Microbiology Exam One

Fleming's Contributions

He discovered the enzyme lysozyme (damaged bacterial cell walls through hydrolysis). Also discovered the first antibiotic: Penicillin G (treats bacterial infections caused by streptococci and staphylococci)

Describe the ways that bacterial DNA can be transferred vertically and horizontally (laterally) to other cells.

Horizontal- the exchange of genes within microbes of the same generation Vertical- the passing of genes to the next generation; performed through sexual reproduction

Define host cell & viral host range; list factors that determine host range.

Host range is determined by specific host attachment site, and cellular factors. Factors include: host receptors, transmission, virulence factors, host immune system.

Define and understand the applications of gene therapy and CRISPR

Human gene therapy is a recombinant DNA procedure that seeks to treat disease by altering the genes of the afflicted person. The mutant version of a gene is replaced or supplemented with a properly functioning one

Define prion and describe the types of diseases caused by prions.

Infectious proteins Inherited and transmissible by ingestion, transplant, & surgical instruments Spongiform encephalopathies: Sheep scrapie, Creutzfeldt-Jakob disease, Gerstmann-Sträussler-Scheinker syndrome, fatal familial insomnia, mad cow disease PrPC, normal cellular prion protein, on cell surface PrPSc, scrapie protein, accumulate in brain cells forming plaques, converts PrPC to PrPSc

Understand the 5 I's of studying microbes.

Inoculation: introducing it to a medium. Incubation: proper environment; warming. Isolation: separation. Inspection: visual, microscopic. Identification.

Koch's Contributions

Known for his role in identifying the specific causative agents of tuberculosis, cholera, and anthrax and for giving experimental support for the concept of infectious disease. In addition to his innovative studies on these diseases, Koch created and improved laboratory technologies and techniques in the field of microbiology, and made key discoveries in public health. His research led to the creation of Koch's postulates, a series of four generalized principles linking specific microorganisms to specific diseases that remain today the "gold standard" in medical microbiology.

Describe the basic differences between animals, plants, fungi, & protists.

- Animalia: Multicellular; no cell walls; chemoheterotrophic · Plantae: Multicellular; cellulose cell walls; usually photoautotrophic · Fungi: Chemoheterotrophic; unicellular or multicellular; cell walls of chitin; develop from spores or hyphal fragments · Protista: A catchall for eukaryotic organisms that do not fit other

Distinguish between latent viral infections and persistent viral infections.

Latent Viral Infections: Virus remains in asymptomatic host cell for long periods Cold sores, shingles Persistent Viral Infections: Disease processes occurs over a long period, generally fatal Subacute sclerosing panencephalitis (measles virus)

Jenner's Contributions

Pioneered the small pox vaccine; the world's first vaccine.

Describe the structure of bacterial DNA. List the four nucleic acids that make up DNA & RNA.

Polymer of nucleotides: adenine, thymine, cytosine, guanine

Describe the differences between prokaryotic cells (bacteria) and eukaryotic cells (animals, plants, fungi, protists).

Prokaryote: one chromosome, no histones, no organelles, peptidoglycan cell walls (plants), reproduce through binary fission. Eukaryote: paired chromosomes, histones, organelles, reproduce through mitosis, polysaccharide cell walls (plants).

Understand the general size scale of microorganinsms

1 Meter 1 mm = 1x10-3 1/1,000 of a meter (milli) 1um = 1x10-6 1/1,000,000 of a meter (micro) 1nm = 1x10-9 1/1,000,000,000 of a meter (nano) 1 pm = 1x10-12 1/1,000,000,000,000 of a meter (pico)

Define biofilm and explain its role in disease.

A film of bacteria that grows on surfaces. It's harder to kill biofilms b/c of their layers, so it's difficult to eradicate to the base aka "root.

Define metabolism, catabolism, anabolism, glycolysis, anaerobic respiration, aerobic respiration, and fermentation.

