Test #1, Chapter 1, 4 & 10

Understand and be able to distinguish the following: - - Algae

- A eukaryote - Reproduce sexually & asexually - Photosynthetic: need light & air for food production & growth. - Produce oxygen & carbohydrates which are utilized by other organisms. - Cell walls of many are composed of cellulose (like plants). - Found in fresh, salt water, soil & plants.

Understand and be able to distinguish the following: - Protozoa

- A eukaryote (genetic material is contained in a nucleus which is surrounded by a special envelope called nuclear membrane. A eukaryote can be single or multicellular.) - Unicellular - Move with pseudopods (false feet), flagella, or cilia - Live free or as parasites - Get nutrition by absorbing or ingesting organic compounds from the environment - Reproduce sexually or asexually Example: - Giardia lambilia = diarrhea

Understand and be able to distinguish the following: - Fungi

- A eukaryote (genetic material is contained in a nucleus which is surrounded by a special envelope called nuclear membrane. A eukaryote can be single or multicellular.) - Unicellular or multicellular - Multicellular = mushrooms - Unicellular = Yeasts - Molds (most typical) - Cell wall composed primarily of chitin (a fibrous substance consisting of polysaccharides and forming the major constituent in the exoskeleton of arthropods and the cell walls of fungi.) - Reproduce sexually or asexually - Get nutrition by absorbing solutions of organic material from the environment.

Define protoplast:

- A gram-positive bacterium or plant cell treated to remove the cell wall. - Wall-less cells of gram positive bacteria. - Still capable of carrying on metabolism - Will burst in pure water or very dilute salt or sugar solutions because surrounding fluid will move into and enlarge the cell = osmotic lysis

Understand and be able to distinguish the following: - Archea

- A prokaryote (genetic material no enclosed in a special membrane called a nucleus). - Single-celled organisms - Cell wall composed of carbohydrates, there's no peptidoglycan - Do not cause disease in humans Three groups: Extremist of microorganisms: 1. Methanogen - produce methane as waste 2. Extreme halphiles - live in salty conditions (great salt lakes) 3. Extreme thermopiles - live in hot surface water (hot springs).

Understand and be able to distinguish the following: - Bacteria

- A prokaryote (genetic material not enclosed in a special membrane called a nucleus). - Single-celled organism - Cell wall composed of carbohydrates and peptidoglycan. Gets nutrition in a variety of ways: - Using organic chemicals from living or dead organisms - Produces own food by photosynthesis - Get nutrients from inorganic substances (carbon dioxide) Examples of medically significant bacteria involved in food poisoning: - Salmonella sp. - Clostidium botulinum - Staphylococcus aureus - Shigella sp. - Escherichia coli

Be able to describe what Antoni Van Leeuwenhoek did and what their experiment showed:

- Antoni Van Leeuwenhoek = "animalcules" from scrapings of teeth. - Probably the first to actually see microbes with magnifying lenses of more than 400 microscopes he constructed. - Used scrapings of his teeth - "animalcules" (1673)

Understand what the axial filaments are and how they contribute to the virulence of bacteria.

- Axial filaments are external to the prokaryotic cell wall. - Spirochetes move by means of axial filaments, or endoflagella, bundles of fibrils that arise at the ends of the cell beneath an outer sheath and spiral around the cell. - Axial filaments propel the spirochetes in a spiral motion. - Well known spirochetes are Treponema pallidum, (syphillis) & Borrelia burgdorferi (Lyme disease). -Similar to flagella, but wrap around the cell

Understand what the fimbriae are and how they contribute to the virulence of bacteria.

- Fimbriae are external to the prokaryotic cell wall. - Found on many gram-negative bacteria - Hairlike appendages that are shorter, straighter, and thinner than flagella that are used for attachment and transfer of DNA rather than for motility. - Fimbriae can occur at the poles of the bacterial cell or can be evenly distributed over the entire surface of the cell. Can be just a few or several hundred. - Fimbriae tend to adhere to each other and to surfaces. As a result, they are involved in forming biofilms and other aggregations on the surfaces of liquids, glass, & rocks. - Fimbriae can also help bacteria adhere to epithelial surfaces on the body. For example fimbriae on Neisseria gonorrhoeae (gonorrhea) help the microbe colonize mucous membranes, causing disease. - When fimbriae are absent (because of genetic mutation) colonization cannot happen, and no disease can ensue.

Understand what flagella is and how it contributes to the virulence of bacteria.

- Flagella is external to the prokaryotic cell wall. - Flagella are long filamentous appendages that propel bacteria. 4 possible arrangements: 1). 1 Flagellum = monotrichous 2). Tufts of flagella at each end = amphitrichous 3). Two or more at one end = lophotrichous 4). Flagella all over = peritrichous - This motility enables a bacterium to move toward a favorable environment or away from an adverse one (called taxis). Structure of Flagella: 3 main parts: -Filament: contains flagellin protein arranged in chains that intertwine to form helix -functions as an antigen. -Hook: Sharp bend just outside cell wall that allows the flagella to point directly away from the cell -Basal body: anchors the flagellum to the cell wall and plasma membrane Function: Allows bacteria to be motile -filament moves from the rotation of basal body a). Clockwise b). Counterclockwise Bacteria movement: Taxis (Positive and Negative) a). Run or Swim: Bacteria move in the same direction for long periods of time b). Tumble: random change in direction

28. Understand what flagella is and how it contributes to the virulence of bacteria

- Flagella is external to the prokaryotic cell wall. - Flagella are long filamentous appendage that propels bacteria 4 possible arrangements: 1). 1 Flagellum = monotrichous 2). Tufts of flagella at each end =amphitrichous 3). Two or more at one end = lophotrichous 4). Flagella all over = peritrichous - This motility enables a bacterium to move toward a favorable environment or away from an adverse one (called taxis). Structure of Flagella: 3 main parts: -Filament: contains flagellin protein arranged in chains that intertwine to form helix -functions as an antigen. -Hook: Sharp bend just outside cell wall that allows the flagella to point directly away from the cell -Basal body: anchors the flagellum to the cell wall and plasma membrane Function: Allows bacteria to be motile -filament moves from the rotation of basal body a). Clockwise b). Counterclockwise Bacteria movement: Taxis (Positive and Negative) a). Run or Swim: Bacteria move in the same direction for long periods of time b). Tumble: random change in direction

Understand what the structure glycocalyx: Capsule vs. Slime layer and which contribute to the virulence of bacteria?

