BIOL 209 Microbiology Final Exam Study Guide

BIOL 209 Microbiology Final Exam Study Guide Chapter 1 Microbiology- the study of organisms, that are invisible unless they are magnified, which include algae, bacteria, fungi, helminths, protozoa, and viruses Bacteria are ubiquitous- they are everywhere including deep within the earth, in oceans, and on polar ice caps, and within plant and animal “bodies” Oceans are mostly populated by bacteria Our ocean’s most abundant inhabitants are viruses Microbes are beneficial to humans in several ways to include: o Biotechnology- microbes making industrial products, mining metals, and reducing man-made contamination o Bioremediation- cleaning up toxic pollutants o Genetic engineering- creating new products and genetically modified organisms by manipulating the genetics of plants, animals, and microbes The overwhelming majority of microbes which ‘associate’ with humans do not cause disease o Pathogens- over 2,000 kinds that cause diseases Diseases once thought to be non-infectious are now considered to indeed be caused by microbial infection o Gastric Ulcers- caused by helicobacter ▪ Etiological agent- a chemical, biological, or physical entity that may cause disease in an organism Other diseases ‘now associated’ with microbes include certain cancers, Coronary Heart Disease, Obsessive Compulsive Disorder, Multiple Sclerosis and Obesity Bacteria are considered microorganisms, while viruses are considered small particles Spontaneous Generation- the early belief that the development of living things resulted from abiogenesis (from invisible vital forces) Began is the Mid 1600’s Disproven in Mid 1800’s via research which demonstrated that air and dust were indeed the sources of microbes Swan Neck Flask Experiment- airborne microbes entered and grew within flasks of sterile broth which were exposed to the air whereas microbes which entered into flasks of sterile broth which were then maintained intact and thus not exposed to the air were “trapped” at the base thereby preserving the sterility of the broth o Lewis Pasteur Biogenesis- scientists believed that living things resulted from biogenesis (from other living things of the same kind) The Scientific Method- historical model for scientific research Consists of 6 primary steps: o Question formulation o Background research o Hypothesis development o Testing hypotheses experimentally o Data analysis and hypotheses acceptances/eliminations o Result communication Sterile- the scientific term for the complete absence of all life forms and virus particles Surgeon Joseph Lister- introduced methods to reduce microbes in a medical setting to prevent infections within wounds Aseptic techniques- aimed at reducing microbes in a medical setting and preventing wound infections Genetics based human microbiome research has shown that 90% of the cells on and within the human body are not human but rather microbial Germ Theory of Disease- the ability to distinguish disease causing microbes from non-disease-causing microbes o Robert Koch established Koch’s Postulants- a series of proofs, or logical steps, that verified the germ theory and could establish whether an organism was pathogenic and which disease it caused ▪ In 1875 Koch shoed that anthrax was caused by a bacterium called bacillus anthracis ▪ 20 other diseases were discovered between ▪ Still used today The basic structure of monosaccharide carbohydrates is three to seven carbon sugars, while the basic structure of proteins is a chain of amino acids Polysaccharides play key roles in protection, structural support, and serve as energy and nutrient stores DNA is commonly referred to as cells’ “master computer” via it’s genetically coded program consisting of specific and detailed instruction relative to each organism’s heredity Three primary types of RNA essential for protein synthesis are: o Messenger RNA (mRNA) o Ribosomal RNA (rRNA) o Transfer RNA (tRNA) Microbial nomenclature involves the naming of microbes by varying taxonomic division, whereas microbial classification involves the hierarchy arrangement of organisms The 9 taxonomic categories from top to bottom: o Domain o Kingdom o Phylum o Division o Class o Order o Family o Genus o Species Medical Moment Medications from Microbes Penicillin is a worthy example of how microorganisms can be used to improve human life. Alexander Fleming, a Scottish bacteriologist, discovered penicillin quite by accident in 1928. While growing several bacterial cultures in Petri dishes, he accidentally forgot to cover them. They remained uncovered for several days; when Fleming checked the Petri dishes, he found them covered with mold. Just before Fleming went to discard the Petri dishes, he happened to notice that there were no bacteria to be seen around the mold—in