Transcript Respiration 2015

Define cellular respiration
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Cell respiration is the
controlled release of
energy from organic
compounds in cells to form
ATP
Covalent bonds are slowly
oxidized by enzymes
releasing ATP molecules
Takes place in the
presence or in absence of
oxygen
Know These
Numbers
Glycolysis
glucose + 2 ATP
2 pyruvate + 4 ATP + 2 NADPH
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The breakdown of one molecule of glucose into two
molecules of pyruvate with the release of some energy
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Takes place in the cytoplasm
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Does not require oxygen
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Glycolysis Video
Alcoholic Fermentation
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Done when no oxygen is present
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Starts with glycolysis
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The pyruvate is then broken down further
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Yeast turn the pyruvate into ethanol
and carbon dioxide
Used to make bread and alcohol
Lactic Acid Fermentation
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Cell that normally do aerobic respiration can
perform fermentation
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Done when you sprint and the body can not
supply the muscles with enough oxygen to
perform aerobic respiration
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Can cause muscle cramps
Aerobic cellular respiration
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In the presence of
oxygen pyruvate is
broken down in the
mitochondria into carbon
dioxide and water
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This is the most efficient
use of this molecule to
harvest energy
Reaction takes place in
the mitochondria
Yields approximately 2834 more ATP
Oxidation and Reduction
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Redox (reduction – oxidation) reaction: the
enzyme controlled transfer of electrons
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Oxidation Is the Loss of electrons
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Involves gaining an oxygen or losing a hydrogen
Energy is lost (exergonic reaction)
In respiration glucose is oxidised to carbon dioxide
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Reduction Is the Gain of electrons
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All hydrogens are gradually removed from the
glucose molecule
Involves losing oxygen or gaining hydrogen
Energy is absorbed (endergonic reaction)
This substance now has the power to reduce other
substances and become oxidised in the process
In respiration oxygen is reduced to water
Remember it by the saying OIL RIG
Oxidation
Reduction
Loss of electrons
Gain of electrons
Gain of oxygen
Loss of oxygen
Loss of hydrogen
Gain of hydrogen
Results in many C-O bonds
Results in many C-H bonds
Result is a compound with low
potential (stored) energy
Result is compound with high
potential (stored) energy
Glycolysis
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Linear series of reactions in which glucose is broken down into 2
molecules of pyruvate
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Glycolysis takes place in the cytoplasm
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Glucose + 2ADP + 2Pi + 2NAD+
2H20
2Pyruvate + 2ATP + 2NADH + 2H+ +
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Anaerobic process that does not require oxygen
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Glycolysis takes a 6-carbon hexose sugar and created 2 3-carbon
monosaccharides
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The first step is phosphorylation
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ATP is used to add a phosphate group to the glucose
A second phosphorylation using another ATP follows adding a second
phosphate
This creates fructose biphosphate
2 molecules of ATP are consumed for every molecule of glucose at
this point
Glycolysis Cont.
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The second step is lysis
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The third step is oxidation
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The above chemicals are then involved in a combined oxidation
phosphorylation reaction
Hydrogen is removed from the triose phosphates
NAD acts as the hydrogen receptor
The last step is ATP formation
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Fructose biphosphate is split producing 2 triose phosphate
molecules each with 3 carbons
Lastly the triose biphosphate gives up one of the phosphates to
ADP to make it ATP and producing pyruvate
Total ATP production for each glucose molecule is 4 but the
NET gain is only 2
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Remember we spent 2 ATP at the beginning to start the process
Electron Micrograph of a
Mitochondria
Micrograph Explained
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Found in the cytoplasm of all Eukaryotic cells,
usually in large numbers
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Large organelle surrounded by an outer
membrane and an inner membrane
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Inner membrane is folded – cristae
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Between the inner membrane and the outer
membrane is the matrix
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Inside is a watery fluid containing enzymes and
molecules
There are also ribosomes and DNA
The DNA is maternal DNA and can be used to trace
heredity
Structure and Function
Structure
Function / Role
External Double Membrane
Permeable to pyruvate, CO2, O2 and
NAD/NADH
Matrix
Site of enzymes of link reaction and
Krebs cycle
Inner Membrane
Surface area greatly increased by in
tucking to form cristae (increases
surface area for electron chain),
impermeable to hydrogen ions (allows
for a concentration gradient to be
created
Inter-membrane Space
Relatively tiny space, allows the
accumulation of hydrogen atoms ,
facilitates phosphorylation
Aerobic Respiration
Link Reaction
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Forms the link between glycolysis and the
Krebs cycle
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Pyruvate is transferred from the cytoplasm to
the mitochondrial matrix
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Pyruvate + CoA + NAD+
Acetyl CoA + CO2 + NADH + H+
This reaction is known as decaboxylation of
pyruvate
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A carbon dioxide is removed
The molecule is also oxidised by the removal of a
hydrogen
NAD is formed at this time
Aerobic Respiration
Krebs Cycle
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Also known as
tricarboxylic citric acid
cycle or TCA cycle
Occurs in the matrix of
the mitochondria
1 molecule of acetyl CoA
yields
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2 CO2
3 NADH + 3H+
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1 FADH2
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1 ATP
Krebs Cycle Details
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Acetyl CoA combines with a 4-carbon compound to create
a 6-carbon compound
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This compound is then decarboxylated
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A CO2 is removed
5-carbon compound is created
The 5-carbon compound is decarboxylated
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A CO2 is removed
4-carbon compound is created
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This takes us back the original 4-carbon compound that
starts the cycle
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The main outputs are energy freed from the compounds
Krebs Cycle Important
Notes
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per molecule that enters
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Two molecules of
carbon dioxide are
given off in separate
decaboxylation
reactions
One molecule of ATP is
formed
Three molecules of
NADH (aka reduced
NAD) are formed
One molecule of FADH
(aka reduced FAD) is
formed
Summary to this Point
Step
CO2
ATP
NADH
FADH
Glycolysis
0
2
2
0
Link
Reaction
2
0
2
0
Krebs
Cycle
4
2
6
2
Totals
6 CO2
4 ATP
10
NADH
2 FADH
Terminal Oxidation and oxidative phosphorylation
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A.K.A. – the electron transport chain
The removal of H+ from NADH and FADH
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Releases energy that is transferred to ADP to form ATP
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End receiver of the H+ is O2 and this forms water
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For every molecule of NADH that is reduced – 3 ATP are
formed
Total yield from aerobic respiration is 38 ATPs
Phosphorylation by Chemiosmosis
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The synthesis of ATP is coupled to electron transport via
the movement of protons
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Electron –carrier proteins are arranged in the inner
mitochondrial membrane
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Oxidize the reduced coenzymes
Energy from the oxidation is used to pump hydrogen ions
from the matrix into the space between the inner and
outer membranes of the mitochondria
A gradient forms generating a potential difference
across the membrane – a store of potential energy
Hydrogens flow back across the membrane through ATP
synthesis enzymes (ATPase)
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Follow the concentration gradient from high hydrogen to
low hydrogen
Energy is transferred to ATP
Role in Fat Metabolism
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Your body can plug other things into the Krebs cycle to
generate energy including
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Starch
Glycerol
Fatty acids
Amino acids
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Plants can also add cellulose to this list
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Explains why fats are considered to be energy sources
to the body
Cheesy Songs
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Song 1
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Song 2
Bozeman
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