Aerobic respiration: The final electron acceptor in the electron transport chain is molecular oxygen (O2). Anaerobic respiration: The final electron acceptor in the electron transport chain is not O2. Metabolism: is the sum of the chemical reactions in an organism. Catabolism: is the energy-releasing processes. Refers to the breakdown of complex organic compounds into smaller ones and in the process, energy is released from the chemical bonds and transferred to other molecules for storage or is lost as heat Large molecules to smaller; energy released & stored in ATP. Anabolism: is the energy-using processes. Anabolism refers to the building up of complex molecules from simpler ones. Small molecules to larger; energy from ATP needed. Glycolysis: Fermentation: Releases energy from oxidation of organic molecules. Does not require oxygen. Uses an organic molecule as the final electron acceptor.

Understand why agar is used in solid media.

Agar is a solidification agent, otherwise the media would be liquid.

Give examples of some common products produced by microbial fermentation.

Alcohol, foods

List some of the applications of genetic engineering, particularly those that are health related.

Antibiotics

Describe the phases of the bacterial growth curve.

Bacterial Growth Curve : When bacteria are inoculated into a liquid growth medium, we can plot of the number of cells in the population over time. 1. Lag Phase: 4 Period of adjustment to new conditions. 4 Little or no cell division occurs, population size doesn't increase. 4 Phase of intense metabolic activity, in which individual organisms grow in size. 4 May last from one hour to several days. 2. Log Phase: 4 Cells begin to divide and generation time reaches a constant minimum. Period of most rapid growth. Number of cells produced > Number of cells dying. Cells are at highest metabolic activity. Cells are most susceptibleto adverse environmental factors at this stage. • Radiation • Antibiotics 3. Stationary Phase: Population size begins to stabilize. Number of cells produced = Number of cells dying. Overall cell number does not increase. Cell division begins to slow down. Factors that slow down microbial growth: • Accumulation of toxic waste materials • Acidic pH of media • Limited nutrients • Insufficient oxygen supply 4. Death or Decline Phase: Population size begins to decrease. Number of cells dying > Number of cells produced. Cell number decreases at a logarithmic rate. Cells lose their ability to divide. A few cells may remain alive for a long period of time.

Define enzyme, list its basic structure (protein), & describe how enzymes work.

Biological catalysts Specific for a chemical reaction; not used up in that reaction Apoenzyme: protein They act on only a specific substance (to break it down or build it up). The substance they act on is called the substrate; the substances produced are called the products Always have a protein as their main component. Enzymes work by binding to substrate and turning the substrate so that it the probably of the reaction occurring is increased.

Describe the 3 basic shapes of bacteria.

Coccus: spherical Bacillus: rod shaped. Spirillium: cork screw shaped.

Understand the terms culture, culture medium, sterile, inoculum, chemically defined media, enriched media and complex media.

Culture medium: nutrients prepared for microbial growth. Sterile: no living microbes Inoculum: introduction of microbes into medium. Chemically defined media: exact chemical composition is known. Enriched media: organisms will not grow without specific nutrients, so the media must be enriched with nutrients to encourage their growth. (ex: blood agar plates to detect hemolysis) Culture: Microbes growing in/on culture medium. Complex media: extracts and digests of yeasts, meat, or plants. (ex: chicken broth)

List the methods used to diagnose viral infections.

Cytopathic effects: detects changes in tissues/cells. Serological tests: detects changes in blood, and antibodies. Detecting nucleic acids to find any viral DNA or RNA.

Define denaturization of proteins & list some of the ways proteins can be denatured.

Denaturation means that the shape of the protein is changed. Denaturation of enzymes will prevent the enzyme from working properly so the part of the metabolism related to that enzyme will stop. Can cause the cell to die Several factors can denature protein, including temperature and pH.

Van Leeuwenhoeck's Contributions

Discovered microscopy

Lister's Contributions

Discovered sterile fields, and aseptic techniques.

Semmelweise's Contributions

Discovered the incidence of puerperal fever amongst children, and introduced handwashing to obstetric clinics.

Erlich's Contributions

Discovered the method of gram staining bacteria to discover numerous of blood diseases.

Pasteur's Contributions

Discovered the method of pasteurization; a process of heating liquid to destroy harmful bacteria, and returning it back to preheat. Also known for discovering vaccinations (rabies and anthrax) and microbial fermentation.

