The Sun is the source of all energy

Unit 1 Section 4: Photosynthesis & Cellular Respiration

S4. C1.PO(1,3,4) C5.PO(1-2) S1.C3.PO(3)

Cellular Respiration:
the release of chemical energy for cellular use.

click to find the answer to today's question What is the chemical formula for glucose?

The chemical equation for respiration is:

C6H12O6 + 6O2 6CO2 + 6H2O

Glucose + Oxygen Carbon Dioxide + Water

The key points:

Glucose stores the sun's energy in chemical form.
Adenosine triphosphate - ATP link to a local picture the molecule organisms can actually use for energy.
Respiration link to an Internet Website the breaking down of pyruvic acid using molecular oxygen.
Glycolysislink to an Internet Website link to an Internet Website

Splits the 6-carbon glucose molecule into two 3-carbon pyruvic acid molecules and 2 ATP molecules. This process is anaerobic, not requiring the presence of molecular oxygen.
Fermentation - the breaking down of pyruvic acid without using molecular oxygen.

At this point, there are three possibilities:

  1. Aerobic respiration - link to an Internet Website
    1. The Krebs Cycle, also known as the Citric Acid Cycle link to an Internet Website link to an Internet Website, produces 2 ATP molecules, 10 carrier molecules, and CO2 from each glucose molecule.
    2. The Electron Transport Chain link to an Internet Website then produces 34 ATP molecules and H2O from the carrier molecules.

      The bulk of a cell's ATP must be produced in the mitochondria.

      To be energy efficient, particles must move through the membrane with little energy expense.

      Electron transport produces an uneven charge on the mitochondria membrane.

      This allows protons to move through the membrane by electrical charge attraction.

      Protons now move through the membrane and are used by ATP synthase enzyme to make ATP.

  2. Lactic acid fermentation link to an Internet Website - Occurs in animal cells due to a lack of oxygen, causing muscle soreness as lactic acid builds up. While no ATP is produced, a carrier compound is produced, allowing glycolysis to continue.
  3. Alcoholic fermentation - Occurs in some plants and unicellular organisms. The process converts pyruvic acid into ethyl alcohol and a carrier compound, which allows glycolysis to continue.

Comparing energy yield:


Assignment 1.4c - Photosynthesis & Cellular Respiration
Scoring criterialink to a local webpage

Honors biology : Only complete section below labeled honors biology

  1. Study this website about ATP. link to an Internet Website Write a paragraph explaining why the three phosphate groups in an ATP molecule are the key to ATP being used for cellular energy.
  2. Write a paragraph explaining what happens when lactic acid builds up in muscles?
  3. How many carbon atoms are in a molecule of pyruvic acid?
  4. What does the term "anaerobic" mean?
  5. What does the term "aerobic" mean?
  6. How many ATP are produced during Glycolysis?
  7. How many ATP are produced during the Krebs Cycle?
  8. How many ATP are produced in the electron transport chain located in the Mitochondria?
  9. How many ATP are produced during Aerobic respiration?
  10. How many ATP are produced during Anaerobic respiration?
  11. Draw a diagram showing the process of cellular respiration in a cell (identify locations & label all parts).
  12. In your words discuss why cellular respiration is so important to living organisms.

  Honors biology

Part 1

    1.  Show your energy and be part of the team as we figure out how your body makes use of the energy you eat. Dive in by clicking here link to a local webpage

Part 2 : Visit this link on Cellular Respiration

  1. Review concept 1 and complete the review (A - H) listing your answer here.
  2. Review concept 2 glycolysis and complete practice 2, listing the 8 output molecules (1-8) in order from start to finish.
  3. Review concept 3 Krebs cycle and complete practice 3.
    1. How many ATP molecules does the Krebs cycle produce in one cycle?
    2. How many CO2 molecules does the Krebs cycle produce in one cycle?
    3. How many electron carrier molecules does the Krebs cycle produce  in one cycle?
    4. Where will all of the electron carrier molecules take their electrons?
  4. Review concept 4 Oxidative phosphorylation and complete practice 4. Starting with the blue NADH electron carrier and protein I in the mitochondrion membrane.
    1. List all of the items that you must use in order to complete the ETC and chemeosmosis for the blue electron carrier NADH (only do NADN).
    2. Give a short description of what each item does.
    3. Example number one would be: NADN  donates electron to the complex one protein
    4. Do this for the remaining 5 steps.
  5. Review concept 5 fermentation, complete practice 5 by filling in the blanks
    1. Only complete A, B, C, F
  6. Complete the self quiz. List the number and its letter answer here. (no need to do 4 or 7)

      Part 3 : Honors biology online text book

1. Complete this assignment link to a local webpageusing the Honors biology online text book, chapter 6, on, how cells harvest energy.

  Research Links:

Biology Class Cell Page










The chemical formula for a glucose molecule is C6H12O6