Introduction to Cell & Molecular Biology
(BIOL121) - Dr. S.G. Saupe (email@example.com); Biology Department, College of St. Benedict/St. John's
University, Collegeville, MN 56321
Study Guide & Review Sheet for Respiration
I. Goal: Life can, in an abstract sense, be viewed as a sustained,
integrated and complex series of chemical reactions. Our goal in this unit will
be an understanding of the basic principles of chemical reactions and biological energetics that govern the major anabolic (photosynthesis) and catabolic
(glycolysis, cellular respiration) reactions of living systems. Specifically, we
will investigate glycolysis, fermentation and cellular respiration.
II. Learning Objectives: Upon completion of this unit you should be
- describe ATP and explain why it is so vitally important for living things.
- describe the difference between a substrate level and oxidative
- describe how most cellular ATP is made.
- describe and explain the major events occurring during glycolysis.
- describe the two major anaerobic pathways for pyruvic acid metabolism
- explain the significance/importance of glycolysis and fermentation.
- describe the structure of the mitochondrion.
- describe and explain the major events occurring during the Citric Acid
Cycle and their significance.
- describe and explain the major events occurring during the electron
transport chain and their significance.
- explain the chemi-osmotic hypothesis for ATP synthesis.
- summarize the energy yield from glucose during glycolysis,
fermentation, and aerobic respiration.
- write and explain the general equation for glucose catabolism
IV. Learning Activities: here are a few possible learning activities
- prepare written answers to the objectives
- write a dialog using as many of the terms in the chapter as possible
- prepare a concept map for this material
- answer the questions at the end of the chapter
- go through the CD-ROM that accompanies the text.
- Define the following terms:
Citric Acid Cycle
substrate level phosphorylation
V. Study Hints:
- Do not memorize the various pathways; strive to understand what is
occurring during each.
- For each major pathway, know where it occurs, briefly what occurs and why
it occurs. Also, know the starting materials and end products.
- Attempt to summarize each pathway in your own words.
- Be able to use conversationally, the terms/concepts listed above or in the
- Read the pertinent text chapter.
- Complete the pertinent sections in the study guide.
- Pretend you are a molecule of glucose. Follow it through all the pathways
and describe what you encounter, where and why.
- Make a concept map for each of the major pathways.
VI. Additional Hints: If I were to take one of my Concepts
exams I would study as follows:
- Lecture Notes. I'd come to class and get a great set of lecture notes.
Write everything down that's said by students, teacher or that you think
about. You should be writing and thinking constantly. Write down questions
or ideas as you go along.
- Web Notes. Get a copy of the notes as soon as they are available.
- Summary Notes. Now, create a summary set of notes by condensing important
info from lecture, web and text. Read the pertinent sections in the text and
record this information as well. This is now your working set of notes.
- Study Time. So far, you really haven't started to "study" - you
have simply gathered information. Now, it's time to process the info. Begin
to ask yourself the "w" questions - why, when, where, how, etc -
for everything that appears in your notes. Can you explain this to someone
else? Imagine you are going to teach someone else about this topic. Could
you do it?
- Test time. Can you answer the questions in the study guide that comes with
the text? in this study guide? in the CD-ROM. Quiz your friends. Talk
biology with someone - call your family or friends and tell them about what
you're learning. Talk biology with your profs. Go to the library and read
additional books about the topic.
VII. Study Questions
→ CO2 + H2O.
Find the areas where these materials are used/produced.
- Under what conditions
does fermentation occur?
- There are two major
types of fermentations that are characterized by their end products.
Identify these and the organisms in which they occur.
- Circle the redox
reaction that occurs during each type of fermentation. Indicate which
components are oxidized and which are reduced. What type of enzyme is
responsible for this reaction?
- Note that ATP is not a
direct product of the reactions of fermentation? So, what is the purpose of
- Locate the redox
reactions that occur in the mitochondria (hint there are five). Write redox
reaction next to each.
- Locate the reactions
in which carbon dioxide is lost (hint there are three).
