UNSW Cell Biology

2008 ANAT3231 Lecture 07 - Cell Energy Production

Introduction

This lecture introduces how the cell generates energy required for cellular processes. We will study this topic at the level of the cellular organelles involved in energy production: chloroplasts and mitochondria. Lecture Text: Lecture Word Document (not linked yet) Lab 04 Cell Fixation	Mitochondria (green) in Cells
Page Links: Introduction | Objectives | Lecture Audio | Textbooks | Double Membrane Organelles | History | Evolution | Chloroplasts | Mitochondria Introduction | Mitochondria Function | Mitochondria Structure EM | Mitochondria Structure | Mitochondria Shape | Abnormalities | References | Online Textbooks | Web Links | Web Movies | 2007 Lecture Slides | Comments Acronyms

Objectives

• Broad understanding of processes requiring energy within the cell
• Understanding structure and function of plant chloroplast
• Understand the structure and function of plant and animal mitochondria
• Brief understanding of mitochondria evolution
• Brief understanding of mitochondrial abnormalities

Lecture Audio

The University has a system for automated recording of lectures called Lectopia (or iLecture).

Lectopia recording: 2008 ANAT3231 Lecture 7 - Cell Energy Production

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Links: Lectopia Login Page | Cell Biology Podcast Page | Current Course Outline 2008

Double Membrane Organelles

• Nucleus
  • All eukaryotes
• Chloroplasts
  • plants
• Mitochondria
  • plants and animals

History

• 1857 Kölliker discovers mitochondria in muscle
• 1929 Karl Lohmann discovered ATP
• 1940s and 1950s ATP is formed in cell respiration in mitochondria and photosynthesis in chloroplasts of plants
• 1960 Efraim Racker and co-workers isolated, from mitochondria, the enzyme "F o F 1 ATPase" now call ATP synthase
• 1992 Wallace identified degenerative disease caused by mtDNA mutations
• 1997 Nobel Prize in Chemistry - The three laureates have performed pioneering work on enzymes that participate in the conversion of the "high-energy" compound adenosine triphosphate (ATP).
  • Paul D. Boyer and John E. Walker
    • "for their elucidation of the enzymatic mechanism underlying the synthesis of adenosine triphosphate (ATP)"
  • Jens C. Skou
    • "for the first discovery of an ion-transporting enzyme, Na+, K+ -ATPase
    

  Links: 1997 Nobel Prize - Chemistry |

Evolution

• primitive Eubacterium
• symbiotic relationship with eukaryotic cell
• genes transferred to nucleus
• mitochondrial genome 366,924 Arabidopsis 16,569 Human 5966 Plasmodium

Chloroplasts

• Double membrane
• photosynthetic Eubacteria, algae and plants
• photosynthesis
• chlorophyll captures light energy
• chloroplasts interact with peroxisomes

(MH - will not cover this cell organelle in any depth in current course)

Links: Electron micrographs of chloroplasts | Chloroplasts | A mitochondrion and chloroplast compared

Mitochondria Introduction

• Greek, mito = thread; chondrion = granule
• Located throughout  cytoplasmic compartment
  • has itself several membrane enclosed compartments
  • each compartment has different function
• Ancient aerobic organisms in symbiosis (endosymbiosis)
• present in all cells

Mitochondria Function

• Energy production
  • Respiratory Chain
• Apoptosis role
  • Programmed cell death

Mitochondria Structure EM

Mitochondria Structure

• Double membrane
• outer membrane
• intermembrane space
• inner membrane
• crista (plural, cristae)
  • originally considered specialized folds of the inner membrane
  • variable invaginations with narrow tubular connections to each other and by crista junctions to the peripheral region of inner membrane
• matrix

Links: Mitochondria Electron Tomography |

Mitochondria Shape

• Come in different shapes & sizes
• Can rapidly change shape (minutes)
• EM: Mitochondria
• EM: Mitochondria
• EM: Mitochondria
• Mitochondrial Morphology

Mitochondria Movie

Mitochondria Motility

• can be moved about within cytoplasm
• cytoskeleton
• microfilaments and microtubules
• located where energy required

Mitochondria Location

• cells with high energy requirements: Muscle, sperm tail, flagella
• generally located where energy consumption is highest in the cell
• Mitochondria (fibroblasts)
• Mitochondria (sperm)
  • Packed around initial segment
  • Energy for sperm motility, microtubules (9+2)
• (MH- Covered in cytoskeleton lecture)

Mitochondria Components

• Outer Membrane
  • porin - membrane channel, allows ions amd metabolites into the mitochondria
• Intermembrane Space
  • enzymes that use ATP
• Inner Membrane
  • cardiolipin - phospholipid
• Cristae
  • Adenosine triphosphate (ATP) synthase
  • respiratory electron transfer chain proteins
  • transport proteins
• Matrix
  • metabolic enzymes of citric acid cycle (=Krebs) (100s of enzymes)
    • (MH- do not need to know details of this cycle)
  • genetic material DNA, tRNA, ribosomes
  

Mitochondria DNA

• double stranded circular DNA (mitoDNA. mtDNA)
• 1981 complete human sequence (16,569 nucleotides)
• encodes 13 polypeptides
• multiple copies within the matrix
• maternally inherited
• remainer encoded by nuclear DNA
• proteins made in cytosol and imported into mitochondria

Mitochondria Protein Synthesis

• yeast - Petite mutants
• all mitochondrion-encoded gene products missing
• forms small anaerobic colonies
• organelle is constructed entirely from nucleus-encoded proteins
• http://www.nature.com/emboj/journal/v20/n7/full/7593682a.html Replication and preferential inheritance of hypersuppressive petite mitochondrial DNA

Mitochondria Division

• Divide independently of the whole cell cycle
• Generated by existing mitochondria
• inward furrowing like bacterial division
  • fission
• inheritance?

