Download Ch. 9 Cellular Respiration

CH. 9 CELLULAR
RESPIRATION
This football player uses cellular respiration to get energy during football
games
9-1 CHEMICAL PATHWAYS
An overview of glycolysis, cell respiration, & Fermentation
I. CHEMICAL ENERGY AND
FOOD
1. Humans use fats,
proteins, and
carbohydrates as
sources of energy or
food.
2. When you eat food
energy is released
3. Calories can measure
how much energy is in
the food you eat
4. Calorie- the amt. of
energy needed to raise
the temp. of 1 gram of
water 1oC
The fruit this lady eats will be digested &
the energy from the food will be released into
her body.
II. OVERVIEW OF
CELLULAR RESPIRATION
1. During cellular respiration energy is
released from food by breaking it down in
the presence of oxygen (O2)
The equation for cellular respiration is:
6O2 + C6H12O6 → 6CO2 + 6H2O + Energy
oxygen + glucose → carbon dioxide + water + energy
2. Food is the material for the
mitochondria in the cells in the body
& to produce energy.
Animal
Animal Cell
Mitochondria
Plant
Plant Cell
Discuss w/ Partner
1. What chemical in organisms is used as a
source of energy?
* Hint- it has three letters
Answer
ATP
III. GLYCOLYSIS
1. Glycolysis– the
process that breaks
one molecule of
glucose (C6H12O6) a
6- carbon compound
in half into pyruvic
acid, a 3- carbon
compound.
2. Glycolysis happens in
the cytoplasm of the
cell
3. Glycolysis can take
place w/ or w/o
oxygen
The glycolysis pathway
4. During glycolysis:
NAD+ becomes NADH
Pyruvic Acid (a 3-carbon
molecule) is formed
5. Glycolysis results in :
• 2 ATP molecules
• 2 NADH molecule
• 2 pyruvic acid
Discuss w/ Partner:
•What kind of molecule is
+
NAD ?
•*Hint: think of
photosynthesis!
Answer!
•An electron Carrier!
•It carries hydrogen electrons
like NADP+ carries hydrogen
electrons during
photosynthesis
6. ATP Production
• At the beginning of glycolysis, the cell
uses up 2 molecules of ATP to start
glycolysis
2 ADP
4 ADP
2
4 ATP
Show How Cells Get Energy Video
Discuss w/ Partner:
• Look at Figure 9-2 on page 222 and
answer the following questions.
• 1. Where does the glucose used in
respiration come from?
• 2. How do you know that this series of
reactions occurs in the presence of
oxygen?
• 3. What does glycolysis supply to the
Krebs Cycle and to the electron transport
chain?
7. Advantages of
glycolysis:
a) No oxygen is needed
b) Takes place
extremely fast
thousands of ATP
molecules can be
produced in less than
one second.
Every molecule of glucose in the bread
this little girl eats will turn into 2 ATP
molecule and 2 pyruvic acid molecules
IV. FERMENTATION
1. If no oxygen is present after glycolysis
2.
3.
4.
5.
fermentation takes place
Fermentation- the release of energy
from food without oxygen being present
Fermentation is an anaerobic process
Anaerobic- Oxygen is not needed (w/o
oxygen)
There are two types of fermentation:
a) Alcoholic
b) Lactic Acid
6. Alcoholic
Fermentation
• Pyruvic acid from
glycolysis forms ethyl
alcohol and carbon
dioxide as waste
• Used by yeasts and other
organisms
• The equation for alcoholic
fermentation after
glycolysis is:
pyruvic acid + NADH →
alcohol + CO2 + NAD+
7.
Lactic Acid Fermentationforms 2 lactic acid
molecules from 2 pyruvic
acid molecules; results in
the production of ATP
• Regenerates NAD+ so
glycolysis can continue
• Takes place in muscle
cells during rapid
exercise due to lack of
O2
• The result: the muscle
cells are able to
produce ATP
• Some unicellular
organisms produce
lactic acid as a waste
product, which allows
humans to make
cheese, yogurt, etc.
• The equation for lactic
acid fermentation after
glycolysis is:
• pyruvic acid + NADH
→ lactic acid + NAD+
Discuss w/ Partner:
Does Fermentation
take place with O2?
Answer
•NO
•Fermentation takes place
after glyco lysis if there is no
oxygen!