- Locate a substrate
level phosphorylation reaction in the mitochondrion. Label it.
- Acetyl coenzyme A can
be considered a �carrier� molecule. Find two reactions in which it is
- When pyruvic acid
enters the mitochondrion it gets oxidized and converted to acetyl coenzyme A
and carbon dioxide by a large enzyme complex in the inner mitochondrial
membrane. Locate this reaction and label it �Pyruvate oxidation complex.�
- Locate the electron
transport chain. Label I �NADH-Q reductase complex;� label III �Cytochrome
c reductase complex;� label IV �cytochrome c oxidase complex;� and label II
�Succinate-Q reductase complex.� Label Q � �Ubiquinone.�
- Write pH 5 and pH 7 in
the appropriate regions in the mitochondrion.
- Locate and color the Fo/F1
Coupling Factor ATPase that produces most of the ATP in the mitochondrion.
- Explain why the
oxidation of each NADH yields 3 ATP but the oxidation of each FADH2
only yields two.
- Recall the summary
equation for respiration: glucose + O2
SAMPLE TEST QUESTIONS:
- Which of the following does not occur in the Kreb's Cycle? (moderately
a. redox reactions
b. production of NADH
c. production of FAD+
d. production of carbon dioxide
e. synthesis of ATP
- Glycolysis occurs in the: (simple)
- The reason that organisms ferment pyruvic acid is to: (moderately
a. regenerate oxidized coenzymes
b. produce lactic acid
c. produce ethanol
d. produce ADP
e. recycle carbon dioxide
Some Additinal Questions:
1. For each of the following, name the reaction(s) that occurs in that
2. Consider a yeast cell that is fed glucose in which all the carbon atoms
are radioactively labeled with carbon-14. Answer the following true or false.
Then, correct any false statements:
- Under aerobic conditions, radioactivity would be found in water, ATP,
and carbon dioxide
- Under anaerobic conditions, radioactivity would be found in carbon
dioxide and lactic acid
- NAD would become labeled under aerobic or anaerobic conditions.
3. We discussed allosteric regulation in a previous class. Explain the
advantage to the cell for each of the following regulatory mechanisms: (a)
Isocitrate dehydrogenase is allosterically activated by ADP; and (b)
phosphofructokinase is allosterically inhibited by citrate.
4. Cyanide is a potent inhibitor of the electron transport chain.
Specifically, cyanide blocks the cytochrome a-a3 complex from
reducing oxygen. Which of the following is true concerning a cell treated with
cyanide? (can you correct the false statements?):
- cells use more oxygen
- NADH accumulates in the cell
- the rate of electron flow in the chain increases
- glycolysis will stop
Though Questions: (these questions were 'borrowed' from a cell
biology text whose author I have forgotten - sorry)
1. Normally, oxidative phosphorylation is tightly coupled to electron
transport. Or in other words, no electron flow through the ETC will occur unless
ATP can be made. However, there are certain uncoupling agents that allow
electron flow while preventing ATP synthesis. One such agent is
2,4-dinitrophenol (DNP) which is toxic to humans causing a marked increase in
metabolism and temperature, sweating, collapse and death. For a brief period in
the 1940�s, sublethal doses of DNP were actually prescribed as a means of
weight reduction in humans.
- Why would an uncoupling agent like DNP be expected to cause an increase
in metabolism, as evidenced by consumption of oxygen or catabolism of
- Why would consumption of DNP lead to an increase in temperature and to
- DNP has been shown to carry protons across membranes. How might this
observation be used to explain its uncoupling effect?
- Why would DNP have been considered a drug for weight reduction? Can you
guess why it was abandoned as a reducing aid?
2. Recall that in the enzyme unit we mentioned that elevated levels of
lactate dehydrogenase (LDH) in the blood is an indication of a heart attack.
Knowing that LDH catalyzes the reduction of pyruvate to lactate in an anaerobic
environment, explain why might there be a relationship between a heart attack
and this enzyme.
Last updated: July 14, 2009
� Copyright by SG Saupe