LEC-Cellular_Respiration (lower section1).ppt

Biology
Science Department
Deerfield High School
LEC: Energy Transformations in
Living Organisms: Cellular
Respiration
Unit 3: Energy Transformations
Chapter 9, Sections 1 & 2 (Pages 220-232)

Biology
Science Department
Review: Producers
 Producers get their
energy from the sun.
 Producers convert this
light energy into
stored chemical
energy (glucose).
 This process is called
photosynthesis.

Biology
Science Department
Review: Consumers
 Consumers get their
energy from the
producers.
 Consumers convert
stored chemical
energy (glucose) into
usable chemical
energy (ATP).
 This process is called
cellular respiration.

Biology
Science Department
Cellular Respiration (aerobic)
 Cellular respiration is the process by which
glucose (C6H12O6) is broken down to
release energy for making ATP, another
form of chemical energy.

Biology
Science Department
Aerobic Respiration – Equation
C6H12O6 + 6 O2 6 H2O + 6 CO2 + 36 ATP
food
(glucose, a carbohydrate)
oxygen water carbon
dioxide

Biology
Science Department
BioTheme: Interdependence!
Photosynthesis:
6 H2O + 6 CO2 + energy (sun) → C6H12O6 + 6 O2
Aerobic Cellular Respiration:
C6H12O6 + 6 O2 → 6 H2O + 6 CO2 + energy (ATP)

Biology
Science Department
Why ATP? An analogy to money…
 Glucose in our food is a great source of energy! ($100 bill)
 However, individual cell processes may only require a small
amount of energy ($1 bill)
 Analogy: most vending machines do not accept $100 bills!
We need a smaller form of “currency” for these processes.
 ATP (adenosine triphosphate) is this important cellular
“currency” for life.
 ATP releases more appropriate amounts of energy for the
individual cellular processes that require energy.
(We will study this molecule in detail in our next activity!)

Biology
Science Department
The BIG Question is…
Do only animals respire?
Or do plants respire too?
 Only plants perform photosynthesis
 Plants AND animals perform cellular
respiration!
(Can you explain why??)

Biology
Science Department
Site of Cellular Respiration
 Plant and animal cells contain mitochondria: cell
structures that transform chemical energy from
glucose to ATP.

Biology
Science Department
Significant ATP Production
 Aerobic cellular respiration releases energy
SLOWLY, using oxygen to convert ONE
molecule of glucose to 36 ATP!

Biology
Science Department
Cellular Respiration (anaerobic)
 What happens when cells don’t have enough oxygen?
 Some organisms live in an oxygen-free environment.
How do they get their energy?

Biology
Science Department
Cellular Respiration (anaerobic)
 Anaerobic respiration is also called
fermentation, or the process by which
energy is released from glucose when
oxygen is NOT available.
 This process allows organisms to continue
to produce energy until oxygen is available.
 However, this process only releases 2 ATP
per molecule of glucose.

Biology
Science Department
Alcoholic Fermentation
 Anaerobic way of converting energy for
yeast and other microorganisms
 Glucose broken down to produce alcohol,
CO2 and energy (ATP)
 C6H12O6  ethanol + CO2 + 2 ATP
 EX: baking bread with yeast
fermenting wine & beer

Biology
Science Department
Fermentation - Bread
 Source of sugar?
 DOUGH! (sugar and/or flour)
 Yeast use up the O2 and ferment sugar
 Produce CO2, which is trapped within
tiny bubbles & results in the dough rising
 Produce ethanol, which evaporates in the
baking process

Biology
Science Department
Fermentation - Wine
 GRAPES!
 Produce CO2 (kept only in champagne)
 Produce ethanol (% alcohol varies based on
sugar content of grapes and # of fermentations)

Biology
Science Department
Fermentation - Beer
 BARLEY!
 Hops are added as a preservative
and for added flavor
 Produce CO2 and ethanol also
 Various carbohydrates can be used to make
alcohol – including wheat, rice, and potatoes!

Biology
Science Department
Other side effects of fermentation?!
 “Drunken Swedish moose drowns after
fermented apple binge”
http://www.usatoday.com/news/offbeat/2006-11-24-moose_x.htm
 “Drunk Moose Invade Seniors Home”
http://www.wtopnews.com/index.php?nid=456&sid=620430

Biology
Science Department
Lactic Acid Fermentation
 Anaerobic way of converting energy in
animal cells and some microorganisms
 Glucose broken down to produce lactic
acid, CO2 and energy (ATP)
 C6H12O6  lactic acid + CO2 + 2 ATP
 EX: muscle cells during strenuous exercise
fermenting cheese, yogurt, sour cream

Biology
Science Department
Strenuous Exercise
 Lactic acid is produced by your muscle
cells during rapid exercise when the body
cannot supply enough O2 to tissues.
 Without enough O2, the body is NOT able
to produce all of the ATP that is required.
 The buildup of lactic acid can cause painful
burning in your muscles!

Biology
Science Department
Minimal ATP Production
 In the absence of oxygen, anaerobic
respiration only releases 2 ATP for each
molecule of glucose broken down.

Biology
Science Department
Comparing ATP Production
 First, your body breaks down glucose through
aerobic respiration to produce 36 ATP per
glucose molecule; however, this is a slow process.
 When muscle cells cannot get enough O2 they
break down glucose through lactic acid
fermentation to produce 2 ATP per glucose…
 Therefore, AEROBIC RESPIRATION is much
more efficient in terms of ATP production –
36 ATP compared to 2 ATP!

Biology
Science Department
Aerobic Training
 Ex: long runs, biking, swimming
 Can increase the size and number of
mitochondria in muscle cells
 Can increase the delivery of O2 to muscles by
improving the heart and lungs

Biology
Science Department
Anaerobic Training
 Ex: sprints, strides,
quick bursts of energy
 Increase the glycogen levels in the muscles
 Increase body’s tolerance to lactic acid

LEC-Cellular_Respiration (lower section1).ppt

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