Cellular Respiration Ch.9 sec.3
 Have
your text
book open to
page 208
during this selftutorial
overview of
cellular
respiration.
Rewind: Do I understand how photosynthesis
relates to cellular respiration?
Fill in the following vocabulary:
photosynthesis
____________
the process by which plants
make their own food.
autotroph
2. ____________
an organism that makes its
own food.
heterotroph
3. ____________
an organism that gets its
food from another source
cellular respiration
4. ____________
the process by which cells
make ATP by breaking down organic
compounds.
1.
I. Glycolysis = the
pathway by which
glucose
_________
(C6H12O6)
is oxidized to
Pyruvate
produce ________
also known as pyruvic
acid a 3 Carbon molecules)
Glycolysis occurs in the
Cytosol
__________of
the cell
What is
another
name for
cytosol in
this animal
cell?
Glycolysis occurs in the cytosol of both plant and animal cells
A series of enzymes
slowly catalyzes
these chemical
reactions that
change glucose into
other molecules so
that energy is
captured a little at a
time as the bonds
are broken
3 main steps to Glycolysis:
(be sure to circle the items mentioned on your note sheet on the
diagram at the bottom of the note sheet!)
1. Two phosphate groups are attached to
glucose (these phosphate groups are supplied
by 2 ATP molecules)
2. The 6 carbon molecule that is formed is
split into two three carbon molecules of PGAL.
The 2 PGAL molecules are oxidized (each
loses an electron) These electrons combine
with NAD+ to form a new high energy
compound called NADH (similar to NADP+)
3. The 4 phosphate groups that were added
are now removed and 2 pyruvate molecules
are produced (also known as pyruvic acid)
Note: (look at the diagram at the bottom of your note sheet!)
Each phosphate group removed combines
ATP
with an ADP to form what? ______
4 ATP’s
 This makes a gain of ___
 Recall, though, that step one uses 2
ATP’s… so for every molecule of glucose
that is converted to pyruvate we have a
2
net gain of ____ATP’s

Did I comprehend what I just learned?
Glycolysis simply
begins the process of
cellular respiration.
Depending on whether
Oxygen is present or
not, this biochemical
pathway can take one
of two possible turns:
Notice the oxygen present or not
present on the diagram to the right:
Possibility #1

Oxygen not present - anaerobic
fermentation occurs
*Etymology review:
 the prefix "an-"
without
means____________

the word "aerobe"
oxygen
means____________
Possibility #2

Oxygen present = aerobic respiration
occurs
Which process is MORE efficient, aerobic or anaerobic???
Fermentation:
glycolysis
combination of ___________
and some additional chemical
reactions that occur in the ABSENCE
of oxygen. No ATP are produced!
 The
We will experiment with
“yeast” tomorrow during our
fermentation lab (growing
or budding yeast is pictured
to the left)
A. Lactic Acid Fermentation




An enzyme converts pyruvic acid into another
three carbon molecule, called lactic acid.
– this occurs when Pyruvic acid receives two
hydrogen atoms from NADH and H+ forming
lactic acid and NAD+ (refer to picture in your book)
– What would NAD+ help to keep
glycolysis
working?_____________
Lactic acid fermentation occurs by
microorganisms in the production of yogurt and
cheese
Lactic acid fermentation can occur in human
muscles during very strenuous exercise
NO additional ATP is synthesized!
Lactic acid fermentation occurs when
bacteria is added to milk products and
allowed to ferment:
What kingdom
is bacteria
from? Monera
Is bacteria
unicellular or
multicellular?
Unicellular
When we exercise beyond what our
muscle cells are able to handle, lactic
acid builds up. This “acidity” in the cell
causes us pain
What can you do to
prevent lactic acid
fermentation in your
muscle cells?
= train properly, or
work your muscles up,
slowly, to the level you
desire.
B. Alcoholic Fermentation:




The process where plant cells and
unicellular organisms (like yeast) convert
pyruvic acid into ethyl alcohol.
– First, a CO2 molecule is removed from
pyruvic acid thus converting it into a 2carbon compound.
– Then, two hydrogen atoms are added to
the 2-carbon compound to make ethyl
alcohol. (refer to picture in your book)
Wine and beer industries allow ethyl alcohol
to accumulate to 12%
Making bread: the CO2 becomes trapped
inside the rising bread dough, and then the
alcohol evaporates during baking.
NO additional ATP is synthesized!
Summary:
Did I comprehend what I just learned?
 Anaerobic
pathways provide only
enough energy for unicellular and
small multicellular organisms. The
Fermentation pathways are not
efficient enough to provide the
energy for larger organisms.
Instead, aerobic respiration is the
pathway used.
Right now on your note sheet: Write the cellular respiration
pathway each of the following organisms would use below
each picture?
Is it anaerobic = fermentation or aerobic = respiration
At this point you should be able to write the cellular
respiration chemical equation, which is a direct reversal of
photosynthesis: (write it in the margin of your note sheet)
Try to write out the balanced respiration equation using glucose as
the carbohydrate being broken down:
__________ + _________  __________ + __________ + ________
Did you see the difference in the examples below?
Is it anaerobic = fermentation or aerobic = respiration
Anaerobic
fermentation
Aerobic
respiration
Aerobic
respiration
Aerobic
respiration
Anaerobic
fermentation
Anaerobic
fermentation
Check your Aerobic Respiration chemical equation:
Try to write out the balanced respiration equation using glucose as
the carbohydrate being broken down:
ATP
energy
CO2
H2O
O2
Glucose
__________
+ _________
 __________
+ __________
+ ________