Microbiology chp 1 notes PDF

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Micro chp 1 notes 1.1 microbiology- A specialized area of biology that deals with living things ordinarily too small to be seen without magnification, including bacteria archaea, fungi, protozoa, and viruses microbistatic The quality of inhibiting the growth of Microbes microscopic- Invisible to the naked eye. microorganism- A living thing ordinarily too small to be seen without magnification: an organism of microscopic size. Microbesbacteria- (singular bacterium), category of prokaryotes when peptidoglycan in their cell walls and circular chromosome(s). This group of small cells is widely distributed in the earth’s habitats archaea- prokaryotic single-celled organisms of primitive origin that have unusual anatomy, physiology, and genetics and live in harsh habitats; when capitalized (Archaea), the term refers to one of the three domains of living organisms as proposed by Woese protozoa- A group of single-celled, eukaryotic organisms. fungi Macroscopic and microscopic heterotrophic eukaryotic organisms that can be uni- or multicellular. helminth- A term that designates all parasitic worms. virus Microscopic, acellular agent composed of nucleic acid surrounded by a protein coat.

Algae- photosynthetic, plantlike organisms that generally lack the complex structure of plants; they may be single-celled or multicellular and inhabit diverse habitats such as marine and freshwater environments, glaciers, and hot springs eukaryotic cell- A cell that differs from a prokaryotic cell chiefly by having a nuclear membrane (a well-defined nucleus), membrane-bound subcellular organelles, and mitotic cell division. prokaryotic cells- Small cells, lacking special structures such as a nucleus and organelles. All prokaryotes are microorganisms (prenucleus) ubiquitous Present everywhere at the same time. theory of evolution- The evidence cited to explain how evolution occurs. evolution- Scientific principle that states that living things change gradually through hundreds of millions of years, and these changes are expressed in structural and functional adaptations in each organism. Evolution presumes that those traits that favor survival are preserved and passed on to following generations, and those traits that do not favor n or survival are lost. photosynthesis A process occurring in plants, algae, and some bactena tiat traps the sun's energy and converts it to ATP in the cell. This energy i used to fix CO, into organic compounds. Biotechnology- the intentional use by humans of living organisms or their products to accomplish a goal related to health or the environment genetic engineering- A field involving deliberate alterations (recombinations) of the genomes of microbes, plants, and animals through special technological processes.

recombinant DNA technology- A technology, also known as genetic engineering, that deliberately modifies the genetic structure of an organism to create novel products, microbes, animals, plants, and viruses. Bioremediation- decomposition of harmful chemical s by microbes or consortia of microbes pathogen Any agent (usually a virus, bacterium, fungus, protozoan, or helminth) that causes disease. infectious disease The state of damage or toxicity in the body caused by an infectious agent. organelle A small component of eukaryotic cells that is bounded by a membrane and specialized in function. 1.2 spontaneous generation- Early belief that living things arose from vital forces present in nonliving, or decomposing, matter. Abiogenesis- the belief in spontaneous generation as a source of life Biogenesis- belief that living things can only arise from others of the same kind sterile Completely free of all life forms, including spores and viruses. Asepsis- a condition free of viable pathogenic microorganisms aseptic technique- method of handling microbial cultures, patient specimens, and other sources of microbes in a way that prevents infection of the handler and others who may be exposed germ theory of disease- A theory first originating in the 1800s that proposed that microorganisms can be the cause of diseases. The concept is actually so well

established in the present time that it is considered a fact. 1.3 macromolecules- Large, molecular compounds assembled from smaller subunits, most notably biochemicals. monomer A simple molecule that can be linked by chemical bonds to form larger molecules. polymer A macromolecule made up of a chain of repeating units; examples: starch, protein, DNA. carbohydrate A compound containing primarily carbon, hydrogen, and oxygen in a 12:1 ratio. carbohydrate fermentation medium- A growth medium that contains sugars that are converted to acids through fermentation. Usually contains a pH indicator to detect acid protection. hexose A 6-carbon sugar such as glucose and fructose. pentose A monosaccharide with five carbon atoms per molecule; examples: arabinose, ribose, xylose. glucose One of the carbohydrates commonly referred to as sugars. Glucose is characterized by its 6-carbon structure. fructose One of the carbohydrates commonly referred to as sugars. Fructose is commonly fruit sugars. lactose One of the carbohydrates commonly referred to as sugars. Lactose is commonly found in milk. maltose One of the carbohydrates referred to as sugars A fermentable sugar