Energy Production

• Raw Materials
  • Oxygen
  • Pyruvate & Fatty Acids
• Products
  • Carbon Dioxide
  • Adenosine Triphosphate (ATP)

Links: The Cell - Model of lamin assembly |

Apoptosis

(Images:RnD Systems)

• cytochrome C release activates caspases
• other changes include
  • electron transport, loss of mitochondrial transmembrane potential
  • altered cellular oxidation-reduction
  • Bcl-2 family proteins (pro- and antiapoptotic)
• Vesicular Mitochondria
• begin to appear during the release of cytochrome C which initiates mitochondrial mediated apoptosis
  • transformation from normal morphology
    • with an inner boundary membrane connected to lamellar cristae via crista junctions
  • multiple vesicular matrix compartments
  • facilitates membrane fission or fragmentation as the matrix is fragmented at this stage,
  • fragmentation of the mitochondrion requires only outer membrane fission.

Links: Movie - Vesicular Mitochondria | Role of mitochondria in apoptosis |

Abnormalities

Mitochondrial Myopathies http://www.mda.org/disease/mito.html http://www.clevelandclinic.org/health/health-info/docs/1600/1678.asp?index=6957 http://www.genetests.org/query?dz=mt-overview

Friedreich's ataxia (FRDA) mutation in gene for frataxin (a mitochondrial iron (Fe) chaperone) mechanism may be a mitochondrial iron (Fe) loading and reactive oxygen species animal models show H2O2 is an important pathogenic substrate underlying the phenotypes arising from frataxin deficiency Genes and Diseases - Friedreich's ataxia | Genes and Diseases http://www.ncbi.nlm.nih.gov/books/bookres.fcgi/gnd/tocstatic.html OMIM - Online Mendelian Inheritance in Man http://www.ncbi.nlm.nih.gov/sites/entrez?db=omim

Links: NCBI - Genes and Diseases | NCBI - OMIM |

References

There is a complete list of online textbook links at 2008 ANAT3231 Lecture 07 - Cell Energy Production - References

 

• Essential Cell Biology - Chapter

• Molecular Biology of the Cell 4th ed.
  • Alberts, Bruce; Johnson, Alexander; Lewis, Julian; Raff, Martin; Roberts, Keith; Walter, Peter New York and London: Garland Science; c2002
    • The Mitochondrion | Various sizes of mitochondrial genomes
• The Cell - A Molecular Approach -
• Cooper, Geoffrey M. Sunderland (MA): Sinauer Associates, Inc. ; c2000
  • Mitochondria

There is a complete list of online textbook links at 2008 ANAT3231 Lecture 07 - Cell Energy Production - References

• Molecular Cell Biology -

• Lodish, Harvey; Berk, Arnold; Zipursky, S. Lawrence; Matsudaira, Paul; Baltimore, David; Darnell, James E. New York: W. H. Freeman & Co. ; c1999
  • Mitochondria Are the Principal Sites of ATP Production in Aerobic Cells

• Mitochondria references

• Duchen MR. Roles of mitochondria in health and disease. Diabetes. 2004 Feb;53 Suppl 1:S96-102. Review.
• Brown GC, Bal-Price A. Inflammatory neurodegeneration mediated by nitric oxide, glutamate, and mitochondria. Mol Neurobiol. 2003 Jun;27(3):325-55. Review.
• Newmeyer DD, Ferguson-Miller S. Mitochondria: releasing power for life and unleashing the machineries of death. Cell. 2003 Feb 21;112(4):481-90. Review. Erratum in: Cell. 2003 Mar 21;(112)6:873.

There is a complete list of online textbook links at 2008 ANAT3231 Lecture 07 - Cell Energy Production - References

Web Links

Web Movies

Molecular Cell Biology

First link is directly to Quicktime move, followed by associated textbook figure with legend. Look at the movie first, then look at the labelled image.

MCB - Photosynthesis | The primary event in photosynthesis

MCB - Electron Transport | The pathway of electron transport (blue arrows) and proton transport (red arrows) in the inner mitochondrial membrane

MCB - ATP Synthesis | Model of the structure of ATP synthase in the bacterial plasma membrane

MCB - Biological Energy Interconversions | The ATP cycle

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Acronyms

• ATP - Adenosine Triphosphate
• DNA - deoxyribonucleic acid
• EM - electron microscopy
• Fe - iron
• FL - flourescent
• FRDA - Friedreich's ataxia
• OMIM - Online Mendelian Inheritance in Man Database
• RER - rough endoplasmic reticulum

2007 Lecture Slides

(MH - note that content will not match exactly current lecture structure but has been selected as having similar content)

lecture04 1 slide/page (view only) (53 pages, 1 Mb)

lecture04 6 slides/page (print) (9 pages, 516 Kb)

lecture04 outline (print no images) (6 pages, 92 Kb)

See also Lecture Slides Text on this current page

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Links: Download Acrobat Reader 8.0

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Comments

 

	In 2008 a new way of presenting course content online is being trialled. Please let me know of any difficulties/suggestions or things that work well. Notice also that in some slides I have added annotations in brackets with my initials (MH - )
	Links: Current Course Outline 2008