- Glycocalyx (meaning sugar coat) is external to the prokaryotic cell wall, but made inside the cell & secreted to the cell surface. - Glycocalyx is a viscous (sticky), gelatinous polymer (a large number of similar units bonded together) that is composed of polysaccharide, polypeptide, or both depending on the species of prokaryote. - Glycocalyx allows bacteria to attach to surfaces in environment. (ex: bacteria attaching to teeth) Capsule: - A capsule is organized glycocalyx that is firmly attached to the cell wall. The presence of a capsule can be determined by a negative gram stain test. - In certain species, capsules are important in contributing to bacterial virulence (the degree to which the pathogenic bacteria causes disease). - Capsules often protects pathogenic bacteria from phagocytosis (ingestion & digestion of microorganisms and other solid particles). For example: This capsule helps prevent white blood cells (which fight infection) from ingesting the bacteria. - Capsules protect bacteria from being lysed (the disintegration of a cell by rupture of the cell wall or membrane). - Capsules protect bacteria from dehydration. - Example: Streptococcus pneumoniae Capsule present = causes pneumonia Uncapsulated = no pneumonia Slim layer: - If the substance is unorganized and only loosely attached to the cell wall, the glycocalyx is described as a slim layer.

Understand structure of cell wall in Eukaryotic cells walls: (simpler structure....not all have cell wall....i.e. animal cells do not have a cell wall)

- Most Eukaryotic cells have cell walls - Generally simpler than those of prokaryotic cells - Cell walls do not contain peptidoglycan - Plants, algae, and fungi cell walls composed of cellulose or chitin. - Cell wall of protozoa = flexible outer covering called pellicle. - Animal cells = no cell wall Plasma membrane: - Some eukaryotic cells including animal cells are covered by a glycocalyx plasma membrane (layer of membrane containing sticky carbohydrate, strengthens cell surface, helps attach cells together & may contribute to cell to cell recognition) - Since Eukaryotic cell wall do not have peptidoglycan antibiotics such as penicillin and ceplosporin don't harm human cells since they act against peptidoglycan. - The plasma membrane is very similar in function and structure to prokaryotic cells. Phospholipid bilayer with proteins - Differ in type of proteins found in membrane Also contain: 1). Carbohydrates: serves as receptor site that assumes a role in function such as cell-cell recognition. -also provides attachment site for bacteria. 2). Sterols: associated with ability of membrane to resist lysis resulting from increased osmotic pressure. Transport across membrane occurs same way, but: - No group translocation in Eurkaryotic cells Can use: Endocytosis (a segmented plasma membrane surrounds a particle, enclosed it, and brings into the cell) - One way viruses enters cells

Understand and be able to distinguish the following: - - Viruses

- Not cellular - Very small (need electron microscope to see them) - Reproduce by using cellular machinery of other organisms, can't reproduce on their own Structure: - Core which has only one type of genetic material (DNA or RNA) Viruses are different from other microbial groups: - All living cells besides viruses have both RNA & DNA, carryout chemical reactions & can reproduce as self sufficient units. - Considered living when multiply within host. - When outside the host lifeless and not considered living. Examples: - Cold viruses - Human immunodeficiency viruses (HIV)

-Membrane bound organelles vs. nonmembrane bound in prokaryotes

- Organelles are specialized membrane-enclosed structures in the cytoplasm of eukaryotic cells. - Prokaryotes are defined by their lack of membrane-bound organelles, so the reason prokaryotes don't have them is that any cell that does have membrane-bound organelles would, by definition, not be called a prokaryote. - Only eukaryotic cells contain membrane-bound organelles.

Phage typing

- Phage = bacteria viruses that cause lysis of the bacterial cell they infect. - Phage are highly specialized = only infect members of a particular species or even particular strain within a species Phage typing: - A method of identifying bacteria using specific strains of bacteriophages (viruses that attack bacteria). - Viruses will only attach to and infect a specific host. - Use the viruses as "tags" to identify microorganisms. -Test determine which phage (virus) a bacteria is susceptible to. Phage testing: 1). Grow Bacteria on agar 2). Place drop of phage on bacterial lawn 3). When phage infect a bacteria cell causes lysis of cell which is seen by clearing of bacteria growth -Bacteria isolated from surgical wound will have same pattern of phage sensitivity as those isolated from infecting operating surgeon

Understand what pili are and how they contribute to the virulence of bacteria.

- Pili are external to the prokaryotic cell wall. - Found on many gram-negative bacteria. - Used for motility & DNA transfer. - Hairlike appendages that are shorter, straighter, and thinner than flagella that are involed in motility & join bacteria cells in preparation for the transfer of DNA from one cell to another. - Longer than fimbriae. - Only one or two per cell. - In one type of motility, called twitching motility, a pilus extends by the addition of subunits of pilin, makes contact with a surface or another cell, and then retracts (powerstroke) as the pilin subunits are disassembled. Observed in strains of E.coli. - The other type is motility associated with pili is gliding motility, the smooth gliding movement of myxobacteria. Although the exact mechanism is unknown for most myxobacteria, some utilize pilus retraction. Gliding motility allows microbes to travel in environments with a low water content, such as biofilms & soil. - Some pili are used to bring bacteria together allowing transfer of DNA from one cell to another, a process called conjugation. This can cause antibiotic resistance or the ability to digest its medium more efficiently.

Describe cell wall composition of gram-negative bacteria. Understand the structure of gram-negative bacteria.

- Stains pink - In contrast to gram-positive bacteria, gram-negative bacteria cell walls contain only a thin layer of peptidoglycan and outer membrane (no teichoic acids). Only one or very few layers of peptidoglycan. - Peptidoglycan is bonded to lipoproteins in the outer membrane and is in the periplasm (a fluid-filled sac between the outer membrane and the plasma membrane). - Periplasm contains a high concentration of degradative enzymes and transport proteins for nutrient acquisition and peptidoglycan synthesis. The outer membrane of gram-negative cells Consists of: a). Lipopolysaccharide (LPS) b) Lipoproteins c) Phospholipids: bilayer structure The function of the outer membrane: 1). Strong negative charge important factor in evading phagocytosis of host defense system 2). The barrier to certain antibiotics, enzymes, detergents, heavy metals, bile salts, certain dyes: Porin proteins (proteins that form a channel) doesn't allow the material to pass into the cell 3). Nutrients pass through outer membrane by porins Lipopolysaccharide (LPS): - Provides characteristics of gram-negative bacteria Two components: 1). Polysaccharide portion : - Sugars called O- polysaccharides - Function as antigen(distinguishing different bacteria) (comparable to the role of teichoic acids in Gram-positive bacteria) 2). Lipid portion(lipid A) = endotoxin - A toxin that is part of the cell wall of gram-negative bacteria - When cell lysed toxin is released (why when start taking antibiotics can start to feel worse before feeling better) - Toxic when in hosts bloodstream or gastrointestinal tract - Causes extreme immune response that can lead to fever, shock, and sometimes death.

