotrophs are organisms that make their own food.
Heterotrophs are organisms that need to ingest food to obtain energy.

6. All of the chemical reactions in a cell
Chapter 8
Cellular Energy
8.1 How Organisms Obtain Energy
Metabolism
All of the chemical reactions in a cell
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

7. ATP: The Unit of Cellular Energy
Chapter 8
Cellular Energy
8.1 How Organisms Obtain Energy
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.

8. Overview of Photosynthesis
Chapter 8
Cellular Energy
8.2 Photosynthesis
Overview of Photosynthesis
Photosynthesis occurs in two phases.
Light-dependent reactions
Light-independent reactions

9. Phase One: Light Reactions
Chapter 8
Cellular Energy
8.2 Photosynthesis
Phase One: Light Reactions
The absorption of light is the first step in photosynthesis.
Chloroplasts capture light energy.

10. Chapter 8
Cellular Energy
8.2 Photosynthesis
Electron Transport
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.

11. Chapter 8
Cellular Energy
8.2 Photosynthesis
The excited electrons move from photosystem II to an electron-acceptor molecule in the thylakoid membrane.
The electron-acceptor molecule transfers the electrons along a series of electron-carriers to photosystem I.

12. Photosystem I transfers the electrons to a protein called ferrodoxin.
Chapter 8
Cellular Energy
8.2 Photosynthesis
Photosystem I transfers the electrons to a protein called ferrodoxin.
Ferrodoxin transfers the electrons to the electron carrier NADP+, forming the energy-storing molecule NADPH.
Visualizing Electron Transport

13. Phase Two: The Calvin Cycle
Chapter 8
Cellular Energy
8.2 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.

14. Chapter 8
Cellular Energy
8.2 Photosynthesis
Six CO2 molecules combine with six 5-carbon compounds to form twelve 3-carbon molecules called 3-PGA.
The chemical energy stored in ATP and NADPH is transferred to the 3-PGA molecules to form high-energy molecules called G3P.

15. Chapter 8
Cellular Energy
8.2 Photosynthesis
Two G3P molecules leave the cycle to be used for the production of glucose and other organic compounds.
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.

16. Alternative Pathways C4 plants CAM plants 8.2 Photosynthesis Chapter 8
Cellular Energy
8.2 Photosynthesis
Alternative Pathways
C4 plants
CAM plants

17. Overview of Cellular Respiration
Chapter 8
Cellular Energy
8.3 Cellular Respiration
Overview of Cellular Respiration
Organisms obtain energy in a process called cellular respiration.
The equation for cellular respiration is the opposite of the equation for photosynthesis.

18. Cellular respiration occurs in two main parts.
Chapter 8
Cellular Energy
8.3 Cellular Respiration
Cellular respiration occurs in two main parts.
Glycolysis
Aerobic respiration

19. Chapter 8
Cellular Energy
8.3 Cellular Respiration
Glycolysis
Glucose is broken down in the cytoplasm through the process of glycolysis.
Two molecules of ATP and two molecules of NADH are formed for each molecule of glucose that is broken down.

20. Glycolysis has a net result of two ATP and two pyruvate.
Chapter 8
Cellular Energy
8.3 Cellular Respiration
Krebs Cycle
Glycolysis has a net result of two ATP and two pyruvate.
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.

21. Chapter 8
Cellular Energy
8.3 Cellular Respiration
The net yield from the Krebs cycle is six CO2 molecules, two ATP, eight NADH, and two FADH2.

22. Final step in the breakdown of glucose
Chapter 8
Cellular Energy
8.3 Cellular Respiration
Electron Transport
Final step in the breakdown of glucose
Point at which ATP is produced
Produces 24 ATP

23. Anaerobic Respiration
Chapter 8
Cellular Energy
8.3 Cellular Respiration
Anaerobic Respiration
The anaerobic pathway that follows glycolysis
Two main types
Lactic acid fermentation
Alcohol fermentation
Cellular Respiration

24. Chapter Resource Menu Chapter Diagnostic Questions
Cellular Energy
Chapter Resource Menu
Chapter Diagnostic Questions
Formative Test Questions
Chapter Assessment Questions
Standardized Test Practice
biologygmh.com
Glencoe Biology Transparencies
Image Bank
Vocabulary
Animation
Click on a hyperlink to view the corresponding lesson.

