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MITOCHONDRIAAND BIOENERGETICS
Mitochondria
Discovery
Structure
Function
Origin
Cellular
Respiration
Glycolysis
Pyruvate
Oxidation
(Preparatory
Reaction) Krebs Cycle
Electron Transport
System
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MITOCHONDRIA
rod-shaped organelles that can be considered thepower generators of the cell
vary greately in both size (0.5 micrometers - 10micrometers) and number (1 - over 1000) per cell
site of oxidative phosphorylation
provide the chemical energy necessary to carry out
the various cellular activities
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DISCOVERY
Early 1850s - Rudolf Klliker, a German
biologist describe the presence of what he
called ordered array ofparticles in muscle
cells.
1898 - The term 'mitochondria (meaning
thread-like granules) was coined by Carl
Benda.
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1957 - Philip Siekevitz dubbed them 'thepowerhouse of the cell'.
1984 - Richard Altmann, established themas cell organelles and called them'bioblasts'.
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STRUCTURE
contains outer and inner membranes composed ofphospholipid bilayers and proteins. Because of
this double-membraned organization, there are
five distinct compartments within the
mitochondrion. They are: the outer mitochondrial membrane,
the intermembrane space (the space between the outer
and inner membranes),
the inner mitochondrial membrane,
the cristae space (formed by infoldings of the inner
membrane), and
the matrix (space within the inner membrane).
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Mitochondria
semi-autonomous in that they are onlypartially dependent on the cell to
replicate and grow.
They have their
own DNA, ribosomes and can make
their own proteins.
Similar to bacteria, mitochondria have
circular DNA and replicate by a
reproductive process called fission.
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Due to the independence from the
nuclear DNA and similarities with
bacteria, it is believed thatmitochondrion have originated from
bacteria by endosymbiosis.
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ENDOSYMBIOTIC HYPOTHESIS
Symbionts live
together in a situation
in which both benefit
mitochondria have
their own DNA and
ribosomes
They also divide just
like bacteria
So, it could be that
mitochondria are
bacteria that invaded
eukaryotic cells.
Both would benefit
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FUNCTION
production of energy
Site of cellular respiration
It is important to maintain proper
concentration of calcium ions within the
various compartments of the cell. Mitochondria
help the cells to achieve this goal by serving as
storage tanks of calcium ions.
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Mitochondria helps in the building of certain
parts of the blood, and hormones liketestosterone and estrogen.
Mitochondria in the liver cells have enzymes
that detoxify ammonia.
Other functions of the mitochondria include
controlling the cell cycle - signaling,differentiation, growth and death - and
assisting with cellular aerobic respiration.
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CELLULAR
RESPIRATION
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CELLULAR RESPIRATION
enzymatic breakdown of glucose (C6H12O6) in
the presence of oxygen (O2) to produce cellularenergy (ATP)
Overall reaction:
C6H12O6 + 6O2 -------> 6 CO2 + 6H2O + 36
ATP
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TYPESOF CELLULAR RESPIRATION
There are two types of cell respiration
aerobic and anaerobic.
1. Aerobic respiration occurs in thepresence of oxygen.
2.Anaerobic respiration occurs in theabsence of oxygen.
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3 STAGESOF CELLULAR RESPIRATION
Glycolysis
Oxidation of Pyruvate
Krebs Cycle
Electron Transport
System
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GLYCOLYSIS
Breaking down glucose
glycolysis (splitting sugar)
starting point for all cellular respiration in cytosol
10 steps
inefficient generate only 2 ATP for every 1 glucose
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GLYCOLYSIS
Glycolysis can occur with or withoutoxygen. In the presence of oxygen,glycolysis is the first stage of cellularrespiration. Without oxygen, glycolysisallows cells to make small amounts of
ATP. This process is called fermentation.
Summary reaction (Aerobic):Glucose + 2 NAD+ + 2 Pi+ 2 ADP 2 pyruvate + 2 NADH + 2 ATP + 2 H+ + 2H2O+energy
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FERMENTATION
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TWO PHASES
Energy Investment PhaseATP is
consumed
Energy Pay-off PhaseATP is produced
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PYRUVATE OXIDATION
Conversion of pyruvate into Acetyl Coenzyme A
Overall reaction:
2PA + 2CoA+ 2NAD ---> 2 Acetyl CoA + 2Co2 + 2NADH+H
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KREBS
CYCLE
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T HEK REB SCYCLE
Hans Adolf Krebs
a British biochemist who recognized it in1937
occur in the matrix (inner compartment) ofthe mitochondria.
aerobic process (require O2)Sources of compounds
Carbohydrates
Lipids
Proteins
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ELECTRON TRA N SPORT CHAIN
inner membrane of the mitochondria.
the site of oxidative phosphorylation in eukaryotes
NADH and succinate generated in the citric acid cycle areoxidized, providing energy to power ATP synthase
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Krebs cycle produces NADH and FADH2 in thematrix, CO2 is generated in process of producing ATP.
Protein complex in inner membrane removes
electrons from NADH and FADH2 Protein complexes transport H+ ions from matrix to
the intermembrane space.
A pH and electrical gradient are created across the
inner membrane by H+
into the intermembrane space.
Channel Protein assist ATP synthase by allowingprotons in intermembrane to flow back into matrix.
OX I DATI V E PHOSPHORY LATI ON
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Oxidation Phosphorylation
Krebs Cycle produce NADH and FADH2
Electrons are removed from NADH andFADH2
H+ ions are transported to intermembrane
pH and electrical gradient are created ATP synthase generates ATP
CHEMIOSMOSIS
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