Understand structure of peptidoglycan.

- The bacterial cell wall is composed of a macromolecular network called peptidoglycan (aka murein), which is present either alone or in combination with other substances. -A repeating disaccharide chain that is attached by polypeptides to form a lattice that surrounds the & protects the entire cell. - The disaccharide portion is made up of monosaccharides called N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM) (from Murus meaning wall), which are related to glucose. - Alternating NAM & NAG molecules are linked in rows of 10 to 65 sugars to form a carbohydrate "backbone" (the glycan portion of peptidoglycan). -Rows are linked by polypeptides that include: Side chains of 4 amino acids, which are linked to NAM backbone. Penicillin: - Interferes with final linkage of peptidoglycan rows and destroys it by interfering with the formation of peptide cross-bridge of peptidoglycan, thus preventing the formation of cell wall which results in a weakened and the cell undergoes lysis (destruction caused by rupture of the plasma membrane and the loss of cytoplasm).

Understand the structure of the outer membrane

- The outer membrane of gram-negative cells consits of LPS (lipoplysaccharides), lipoproteins, & phospholipids. The outer membrane has several specialized functions. - Cell wall consists of the outer membrane & peptidoglycan. Function of outer membrane: 1. Strong negative charge important factor in evading phagocytosis of host defense system. 2. Barrier to certain antibiotics, enzymes, detergents, heavy metals, bile salts, certain dyes: Porin proteins (proteins that form channel) doesn't allow material to pass into cell. 3. Nutrients pass through outer membrane by porins.

Define spheroplast:

- When lysozyme is applied to gram-negative cells, usually the wall is not destroyed to the same extent as in gram-positive cells; some of the outer membrane also remains. In this case, the cellular contents, plasma membrane, and the remaining outer wall layer are called a spheroplast, also a spherical structure. - A gram-negative bacterium treated to damage the cell wall, resulting in a spherical cell. - Lysozyme does not cause as much damage to gram-negative cells. - Some of the outer membrane will remain = spheroplast. - Will burst in pure water or very dilute salt or sugar solutions because surrounding fluid will move into and enlarge the cell = osmotic lysis

13). List 3 things all organisms have in common for classification purposes

1. Composed of cells surrounded by a plasma membrane 2. Use ATP for energy 3. Store Genetic information in DNA

Why are today's antibiotics not as effective as they once were?

1. People taking Antibiotics for no reason has lead to resistance. 2. Taking medications inappropriately. Take all medication as prescribed. If you don't take all medication, you are only weakening bacteria and allowing it to come back stronger 3. People take antibiotics like they are aspirin. Only take antibiotics when they are necessary and not as a way of treating your self 4. Traveling. People are traveling all over the world and are being exposed to new microorganisms that have not been seen before. Drug resistance occurs from genetic changes in microbes that enable them to tolerate antibiotic that normally would kill them Side notes: - You should not take Antibiotics if you have a cold or other viruses - Antibiotics do not work against viruses

15). Definition of: Cladogram

A branching diagram showing the cladistic relationship between a number of species.

Be able to describe what Alexander Fleming did and what their experiment showed:

Alexander Fleming = Discovered penicillin by accident, producing the first antibiotic. - Bacteria plates became contaminated with mold - Bacteria did not grow around mold (area of inhibition). - The mold was later identified as Penicillium. - Fleming later named the active inhibitor penicillin. - Antibiotics = chemical produced naturally by bacteria or fungi that acts against other microorganisms. - 1940: Penicillin used clinically and mass produced. (1928)

15). Definition of: Dichotomous key

An identification scheme based on succesive paired questions; answering one question leads to another pair of questions, until the organism is identified.

What experiments help prove or disprove antibiotic vs synthetic drugs?

Antibiotic - Chemicals produced naturally by bacteria and fungi to act against other microorganisms. Synthetic drugs - Chemotherapeutic agents prepared from chemicals in the lab. - In 1928 Alexander Fleming discovered penicillin by accident, producing the first antibiotic. Fleming was working with bacteria plates when they became contaminated with mold. Bacteria did not grow around mold (area of inhibition). The mold was later identified as Penicillium. Fleming later named the active inhibitor penicillin. In 1940, penicillin began to be used clinically and was mass produced as an antibiotic. - In 1910 Paul Ehrlich found a chemotherapeutic drug called salvarsan (arsenic derivitive) that was effectie against syphillis. These chemotherapeutic drugs which are man-made (synthetic) could destroy microorganisms without harming the infected host.

12). Understand mode of action of different antibiotics that effect different structures of cell...why do they damage cell...what happens? -cell wall acting antibiotics..... -compounds that damage plasma membrane -compounds that inhibit protein synthesis

Antibiotics - Several antibiotics work by inhibiting protein synthesis on prokaryotic ribosome. Example: - Streptomycin and Gentamicin: attach to 30s subunit and interfere with protein synthesis - Erythromycin and Chloramphenicol: attach to 50s subunit and interfere with protein synthesis. - Because of difference in bacteria ribosome and host ribosome (bacteria cells can be killed and host cell remain unaffected). INHIBITS PROTEIN SYNTHESIS - It interferes with the synthesis of peptidoglycan. This weakens the cell walls of dividing bacteria, so they burst and die because of osmotic pressure. Antibiotics : Penicillin - Destroys by interfering with formation of peptide cross-bride of peptidoglycan thus preventing the formation of cell wall. - Gram positive bacteria much more susceptible then gram negative: - Gram negatives outer membrane forms a barrier that inhibits the entry of this and other substances -have fewer peptide cross-bridges. - Gram negative bacteria more susceptible to B-lactam antibiotics: - Penetrates the outer membrane better then penicillin. Cell Wall Damage: - Cell walls are target for antimicrobial drugs Example: Lysozyme: digestive enzyme found in tears, mucus, and saliva - Active mainly on major cell wall components of gram positive bacteria—causes lysis - Breaks bonds between the sugars in the repeating disaccharide backbone of peptidoglycan NAM-NAG - Gram positive cell wall is almost completely destroyed by lysozyme

Describe cell wall composition of archea.

