mitochondria and bioenergetics_report2

8/2/2019 Mitochondria and Bioenergetics_report2

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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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