Define replication, translation, transcription and list the part of the cell where each takes place.

During Replication, the strands of the double helix separate and each strand is used as a template to make two new strands of DNA each identical to the original. The replication process is referred to as "semi-conservative" because each new double helical strand has one original strand and one new strand. The process of translation - making proteins requires the cell to expend a lot of energy (Anabolic process). The cell tries to limit the energy needed by only producing those proteins (enzymes) that it needs at any particular time. DNA is transcribed to make RNA (mRNA, tRNA, and rRNA) mRNA is translated in codons (3 nucleotides) by ribosome

When given the scientific name of an organism, list its genus and species. FIX*

EXAMPLE: Staphylococcus aureus and Esherichia coli are found in the body. S. aureus is on skin and E. coli, in the large intestine.

Describe the differences between prokaryotes and eukaryotes; list the parts of prokaryotic (bacterial) cells and describe their function.

Eukaryotic species: A group of closely related organisms that breed among themselves. Paired chromosomes, in nuclear membrane, Histones, Organelles, Polysaccharide cell walls, Mitotosis Prokaryotic species: A population of cells with similar characteristics. Clone: Population of cells derived from a single cell (genetically identical). One circular chromosome, not in a membrane. Most have no histones (Archaea exception), No organelles, Peptidoglycan cell walls, Binary fission. Bacteria: 2-5mm is average size of bacteria

Define strict (obligate) anaerobe & aerobe; facultative anaerobe; microaerophile; capnophile.

Facultative Anaerobes: Can use oxygen, but can grow in its absence. Have complex set of enzymes. Obligate Anaerobes: Cannot use oxygen and are harmed by the presence of toxic forms of oxygen. Obligate Aerobes: Require oxygen to live. Microaerophiles: Require oxygen, but at low concentrations. Sensitive to toxic forms of oxygen.

Understand the basic difference between a light, fluorescent and electron microscope. Which microscope provides the highest resolution.

Light: resolution; the ability of lenses to distinguish two points. A microscope with a resolving power of 0.4nm can distinguish between two points >_ 0.4nm. Shorter wavelengths provide greater resolution. Fluorescent: Uses UV light, absorbs UV light and emit visible light, cells may be stained with fluorescent dyes. Electron: Uses electrons instead of light, shorter wavelengths of electrons gives greater resolution.

Define bacterial growth & generation time.

Microbial growth = increase in number of cells, not cell size Generation Time: Time required for a cell to divide, and its population to double. Varies considerably.

Know the requirements of growth

Microbial growth = increase in number of cells, not cell size. Require: carbon, salts, or pH Ways to increase the number of cells chemically: C, N2, O2, S, P.

Hooke's Contributions

Microscopy, and refraction of lights - The first person to view cells under a microscope

List some of the ways that mutations can be induced in cells and what are the possible results of a mutation.

Missense mutation- Result in change in amino acid Silent Mutation- Changes codon but encodes same amino acid Spontaneous mutations- Occur in the absence of a mutagen Frameshift mutation- Insertion or deletion of one or more nucleotide pairs

List the optimum pH range for most bacteria and for fungi.

Most bacteria prefer neutral pH (6.5-7.5).

Define mutation, plasmid, and mutagen.

Mutagen: Agent that causes permanent mutations. Mutagens can be chemicals or can be high energy waves like UV, Gamma rays, X-Rays Mutations may be neutral, beneficial, or harmful. Change in the genetic material. However, sometimes something causes a change in the nucleotide sequence of DNA. We call this a mutation. There are several types of mutations that may occur during replication of the DNA strand. Plasmids are smaller pieces of DNA that code for production of non-essential proteins. E.g. protein that allows organism to make pili (F factor) or protein that may confer resistance to some antibiotic (R factor).

Describe how members of the genera Mycoplasma, Chlamydia, & Rickettsia differ from most other bacteria.

Mycoplasma: lack cell walls, and contain sterols in plasma membrane. Chlamydia: require host cell, not transmitted by arthropods, transmitted by direct contact. Rickettsia: very tiny, gram negative, cannot survive or multiply outside the host cell, cannot carry out metabolism completely on their own.