Archea: - May lack cell walls or have unusual composition - Do not contain peptidoglycan, contains pseudomurein

What experiments help prove or disprove aseptic techniques?

Aseptic techniques: Techniques that prevent contamination by unwanted microorganisms (now standard practice in labs & many medical procedures). - Pasteur lent proof of Rudolph Virchow's theory of biogenesis (the claim that living cells can only arise from preexisting living cells) through his two experiments involving specific shaped flasks filled with beedf broth and then boiled. The covered and s-shaped necked flasks had no microbes, whereas the uncoverede flask did have microbes. This gave rise to aseptic techniques.

Nucleic acid analysis: B). DNA fingerprinting

B). DNA fingerprinting: - Allow researchers to compare base sequences without sequencing. 1). Treat DNA with restriction enzymes (cut at specific site) 2). Electrophoresis 3). Compare the size and number of fragments

15). Definition of: Pure culture of bacteria

Bacteria culture - Bacteria grown at a given time. Pure culture - Population of cells derived from a single parent cell.

Biochemical tests

Biochemical Test: - Determine the presence of various enzymes Examples: - Able to ferment carbohydrates can the organism use glucose, lactose, sucrose - Does the organism produce enzymes that allow it to utilize fat or proteins for energy source.

What experiments help prove or disprove the theory of biogenesis?

Biogenesis: The claim that living cells can only arise from preexisting living cells. - In 1858 Rudolf Virchow challenged the case for spontaneous generation with the concept of biogenesis. (No experiments listed on professor's study guide or in book.) - In 1861 Pasteur lent proof of Rudolph Virchow's theory of biogenesis through his experiment with s-shaped necked flasks. These flasks allowed air to flow through after the beef broth was allowed to cool. Even after a month the s-shaped flasks did not have microbes in the solution. This gave rise to aseptic techniques.

Compare and contrast Prokaryotic vs. Eukaryotic cells: - Understand structure and components of Prokaryotic cells - Understand structure and components of Eukaryotic cells - What are the components of these cells and what do they do for the cell?

Both contain: - nucelic acids - proteins - lipids - carbohydrates - They use the same kinds of chemical reactions to metabolize food, build proteins, and store energy. - It is primarily the structure of cell walls and membranes that have specific functions the distinguish prokaryotes from eukaryotes. Prokaryotes: 1. Their DNA is not enclosed within a membrane and is usually a singular circularly arranged chromosome. (Some bacteria have 2 chromosomes & some have linearly arranged chromosome). 2. Their DNA is not associated with histones (special chromosomal proteins found in eukaryotes). 3. They lack membrane-enclosed organelles. 4. Their cell walls almost always contain the complex polysaccharide peptidoglycan. 5. They usually divide by binary fission. During this process, the DNA is copied, and the cell splits into two cells. Involves fewer structures & processes than eukaryotic cell division. - Major structures inside prokaryotic cells are ribosomes, inclusions, DNA & a nuclear area, but they are not organelles because they are not enclosed in membranes. Eukaryotes: 1. Their DNA is found in the cell's nucleus, which is separated from the cytoplasm by a nuclear membrane, and the DNA is found in multiple chromosomes. 2. Their DNA is consistently associated with chromosomal proteins called histones and with nonhistones. 3. They have a number of membrane-enclosed organelles, including mitochondria, endoplasmic reticulum, golgi complex, lysosomes, and sometimes chloroplasts. 4. Their cell walls, when present, are chemically simple. 5. Cell division usually involves mitosis, in which chromosomes replicate and an identical set is distributed into each of the two nuclei. This process is guided by the mitotic spindle, a football-shaped assembly of microtubules. Division of the cytoplasm and other organelles follows so that the two cells produced are identical to each other.

Western blot

C) Western Blot: - Used to ID bacterial antigens in a patient's serum - Proteins including bacterial proteins in a patient's serum are separated by electrophoresis. - Proteins are transferred to a filter by blotting - Antibodies tagged with and enzyme are washed over the filter. - If specific antigen is present in serum the antibodies will combine with it and will be visible as a color band after the addition of enzyme substrate.

Nucleic acid analysis: C). Ribosomal sequencing

C). Ribosomal RNA Sequence: - Used to determine the diversity of organisms and the phylogenetic relationship among them rRNA advantages: a). All cells contains ribosomes b). Two closely related organisms will have fewer differences in their base composition of their rRNA than two organisms that are distantly related c). RNA genes have undergone few chances overtime. d). Cells do not have to be cultured in lab in order to compare. - Amplify DNA by PCR reaction using an rRNA primer and evaluate to determine similarities.

How does lysozyme damage cells?

Cell Wall Damage: -Cell walls are the target for antimicrobial drugs Example: - Lysozyme: digestive enzyme found in tears, mucus, and saliva - Active mainly on major cell wall components of gram-positive bacteria—causes lysis - Breaks bonds between the sugars in the repeating disaccharide backbone of peptidoglycan NAM-NAG. (Like cutting the steel supports of a bridge with a cutting torch: the gram-positive cell wall is almost completely destroyed by lysozyme). - Gram positive cell wall is almost completely destroyed by lysozyme. - For lysozyme to exert its effect on gram-negative cells, the cells are first treated with EDTA (ethylenediaminetetraacetic acid). EDTA weakens ionic bonds in the outer membrane and thereby damages is, giving the lysozyme access to the petidoglycan layer.

What experiments help prove or disprove cell theory?

Cell theory: The theory that all living things are composed of cells. - In 1665 one of the first most important discoveries in the history of biology was made by Robert Hooke. He observed a thin slice of cork using his improved compound microscope (without the use of stain) and saw small structures that looked like "little boxes" or "cells". Hook's discovery marked the beginning of the cell theory (the theory that all living things are composed of cells). (He was not the first to see microbes). - In 1673 Antoni Van Leeuwenhoek was probably the first to actually see microbes with magnifying lenses (of more than 400 microscopes he constructed). Leeuwenhoek saw what he called "animalcules" from scrapings of teeth.