25. Which statement describes the law of conservation of energy?
Chapter 8
Cellular Energy
Chapter Diagnostic Questions
Which statement describes the law of
conservation of energy?
Energy cannot be converted or destroyed.
Energy can be converted and destroyed.
Energy can be converted but not destroyed.
Energy can be destroyed but not converted.

26. In which metabolic process are molecules
Chapter 8
Cellular Energy
Chapter Diagnostic Questions
In which metabolic process are molecules
broken down to produce carbon dioxide and
water?
photosynthesis
cellular respiration
homeostasis
fermentation

27. At the end of the Calvin cycle, where is energy stored?
Chapter 8
Cellular Energy
Chapter Diagnostic Questions
At the end of the Calvin cycle, where is energy
stored?
NADPH
ATP
chloroplast
glucose

28. Which law of thermodynamics explains
Chapter 8
Cellular Energy
8.1 Formative Questions
Which law of thermodynamics explains
why the ladybug receives the least amount
of usable energy?

29. the first law of thermodynamics the second law of thermodynamics
Chapter 8
Cellular Energy
8.1 Formative Questions
the first law of thermodynamics
the second law of thermodynamics

30. All of the energy from the food you eat comes from the sun.
Chapter 8
Cellular Energy
8.1 Formative Questions
True or False
All of the energy from the food you eat
comes from the sun.

31. Why is cellular respiration a catabolic pathway?
Chapter 8
Cellular Energy
8.1 Formative Questions
Why is cellular respiration a catabolic pathway?
Energy is used to form glucose and
oxygen.
Energy is converted from water to
carbon dioxide.
Energy that is lost is converted to
thermal energy.
Energy is released by the breakdown
of molecules.

32. Why is adenosine triphosphate (ATP) such an
Chapter 8
Cellular Energy
8.1 Formative Questions
Why is adenosine triphosphate (ATP) such an
important biological molecule?
It captures light energy from the sun.
It is produced in anabolic pathways.
It stores and releases chemical energy.
It converts mechanical energy to thermal
energy.

33. Where in the plant cell does photosynthesis take place?
Chapter 8
Cellular Energy
8.2 Formative Questions
Where in the plant cell does photosynthesis
take place?
chloroplasts
Golgi apparatus
mitochondria
vacuoles

34. Which range of wavelengths is reflected by chlorophylls a and b?
Chapter 8
Cellular Energy
8.2 Formative Questions
Which range of wavelengths is reflected by
chlorophylls a and b? nm nm nm

35. Which mechanism of photosynthesis uses
Chapter 8
Cellular Energy
8.2 Formative Questions
Which mechanism of photosynthesis uses
the movement of hydrogen ions (H+) across
a concentration gradient to synthesize ATP?
absorption
chemiosmosis
electron transport
C2 pathway

36. How are the C4 pathway and the CAM pathway
Chapter 8
Cellular Energy
8.2 Formative Questions
How are the C4 pathway and the CAM pathway
an adaptive strategy for some plants?
They accelerate photosynthesis.
They release more oxygen.
They help the plant conserve water.
They reduce the requirement for ATP.