other words, the mold was killing all of the bacteria in its vicinity. Recognizing the importance of this discovery, Fleming experimented with the mold (of the genus Penicillium) and discovered that it effectively stopped or slowed the growth of several bacteria. The chemical that was eventually isolated from the mold—penicillin— became widely used during the Second World War and saved many soldiers’ lives, in addition to cementing Fleming’s reputation. Inside the Clinic: The Vaccine Debate Although we have the knowledge and the means to eradicate many diseases that threaten human life, in the recent past there has been a small but highly significant public movement in some developed countries (including the United States) against vaccinating children. Childhood immunization programs protect against infections that were once widespread and deadly, with high morbidity and mortality rates, such as measles, diphtheria, and whooping cough. Individuals who choose to not immunize their children generally do so for three main reasons: (1) They fear that immunizations are unsafe or will cause adverse side effects (i.e., the autism debate); (2) they do not believe immunizations are effective or necessary; or (3) they wrongly assume that, if everyone else vaccinates their children, their own children are safe from these illnesses. Other factors in choosing to not vaccinate include antigovernment sentiment, religious considerations, and cost. Herd immunity is the term used to describe the concept of vaccines preventing illness in people who have not been vaccinated themselves or who have not been exposed to the natural disease. The crux of this theory is as follows: If most people around you are immune to a certain illness because they have been vaccinated, then they cannot become ill and infect you or others who have not been immunized. However, there is a catch: Herd immunity declines as immunization rates decline. For example, it is estimated that immunization rates for whooping cough must be 92% or higher to prevent outbreaks of the disease. The result of this failure to vaccinate is the reappearance or resurgence of diseases that were once relatively rare. Measles is a prime example. In 2000, endemic transmission of the disease was eradicated in the United States and the Americas. It was eliminated in the United Kingdom in 1995. However, after the publication in the United Kingdom in 1998 of a misleading paper linking the vaccination to autism (that was later completely discredited), many parents stopped vaccinating against this deadly disease. Rates of the disease skyrocketed in the United Kingdom, and it is now considered endemic there once again. In the United States, measles rates in 2012 were the highest they had been since 1996. Several studies have shown that the number of parents refusing to vaccinate their children is continuing to grow, a problem that is resulting in decreased herd immunity and a resurgence of diseases like measles and whooping cough. We’ll investigate vaccine safety later in this book. 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 discovered 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 subunits (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. Multiple Choice Questions: 1. Which of the following is not considered a microorganism? a. Alga b. Bacterium c. Protozoan d. Flea 2. Which process involves the deliberate alteration of an organism’s genetic material? a. Bioremediation b. Biotechnology c. Decomposition d. Recombinant DNA technology 3. Abiogenesis: a. Refers to the spontaneous generation of organisms from nonliving matter b. Explains the development of life forms from preexisting life forms c. Only takes place in the absence of aseptic technique d. Was supported by Pasteur’s swan-necked flask experiment 4. When a hypothesis has been thoroughly supported by long-term study and data, it is considered a. A law b. A speculation c. A theory d. Proved 5. Which is the correct way to denote the scientific name of a microorganism? a. e. coli b. E. coli c. E. coli d. e. Coli 6. Which of the following is an acellular microorganism lacking a nucleus a. Bacterium b. Helminth c. Protozoan d. Virus 7. Which is a correct statement about proteins? a. They are made up of nucleic acids b. They contain fatty acids c. They primarily serve as energy source within the cell d. Their shape determines their function 8. DNA is a hereditary molecule that is composed of a. Deoxyribose, phosphate, and nitrogen bases b. Deoxyribose, a pentose, and nucleic acids c. Sugar, proteins, and thymine d. Adenine, phosphate, and ribose Chapter 3 Unlike eukaryotes, bacteria and archaea have neither organelle-surrounding membranes nor a nucleus Internal components of bacterial cells: o Cytoplasm o Ribosomes o Inclusions o