18). Understand Bergy's manual of classification

Classification of Prokaryotes: - Classification scheme found in Bergey's Manual of Systematic Bacteriology: Prokaryotes divided into 2 domains: a). Bacteria b.) Archea Which are then Divided into: Phyla Class Order Family Genus Species - Bacteria are broken down into different Phylum's not different kingdoms Bergy's Manual is a classification scheme for prokaryotes: - Reference manual - Based on a taxonomic organization (common characteristics). - Important to know name or identification of organism in order to treat properly. - Provides a reference for identifying bacteria in lab and classification scheme. - Does not classify bacteria according to evolutionary relatedness but provides identification scheme Example: Bacteria are grouped by things such as a). Cell wall structure (gram positive or negative) b). Do they have flagella? c). What shape? Rod , Cocci, Spiral

Nucleic acid analysis: D). DNA hybridization

D). Nucleic Acid Hybridization: - Used to determine the extent of similarity between the base sequence of two organisms. -Procedure assumes that if two species are similar or related a major portion of their nucleic acid sequence will also be similar. - Measure the ability of DNA strand from one organism to hybridize with DNA strands of another organism. - The greater the degree of hybridization the greater the degree of relatedness.

14). 2 domain vs. 3 domain classification system (what each are based on and what each domain differs by)

Definition of domain: the top-level grouping of organisms in scientific classification. Currently living organisms divided into Three domains: 3 Domains system based on: - Ribosomes are present in all cells but not the same - Compared sequence of nucleotides in the ribosomal RNA from different kinds of cells, this showed 3 Different groups. 3 Domains Include: 1). Eukaryotes 2). Bacteria 3). Archea Domain: Eukaryotes consists of: a). Plants b). Animals c). Fungi Domain: Bacteria consists of: a). Pathogenic bacteria b). Nonpathogenic bacteria c). Chloroplasts Domain: Archea consists of: a). Methogens b). Extreme halphiles c). Hyperthermophiles. Classification of Prokaryotes: - Classification scheme found in Bergey's Manuel of Systematic Bacteriology Prokaryotes divided into 2 domains: a). Bacteria b). Archea Which are then Divided into: Phyla Class Order Family Genus Species Bacteria are broken down into different Phylum's not different kingdoms

How does differential staining work?

Differential Staining: - Gram staining (gram positive or negative) - Acid-fast stain (binds to waxy material in cell wall of mycobacterium)

16). Understand definition and order of Taxonomic hierarchy Domain, Kingdom, phylum, class, order, family, genus, species

Domain: is the top-level grouping of organisms in scientific Kingdom = all phyla or divisions that are related to each other Phylum or division - a group of related classes Class - a group of similar orders Order - a group of similar families Family - related genera Genus - similar species Species = Lowest level (most detailed level of description)

Be able to describe what Edward Jenner did and what their experiment showed:

Edward Jenner = Embarked on an experiment to find a way to protect people from smallpox. Development of the first Vaccine. - Trying to prevent people from dying from smallpox. - A girl told Jenner that she could not get smallpox b/c already had cowpox. Jenner tested girls theory: - Collected scrapings from cowpox blister & inoculated into 8-year-old volunteer by scratching her arm with a pox-contaminated needle. - The volunteer only got mildly sick - the scratch turned into a raised bump. - The volunteer did not get smallpox and this process was called vaccination, which caused immunity. - Cowpox virus is so similar to the smallpox virus that it causes immunity from the smallpox virus when used as a vaccine. - Developed vaccines before Pasteur proved bacteria were in the air.

Be able to describe what Francesco Redi did and what their experiment showed:

Francesco Redi = Wanted to disprove the theory of spontaneous generation - 1st Experiment: Filled 2 jars with decaying meat. The first jar was left unsealed; flies laid their eggs on the meat & the eggs developed into larvae. The second jar was sealed & no maggots appeared. - 2nd Experiment: Covered a jar of decaying meat with a fine net instead of sealing it to allow air to pass through because antagonists were convinced spontaneous generation needed air to take place. No larvae appeared in the jar because flies were unable to get in to leave their eggs. - A serious blow to spontaneous generation theory but people still believed (1668)

Describe cell wall composition of gram-positive bacteria. Understand the structure of gram positive bacteria.

General note: Clinically, the cell wall is important because it contributes to the ability of some species to cause disease and is the site of action of some antibiotics. In addition, the chemical composition of the cell wall is used to differentiate major types of bacteria. - In most gram-positive bacteria, the cell wall consists of many layers of peptidoglycan, forming a thick, rigid structure. - Stains purple when doing a gram stain test. - Also contain teichoic acids, which primarily consist of an alcohol (such as glycerol or ribitol) and phosphate (a salt or ester of phosphoric acid). - There are two types of teichoic acids: 1. lipoteichoic acid, which spans the peptidoglycan layer and is linked to the plasma membrane, and 2. Wall teichoic acid, which is linked to the peptidoglycan layer. The function of teichoic acid: - Since phosphates have a negative charge may bind and regulate the movement of positive ions into and out of the cell. - Plays role in cell growth - Prevents breakdown and lysis of the cell - Provides walls antigenic specificity which allows for identification of bacteria

What experiments help prove or disprove germ theory?

Germ Theory - Scientist started accumulated data to support the theory that microbes caused disease. At one time people believed diseases were caused by peoples misdoings and not by microbes. - In 1865, Pastuer was asked by the silk industry to help in the fight of the silkwork disease. In 1835 Agostino Bassi has proved that a different silwork disease was caused by fungus. Using data provided by Bassi, Pasteur found this new disease to be caused by a protozoan (single-celled eukaryotes). He then developed a method for recognizing afflicted silkwork moths. - In the 1860s Joseph Lister realized that OBs that did not wash their hands routinely transmitted infections from one patient to another. Lister started treating surgical wounds with a phenol (carbolic acid) solution which reduced incidences of infection and deaths. Lister applied Germ theory to the medical procedure because of Pasteur's work connecting microbes to animal disease. Lister's actions proved microorganisms caused surgical infection. - In 1876 Robert Koch was the first person to prove bacteria caused disease. Koch was Pasteur's young rival in the race to discover the cause of anthrax, a disease that was destroying cattle & sheep in Europe. Koch discovered rod-shaped bacteria (Bacillus anthracis) in the blood of cattle that died from anthrax. He cultured this bacteria on nutrients from dead animals and injected it into healthy animals; the healthy animals became sick and died. The bacteria isolated from animals injected that had died had the same bacteria found as the original isolate from animals that previously died. This gave rise to Koch's postulate in which directly related a specific microbe to a specific disease.

