Biology lecture 4 pre-note

Biology lecture 4 pre-note - Learn about cutting-edge...

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1 Learn about cutting-edge research over lunch with cool profs September 12 - 16, 2011 11:30 AM 11:30 AM Redpath Museum More info: www.mcgill.ca/science/ Announcements. .. Please read the course syllabus before sending emails about exams, how to deal LECTURE content related questions suzanne.gray@mail.mcgill.ca LAB related questions: katherine.velghe@mail.mcgill.ca with missed labs, etc. 2 Lecture Exams: multiple choice lecture content only
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2 Transforming Energy Despite their simplicity in cell structure, prokaryotes are extremely diverse in their Lecture 3, continued metabolic abilities. Variety due to diverse habitats and long evolutionary history 3 volcanic vent, Japan salt ponds, San Francisco Bay Some bacteria are photoautotrophic . Lecture 3, continued cyanobacteria 4 transform light E into chemical E = photosynthesis absorb light E with chlorophyll use light E to convert CO 2 into glucose produce O 2 as a waste product
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3 Some bacteria are photoautotrophic but produce sulfur instead of oxygen. Lecture 3, continued perform photosynthesis: use other pigments to absorb different light wavelengths Purple sulfur bacteria are anaerobic. Anaerobic vs aerobic metabolism anaerobes – do not require O 2 for metabolism make ATP using fermentation not cellular respiration Lecture 3, continued make ATP using fermentation, not cellular respiration obligate anaerobes –O 2 is toxic facultative anaerobes – use O 2 if available aerotolerant anaerobes – can survive in O 2 environment, but do not use O 2 aerobes (obligate) must use O for long term 6 (obligate) – must use O 2 for long-term metabolism Which is the older metabolic pathway?
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4 Most prokaryotes (and other organisms) are (chemo) heterotrophs . consume organic molecules for Lecture 3, continued consume organic molecules for carbon and E source roles that heterotrophic prokaryotes can play in biosphere: 7 decomposers symbiosis with eukaryotes pathogens decomposition is essential for nutrient Lecture 3, continued Most bacteria are decomposers. recycling 8 Salmon returning to home stream in Alaska Salmon being recycled
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5 Many prokaryotes have a beneficial relationship with eukaryotes. mutualistic relationship (+/+ Lecture 3, continued relationship (+/+) 9 Humans are unable to make vitamin K important to blood clotting. Herbivores cannot digest cellulose. A small number of bacteria are pathogens. illness to host is caused by bacterial toxins Lecture 3, continued exotoxins – secreted proteins, very toxic ex: botulism, tetanus endotoxins – outer bacterial membrane, rarely 10 fatal ex: Salmonella & E. coli (food poisoning) botox treatment
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6 Bacterial classification • Traditional – shape Gram-negatives Lecture 3, continued – gram stain • Now based more on DNA sequencing Gram-negatives Gram-negat.
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Biology lecture 4 pre-note - Learn about cutting-edge...

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