Nucleoid/chromosome o Cytoskeleton o Endospore o Plasmid o Microcompartments External components of bacterial cells: o Appendages ▪ Flagella ▪ Pili ▪ Fimbriae o Surface layers ▪ S layer ▪ Glycocalyx ● Capsule ● Slime layer Explain the sentence “for the most part, bacteria function as independent single-celled, or unicellular, organisms. o Bacteria can carry out all necessary life activities: reproduction, metabolism, nutrient processing Explain the sentence “on the other hand, sometimes bacteria can act as a group. o Closely located bacteria can communicate with each other via chemicals that effect behavior Thiomargarita namiibiensis- the largest bacteria as their size ranges from 100 to 750 um Large enough to be seen without a microscope By comparison mycoplasma cells are barely visible even via light microscopes as their size ranges from 0.15 to .30 um Pleomorphic- means bacteria can vary in shape and size Differing arrangements of cocci o Single o Pairs= diplococci o Groups of 4= tetrads o Clusters= staphylococci o Groups of 8= sarcinae Flagellum- gives bacterial the ability to move about freely Composed of: o Basal body o Hook o Filament Chemotaxis- ability to relocate in response to chemical entities in flagellated bacteria Occurs positive- movement toward a nutrient Occurs negative- movement away from potential harmful entities Flagella enable certain bacteria to attach to surfaces o Flagellar components which permit this function are called fimbria and pilus Bacteria only produce protective “S Layers”, made of multiple copies of a single protein when experiencing a hostile environment Glycocalyx- a protective coating comprised of glycoprotein and polysaccharide components Bacterial cell walls- determine shape and provide protection against bursting or collapsing when encountering variations in osmotic pressure Hans Graham is credited with developing a stain which differentiates bacteria into two groups: o Gram positive o Gram negative Four steps to gram stain: o Crystal violet o Gram’s iodine o Alcohol o Safranin Acid fast stain- used to diagnose tuberculosis and leprosy Bacteria do not have eukaryotic organelles o Bacterial structural component cytoplasmic membrane enables: ▪ Synthesis ▪ Processing of nutrients ▪ Energy reactions Ribosomes- serves as a location for protein synthesis in bacterial cells Consist of protein and rRNA Endospore- “dormant bodies” produced by bacteria, to include bacillus and clostridium Bacteria have two-phase life cycles: o Vegetative cell o Endospore While both Gram+ and Gram- bacteria can form endospores, but the medically important ones are all Gram+ Endospores are of medical significance in that they are formed by both essentially harmless bacteria as well as pathogens. o When the spores of two clostridium species enter/invade a wound that contains ‘dead tissue’, they can actually grow and release toxins Endospores resist commonly used cleaning materials which contain soap, disinfectants, and even boiling water. Characteristics Bacteria Archaea Flagellum Bacterial flagellum Archaellum Chromosomes Single or few, circular Single, circular Bergey’s Manual of Determinative Bacteriology- characterizes bacteria by “traits” which are analyzed/studied in clinical labs Bergey’s Manual of Systematic Bacteriology- presents detailed classifications based in part on rRNA Medical Moment Outsmarting Encapsulated Bacteria Catheter-associated infections in critically ill patients requiring central venous access are unfortunately all too common. It has been estimated that bloodstream infection, a condition called sepsis, affects 3% to 8% of patients requiring an indwelling catheter for a prolonged period of time. Sepsis increases morbidity and mortality and can increase the cost of a patient’s care by approximately $30,000. In order to colonize a catheter, microorganisms must first adhere to the surface of the tip on this medical device. Fimbriae and glycocalyces are bacterial structures most often used for this purpose. Researchers have now found a way to outsmart bacterial pathogens by creating catheters that are coated with antibacterial compounds. These agents prevent the bacteria from attaching to the device, eliminating their ability to colonize into thick biofilms capable of spreading infectious agents. Catheters coated with a combination of rifampin and minocycline or chlorhexidine and silver sulfadiazine have been documented to reduce rates of infection. However, these agents can damage the catheter itself and may trigger drug resistance or tissue toxicity. New studies show that coating the tips in an antibiotic- and antiseptic-free polymer efficiently blocks bacterial colonization of the catheters and poses no threat to patient cells or tissues. To learn more about how biofilms Inside the Clinic: A Sticky Situation A study published in the Proceedings of the National Academy of Sciences in 2013 revealed just how quickly biofilms can clog commonly used medical devices, such as cardiovascular stents. Researchers from Princeton utilized narrow tubes closely resembling those found in certain medical devices. Specific materials were chosen to replicate the surface of the equipment, and the tubes were then exposed to fluid under pressure in order to closely mimic conditions within the human body. The researchers used microbes that are known to contaminate medical devices and engineered them to produce a green pigment that could be observed microscopically. After forcing a stream of these microbes through the experimental tubes for approximately 40 hours, microscopic analysis revealed the formation of a biofilm on the inside walls of the device. Over the next few hours, the researchers then forced a stream of different microbes into the experimental tubes. These cells had been engineered so that they glowed red when viewed microscopically. Within a short period of time, red cells were noted adhering to the biofilm-coated inner walls of the tubes. Further analysis revealed that the flow within the narrow tubes nudged the trapped cells into threadlike “streamers” that rippled along with the moving fluid. Initially, the formation of these microbial threads only slightly decreased the rate of fluid flow within the experimental tubes. However, after 55 hours, the streamers began to weave together, creating a net similar to a spider’s web. This newly formed structure spanned the diameter of the narrow tube and trapped even more flowing cells, triggering a total blockage of the experimental tube within an hour. This experiment revealed an important phenomenon that may explain why devices such as stents often fail. In addition, the researchers were able to identify which bacterial genes are likely involved in biofilm formation within a fluid environment. These data could lead to new strategies that maintain flow through medical devices, which could prevent unnecessary replacement of these devices or, in some cases, even death. Summary 3.1 Form and Function of Bacteria and Archaea ● Bacteria and archaea are distinguished from eukaryotes by (a) the way their DNA is packaged, (b) their cell walls, and (c) their lack of membrane-bound internal structures. ● Bacteria invariably have a cytoplasmic membrane, cytoplasm, ribosomes, a nucleoid, and a cytoskeleton. ● Bacteria may also have a cell wall, a glycocalyx, flagella, an outer membrane, a pilus, plasmids, inclusions and/or microcompartments. ● Most bacteria have one of three general shapes: coccus (round), bacillus (rod), or spiral (spirochete, spirillum). Additional shapes are vibrio and branching filaments. ● Shape and arrangement of cells are key means of describing bacteria. Arrangements of cells are based on the number of planes in which a given species divides. 3.2 External Structures ● The external structures of bacteria include appendages (flagella, fimbriae, and pili) and the glycocalyx. ● Flagella vary in number and arrangement as well as in the type and rate of motion they produce. 3.3 The Cell Envelope: The Wall and Membrane(s) ● The cell envelope is the boundary between inside and outside in a bacterial cell. Gram-negative bacteria have an outer membrane, the cell wall, and the cytoplasmic membrane. Gram-positive bacteria have only the cell wall and cytoplasmic membrane. ● In a Gram stain, gram-positive bacteria retain the crystal violet and stain purple. Gram-negative bacteria lose the crystal violet and stain red from the safranin counterstain. ● The outer membrane of gram-negative cells contains lipopolysaccharide (LPS), which is toxic to mammalian hosts. ● The bacterial cytoplasmic membrane is ^ typically composed of phospholipids and proteins, and it performs many metabolic functions as well as transport activities. 3.4 Bacterial Internal Structure ● The cytoplasm of bacterial cells serves as a solvent for materials used in all cell functions. ● The genetic material of bacteria is DNA, arranged on large, circular chromosomes. Additional genes can be carried on plasmids. ● Bacterial ribosomes are dispersed in the cytoplasm and are also embedded in the cytoplasmic membrane. ● Bacteria may store nutrients or other useful substances in their cytoplasm in either inclusions or microcompartments. ● Bacteria manufacture several types of proteins that help determine their cellular shape. ● A few families of bacteria produce dormant bodies called endospores, which are the hardiest of all life forms, surviving for hundreds or thousands of years. ● The genera Bacillus and Clostridium are endospore formers, and both contain deadly pathogens. 