The Efficiency of Cellular Respiration
LEARN Section 4.3
Use the following questions to generate a summary note of the key points of chapter 4.3 of your
textbook. You do not need to answer them stepwise, but rather use them to guide the content of your
summary note. You are encouraged to write in point form and use subheadings. Your note should be
detailed enough that any student could easily answer each question if they used your note alone.
1) In your own words, explain what is meant by the term “efficiency”. You may want to mention what
it means to be inefficient too. Clever wording will allow you to say it all in one definition.
2) What is the maximum number of ATP produced per NADH and per FADH2 made during cellular
respiration? Give at least three clear reasons why this is not a precise value. You should use
incorporate information from page 183 AND the first paragraph of page 184 into your answer.
3) How does NADH produced during glycolysis present a problem for the overall efficiency of cellular
respiration?
4) Explain the malate-aspartate shuttle and the glycerol-phosphate shuttle in a diagram. You may
choose to model your diagram after the proposed outline below. You may want to note (but this is
extra info only) that the glycerol-phosphate shuttle is mostly present in brown fat and this
inefficiency is used as an additional release of heat energy.
What molecule is produced?
CYTOPLASM
NADH
glycerol-phosphate
shuttle
NADH
__ ATP
FADH2
__ ATP
MITOCHONDRIA
NADH
malate-aspartate
shuttle
How many ATP
5) Either from memory, or modeled after figure 1 on page 184, create a summary table (not a pretty
diagram) that summarizes the key tallies for each major part of cellular respiration. You may follow
the suggested table format on the next page, or make your own comprehensive summary table.
Use the glycerol-phosphate shuttle model for your tallies to approximate some of the inefficiencies
of cellular respiration in all cells. Your tallies should reflect the number of molecules produced PER
GLUCOSE!
CO2
ATP
NADH
FADH2
released
Net produced
directly
(substrate level
phosphorylation)
Glycolysis
0
2
2
0
4
Transition Reaction
(pyruvate oxidation)
Kreb’s Cycle
(citric acid cycle)
2
0
2
0
6
4
2
6
2
22
TOTALS
6
4
10
2
32
Produced Produced
Grand
Total ATP
produced
ATP
generated
through
oxidative
phosphorylation
36
6) Show the full mathematical calculation for the efficiency of cellular respiration. Assume that 36, not
38 ATP are produced.
7) What percentage of the energy in glucose is released as heat during cellular respiration? (assume 36 ATP)
8) Include the following summary table in your notes:
Process or device
approx. max
efficiency
Cellular Respiration
Automobile (internal combustion engine)
Compact fluorescent light bulb
41%
25%
9%
9) Why and how does creatine (a derivative of amino acids) help supply skeletal muscles with
additional ATP when your muscles are being used? A word equation might be useful in your notes to
illustrate the point
10) Define and compare the terms metabolic rate and basal metabolic rate (BMR). What percentage of
your dialy caloric intake is used to maintain your BMR? How does fat tissue affect your BMR?
11) Why is ATP an inhibitor of phosphofructokinase? What happens to glucose if there is excess ATP?
12) Describe how fats (triglycerides) are used as an energy source. Be sure to use and explain the term
beta oxidation. Why is this a more favourable way for animals to store energy than using
polysaccharides or large stores of mono or disaccharides?
13) What characteristic of amino acids (the building blocks of proteins) to enter at several different
places in cellular respiration?
14) Copy table 1 into your notes