formed from starch. sucrose One of the carbohydrates commonly referred to as sugars. Common table or cane sugar. cellulose A long, fibrous polymer composed of 3glucose, one of the most common substances on earth. Agar- a polysaccharide found in seaweed and commonly used to prepare solid culture media chitin A polysaccharide similar to cellulose in chemical structure. This polymer makes up the horny substance of the exoskeletons of arthropods and certain fungi. gradient (toward an attractant or to avoid adverse stimuli). peptidoglycan (PG) A network of polysaccharide chains cross-linked by short peptides that forms the rigid part of bacterial cell walls. Gram-negative bacteria have a smaller amount of this rigid structure than do m gram-positive bacteria. lipopolysaccharide A molecular complex of lipid and carbohydrate found in the bacterial cell wall. The lipopolysaccharide (LPS) of gram-negative bacteria is an endotoxin with generalized pathologic effects such as fever. glycocalyx A filamentous network of carbohydrate-rich molecules tha coats cells. triglyceride A type of lipid composed of a glycerol molecule bound to three fatty acids. cholesterol Best-known member of a group of lipids called steroids. Cholesterol is commonly found in cell membranes and animal hormones. protein Predominant organic molecule in cells, formed by long chains of amino acids.

Amino acids- the building blocks of protein. Amino acids exist in 20 naturally occurring forms that impart different characteristics to the various proteins they compose peptide Molecule composed of short chains of amino acids, such as a dipeptide (two amino acids), a tripeptide (three), and a tetrapeptide (four). polypeptide A relatively large chain of amino acids linked by peptide bonds primary structure Initial protein organization described by type, number, and order of amino acids in the chain. The primary structure varies extensively from protein to protein. secondary structure Protein structure that occurs when the functional groups on the outer surface of the molecule interact by forming hydrogen bonds, These bonds cause the amino acid chain to either twist, forming a helix, or to pleat into an accordion pattern called a 3-pleated sheet. tertiary structure Protein structure that results from additional bonds forming between functional groups in a secondary structure, creating a three dimensional mass. cystine An amino acid, HOOC-CH(NH,)-CH,-S-S-CH,-CH(NH,)COOH. An oxidation product of two cysteine molecules in which the OSH (sulfhydryl) groups form a disulfide union. Also called dicysteine. quaternary structure Most complex protein structures characterized by the formation of large, multiunit proteins by more than one of the polypeptides. This structure is typical of antibodies and some enzymes that act in cell synthesis. enzyme A protein biocatalyst that facilitates metabolic reactions.

Antibody- a large protein molecule evoked in response to an antigen that interacts specifically with that antigen nucleic acid A polymeric strand of nucleotides; exists in two forms: ribonucleic acid (RNA) and deoxyribonucleic acid (DNA). adenosine triphosphate (ATP)- a nucleotide that is the primary source of energy to cells cell 1.4 taxonomy The formal system for organizing, classifying, and naming living things. taxa Taxonomic categories. Binomial system- scientific method of assigning names to organisms that employs two names to identify every organism-genus name plus species name domain In the levels of classification, the broadest general category to which an organism is assigned. Members of a domain share only one or a few general characteristics. kingdom In the levels of classification, the second division from more general to more specific. Each domain is divided into kingdoms. phylum In the levels of classification, the third level of classification from general to more specific. Each kingdom is divided into numerous phyla. Sometimes referred to as a division. division In the levels of classification, an alternate term for phylum. class In the levels of classification, the division of organisms that follows phylum. order In the levels of classification, the division of organisms that follows class.