Define recombination, transformation, conjugation, transduction, cloning.

Recombination- Exchange of genes between two molecules of DNA. Can happen in nature or be done deliberately in the lab. Conjugation- Another mechanism that occurs in nature. Some bacteria have organelles called pili that allow them to transfer material to other cells. Transduction- is another way that bacterial DNA can be transferred. Involves the use of a virus that infects bacterial called a bacteriophage. Can happen in nature. Can be done purposefully in the lab.

Understand the concepts of refraction and resolution.

Resolution is the ability of the lenses to distinguish two points. The refractive index is a measure of the light-bending ability of a medium. The light may bend in the air so much that it misses the small, high-magnification lens. Immersion oil is used to keep light from bending

Know the media terms: selective, differential, indicator, defined and undefined.

Selective - Selects for growth a particular subset of organisms (other organisms prevented from growing). Differential - Allows differentiation of growing organisms. Indicator Plates - Usually a colorimetric indicator identifies a characteristic Defined: chemical composition known. Undefined: includes natural products without known composition.

Know the differences between a simple, differential, Gram and acid-fast stains.

Simple stains: used to see the enlargement of the cell. Mordant makes the dye stick to the specimen's cell wall. Differential stains: used to distinguish between bacteria. Gram stain: differences in the cell membrane. Acid-fast stain: stained waxy cell wall is not decolorized by acid-alcohol.

Describe the role of oxygen in respiration and fermentation.

Some organisms can also ferment sugars. Because fermentation usually takes place in the absence of oxygen, strict anaerobes can usually also ferment glucose. Some organisms that undergo aerobic cellular respiration can also ferment carbohydrates even when oxygen is not present. They are called facultative anaerobes.

Describe how scientific names for microorganisms are determined (i.e. genus & species).

The genus is capitalized and the specific epithet is lower case. We often abbreviate the genus by using just the first letter. There is a two part name for each species: the first part describes a slightly broader group to which the organism belongs; the second part describes the specific group to which the organism belongs.

What is the Germ Theory of Disease? What is the Theory of Spontaneous Generagtion?

The germ theory of disease states that many diseases are caused by microorganisms. These small organisms, too small to see without magnification, invade humans, animals, and other living hosts. Their growth and reproduction within their hosts can cause a disease. Before the discovery of microbes, it was widely thought that life, as in the case of rotting food, arose from nothing. This idea was referred to as spontaneous generation.

Explain Koch's postulates.

The microorganism must be found in abundance in all organisms suffering from the disease, but should not be found in healthy organisms. The microorganism must be isolated from a diseased organism and grown in pure culture. The cultured microorganism should cause disease when introduced into a healthy organism. The microorganism must be reisolated from the inoculated, diseased experimental host and identified as being identical to the original specific causative agent

Understand the 3 domains of life tree and how it relates to classic taxonomy (i.e. Kingdom, phylum, class, etc.)

Three domains of life: Bacteria, Archaea, and Eukaryotes Bacteria: prokaryotes; "pre nucleus" very primitive, no internal membrane. Bacteria have cell walls (peptidoglycan walls). Bacterial offspring come in one size, and their reproduction is through binary fission. Bacteria only have one single chromosome. Archaea: Not usually associated with humans, lack peptidoglycan, archaea can live in extreme environments (thermophiles), typically are more attracted to salts unlike other organisms (halophiles), methanogens (produce methane), archaea typically live in the guts of animals; help with the destruction of cellulose. Single chromosome. Eukaryotes: Mostly animals, fungi, protozoa, and algae. Most are multicellular, contain membrane-bound organelles (nucleus, mitochondria, etc.)

Describe the difference between viruses and living cells; explain how viruses replicate.

Viruses contain DNA and RNA, a protein coat, some have envelopes or spikes, most viruses infect only specific types of cells in one host, non-cellular, require a host cell to reproduce. Living cells can reproduce on their own, and viruses can't. Viruses replicate by invading normal cells and using those cells to produce viruses like themselves.