Chater 8 and 9 Energy in Living
Organisms
CELL METABOLISM
• Metabolism
o The chemical processes occurring within a living
cell
o Necessary for maintaining life
o Uses enzymes
Breaks down or builds
o _____________________materials
the cell needs
Enzymes
proteins
o Are ____________
o Required for every chemical reaction in an organism
homeostasis
o Without, would not be able to maintain ___________
Don’t make the reaction happen that couldn’t happen
on its own
o Make the reaction occur much _____
faster
• Function of Enzymes
catalysts
o Serve as _________
activation energy
o Work by lowering the _______________
 energy required to get the reaction started
• Characteristics of Enzymes
pH & temperature range
o Work best in a narrow ______________________
o They are not changed or used up in the reaction;
used over & over
can be _______________
again
substrate-specific
shape
o They are_______________;
because of their_____
Substrate
• _________surface to which the enzyme binds
Active site where substrate binds and
• __________undergoes a chemical reaction
BREAKING DOWN MOLECULES
BUILDING MOLECULES
CELL ENERGY
ability to do work
• Energy is the ____________________
Heterotrophs
• ____________:
Organisms that obtain energy from
consuming food
Autotrophs
• ____________:
Organisms that use sunlight or
chemicals to convert inorganic
compounds into food for energy.
photosynthesis to
o Example: Plants – use the process of_____________,
make their own food. This process
chloroplasts
occurs in the ____________
o The equation for photosynthesis:
 CO2 + H2O + energy → C6 H12 O6 + O2
Chemical Energy
chemical bonds
• Stored in ______________
• Potential energy
o When bonds are broken;
useable energy
converted to _____________
ATP
in the form of ____
• Food molecules cannot be
used directly
ATP
o The amount of energy
destructive
wasteful
released would be ________and
__________
ATP- Adenosine Triphosphate
Nucleotide
o ____________composed
of:
• Nitrogen base - ________
adenine
ribose
• 5-carbon sugar- ________
3
• __phosphate
groups
ATP
• Energy is stored in ________________________bonds.
phosphate – phosphate
• ATP works like a _____________________.
rechargeable battery
• Cells are able to use and recycle ATP by ____________
breaking
________________a
phosphate group
off or adding
o Energy is _________
released when the
phosphate bond is broken
o ATP is converted to _____________
ADP- adenosine
____________
diphosphate
o ADP is like an “____________”
uncharged battery
stored when phosphate
o Energy is _______
bond is added to ADP making ATP
recharged like a fully
• ATP is “__________”
charged rechargeable battery
Like a Rechargeable Battery
ATP – ADP CYCLE
Phosphate bonds
Cellular Respiration
• Aerobic energy production
o Breakdown of glucose in presence of oxygen
o Produces ATP
o Occurs in mitochondria of eukaryotic cells
o Equation for cellular respiration
• C6 H12 O6 + O2 → CO2 + H2O + energy (ATP)
CELLULAR RESPIRATION
2
2
2
34
3 STEPS TO CELLULAR RESPIRATION
o Glycolysis
• Occurs in cytoplasm
• Uses 1 glucose molecule and O2
• Produces 2 Pyruvic acids, 2 ATP’s and high energy e-
o Krebs Cycle
• Occurs in outer membrane of mitochondria
• Produces CO2 as waste, 2 ATP’s and high energy e-
o Electron Transport Chain
• Occurs in the inner membrane of mitochondria
• Uses O2 and high energy electrons from first 2 steps
• Produces H2O and 32 ATP’s
GLYCOLYSIS
KREBS CYCLE
ELECTRON TRANSPORT CHAIN
1 GLUCOSE
STAGE
WHERE
GLYCOYSIS
CYTOPLASM
KREBS
CYCLE
OUTER
MITOCHONDRIA
ELECTRON
TRANSPORT
CHAIN
INNER
MITOCHONDRIA
# ATP
2
2
32
TOTAL ATP GAIN IN
CELLULAR RESPIRATION
36 ATP per MOLECULE
OF GLUCOSE
Fermentation
• Anaerobic Energy Production
o Occurs if oxygen is not available
o Glycolysis still takes place
o 2 ATP’s are made for 1 glucose
• 2 types:
o Lactic acid fermentation
o Alcoholic fermentation
Lactic Acid Fermentation: Produces Lactic acid
• Human Muscle Cells
o Occurs when muscles run out of oxygen
o Muscle switches to fermentation
o Lactic acid builds up; causes pain, soreness & fatigue
o Will switch back to Cellular Respiration when oxygen
is re-supplied
o Lactic acid is sent to liver to be broken down
• Bacteria
o some bacteria
o during anaerobic conditions
o Utilized by dairy industry to produce yogurt & cheese
Alcoholic Fermentation: Produces alcohol and CO2
• Occurs in Yeast during anaerobic conditions
• Important in brewing & baking industries
TOTAL ATP GAIN IN
FERMENTATION
2 ATP per MOLECULE
OF GLUCOSE
PHOTOSYNTHESIS
Process in which energy of sunlight is used to convert water and carbon
dioxide into high-energy carbohydrates (sugar and starches) and oxygen, a
waste product
Factors affecting photosynthesis
• Temperature
• photosynthesis depends on enzymes that function best between 0o and 35o C
• Availability of water
• Shortage of water can slow or even stop photosynthesis
• Amount of Light
• Increasing light intensity increases the rate of photosynthesis
Light and Pigments
• In addition to water and carbon dioxide, photosynthesis
requires light and chlorophyll, a molecule found in
chloroplasts.
• Pigment: light absorbing molecule
o Principal pigment is chlorophyll
o 2 main types
• chlorophyll a
• chlorophyll b
• Energy absorbed by chlorophyll
is transferred directly to
electrons in the chlorophyll
o Makes photosynthesis possible
• These high-energy electrons are
used to help build carbohydrates.
COMPARING PHOTOSYNTHESIS AND CELLULAR RESPIRATION
Photosynthesis
•
•
•
•
•
Occurs in the chloroplast
Uses sunlight to convert H2O and CO2
into high energy sugars and O2
uses water and light
splits water and releases O2
produces O2 and glucose
Cellular Respiration
•
•
•
•
Occurs mostly in mitochondria
Uses O2 and glucose to produce H2O,
CO2 and ATP
uses oxygen and glucose
produces carbon dioxide, water and
energy (36 ATP)