Topic 7 - Commonality

Transcription

1 II. Organism Topic 7 - Commonality From Viruses to Bacteria to Genetic Engineering

2 Prebiotic Period Refers to before life Early Earth contained little O 2 O 2 prevents complex molecules Complex organic molecules before life Origin of complex organics?

3 1954 Miller-Urey Experiment Same gases as in Earth s early atmosphere Add electric current Abiogenesis Product = Amino acids

4 Sources of Organics Earth: Miller-Urey Experiment: basic elements in the atmosphere + electricity Meteorites: contain organics Murchison meteorite Star Dust: organics fall to Earth from space Comets: carry amino acids, collision with Earth causes Peptide formation Peptides make up proteins!

5 Influenza Virus Spanish Flu epidemic : million deaths worldwide Asian flu : 1-4 million deaths worldwide RNA Virus 8 RNA pieces Hemagglutinin (H) Attachment Neuraminidase (N) Release and penetration Photo Credit: Cynthia Goldsmith

6 Non-living particle Virus No means of energy use Uses a living cell to reproduce Simple genetic structure Chicken pox HIV

7 Recognizing Invaders Antigens: molecules that your body recognizes as foreign (surface) Antibodies: proteins produced by your immune system to destroy antigens How do viruses stay infectious?

8 Antigenic Drift Mutation Genetic change (random mistakes in copying) Minor annual changes in antigens Flu: H antigen N antigen H1N1: Swine flu (2009) H5N1: Bird flu (2012) Flu shots: only effective for predicted strains vaccine has to be remade annually

9 Antigen Shift Gene mixing and recombination Species specificity Human Swine (H1N1) Avian (H5N1) Strains are serious when: capable of infecting humans become airborne bird flu: feces of birds, cannot infect humans mixing of strains can lead to this

10 What is Life? Basis for Life? Complex Organized Utilize energy Growth Reproduce Evolve Carbon (or Silicon) Liquid water Certain Environment Temperature Pressure ph Salt concentration Life needs a container

11 Container for Life Cell membrane use Murchison meteorite building blocks Grow primitive containers that can: Grow Divide Self-replicate Accumulate gene-like materials (RNA) What about the genes?

12 Creating Life Make membranes that grow, divide Make genes from scratch But.Life is much more complicated Bacteria (E. coli) 4,100 genes

13 Creating Life May 2010 (Celera Genomics) Dr. Craig Venter Used a computer to sequence DNA Put that DNA in proper order Placed the DNA inside a bacterium that lacked DNA New DNA caused the bacterium to boot up and start reproducing First artificial genome

14 Categories of life Prokaryotes No organelles Cell wall Usually smaller Eukaryotes Organelles Membrane around nucleus Usually larger No nucleus Endosymbiosis: structures within cell were once free living (Mitochondria: ATP, Chloroplasts: photosynthesis)

15 Three Life Domains Bacteria Archaea Extremophils Eucarya Plants Animals Fungi

16 Bacteria Most abundant life on Earth 100,000 Billion on each of us! Small micrometers (250,000 in a period) Single cells, divide rapidly by fission Most important life form processing of waste, symbiosis with animals (gut), production of materials, base of most food chains Extremophils: bacteria capable of living in extreme environments (temperature, pressure, chemicals)

17 Defenseless against bacteria Boy in the bubble David Vetter ( ), Severe Combined Immune Deficiency Syndrome

18 Tuberculosis (TB) Mycobacterium tuberculosis Lung infection, death Multi-drug resistance /06/25/mycobacterium_tuberculosis.jpg Antibiotic resistance: overexposure to antibiotics leads to resistant strains of bacteria Microevolution in action!

19 Pathogenic Bacterial Diseases Anthrax Bacterial meningitis Brucellosis Bubonic plague Cholera Diphtheria Epidemic typhus Gonorrhea Legionellosis Leprosy Listeriosis Lyme disease Pertusis Pneumococcal pneumonia Psittacosis Q-fever Salmonellosis Scarlet fever Shigellosis Syphilis Tetanus Trachoma Tuberculosis Typhoid Fever Typhus Whooping cough : 25 million people (30% Europe)

20 Enzymes Genetic material is like Lego! Proteins that affect biochemical functions Herbert Boyer and Stanley Cohen, 1973 Restriction enzymes Gene splicing: from one organism to another

21 Genetic Engineering Uses Identification and Treatment of disease Gene therapy: virus inserts a defective gene (Cystic Fibrosis) Synthesize drugs: Insulin, Human growth hormone Genetically modified organisms (GMOs) Plants: Round-up ready soybeans Animals: BioSteel : spider silk gene into goat milk Drawbacks? Effects on ecosystems, escape, function not understood How far to go (improvement vs. fixing)

22 What else? Ch. 18 What are the Lost City microbes? What are the conditions like there? What is nitrogen fixation and why is it important for life? What are two structures in bacteria that help them adhere to surfaces?