Be able to describe what John Needham did and what their experiment showed:

John Needham = strengthened claims of spontaneous generation - Claimed that microorganisms could arise spontaneously from heated nutrient broth Experiment: Heated broth before pouring into covered flasks, the cooled solutions were soon teeming with microorganisms. - Needham claimed that microbes developed spontaneously from the fluids. (1745)

Be able to describe what Joseph Lister did and what their experiment showed:

Joseph Lister = Realized that OBs that did not wash their hands routinely transmitted infections from one patient to another. Started treating surgical wounds with a phenol (carbolic acid) solution which reduced incidences of infection & deaths. 1860s Joseph Lister, a Surgeon •Applied Germ theory (theory that diseases are caused by microorganisms) to the medical procedure because of Pasteur's work connecting microbes to animal disease -Proved microorganisms caused surgical infection Development of Germ Theory: - At one time people believed diseases were caused by peoples misdoings and not by microbes (1860s)

Be able to describe what Lazzaro Spallanzani did and what their experiment showed:

Lazzaro Spallanzani = Repeated Needham's experiment and suggested that Needham's results were due to microorganisms in the air entering the broth after being boiled. - Microorganisms must be coming from air because if container were sealed = no microorganisms a). Microorganisms did not grow in covered flasks b). Microorganisms grew in uncovered flasks (1765)

Be able to describe what Louis Pasteur did and what their experiment showed:

Louis Pasteur = Demonstrated that microorganisms are present in the air & can contaminate sterile solutions, but that air itself does not create microbes. 1st Experiment: -Filled short neck flasks with beef broth & then boiled -Left some flasks open, some flasks sealed Results: - Sealed flasks free of microbes - Unsealed flasks contaminated with microbes Pasteur demonstrated: Microorganisms are in the air everywhere and offered proof of Rudolph Virchow's theory of biogenesis 2nd Experiment: -Filled long bent neck (s-shape) shaped flask (to allow air in) with beef broth, boiled and cooled Results: Even after a month, no microbes -Air could pass through flask, but curved neck trapped microbes from entering into the broth Pasteur showed: - Microbes can live on solids, liquids and in air - Microbes can be destroyed by heat and kept from contamination - Microbes can not originate from mystical forces = no spontaneous generation - Gave rise to Aseptic Techniques = preventing contamination -Discoveries led to the development of aseptic techniques used in laboratory and medical procedures to prevent contamination of microorganisms that are in the air (1861)

Understand how material moves across plasma membrane of both prokaryotic and eukaryotic cells -Passive process vs. active process -Group translocation (prokaryotes only) -endocytosis (eukaryotes only)

Material move across plasma membrane of both prokaryotic and eukaryotic cells by: Passive Process: 1). Passive process: substances cross the membrane from an area of high concentration to and area of low concentration - No energy expenditure 2.) Simple Diffusion: - Movement from high concentration to low concentration until equilibrium reached - Used for movement of oxygen, carbon dioxide 3.)Facilitated Diffusion: - Substances are transported by transporter protein across membrane from areas of high to low concentration 4. Osmosis: - movement of water across a selectively permeable membrane from an area of higher concentration to an area of lower water concentration until equilibrium reached - Living systems, water is the chief solvent Example: Sucrose contained in water permeable membrane (Bacterial cell may be subjected to 3 kinds of osmotic solutions:Isotonic, Hypertonic & Hypotonic) Active Process: - The cell uses energy to transport substances across the plasma membrane (transport from low concentration) - The cell can uses transporter proteins in the plasma membrane and use energy Group translocation (active process - prokaryotes only): - A special form of active transport that occurs in prokaryotes - The substance is chemically altered during transport across the membrane - Once the substance is altered and inside the cell, the plasma membrane is impermeable to it, so it remains in the cell - Enables cells to accumulate various substances even though they may be low in concentration outside the cell. Endocytosis (active process - eukaryotes only): - A segmented plasma membrane surrounds a particle, encloses it, and brings into the cell - One way viruses enter cells Types of Endocytosis: a). Phagocytosis: cellular projection called pseudopod engulf particle and brings them into the cell - Used by white blood cells to destroy bacteria and foreign substances b). Pinocytosis: plasma membrane folds inward, bringing extracellular fluid into the cell along with whatever else is in fluid

Harmful vs. Helpful bacteria....ways bacteria help and harm humans

Microbes and Human Welfare: 1. Microorganisms degrade dead plants and animals and recycle chemical elements to be used by living plants and animals. 2. Sewage treatment: Using microbes to recycle water: Bacteria are used to decompose organic matter in sewage. Bacteria convert left behind liquid & organic materials into such by- products as carbon dioxide, nitrates, phosphates, sulfates, ammonia, hydrogen sulfide & methane. 3. Bio-remediation: using microbes to clean up pollutants: processes uses bacteria to clean up toxic waste. Toxins can be removed from underground wells, chemical spills, toxic waste sites, and oil spills. 4. Bacteria are being used as biological controls of specific insects and pests without harming the environment. Uses as GMO or dust used on top of crops. 5. Use microbes to make products such as food and chemicals. 6. Using recombinant DNA bacteria can produce substances like proteins, vaccines, and enzymes. 7. In gene therapy viruses are used to carry replacement for defective or missing genes into human cells. This technique uses a harmless virus to carry the missing or new gene into certain host cells, where the gene is picked up & inserted in to the appropriate chromosome. 8. Genetic engineering is used in agriculture to protect plants from frost and insects and to improve the shelf life of produce. 9. Normal microbiota live on and inside our bodies and in some cases benefit us by preventing overgrowth of harmful microbes. Others produce vitamin K & some B vitamins. When normal microbiota leave their habitat they can cause disease. 10. Biofilms can be beneficial or harmful. Biofilms can be slime on rocks, the substance that lines your teeth, or float on top of aquatic environments. They can protect your mucous membranes from harmful microbes, are a food source for aquatic animals. Or they can be harmful by clogging water pipes, and on medical implants such as joint prostheses and catheters they can cause infections such as endocartis (inflammation of the heart). Often resistant to antibiotics. 11. An infectious disease is one in which a pathogen invades a susceptible host. It is a disease that can be transmitted from person to person or from organism to organism, and is caused by a microbial agent. 12. An emerging infectious disease is a new or changing disease showing an increase in incidence in the recent past or a potential increase in the near future. Can be due to things like: a). Resistance of bacteria to antimicrobial agents b). People not being vaccinated c). Development of new diseases

19). Understanding ways of Classifying and Identifying microorganisms. How does morphological characteristics work?

Morphological Characteristics : - Different structure that organism might have a). Flagella b). Endospores c). Shape of cell (rods, cocci) - Hard to use as the only way of ID because microorganism look to similar.

Describe the cell wall composition of mycoplasma bacteria.

Mycoplasma: - Smallest bacteria know to grow and reproduce outside living host cells. - No cell wall. - Pass through bacterial filters because so small. - Plasma membrane has lipids called sterols, which protect from lysis.

