Cellular Respiration Overview
April 1, 2013
• Students will be able to explain where
organisms get the energy they need for life
• Students will be able to define cellular
• Students will be able to compare
photosynthesis and cellular respiration.
• Watch the Chapter Mystery video on page 431
at the beginning of Chapter 9.
• What adaptations do you think whales have
that allow them to go so long without
Where do organisms get energy?
• Autotrophs – make their
own food through
• Heterotrophs – must
consume other organisms
• Food molecules contain
chemical energy that is
released when chemical
bonds are broken.
Energy in food
• How much energy is in
• Varies with the type of
– Depends on chemical
• Energy in food is
described in units of
– Amount of energy
needed to raise the
temperature of 1 gram
of water 1 degree
Cells and Food Energy
• Cells break down food slowly, capturing
chemical energy at key steps
• Cellular respiration is the process that
releases energy from food in the presence of
• Overall reaction for cellular respiration
• Requires oxygen and food (such as glucose)
• Happens in a series of steps to control the
energy being released from the food.
• Energy from the reactions is stored as ATP.
• Do plants undergo cellular respiration? What
organelle(s) do they have that helps you
determine the answer?
Stages of Cellular Respiration
• Three main
– Krebs cycle
• Most of the
Oxygen and Energy
• Oxygen is a powerful electron
• Aerobic processes – require
oxygen, such as Krebs cycle
and the electron transport
• Anaerobic processes – do not
require oxygen, such as
• In the absence of oxygen,
fermentation keeps glycolysis
going to provide ATP for
• Mitochondria are organelles that convert
chemical energy in food to usable energy for
• Glycolysis generally occurs in the cytoplasm,
but the Krebs cycle and the electron transport
chain take place inside the mitochondria.
• Make a flowchart that shows the different
steps of cellular respiration.
• Chapter mystery clue – If whales remain
underwater for 45 minutes or more, do you
think they rely primarily on aerobic or
Photosynthesis and Cellular Respiration
removes CO2 from
the air and cellular
respiration puts it
releases O2 into the
uses that oxygen to
release energy from
– Why do food molecules differ in the amount of energy
– Write the overall reaction for cellular respiration.
– In what ways are cellular respiration and
photosynthesis considered opposite processes?
– The Greek word glukus means “sweet” and the Latin
word lysis refers to a process of loosening or
decomposing. Based on this information, write a
definition for the word glycolysis.
• Analyzing Data activity – page 433 “You are what