IB Biology 2015

1. Essential idea: Cell respiration supplies energy for the
functions of life
2.8 Cellular Respiration
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Usain-Bolt-runs-to-a-first-place-finish-in-his-mens-200m-round-1-heat.jpg

2. Statement Guidance
2.8.U1 Cell respiration is the controlled release of energy
from organic compounds to produce ATP.
Details of the metabolic pathways
of cell respiration are not needed
but the substrates and final waste
products should be known.
2.8.U2 ATP from cell respiration is immediately available
as a source of energy in the cell.
2.8.U3 Anaerobic cell respiration gives a small yield of
ATP from glucose.
2.8.U4 Aerobic cell respiration requires oxygen and gives
a large yield of ATP from glucose.
Understandings

3. Applications and Skills
Statement Utilization
2.8 A.1 Use of anaerobic cell respiration in yeasts to
produce ethanol and carbon dioxide in
baking.
2.8 A.2 Lactate production in humans when
anaerobic respiration is used to maximize the
power of muscle contractions.
2.8 S.1 Analysis of results from experiments
involving measurement of respiration rates
in germinating seeds or invertebrates using a
respirometer.
There are many simple
respirometers which could be
used. Students are expected to
know that an alkali is used to
absorb CO2, so reductions in
volume are due to oxygen use.
Temperature should be kept
constant to avoid volume changes
due to temperature fluctuations.

4. 2.8 U.1 Cell respiration is the controlled release of energy from organic
compounds to produce ATP.
• Organic compounds from the food
we eat such as glucose contain
stored energy within their covalent
bonds.
• All living organisms carry out cell
respiration in order to convert
stored energy into a form that can
be used by the cell.
• When organic molecules are
broken down, the energy formed is
eventually stored in a high energy
molecule called ATP.
• Cell respiration is the controlled
release of energy from organic
compounds in cells to produce ATP.
http://www.bio.miami.edu/~cmallery/150/metab/sf6x1a.jpg
http://media.wnyc.org/media/photologue/photos/cache/4%20Sci
ence%20Ink%20Photo%20Selection%201_storyslide_image.jpg

5. 2.8 U.2 ATP from cell respiration is immediately available as a source of
energy in the cell.
• Energy for all types of cellular processes is immediately supplied by
ATP
• The main types of cellular activity include synthesizing large
molecules, pumping ions across membranes by active transport, and
moving things around the cell, such vesicles, chromosomes and
muscle contraction
• Energy is released by spitting ATP -> ADP + Pi
http://www.goldiesroom.org/Multimedia/Bio_Images
/07%20Respiration/03%20ADP%20to%20ATP.jpg

6. 2.8 U.2 ATP from cell respiration is immediately available as a source of
energy in the cell.

7. 2.8 U.2 ATP from cell respiration is immediately available as a source of
energy in the cell.

8. 2.8 U.2 ATP from cell respiration is immediately available as a source of
energy in the cell.

9. 2.8 U.3 Anaerobic cell respiration gives a small yield of ATP from glucose
• Glucose (6C) is broken down
into a 2 pyruvate (3C) in the
cytoplasm by the process of
glycolysis.
• There is a net gain of 2 ATP
molecules.
• Glycolysis does not require
oxygen.
• Anaerobic respiration (does not
require oxygen) occurs in the
cytoplasm.
• In the first stage of glycolysis,
glucose is converted into
pyruvate with a net gain of 2
ATP.
http://philschatz.com/biology-concepts-book/resources/Figure_04_02_02.jpg

10. 2.8 U.3 Anaerobic cell respiration gives a small yield of ATP from glucose
• After glucose is converted to pyruvate,
if no oxygen is available, pyruvate is
further converted into lactate or
ethanol depending on the organism.
• When no oxygen is available, humans
convert pyruvate into lactate (lactic
acid) with no further gain of ATP.
• No CO2 is produced because like
pyruvate, lactate is also a 3 carbon
molecule.
http://philschatz.com/biology-concepts-book/contents/m45440.html

11. 2.8 A.2 Lactate production in humans when anaerobic respiration is
used to maximize the power of muscle contractions.
• During high-intensity exercises,
blood flow to your muscles is
reduced; causing a reduction in
oxygen delivered to the muscles.
• In the absence of oxygen, muscle
cells use glycolysis to produce ATP.
Glycolysis generates ATP much
faster than oxidative
phosphorylation.
• Because glycolysis generates ATP
much faster than oxidative
phosphorylation, some muscles will
resort to glycolysis even in the
presence of oxygen to meet their
energy needs at a faster rate.
• The major consequence of
glycolysis is the production of lactic
acid which accumulates inside of
your muscles to cause soreness and
fatigue.
http://biology-forums.com/index.php?topic=51887.0

12. 2.8 U.3 Anaerobic cell respiration gives a small yield of ATP from glucose
• After glucose is converted
to pyruvate, if no oxygen
is available, pyruvate is
further converted
into lactate or
ethanol depending on the
organism.
• In yeast and plants,
pyruvate is converted into
ethanol (2C) and carbon
dioxide with no further
yield of ATP.
• Ethanol and CO2 are
excreted as waste
products
http://www.classhelp.info/images/AUnit51.jpg

13. 2.8 A.1 Use of anaerobic cell respiration in yeasts to produce ethanol
and carbon dioxide in baking.
1. Carbon dioxide and the baking industry
Yeast is used in baking bread. It is mixed
into dough before baking. The yeast uses
up all the O2 and then produces ethanol
and CO2. The CO2 forms bubbles making the
dough rise.
2. Ethanol and the brewing industry
Yeast is cultured in a liquid containing sugar
and other nutrients without O2 available.
This causes the yeast to use anaerobic
respiration for metabolic activities,
resulting in alcohol.

14. 2.8 U.4 Aerobic cell respiration requires oxygen and gives a large yield
of ATP from glucose.
• Aerobic respiration
also begins with
glycolysis which
produces 2 pyruvate
molecules per glucose.
• Aerobic respiration
(requires oxygen) and
occurs in
the mitochondria.
• Aerobic respiration is
much more efficient
than anaerobic
respiration.
Bioninja

15. 2.8 U.4 Aerobic cell respiration requires oxygen and gives a large yield
of ATP from glucose.
• The products created in
the redox reactions of
the Krebs cycle, plus
oxygen (terminal
electron acceptor) will
produce large
quantities of ATP
though oxidative
phosphorylation
(phosphate added to
ADP to form ATP) in the
ETC, with water being
released.
Bioninja

16. 2.8 U.4 Aerobic cell respiration requires oxygen and gives a large yield
of ATP from glucose.
• Overall in aerobic respiration glucose + oxygen will produce carbon
dioxide and water with a large yield of ATP
• About 32-34 molecules of ATP are produced by aerobic respiration,
while in anaerobic respiration, only 2 ATP molecules are produced
http://upload.wikimedia.org/wikipedia/commons/2/27/2508_The_Electron_Transport_Chain.jpg

29. 2.8 S.1 Analysis of results from experiments involving measurement of
respiration rates in germinating seeds or invertebrates using a
respirometer.
Cellular Respiration Lab Walkthrough