BO101 Cell Biology Lecture 1 PDF

Tour of the cell 1 BO101 - Cell Biology - Lecture 1 Dr Andrew Flaus, Biochemistry The cell theory http://ed.ted.com/lessons/the-wacky-history-of-cell-theory History of cell theory ๏ van Leeuwenhoek 1676 ‣ Observed ‘living’ particles ๏ Hooke 1665 ‣ ‘Cells’ as units in cork with walls ‣ Cella...

Tour of the cell 1 BO101 - Cell Biology - Lecture 1 Dr Andrew Flaus, Biochemistry The cell theory http://ed.ted.com/lessons/the-wacky-history-of-cell-theory History of cell theory ๏ van Leeuwenhoek 1676 ‣ Observed ‘living’ particles ๏ Hooke 1665 ‣ ‘Cells’ as units in cork with walls ‣ Cella = ‘small room’ ๏ Schleiden & Schwann 1839 ‣ “All tissues formed of cells” ๏ Virchow 1855 ‣ “Every cell from pre-existing cell” http://ed.ted.com/lessons/the-wacky-history-of-cell-theory Cell theory: Fundamental unit of life 1. All organisms consist of one or more cells 2. The cell is the basic unit of structure for all organisms 3. All cells arise only from pre-existing cells Image from Campbell ed9 ch12 Discovery video: 7.08 Cells Discovery video: 7.08 Cells The cell is a fundamental unit of life ๏ Cell theory ๏ Multicellular organisms ๏ Pathology and cell theory ‣ Disease as alteration of cells in an organism ‣ Perspective for understanding disease for most of 20th century eg Cancer as cell disease ๏ Modern molecular biology ‣ Molecules and cell malfunction ‣ Why biochemistry is useful! Image from Becker’s World of the Cell ed 8, ch24 Scales of observations in cell biology ๏ Unaided eye ‣ Organisms, organs, egg cells ๏ Light microscope ‣ Most cell types ๏ Electron microscope ‣ Cell interior, viruses ‣ Large macromolecule complexes ๏ Biophysical techniques ‣ Molecules Campbell g 7.2 fi Cells can be fractionated for analysis ๏ Lysis ‣ Break down cell membrane to release contents ‣ Homogenous mixture ๏ Centrifugation ‣ Separate on basis of density ‣ Supernatant Suspended, usually in solution ‣ Pellet Insoluble material at base ๏ Analysis of molecules Campbell g 7.4 fi Types of cells and organelles Evolution of prokaryotes and eukaryotes ๏ Prokaryotes include ‣ Bacteria ‣ Archaea Mainly extremophiles Share some characteristics with eukaryotes ๏ Eukaryotes include ‣ Animals ‣ Plants ‣ Fungi Campbell g 22.21 fi  Common features of cells ๏ Plasma membrane ‣ Outer membrane ‣ De nes the cell as a unit ๏ Cytoplasm ‣ Interior of cell, except nucleus ๏ Cytosol ‣ Semi- uid part of cytoplasm ‣ Contains organelles etc ๏ Genetic mechanisms ‣ DNA carries information ‣ Ribosomes translate information Campbell g 1.4 fi fl fi Prokaryotic cell features ๏ Cell boundary ‣ Plasma membrane ‣ Thickened wall Sometimes including ‘capsule’ ๏ Chromosome with DNA ‣ Nucleoid region No membrane around genetic material ๏ Ribosomes ‣ In cytosol, near nucleoid Campbell gs 7.5, 1.4 fi Features of eukaryotic cells ๏ Membrane bound nucleus ‣ Nucleoplasm v cytoplasm ‣ Mitotic, meiotic cell divisions ๏ Endomembrane system ‣ Endoplasmic reticulum, Golgi, vacuoles and vesicles ๏ Organelles ‣ Mitochondria, chloroplasts ๏ Cytoskeleton ๏ Extracellular connections Campbell g 1.4 fi Animal cell features (not in plants) ๏ Lysosomes ‣ Breakdown of materials ๏ Centrosomes ‣ Organises chromosome pulling machinery ๏ Flagella ‣ Locomotion and sensing Campbell g 7.8 fi Plant cell features (not in animals) ๏ Chloroplasts ‣ Photosynthetic machinery ๏ Central vacuole ‣ Repository of ions ๏ Cell wall ‣ Rigid = thickly interwoven ‣ Cellulose = polysaccharide ๏ Plasmodesmata ‣ Cell-cell transport Campbell g 7.8 fi Organelles: membrane bound substructures Campbell g 7.8 fi Tour of a cell Tour of an animal cell features 1. Nucleus ‣ Chromosomes as DNA packaging 2. Endomembrane system ‣ Endoplasmic reticulum ‣ Golgi 3. Energy organelles ‣ Mitochondria 4. Cytoskeleton 5. Extracellular connections Tour of the cell - Stop 1: Nucleus Genetic information and the eukaryotic cell Cell nucleus as information centre ๏ Eukaryote = true nucleus ๏ Contains almost all DNA ‣ DNA packaged as chromatin ๏ Enclosed by nuclear envelope ‣ Two membrane layers ๏ Pores in membrane ‣ Control transport in/out Campbell g 7.9 fi Chromosomes as information storage Campbell g 16.22 fi Transcription and translation (in L3.4) ๏ Central dogma of mol biol ‣ Information ow ‣ DNA > RNA > Protein ๏ Transcription ‣ Read off DNA to mRNA ‣ Export from nucleus through pore ๏ Translation ‣ mRNA is template for order of amino acids in protein ‣ Performed by ribosome Campbell g 17.3 fi fl  Bio ix 7.08: Tour of an Animal Cell Bio ix 7.08: Tour of an Animal Cell fl fl Summary of lecture ๏ Cell Theory ‣ All organisms consist of cells ‣ Cell is the basic unit of structure ‣ Cells arise from pre-existing cells ๏ Types of cells ‣ Common properties of cells ‣ Prokaryotic v eukaryotic ‣ Animal v plant ๏ Organelles ‣ Nucleus Learning outcomes for lecture On successful completion of this lecture, you will be able to: ‣ Explain why the cell is considered to be a fundamental unit of biology ‣ Relate microscope observation resolution to the scale of cells ‣ Compare and contrast prokaryotic and eukaryotic cell structure and organisation ‣ Describe how and where genetic information is stored, translated and processed in eukaryotic cells