Topic 2: Molecular biology (21 hours)
2.8 Cell respiration: Cell respiration supplies energy for the functions of life.
Nature of science: Assessing the ethics of scientific research—the use of invertebrates in respirometer
experiments has ethical implications.
Understandings:
 Cell respiration is the controlled
release of energy from organic
compounds to produce ATP.
 ATP from cell respiration is
immediately available as a source of
energy in the cell.
 Anaerobic cell respiration gives a small
yield of ATP from glucose.
 Aerobic cell respiration requires
oxygen and gives a large yield of ATP
from glucose.
 Details of the metabolic pathways of
cell respiration are not needed but the
substrates and final waste products
should be known.
Applications and skills:
 Application: Use of anaerobic cell respiration in yeasts
to produce ethanol and carbon dioxide in baking.
 Application: Lactate production in humans when
anaerobic respiration is used to maximize the power of
muscle contractions.
 Skill: Analysis of results from experiments involving
measurement of respiration rates in germinating seeds
or invertebrates using a respirometer. 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. The ethics of
the use of animals in experiments could be discussed in
relation to respirometer experiments.
Topic 2: Molecular biology (21 hours)
2.9 Photosynthesis: Photosynthesis uses the energy in sunlight to produce the chemical
energy needed for life.
Nature of science: Experimental design—controlling relevant variables in photosynthesis experiments is
essential.
Understandings:
 Photosynthesis is the production of carbon compounds
in cells using light energy.
 Visible light has a range of wavelengths with violet the
shortest wavelength and red the longest. Visible light
has wavelengths between 400 and 700 nanometres, but
they are not expected to recall the wavelengths of
specific colours of light.
 Chlorophyll absorbs red and blue light most effectively
and reflects green light more than other colours.
 Oxygen is produced in photosynthesis from the
photolysis of water.
 Energy is needed to produce carbohydrates and other
carbon compounds from carbon dioxide.
 Temperature, light intensity and carbon dioxide
concentration are possible limiting factors on the rate of
photosynthesis.
Applications and skills:
 Application: Changes to the Earth’s
atmosphere, oceans and rock
deposition due to photosynthesis.
 Skill: Drawing an absorption
spectrum for chlorophyll and an
action spectrum for photosynthesis.
 Skill: Design of experiments to
investigate the effect of limiting
factors on photosynthesis.
PRACTICAL:
Separation of photosynthetic pigments
by chromatograph. Paper
chromatography can be used to separate
photosynthetic pigments but thin layer
chromatography gives better results.
Biology Journal 12/11/2013
What is the chemical equation for
photosynthesis?
6CO2 + 6H2O →C6H12O6 + 6O2
What happens to CO2 in photosynthesis?
CO2 stays mostly intact. Hydrogen atoms are “fixed” to
CO2, making glucose.
What happens to H2O in photosynthesis?
H2O is split, using the energy from sunlight. This is
called photolysis. The H+ ions are fixed to CO2, and the
O from water is given off as oxygen gas.
Biology Journal 10/27/2014
What do these 3 have in common?
Biology Journal 12/10/2013
The name of the pigment
that plants use for
photosynthesis is ______.
The sunlight that plants are
exposed to contains _____
of the colors of light.
Chlorophyll absorbs ______
and ______ light, while it
reflects ______ light, which
is why plants appear to be
green to us.
Photosynthesis and Cellular Respiration
Whiteboard Review!
What is the chemical formula for
cellular respiration?
C6H12O6 + 6O2 → 6CO2 + 6H2O
What is the chemical formula for
photosynthesis?
6CO2 + 6H2O → C6H12O6 + 6O2
What gasses make up air?
 Name at least 3
The gasses that make up air (in decreasing order):
Nitrogen (N2)
Oxygen (O2)
Argon (Ar)
Carbon Dioxide (CO2)
Neon (Ne)
Helium (He)
Methane (aka natural gas, CH4)
Water Vapor (H2O)
Complete the below Venn diagram!
