Bacteria 10-4 The First Cells

Bacteria are grouped into one of 2 Kingdoms What is the difference between them? –K. Archaebacteria Harsh environments Methanogens – no O 2 ; marshes; cow gut Halophiles – high salt; dead sea; great salt lake Thermophiles – high heat; thermal vents of oceans –K. Eubacteria Common bacteria, found all around us

The Big “5” Type of cell - prokaryotic # of cells - unicellular Cell wall - murien or peptidoglycan –The other 2 traits are variable… examples of bacteria exist for each trait

What structures do all bacteria have? ALL have… –Cell membrane, ribosomes, DNA SOME have… –Flagella, cell wall, capsule, endospore Test Yourself! What do each of the structures listed above do?

What structures do all bacteria have?

How do we classify bacteria? Based on SHAPE: –Round cells (coccus) –Rod cells (bacillus) –Spiral cells (spirillum)

How do we classify bacteria? Based on GROUPINGS: –Pairs (diplo) –Clusters (staphylo) –Chains (strepto)

Test Yourself! What would these look like? Diplobacillus Streptococcus Staphylococcus Diplospirillum

How do bacteria reproduce? 1. binary fission –Asexual (genetically same) –Copies DNA & splits into 2 cells –Very fast!

How do bacteria reproduce? 2. conjugation –Sexual (genes recombine) –Transfer DNA through tube

How do bacteria respire? 10-5 Those that require oxygen are called aerobic –Ex: Mycobacterium tuberculosis, attacks lungs Those that do not require oxygen are called anaerobic –Many are actually poisoned by O 2 –Ex: Clostridium tetani, causes tetanus

Why are some bacteria so tough to kill? Endospores –Tiny structures with tough coatings –Resist high temps, dryness, & chemicals –Holds copy of genes –Ex: C. botulinum (botulism food poisoning)

What are some beneficial impacts & uses of bacteria? 1. nitrogen-fixation – pull N 2 from air & add to soil (N needed to make proteins) 2. decomposition – break down dead stuff 3. O 2 -production – blue-green bacteria 4. food production – cheeses, pickles, yogurt, etc 5. human digestion – vitamin K 6. antibiotics – ex. Streptomycin & acromycin 7. Genetic tech- use to make chemicals

What are some harmful effects of bacteria? 1. agricultural –Crop damage; livestock disease; food spoilage 2. human disease –Strep throat; tetanus; TB; pneumonia; Lyme disease; dental cavities; food poisoning; chlamydia; syphilis; gonorrhea

How do we defend ourselves against bacteria? Non-specific immunity ex. Skin cell barrier antimicrobial fluids (tears, oils, wax) white blood cells Antibiotics ex. Penicillin, streptomycin Penicillin “pokes” holes in the cell membrane Streptomycin disrupts protein synthesis

Quiz - Microbes Use your own paper. Do not write the question. Does not need to be in complete sentences.

Quiz - Microbes 1. The method of asexual reproduction in bacteria is called – –A. conjugation –B. sporulation –C. budding –D. binary fission

Quiz - Microbes 2. Which is a spirillum? 3. Which is a bacillus? 4. Which is a coccus? A B C

Quiz - Microbes 5. The large, rounded structures shown within the bacterial cells below are – –A. capsules-- C. endospores –B. cell walls-- D. pili

Quiz - Microbes 6. List three helpful things that bacteria do or provide. 7. List two diseases caused by bacteria. 8. Of viruses and bacteria – which is easier to treat with antibiotics? 9. What is penicillin actually doing when it kills a pathogen?

Quiz – Microbes (alternate ending) 6. List three helpful things that bacteria do or provide. 7. How does the lysogenic cycle of viruses differ from the lytic cycle? 8. Explain the importance of nonspecific immune defenses. List 2 particular types of nonspecific. 9. What is meant by “specific immune response” as related to your immune system?