BACTERIA Biology Chapter 20 1 Bacteria are very
BACTERIA Biology Chapter 20 1
Bacteria are very small 2
This is a pore in human skin and the yellow spheres are bacteria 3
Bacteria are very small compared to cells with nuclei 4
Bacteria compared to a white blood cell that is going to eat it 5
Clean skin has about 20 million bacteria per square inch 6
Evolution/Classification Most numerous on Earth ¡ Most Ancient ¡ Microscopic Prokaryotes ¡ Evolution has yielded many species adapted to survive where no other organisms can. ¡ Grouped based on: ¡ l l l Structure, physiology, molec. Composition reaction to specific types of stain. Eubacteria= Germs/bacteria Archaebacteria 7
Kingdom Archaebacteria First discovered in extreme environments ¡ Methanogens: Harvest energy by converting H 2 and CO 2 into methane gas ¡ l Anaerobic, live in intestinal tracts Extreme halophiles: Salt loving, live in Great Salt Lake, and Dead sea. ¡ Thermoacidophiles: Live in acid environments and high temps. ¡ l Hot Springs, volcanic vents 8
Volcanic vents on the sea floor 9
Chemosynthetic bacteria use the sulfur in the “smoke” for energy to make ATP. 10
The red color of this snow is due to a blue-green bacteria 11
Kingdom Eubacteria ¡ Can have one of three basic shapes 1. Bacilli – rod-shaped 2. Spirilla – spiral-shaped 3. Cocci – sphere-shaped Staphylococci – grape-like clusters Streptococci – in chains SHOW ME 12
BACTERIA PICS 13
Bacillus bacteria are rod or sausage shaped 14
Coccus bacteria are sphere or ball shaped 15
Spirillium bacteria have a corkscrew shape 16
Diplo-bacteria occur in pairs, such as the diplococcus bacteria that causes gonorrhea 17
Staphylo bacteria occur in clumps, such as this staphylococcus bacteria that causes common infections of cuts 18
Streptobacteria occur in chains of bacteria, such as this streptococcus bacteria that causes some types of sore throats 19
Spirillium bacteria 20
Diplobacillus bacteria 21
Streptococcus bacteria 22
Staphylococcus bacteria 23
The tip of a needle The red and yellow dots are bacteria 24
Gram Stain ¡ Gram-positive retain stain and appear purple l ¡ Have thicker layer in cell wall. Gram-negative do not retain stain and take second pink stain instead. Phylum Shape Motility Metabolism Gram reacion Cyanobacteria Bacilli, Cocci Gliding, some nonmotile Aerobic, Gramphotosynthetic negative autotrophic Spirochetes Spirals Corkscrew Aerobic, and anaerobic; heterotrophic Gram-Pos Bacilli, cocci Flagella; some nonmotile Aer/anaer. ; Mostly gramheterotrophic, positive photosynthetic Proteobacteria Bacilli, cocci, spiral Flagella; some nonmotile Aer/anaer. ; heterotrophic, photosynthetic autotrophic Gramnegative 25
STRUCTURE OF BACTERIA Structure Function Cell Wall Protects and gives shape Outer Membrane Protects against antibodies (Gram Neg. Only) Cell Membrane Regulates movement of materials, contains enzymes important to cellular respiration Cytoplasm Contains DNA, ribosomes, essential compounds Chromosome Carries genetic information Plasmid Contains some genes obtained through recomb. Capsule & Protects the cell and assist in attaching cell to Slime Layer other surfaces Endospore Protects cell agains harsh enviornments Pilus Assists the cell in attaching to other surfaces Flagellum Moves the cell 26
No Nucleus-DNA in Cytoplasm 27
Nutrition and Growth ¡ ¡ Heterotrophic or Autotrophic Some are Photoautotrophs – Use sunlight for Energy Some are Chemoautotrophs. Many are Obligate Anaerobes. l Oxygen = Death ¡ Ex. ¡ Some are Faculatative Anaerobes l With or without Oxygen ¡ Ex. ¡ ¡ Clostridium tetani – Tetanus Escherichia Coli Some are Obligate Aerobes l Ex. ) Mycobacterium tuberculosis Temperature requirements l Some are Thermophilic, Some prefer acidic envmt. 28
Metabolism of Prokaryotes ¡ Heterotrophs are organisms that cannot make their own food and must get it from another source l such as off of decomposing organic molecules or waste 29
Metabolism of Prokaryotes ¡ Others are Autotrophs which are organisms that can make their own food l Photoautotrophs- carry out photosynthesis similar to plants to make their own food Require light for energy ¡ Cyanobacteria are the base of some food chains and might have been the first to put oxygen in the atmosphere ¡ l Chemotrophs- do not require light for energy but get food from breaking down and releasing inorganic compounds in a process called chemosynthesis 30