37. What is the overall purpose of cellular respiration?
Chapter 8
Cellular Energy
8.3 Formative Questions
What is the overall purpose of cellular
respiration?
to make ATP
to process H2O
to store glucose
to deliver oxygen

38. Which represents the general sequence of cellular respiration?
Chapter 8
Cellular Energy
8.3 Formative Questions
Which represents the general sequence of
cellular respiration?
TCA cycle chemiosmosis glycolysis
glycolysis Krebs cycle electron transport
electron absorption catalysis
phosphorylation
fermentation
aerobic pathway anaerobic pathway

39. Which stage of cellular respiration is the anaerobic process?
Chapter 8
Cellular Energy
8.3 Formative Questions
Which stage of cellular respiration is the
anaerobic process?
glycolysis
Krebs cycle
electron transport

40. Which molecule generated by the Krebs cycle is a waste product?
Chapter 8
Cellular Energy
8.3 Formative Questions
Which molecule generated by the Krebs
cycle is a waste product?
CoA
CO2
FADH2
NADH

41. Look at the following figure. Which part of the
Chapter 8
Cellular Energy
Chapter Assessment Questions
Look at the following figure. Which part of the
chloroplast is a sac-like membrane arranged in
stacks?
grana
stroma
thylakoids
Golgi apparatus

42. pyruvate is broken down into what compound?
Chapter 8
Cellular Energy
Chapter Assessment Questions
During the Krebs cycle,
pyruvate is broken down
into what compound?
H2O O2 CO
CO2

43. Look at the following figure. Which molecule is
Chapter 8
Cellular Energy
Chapter Assessment Questions
Look at the following figure. Which molecule is
released when ATP becomes ADP?
phosphate group
water molecule
ribose sugar
energy cells

44. A B Which metabolic process is photosynthesis?
Chapter 8
Cellular Energy
Standardized Test Practice
Which metabolic process is photosynthesis? A B

45. At the beginning of photosynthesis, which
Chapter 8
Cellular Energy
Standardized Test Practice
At the beginning of photosynthesis, which
molecule is split to produce oxygen (O2) as
a waste product?
CO2
H2O
C6H12O6
3-PGA

46. Which molecule helps provide the energy that drives this cycle?
Chapter 8
Cellular Energy
Standardized Test Practice
Which molecule helps provide the energy that
drives this cycle?
3-PGA
CO2
NADPH
rubisco

47. Which product of the Calvin cycle is used for
Chapter 8
Cellular Energy
Standardized Test Practice
Which product of the Calvin cycle is used for
the production of glucose and other organic
compounds?
ADP
CO2
G3P
NADP+

48. What is the final step of cellular respiration?
Chapter 8
Cellular Energy
Standardized Test Practice
What is the final step of cellular respiration?
O2 and H+ form H2O.
Electrons and H2O generate ATP.
C6H12O6 is broken down into CO2.
NADH and FADH2 gain electrons.

49. What prevents pyruvate from entering the Krebs
Chapter 8
Cellular Energy
Standardized Test Practice
What prevents pyruvate from entering the Krebs
cycle and instead results in this pathway?
a buildup of CO2
a lack of oxygen
an excess of
glucose
an increased
demand for ATP

50. Which is not a process that occurs in both
Chapter 8
Cellular Energy
Standardized Test Practice
Which is not a process that occurs in both
cellular respiration and glycolysis?
chemiosmosis
electron transport
glycolysis
production of G3P

51. Glencoe Biology Transparencies
Chapter 8
Cellular Energy
Glencoe Biology Transparencies

52. Chapter 8
Cellular Energy
Image Bank

53. Section 1 Vocabulary energy thermodynamics metabolism Photosynthesis
Chapter 8
Cellular Energy
Vocabulary
Section 1
energy
thermodynamics
metabolism
Photosynthesis
cellular respiration
adenosine triphosphate (ATP)

54. Section 2 Vocabulary thylakoid granum stroma pigment NADP+
Chapter 8
Cellular Energy
Vocabulary
Section 2
thylakoid
granum
stroma
pigment
NADP+
Calvin cycle
rubisco

55. Section 3 Vocabulary anaerobic process aerobic respiration
Chapter 8
Cellular Energy
Vocabulary
Section 3
anaerobic process
aerobic respiration
aerobic process
glycolysis
Krebs cycle
fermentation

56. Visualizing Electron Transport
Chapter 8
Cellular Energy
Animation
Visualizing Electron Transport