Nucleoid area vs. nucleus: Structure of bacteria chromosome vs. eukaryotic chromosome

Nucelus (eukaryotic only): - The most characteristic eukaryotic orangelle. - Usually spherical or oval & usually the largest structure in a eukaryotic cell. - Contains almost all of the cells DNA (some found in mitochondria). - Nucleus is surrounded by double membrane called nuclear envelope. - Nucleus contains both chromosome proteins (histones) and non chromosomal proteins (chromosomes are made up of DNA and protein called chromatin) Nucleoid (prokaryotic only): - The nucleoid of a bacterial cell usually contains a single long, continuous, and frequently circularly arranged thread of a double-stranded DNA called the bacterial chromosome. - Bacterial chromosomes are not surrounded by a nuclear envelope (membrane) and do not include histones (a protein associated with DNA in eukaryotic chromosomes). - Can be spherical, elongated, or dumbbell-shaped. Prokaryotic chromosome do not: - Don't have histone proteins (chromosomal proteins) - Are not enclosed in nuclear envelope - Don't undergo mitosis and meiosis to segregate proteins before cell division. Chromosome: attached to plasma membrane - Proteins in plasma membrane are believed to be responsible for replication of the DNA and segregation of new chromosome for daughter cell in cell division -Nuclear Area also contains Plasmids

Nucleic acid analysis: A). DNA Base composition

Nucleic Acid Analysis: A). DNA Base Composition: Look for G, C content in DNA GC + AT = 100% - Two organism that are closely related will have similar amounts of the various bases in their DNA. - If difference is more then 10% then organism are not related. -Need to sequence DNA to determine base composition Example: Halobacterium species = 67% GC Escherichia coli = 50% GC Campylobacter jeuni = 37% GC

Briefly understand the function of following Nucleus Endoplasmic reticulum Ribosome Golgi complex Mitochondria Chloroplast Peroxisomes Inclusions

Nucleus: - Most characteristic eukaryotic organelle. - Spherical or oval. - Usually largest structure in cell and contains cell hereditary info (DNA). - Nucleus is surrounded by double membrane called nuclear envelope - Nucleus contains both chromosome proteins (histones) and non chromosomal proteins (chromosomes are made up of DNA and protein called chromatin). Endoplasmic Reticulum: -Functions in storage and transport of material -It is a Network of tubules, vesicles and sacs that are interconnected. (Nuclear envelope is attached to ER) -Helps in control of protein synthesis and cellular organization. Types: a). Rough ER: outer layer studded with ribosome -factory for synthesizing proteins and membrane molecules b). Smooth ER: extends from rough ER -network of tubules that synthesizes phospholipids, fats, steroids Function: 1). A surface for chemical reactions 2). Serves as a transporting network 3). Stores and synthesizes molecules 4). Protein synthesis and transport occurs in rough ER Lipid synthesis occurs on smooth ER Ribosome: - Site of protein synthesis: 80S ribosome in Eukaryotic cells: 40s + 60s = 80s Golgi Complex: - Consists of flattened sacs called cisterns - Modifies, sorts and packages proteins that are received from the endoplasmic reticulum (like post office) - Package cell products, such as enzymes and hormones, and coordinate their transport to the outside of the cell. Mitochondria: - Throughout cytoplasm - Chemical reactions occur here including ones that make ATP - Considered the powerhouse of the cell because it's the central role in ATP production Chloroplast: - Found in algae and green plants - Membrane enclosed structure - Contains both chlorophyll and enzymes required for the light gathering phase of photosynthesis Peroxisomes: - Break down fatty acids and amino acids by oxidation reactions (removal of electrons) - These reactions produce hydrogen peroxide which could harm cells if it were allowed to persist. An enzyme (catalase) breaks down the hydrogen peroxide to water and oxygen, both of which can be used by the cell. Peroxisomes also break down alcohol. Centrosomes: - Play role in cell division by organizing mitotic spindle Inclusions (prokaryotes only): - Located within the cytoplasm - Reserve deposits - Cells accumulate nutrients when they are plentiful and use when there is a deficient - Some inclusions are common to a wide variety of bacteria where others are limited to a small number of species.

Describe the function and structure of plasma membrane -sterols only found in eukaryotic plasma membrane -structure of phospholipids and proteins

Plasma membrane function: - Plasma membrane separates cells interior from its surrounding and controls what goes into and out of the cell. - Plasma membrane lies inside the cell wall enclosing the cytoplasm of the cell. - Eukaryotic plasma membrane also contains: carbohydrates, sterols (such as cholesterol) making for a more rigid structure. - Because they lack sterols & consist mainly of phospholipids and proteins prokaryotic plasma membranes are less rigid than eukaryotic membranes. (One exception is the wall-less prokaryote mycoplasma, which contains membrane sterols). a.) The plasma membrane has a selective barrier which determines what material will enter and exit the cell called selective permeability: certain molecules pass through while others are prevented Examples: - Large molecules = can't fit through pores of integral proteins while small ones can - Ions: penetrate slowly - Substances that dissolve easily in lipids can easily enter and exit cell b). Breaks down of nutrients and production of energy: - Plasma membrane contains enzymes capable of catalyzing the chemical reaction that breaks down nutrients and produces ATP (Electron Transport system for ATP production is here) Plasma membrane structure: 1. Phospholipids: are arranged in a bilayer (two parallel rows. Made up of phospholipid heads, glycerol backbones are at the bottom of the head and they hold the fatty acid tails.) 2. Protein component of membrane: a.) Peripheral proteins (lay on top of or slightly into the plasma membrane): - Proteins adhere to the membrane - May function as enzymes to catalyze chemical reactions (could be a hormone). - "Scaffold" for support. - Mediators of changes in the membrane shape during movement. - Peripheral proteins are easily removed from the membrane by mild treatments. b): Integral proteins (stuck into the phospholipid bilayer): - Reside in or span across the membrane. - May act as transporter proteins and transport certain material across the membrane by means of a channel, pore, or hole in the protein itself. - Integral proteins can only be removed from the membrane only after disrupting the lipid bilayer (by using detergents for example).

-Plasmid DNA

Plasmid DNA (found moslty in prokaryotic cells only): - Small circular, double stranded DNA molecules - Contain extrachromosomeal genetic elements - Not connected to main bacterial chromosome - Replicate independently of chromosomal DNA - Contain 5-10 genes not crucial to survival - Used for gene manipulation in biotech - Can carry genes for: a). Antibiotic resistance b). Tolerance to toxic metals c). Production of toxins d). Synthesis of enzymes

List four differences between prokaryotes & eukaryotes.

