Chapter 6
Cellular Respiration
6.1-6.5
Breathing supplies O2 to our cells
and removes CO2
• What is “respiration?”
• An organism obtaining O2
from its environment and
releasing CO2 as waste
product. (AKA: Breathing)
• What is cellular
respiration?
• Aerobic harvesting of
energy from food
molecules.
• What does Aerobic mean?
• Requires or contains
molecular oxygen – O2
• How are breathing and
cellular respiration
related?
• Breathing = Lungs
exchange CO2 & O2
between your body &
atmosphere
• Cellular Respiration =
Your cells consume the
O2 & glucose, and
release CO2 as a waste
product from glucose
• Where does the O2 you inhale
go to?
• Lungs to bloodstream to all
cells.
• What specifically in the cells
can use the O2?
• Mitochondria use O2 to
harvest energy from sugar and
other organic molecules from
food you ate.
• How is this energy from foods
used?
• It is used to generate ATP,
which muscle cells use to
contract. (body movement)
Cellular respiration banks energy
in ATP molecules
• Does the body use or “burn” only glucose for
energy?
• No. Cells use many organic molecules.
(We will just focus on glucose)
• What does this equation tell us?
• Glucose and O2 (reactants) are used to form
CO2 and H2O (products).
• Does your body cell use 100% of energy in glucose?
• No, only about 40% of glucose’s energy is released in
ATP molecules
• What happens to the rest of that energy?
• Lost as heat
• Why is sweating necessary?
• Most of our energy when we exercise is lost as heat,
sweating helps us cool down (evaporative cooling).
The human body uses energy from ATP
for all its activities
• How do our bodies
keep going through all
of our activities just to
stay alive? (breathing,
digestion, heart
pumping)
• ATP, which is made
by cellular respiration,
75% used for this
comes from food we
eat.
Cells tap energy from electrons (rearrangement of
hydrogen atoms) transferred from organic fuel to O2
• How do our cells get energy from organic food?
• By breaking apart chemical bonds in a series of
steps using the energy carried by electrons
• Are electrons then passed around to release
more energy?
• Yes. At each step in Cellular Respiration
electrons go from a molecule where they had
more energy to where they have less energy
• In this diagram do we see the electrons being
transferred?
• No, we see the changes in the H atom distribution.
• Where do the hydrogen go?
• They combine with oxygen to form water.
• What is that hydrogen atom made of…remember?
• Each hydrogen atom consists of an electron and a
proton.
What really happens when electrons move from molecule to molecule.
• What is a Redox reaction
again? (Hint: LEO goes
GER)
• Loose an electron =
oxidation and gain
electron = reduction.
(always together, a donor
& receiver)
• What is happening with
the coenzyme NAD+?
• The sugar loses electrons
to NAD+ reducing it to
become NADH (a
hydrogen carrier.