Aerobic
Respiration
Both
Anaerobic
Respiration
Aerobic
Respiration
Both
Anaerobic
Respiration
•Requires O2
•Metabolic reactions
that generate energy
for the cell
•Happens in the
mitochondria
•Initial steps are
gycolysis (splitting
•Happens in the
glucose into
cytoplasm
pyruvate), which
happens in cytoplasm
•Products are CO2
and H2O
•High yield of ATP
•Reactant is pyruvate
(C3H4O3)
•Happens when O2
runs out
•Products are either:
1. ethanol and CO2
(yeast)
2. lactic acid
(humans)
•Low yield of ATP
Carbon dioxide and water are the reactants in
photosynthesis.
1. What happens to the carbon atoms from CO2?
2. What happens to the oxygen atoms from CO2?
3. What happens to the hydrogen atoms from H2O?
4. What happens to the oxygen atoms from H2O?
6CO2 + 6H2O → C6H12O6 + 6O2
How do you think you could measure how much
photosynthesis a plant is doing?
Measure O2 produced, CO2 consumed, or biomass of
the plant!
Where does the energy to build the
food molecules in photosynthesis
come from?
The Sun
Apollo, god of the sun and Greek restaurants
What is photolysis? When does this
happen?
Photoylsis is the breaking of H2O during
photosynthesis. The O’s in water are
given off as oxygen, and the H’s are
fixed to CO2, to make glucose.
Sketch a graph of how light intensity
effects the rate of photosynthesis.
What kind of organism does
fermentation? What are the
products of this?
Fermentation is done by yeast.
It starts with pyruvate, and
creates CO2 (bubbles) and
ethanol (aka alcohol)
Sketch a graph of how temperature
effects photosynthetic rate.
These are the definitions for what 3 words?
Gas
Exchange
The diffusion of gasses (such
as O2 and CO2) between the air
in the lungs and the blood.
Cellular
Respiration
The controlled release of
energy from organic
molecules in cells to form ATP.
Ventilation
How the muscles (diaphragm
and intercostals [ribs]) move
to push air into and out of the
lungs.
Complete the below Venn diagram!
ATP
Both
ADP
Complete the below Venn diagram!
ATP
Both
ADP
•Adenosine
diphosphate
•Adenosine
triphosphate
•Contain adenosine, and
phosphates (2 or 3)
•High in energy
•Part of the energystorage system of cells.
•Low energy
All cells use ATP/ADP as
energy source.
•Cells have lots of these
“laying around,” ready
to be used
•The last phosphate
bond is high in energy,
and can easily be
formed or broken
What is the difference between
chlorophyll and a chloroplast?
Chloroplast is the part of a plant cell
where the chemical reaction of
photosynthesis happens.
Chlorophyll is the greencolored pigment that absorbs
specific colors of light, to
power photosynthesis.
What color(s) of light do
chlorophylls use?
Chlorophylls uses all the colors
of the rainbow except green!
Chlorophylls reflect green light, so green is not
used. Mostly blue and orange light are used for
photosynthesis.
Which pigment has optimal absorption
only at 400 to 500 nanometers?
Carotenoids! Fun fact: the name comes from
carrots, because the pigment is orange in
color. There’s also lots of them in apricots.
Photosynthesis (mostly) can’t happen in
the winter. Why not?
The sunlight is
dim, and days
are short
CO2 + H2O
→
Water is frozen,
and thus
inaccessible
C6H12O6 + O2
Explain this science joke.
Oxygen does literally grow on trees. Through
photosynthesis, plants make O2, which keeps
us alive. We’d better be nice to the
environment!
Which of these statements are
true:
Write out the numbers 1 through 6. Then, write “true”
or “false” for each one.
1. Plants do photosynthesis.
2. Plants do cellular respiration.
3. Plants create O2.
4. Plants remove CO2 from the air.
5. Plants cause global warming.
6.Plants get the energy for
photosynthesis from water.
Which of these statements are
true:
1. Plants do photosynthesis. True!
2. Plants do cellular respiration. True!
3. Plants create O2. True!
4. Plants remove CO2 from the air. True!
5. Plants cause global warming. False!
6.Plants get the energy for
photosynthesis from water. False!
What reaction does this diagram outline? Fill it in!
What do these 2 have in common?
A coal power plant
Weightlifting
Both of these…






Create CO2
Create H2O
Consume O2
Burn calories
Consume / release energy
Break down organic (carbon-based)
molecules to get energy
 The energy for these molecules at one point
came from the sun (either food or fossil fuels)