Proaryotes: - DNA not enclosed in a membrane. - Lack membrane enclosed organelles. - DNA not associated with histones. - Cell walls almost always contain peptidoglycan. Eukaryotes: - DNA found in a nucleus. - Have many membrane enclosed organelles. - DNA ssociated with histones & nonhistones. - Cell walls are chemically simple.

Understand contents and structure of cytoplasm in prokaryotic cell vs. eukaryotic cells -cytoskeleton and cytoplasmic streaming in eukaryotes

Prokaryote cytoplasm: Fluid component inside the plasma membrane Contains: 80% water Primary proteins(enzymes) carbohydrates lipids inorganic ions Eukaryote cytoplasm: - Encompasses the substance inside the plasma membrane and outside the nucleus - Where various cellular components are found Major Difference of Eukaryotic and Prokaryotic Cytoplasm: -In prokaryotes, the cytoplasm is relatively free of compartments -In eukaryotes, it normally contains a large number of organelles, and is the home of the cytoskeleton 1). Eukaryotic Cytoplasm has a more complex internal structure consisting of: - Small rods called microfilaments - Intermediate filaments - Cylinders called microtubules - The fluid portion of the cytoplasm contains dissolved nutrients, helps break down waste products, and moves material around the cell through a process called cytoplasmic streaming. Cytoplasmic Streaming: movement of eukarytoic cytoplasm from one part of cell to another part - Helps distribute nutrients and move the cell over a surface 2). Many structures found in the cytoplasmic fluid of prokaryotes are sequestered in organelles of eukaryotes.

Be able to describe what Robert Hooke did and what their experiment showed:

Robert Hooke = "little boxes" or "cells" - One of the first most important discoveries in the history of biology. - Observed a thin slice of cork using his improved compound microscope - Saw small structures, looked like "little boxes" or "cells" - Hook's discovery marked the beginning of the cell theory - the theory that all living things are composed of cells. - No stain used so did not see microbes (1665)

Be able to describe what Robert Koch did and what their experiment showed:

Robert Koch = First person to prove bacteria caused disease - Pasteur's young rival in the race to discover the cause of anthrax, a disease that was destroying cattle & sheep in Europe. - Discovered rod-shaped bacteria (Bacillus anthracis) in the blood of cattle that died from anthrax. - Cultured bacteria on nutrients from dead animals and injected it into healthy animals; the healthy animals became sick and died. - Bacteria isolated from animals injected that had died, the same bacteria was found as original isolate from animals that previously died. Used Koch's postulate: - Experimental steps for directly relating a specific microbe to a specific disease (1876)

Be able to describe what Rudolf Virchow did and what their experiment showed:

Rudolf Virchow = challenged the case for spontaneous generation by introducing the concept of biogenesis (living cells can only arise from preexisting living cells). (No experiments listed on professor's study guide or in book) (1858)

Serological tests: Slide agglutination test Elisa

Serology = science that studies blood serum and the immune response. - Microorganism are antigenic = when microorganism enter an animal's body it stimulates the formation of antibodies. - Antibodies are proteins that circulate in the blood and combine in a specific way with the bacteria that caused their production. Antibody: Antigen binding is very specific - Involve reactions of microorganisms with specific antibodies. Reactions of Antigen and Antibody: - Are useful in determining ID different species as well as relationship among organisms - Differentiate not only among microbial species but also among strains within species. Examples of Tests involving Antigen/Antibody reactions: a). Slide agglutination test: - Samples of the unknown bacterium are placed in a drop of saline on several slides. - Different Antibody solution is added to each sample. - Bacteria clump when mixed with antibodies that were produced in response to that species of bacteria. b). ELISA: (Enzyme-Linked Immunosorbent Assay). - Known antibodies are placed in micro-plate and an unknown bacterium is added to each sample. - A reaction between known antibody and bacteria provides ID of the bacteria. - Results are fast and can be read by a computer scanner.

What experiments help prove or disprove spontaneous generation?

Spontaneous generation: Philosophers believed that some forms of life could arise spontaneously from nonliving matter. - In 1668 Francesco Redi wanted to disprove the theory of spontaneous generation. Redi put a serious blow in the spontaneous generation theory by experimenting with decaying meat & air exposure, but people still believed in spontaneous generation. - In 1745 John Needham strengthened claims of spontaneous generation by claiming that microorganisms could arise spontaneously from heated nutrient broth. He heated broth before pouring it into covered flasks & when the the solutions cooled they were soon teeming with microorganisms. Needham claimed that microbes developed spontaneously from the fluids. - In 1765 Lazzaro Spallanzani repeated Needham's experiments and suggested that Needham's results were due to microorganisms in the air entering the broth after being boiled. He found that microorganisms did not grow in covered flasks, but did grow in the uncovered flasks. - In 1858 Rudolf Virchow challenged the case for spontaneous generation with the concept of biogenesis (living cells can only arise from preexisting living cells). - In 1861 Louise Pasteur ultimately disproved the theory of spontaneous generation by demonstrating that microorganisms are present everywhere in the air, on solids & liquids & can contaminate sterile solutions, but that air itself does not create microbes. He also demonstrated that microbes can be destroyed by heat and keep substances free from contamination. In Pastuer's first experiment he filled short neck flasks with beef broth & then boiled them. He left some flasks open & some flasks sealed. The results showed that the sealed flasks were free of microbes & the unsealed flasks were contaminated with microbes. In his second experiment, he filled long bent neck, s-shaped, flasks with beef broth, boiled and then allowed them to cool. The shape of the flask necks allowed air to pass into the flask. Pasteur did this to disprove spontaneous generation because the antagonists of spontaneous generation thought that cells could arise spontaneously. Even after a month, there were no microbes in the s-shape necked flasks. Pasteur lent proof of Rudolph Virchow's theory of biogenesis (the claim that living cells can only arise from preexisting living cells). This gave rise to aseptic techniques (techniques that prevent contamination by unwanted microorganisms, which are now standard practices used in labs & medical procedures to prevent contamination of microorganisms in the air).

15). Definition of: Strain of bacteria

Strain - A group of bacteria that are derived from a single cell. Different strains = pure cultures of same species that are not identical in all ways. Strains - Are identified by number, letter or names that follow the specific epithet.

15). Definition of: Taxonomy

Taxonomy - The classification of organisms on the basis of their evolutionary relationship - The science of classifying organisms - Provides universal names for organisms - Provides a reference for identifying organisms

15). Definition of phylogeny:

The study of evolutionary history.