Aerobes and Anaerobes Aerobes are bacteria that grow in the presence of oxygen, like us without it they die they are called obligate aerobes. ¡ Anaerobes are some bacteria that can grow without the presence of oxygen, and will die in the presence of oxygen these are called obligate anaerobes ¡ Facultative anaerobes live in both oxygen and no oxygen. ¡ 31
These heterotrophic bacteria digest oil -remember oil is partially decayed plant and animal cells 32
REPRODUCTION IN BACTERIA 33
No Nucleus-DNA in Cytoplasm 34
BACTERIA REPRODUCES BY FISSION First the chromosomal DNA makes a copy The DNA replicates 35
NEXT THE CYTOPLASM AND CELL DIVIDES The two resulting cells are exactly the same 36
In addition to the large chromosomal DNA, bacteria have many small loops of DNA called Plasmids 37
Genetic Recombination ¡ Nonreproductive Methods bacteria can acquire new genetic material. Characteristic Transformation Conjugation Transduction Method of DNA Across cell wall Transfer and cell membrane of recepient Through a By a virus conjugation bridge between two cells Plasmid transfer Yes Not likely Chromosome transfer No Sometimes No Antibiotic resistance acquired Yes Sometimes 38
TRANSFORMATION This plasmid of DNA is new to the bacteria – added by transformation! Produces the glowing protein 39
CONJUGATION When two prokaryotes attach to each other and exchange genetic information 40
TRANSDUCTION 41
Bacteria and Disease Pathogen Areas affected Mode of transmission Botulism Clostridium botulinum Nerves Improperly preserved food Cholera Vibrio cholerae Intestine Contaminated water Dental Caries Streptococcus mutans, sanguis, salivarius Teeth Environment to mouth Gonorrhea Neisseria gonorrhoeae Urethra, fallopian Sexual contact Lyme disease Berrelia burgdorferi Skin, joints Tick bite Rocky Mountain SF Rickettsia recketsii Blood, skin Tick bite Salmonella Intestine Contaminated food, water Strep throat Streptococcus pyogenes URT, blood, Sneezes, coughs, etc. skin Tetanus Costridium tetani Nerves Contaminated wounds Tuberculosis Mycobacterium tuberculosis Lung, bones coughs 42
Some bacteria cause diseases -Disease causing bacteria are call PATHOGENIC 43
Helicobacter pylori is the pathogenic bacteria that can causes ulcers 44
Leprosy is a bacterial infection that decreases blood flow to the extremities resulting in the deterioration of toes, ears, the nose and the fingers. 45
BOTULISM 46
CHOLERA 47
DENTAL CARIES 48
ROCKY MOUNTAIN SF 49
LYME DISEASE 50
SALMONELLA 51
STREP THROAT 52
TETANUS 53
TUBERCULOSIS 54
Common Antibiotics Antibiotic Mechanism Target bacteria Penicillin Inhibits cell wall synthesis Gram Positive Ampicillin Inhibits cell wall synthesis Broad spectrum Bacitracin Inhibits cell wall synthesis Gram Positive – Skin Ointment Cephalosporin Inhibits cell wall synthesis Gram Positive Tetracycline Inhibits Protein Synthesis Broad spectrum Streptomycin Inhibits Protein Synthesis Gram Neg. tuberculosis Sulfa drug Inhibits cell metabolism Bacterial meningitis, UTI Rifampin Inhibits RNA synthesis Gram Pos. , some Neg. Quinolines Inhibits DNA Synthesis UTI 55
Some Final Information ¡ ¡ Because antibiotics have been overused, many diseases that were once easy to treat are becoming more difficult to treat. Some Bacteria are Useful l Ex. ) Producing and Processing food Breaking down dead organic material Make unripened cheese like ricotta and cottage by breaking down the protein in milk. 56
VIRUSES Non-living but depends on the living! 57
STRUCTURE ¡ ¡ ¡ Nonliving Composed of Nucleic acid and protein Cause many diseases Virology – Study of Viruses Comparison of Viruses and Cells below Char. Of Life Virus Cell Growth No Yes Homeostasis No Yes Metabolism No Yes Mutation Yes Nucleic acid DNA or RNA DNA Reproduction Only within host cell Independently by cell division Structure Nucleic acid core, protein covering, some have envelope Cytoplasm, cell membrane, etc. . 58
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Here is a non-enveloped bacteria virus inserting it’s DNA into a bacterial cell. 60
Some virus are pushed out by the cell, taking some of the cell membrane with them. 61
Characteristics of Viruses ¡ ¡ ¡ 2 essential features 1. Nucleic Acid l May be DNA or RNA l Helical, closed loop, or long strand 2. Protein Coat – called CAPSID Some have ENVELOPE l Ex. Influenza, chickepox, herpes simplex, HIV VIRAL SHAPE l Icosahedron – 20 triangular faces ¡ Ex. ) herpes, chickenpox, polio l Helix – Coiled spring ¡ EX. )Rabies, measles, tobacco mosaic 62
