Transcript Cellular Respiration

Bell Work
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Complete Bell Work Sheet
Turn in any back work (Plant Pigment Labs)
Work on Vocab Book
Cellular
Respiration
Inside the Mitochondria
Cellular Respiration
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Cellular Respiration is the process that releases energy
by breaking down food molecules in the presence of
oxygen.
Oxygen
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Glucose
Carbon Dioxide
Water
Energy
There are three parts to cellular respiration:
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Glycolysis – takes place in the cytoplasm
Krebs Cycle – takes place in the mitochondria
Electron Transport Chain – takes place in the mitochondria
High Energy Molecules
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NADH – this is a molecule that carries high energy
electrons (NAD+
NADH) it acts just like NADPH
acted in photosynthesis
FADH2 – this is another molecule that can carry high
energy electrons (FAD+
FADH2)
ATP – one of the main chemical compound that living
things use to store energy. Created by adding an extra
phosphate molecule to ADP. This is the same molecule
created in the light dependent reactions during
photosynthesis
Glycolysis
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Glycolysis is the first step of
cellular respiration where one
molecule glucose is broken in
half, producing two molecules of
pyruvic acid
Glycolysis uses two ATP
molecules to get started, but
produces four.
Glycolysis can occur with no
oxygen present.
It also removes electrons from
the glucose. These electrons
bond to NAD+ making it
NADH.
Krebs Cycle
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Only occurs when
oxygen is present
The pyruvic acid
enters the
mitochondria and
there is broken
down into carbon
dioxide through a
series of steps that
release energy
from the carbon
bonds
Kreb’s Cycle: Step 1
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A carbon atom from the pyruvic acid
molecule made during glycolysis is
removed.
That carbon combines with two
oxygen molecules to make a carbon
dioxide molecule
The two carbon atom left over
combines with coenzyme A (CoA)
making acetyl CoA
This then carries the two carbons to
a four carbon group making citric acid
Kreb’s Cycle: Step 2
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A carbon molecule is
pulled off of the citric
acid molecule along with
an electron
This electron is carried
by NAD+ as NADH
creating a high energy
molecule
The carbon that is pulled
of is combined with
oxygen to make carbon
dioxide
Kreb’s Cycle: Step 3
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Another carbon molecule is pulled off of the 5-carbon
compound and used to create a molecule of carbon dioxide
The electrons removed are carried by two NAD+ making it
NADH and one FAD+ making it FADH2
An ATP molecule is
also created during this
step
The end result is a 4
carbon molecule that
can be reused in the
Kreb’s Cycle (added to
acetyl CoA in step 1)
Electron Transport Chain
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The electron carrier molecules (FADH2 and NADH) are
transferred to the electron transport chain.
This is where the energy from the electrons is used to
make more ATP
Electron Transport Chain
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The high energy molecules FADH2 and NADH meet up
with carrier proteins
The carrier proteins embedded in the mitochondrial
membrane remove the H+ ions and electrons (e-)
The H+ ions begin to build up in the intermembrane
space causing it to be positively charged
The H+ ions pass through channel proteins (ATP
synthases) causing it to spin
Each rotation it picks up an ADP molecule and attaches a
phosphate creating ATP
Total Energy Gains
Glycolysis
2 NADH
Kreb’s
Cycle
2 FADH2
6 NADH
Electron
Transport
Chain
2 FADH2
6 NADH
Cellular Respiration Overview
What do you think happens when
there is no oxygen present after
glycolysis to make CO2?
Lactic Acid Fermentation
Fermentation
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The release of energy from food molecules in the
absence of oxygen.
There are two main types of fermentation
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Lactic Acid Fermentation (animals)
Alcohol Fermentation (some microorganisms)
Lactic Acid Fermentation
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Sometimes when we exercise, we cannot supply the
muscles with enough oxygen to complete the Kreb’s
Cycle
Glycolysis can still be completed creating 2 molecules of
pyruvic acid, 2 ATP and 2 NADH
The energy from the 2 NADH molecules are used to
turn the pyruvic acid into lactic acid
This is done so the NADH can be turned back into
NAD+ and be recycled to the glycolysis reactions as
electron carriers
Lactic Acid Fermentation
Pyruvic acid + NADH
Lactic acid + NAD+
Alcohol Fermentation
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Some microorganisms perform a different type of
fermentation that turns the pyruvic acid into alcohol and
carbon dioxide
Yeasts are one example of a microorganism that uses
alcohol fermentation
Consequences of Exercise
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You have enough ATP stored in your muscle cells to last
long enough to carry you through a 50m sprint
If you continue sprinting lactic acid fermentation can
produce enough energy to last one and a half minutes
This is why we have to pace ourselves in long distance
runs
When running we break down our stores of glycogen
using cellular respiration
This lasts about 15-20 minutes, then we break down
other stored molecules like fats.
This is why cardiovascular exercise helps us loose weight
Photosynthesis VS Respiration
Photosynthesis
Function
Location
Reactants
Products
Equation
Cellular Respiration
Energy Storage
Energy Release
Chloroplasts
Mitochondria
CO2 and H2O
C6H12O6 and O2
C6H12O6 and O2
CO2 and H2O
CO2 + H2O
C6H12O6 + O2 C6H12O6 + O2
CO2 + H2O
Cellular Respiration Videos
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http://www.youtube.com/watch?v=6JGXayUyNVw&featur
e=related
http://www.youtube.com/watch?v=aCypoN3X7KQ&featu
re=related
http://www.youtube.com/watch?v=xbJ0nbzt5Kw
http://www.youtube.com/watch?v=tNqfPsVAdYk