Biologist ___________________________
Date ______________
9.1 Cellular Respiration: An Overview
Chemical Energy and Food
Food molecules contain chemical energy that is ________ when its chemical bonds are ______.
Energy stored in food is expressed in units of ____________. A ___________ is the amount of
energy needed to raise the temperature of 1 gram of water by 1 degree Celsius.
1000 calories = 1 ___________, or Calorie.
Overview of Cellular Respiration
If ___________ is available, organisms can obtain energy from food by a process called
cellular respiration. The summary of cellular respiration is presented below.
In symbols:
6 _________ + __________  6 ______ + 6 ________ + ___________
In words:
___________+ ___________ ___________+ ___________+ ___________
Stages of Cellular Respiration
The three main stages of cellular respiration are ___________, the ________ cycle, and the
___________ ___________chain.
Stages of Cellular Respiration
Glycolysis produces only a ________ amount of energy. Most of glucose’s energy (90%)
remains locked in the __________ bonds of ___________acid at the end of glycolysis.
Stages of Cellular Respiration
During the Krebs cycle, a little more energy is ___________from pyruvic acid.
Stages of Cellular Respiration
The electron transport chain produces the ________of the ___________in cellular respiration
by using oxygen, a ___________ ___________acceptor.
Oxygen and Energy
Pathways of cellular respiration that require oxygen are called ___________. The
___________cycle and ___________transport chain are both aerobic processes. Both processes
take place inside the mitochondria.
Oxygen and Energy
___________ is an ___________process. It does not directly require oxygen, nor does it rely on
an oxygen-requiring process to run. However, it is still considered part of cellular
respiration. Glycolysis takes place in the ___________of a cell.
Comparing Photosynthesis and Cellular Respiration
Similarity –
Difference -
9-3 Fermentation
Fermentation
Fermentation is a process by which energy can be released from food molecules in the
___________ of ___________. Fermentation occurs in the ___________of cells.
Alcoholic Fermentation
__________ and a few other microorganisms use alcoholic fermentation that produces ethyl
alcohol and carbon dioxide.
Chemical Equation: ___________+ NADH  ________ + _____ + ________
Lactic Acid Fermentation
______ organisms, including humans, carry out fermentation using a chemical reaction that
converts pyruvic acid to lactic acid.
Chemical equation: ___________+ NADH  ___________+ _______
Energy and Exercise
How does the body produce ATP during different stages of exercise?
Quick Energy
Cells normally contain ______ amounts of ATP produced during cellular respiration, enough
for a few ________ of intense activity.
___________ ___________ can supply enough ATP to last about ____ seconds. However, extra
oxygen is required to get rid of the lactic acid produced. Following intense exercise, a
person will huff and puff for several minutes in order to pay back the built-up “___________”
and ______ the ___________from the body.
Long-Term Energy
For ____________ exercise lasting longer than 90 seconds, ____________ _____________ is
required to continue production of ATP.
Cellular respiration releases energy more _________ than fermentation does.
The body stores energy in the form of the carbohydrate __________. These glycogen stores
are enough to last for ___ to ____ minutes of activity. After that, the body begins to break
down other stored molecules, including _____, for energy.