All viruses have two main parts: 1. DNA or RNA – genetic info 2. Capsid – a protein encasement 63
Grouping Viruses ¡ Grouped according to: l Presence of Capsid and envelope – shape l RNA or DNA, single or double stranded – struct. Viral Group Nucleic Acid Shape and Structure Example Papovaviruses DNA Icosahedral, non-env. Warts, cancer Adenoviruses DNA Icosahedral, non-env. Resp. & intestinal infections Herpesviruses DNA Icosahedral, enveloped Herpes simplex, chicken pox, mono, shingles Poxviruses DNA Complex brick, enveloped Small pox, cow pox Picornaviruses RNA Icosahedral, non-env. Polio, hepatitis, cancer Myxoviruses RNA Helical, enveloped Influenza A, B, C Rhabdoviruses RNA Helical, enveloped Rabies Retroviruses RNA Icosahedral, enveloped AIDS, cancer 64
Grouping Viruses ¡ Viroids- The smallest known particle that can replicate. l l ¡ Disrupt plant cell metabolism Can destroy entire crops Prions – Abnormal forms of proteins that clump together inside cells. l l Clumping eventually kills the cell Examples Scrapie – in sheep ¡ Mad Cow Disease ¡ 65
PRIONS – man-made problem? 66
Viral Replication ¡ ¡ ¡ Can replicate only by invading host cell and using its enzyme and organelles. Bacteriophage – viruses that infect bacteria l Used to study viruses Lytic Cycle l Viral genome is released into the host cell l Replication follows immediately l Cellular components used to make new viruses l Viral enzyme kills cell. 67
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Viral Replication Picture http: //www. mcgrawhill. ca/school. Graphics/biology 2_1. mpg Click Movie to Play 69
Replication cont’ ¡ Lysogenic Cycle l Nucleic acid of virus becomes part of the host cell’s chromosome l Nucleic acid remains in the cell in this form for many generations l HIV follows this pattern l HIV infects WBC and remains as proviruses l As immune system fails, opportunistic infections occur = AIDS 70
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Here is a classic picture of HIV viral progeny being released from the surface of a T- cell. Notice the membrane coating they receive. 72
Viruses and Human Disease ¡ Control and Prevention of spread. l Vaccination & Antiviral drugs ¡ ¡ Emerging Viruses – exist in isolated habitats l ¡ Ex. ) chickenpox vaccine, AZT, Acyclovir, protease inhibitors. Do not usually infect humans unless environmental conditions favor contact. Several viruses are now linked to cancers such as leukemia, liver cancer, Burkitt’s lymphoma, cervical cancer. 73
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PAPOVAVIRUSES BACK 77
ADENOVIRUSES BACK 78
HERPESVIRUSES BACK 79
POXVIRUSES BACK 80
PICORNAVIRUSES BACK 81
After polio infections, the killer T-cell have destroyed the motor neurons that are producing the virus. The result is a loss of muscle control including the diaphragm. The iron lung changes the pressure to pump air in and out of the lungs. 82
Which US President had polio? 83
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MYXOVIRUSES BACK 86
RHABDOVIRUSES BACK 87
RETROVIRUSES BACK 88
What does bacteria have to do with DNA technology? Bacteria are simple ¡ Bacteria have DNA that is made of nucleotides (A, T, G, C) ¡ Bacteria can be grown quickly and easily ¡ l Give them food, warmth and dark (like inside you shoe) and they will multiply like mad (binary fission) 89
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¡ Bacteria have plasmids – extra DNA in the form of a circle 91
¡ ¡ ¡ Plasmids are DNA – made out of A, T, C, G nucleotides The same nucleotides found in human DNA, plant DNA, dog DNA, fish DNA, fungus DNA Get it – it’s all the same molecule 92
¡ So… why not take out a plasmid, cut it apart and add any other DNA piece that we want! 93
¡ Then put it back in the bacteria and grow more bacteria with that new plasmid that we have created! Hmmm? http: //www. learner. org/channel/courses/biology/archive/ani mations. html 94
¡ ¡ Transduction – viruses attack cells Bacteriophages: like tiny little syringes that inject DNA into the cell 95
Look at how the virus infects http: //www. slic 2. wsu. edu: 82/hurlbert/mic ro 101/pages/Chap 11. html 96
Viral Infections Ebola ¡ Smallpox ¡ Flu ¡ Chicken pox ¡ Shingles ¡ Herpes ¡ AIDS ¡ HIV ¡ HPV ¡ Epstein-Barr ¡ 97
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