Increasing similarity may be noticed among organisms assigned to the same order. family In the levels of classification, a mid-level division of organisms that groups more closely related organisms than previous levels. An order is divided into families. genus In the levels of classification, the second most specific level. A family is divided into several genera. species In the levels of classification, the most specific level of organization. archaea- prokaryotic single-celled organisms of primitive origin that have unusual anatomy, physiology, and genetics and live in harsh habitats; when capitalized (Archaea), the term refers to one of the three domains of living organisms as proposed by Woese Bacteria- when capitalized, can refer to one of the three domains of living organisms proposed by Woese containing all nonarchaea prokaryotes Eukarya One of the three domains (sometimes called superkingdoms) of living organisms, as proposed by Woese; contains all eukaryotes.

Chapter Summary

1.1 Microbes: Tiny but Mighty • Microorganisms are defined as "living organisms too small to be seen with the naked eye." Members of this huge group of organisms are bacteria, archaea, protozoa, fungi, parasitic worms (helminths), and viruses. Microorganisms live nearly everywhere and influence many biological and physical activities on earth. • There are many kinds of relationships between microorganisms and humans; most are beneficial, but some are harmful. • Groups of organisms constantly evolve to produce new forms of life. • Microbes are crucial to the cycling of nutrients and energy necessary for all life on earth.

• Humans have learned how to manipulate microbes to do important work for them in industry and medicine and in caring for the environment. In the last 160 years, microbiologists have identified the causative agents for many infectious diseases. They have dis- covered distinct connections between microorganisms and diseases whose causes were previously unknown. • Excluding the viruses, there are three types of microorganisms: bacteria and archaea, which are small and lack a nucleus and (usually) organelles, and eukaryotes, which are larger and have both a nucleus and organelles. • Viruses are not cellular and are therefore sometimes called particles rather than organisms. They are included in microbiology because of their small size and close relationship with cells.

1.2 Microbes in History • The theory of spontaneous generation of living organisms from "vital forces" in the air was disproved finally by Louis Pasteur. • Our current understanding of microbiology is the cumulative work of thousands of microbiologists, many of whom literally gave their lives to advance knowledge in this field. • The microscope made it possible to see microorganisms and thus to identify their widespread presence, particularly as agents of disease. • Medical microbiologists developed the germ theory of disease and introduced the critically important concept of aseptic technique to control the spread of disease agents.

1.3 Macromolecules: Superstructures of Life • Macromolecules are very large organic molecules (polymers) usually built up by polymerization of smaller molecular sub-units (monomers). • Carbohydrates are biological molecules whose polymers are monomers linked together by glycosidic bonds. Their main functions are protection and support (in organisms with cell walls) and also nutrient and energy stores. Lipids are biological molecules such as fats that are insoluble in water. Their main functions are as cell components and nutrient and energy stores. Proteins are biological molecules whose polymers are chains of amino acid monomers linked together by peptide bonds.

• Proteins are called the "shapers of life" because of the many biological roles they play in cell structure and cell metabolism. • Protein structure determines protein function. Structure and shape are dictated by amino acid composition and by the pH and temperature of the protein's immediate environment. • Nucleic acids are biological molecules whose polymers are chains of nucleotide monomers linked together by phosphate- pentose sugar covalent bonds. Double-stranded nucleic acids are linked together by hydrogen bonds. Nucleic acids are information molecules that direct cell metabolism and reproduction. Nucleotides such as ATP also serve as energy-transfer molecules in cells. • As the atom is the fundamental unit of matter, so is the cell the fundamental unit of life.

1.4 Naming, Classifying, and Identifying Microorganisms • The taxonomic system has three primary functions: naming, classifying, and identifying species. • The major groups in the most advanced taxonomic system are (in descending order): domain, kingdom, phylum or division, class, order, family, genus, and species. • Evolutionary patterns show a treelike or weblike branching, thereby describing the diverging evolution of all life forms from the gene pool of a common ancestor. • The Woese-Fox classification system places all organisms into three domains: Eukarya, Bacteria, and Archaea....