3.5 The Archaea: The Other “Prokaryotes” ● Archaea constitute the third domain of life. They superficially resemble bacteria but are most genetically related to eukaryotes. ● Although they exhibit similar external and internal structure, the unusual biochemistry and genetics of archaea set them apart from bacteria. Many members are adapted to extreme habitats with low or high temperature, salt, pressure, or acid. 3.6 Classification Systems for Bacteria and Archaea ● Bacteria and archaea are formally classified by phylogenetic relationships and phenotypic characteristics. ● Medical identification of pathogens uses an informal system of classification based on Gram stain, morphology, biochemical reactions, and metabolic requirements. It is summarized in Bergey’s Manual of Determinative Bacteriology. ● A bacterial species is loosely defined as a collection of bacterial cells that shares an overall similar pattern of traits different from other groups of bacteria and that shares at least 70%-80% of its genes. ● Variant forms within a species (subspecies) include strains, types, and serotypes. Multiple Choice Questions: 1. Which of the following is not found in all bacterial and archaeal cells? a. Cytoplasmic membrane b. A nucleoid c. Ribosomes d. Flagellum 2. refers to chains of spherical bacterial cells while clusters of spherical cells are called . a. Diplococcus, streptococcus b. Staphylococcus, streptococcus c. Streptococcus, staphylococcus d. Micrococcus, sarcina 3. Which structure plays a direct role in the exchange of genetic material between bacterial cells? a. Flagellum b. Pilus c. Capsule d. Fimbria 4. Which of the following is present in both gram+ and gram- cell walls? a. An outer membrane b. Peptidoglycan c. Teichoic acid d. Lipopolysaccharides 5. Bacterial endospores a. Are visualized using the acid-fast stain b. Are a mechanism for survival c. Are used for nutrient storage d. Are easily inactivated by heat 6. Which of the following would be used to identify an unknown bacterial culture in your nursing school laboratory exercise? a. Grey’s Anatomy b. Bergey’s Manual of Systematic Bacteriology c. The Physicians’ Desk Reference d. Bergey’s Manual of Determinative Bacteriology 7. Which stain is most frequently used to distinguish differences between the cell walls of medically important bacteria? a. Simple stain b. Acridine orange stain c. Gram stain d. Negative stain 8. Archaea a. Are most genetically related to bacteria b. Conatin a nucleus c. Cannot cause disease in humans d. Lack peptidoglycan in their cell wall Chapter 4 Nucleus o Migration of macromolecules important for life function Filaments o Cell reinforcement and structure Endoplasmic reticulum o Transport and storage Mitochondria o Energy generation Golgi apparatus o Protein processing and transfer Ribosomes o Protein synthesis and staging Cytoplasm o Synthesis of life activities o Movement Cell wall o Cell support and shape Glycocalyx o Protection and detection Characteristics found in: Bacterial cells- nucleic acids, chromosomes, binary fission, independent biosynthesis, membrane Eukaryotic cells- acids, chromosomes, true nucleus, nucleus envelope, mitosis, sex cells, binary fission, independent biosynthesis, golgi apparatus, endoplasmic reticulum, ribosomes, mitochondria, membrane Viruses- nucleic acids the number of fungi species which have been identified to date: 50,000 o their two basic groups ▪ macroscopic ● mushrooms, puffballs, gill funi ▪ microscopic ● moles, yeast Distinguish yeast cells and hyphae cells o Yeast- surface buds, round -> oval, asexual reproduction o Hyphae- long, thin cell, dimorphic (either form) The number of fungi species which can cause human disease: 300 Mycoses- technical/ medical term for fungal infections Aflatoxin- poison produced by the mold Aspergillus flavus Consequence of consuming: Liver cancer (common in developing countries) Economic disadvantage of fungi o Pathogenic to plants (kills crops, 40% rot) Benefits of fungi o Decompose organic matter o Return nutrients to soil Parasites- they will get located on and get nutrients from living animals and plants Saprobes- get nutrients from dead plants and animals All fungi are heterotrophic o They get nutrients from substrates (organic materials) Name of Infection Etiological Agent Yeast infection Candida albicans Cryptococcosis Cryptococcus neoformans Tinea versicolor Malassezia furfur Dermatophytosis Trichophython Itistoplasmosis Histoplasma capsulatum Protozoan endoplasm functions: feeding, reproduction, and locomotion o Components: nucleus, mitochondria, food vacuole List the disease caused by the following protozoa: Giardia lamblia- giardiasis Cryptosporidium- cryptosporidiosis Acanthamoeba- brain infection Plasmodium vivax- malaria Medical Moment Vaginal Candidiasis Almost every woman will experience a vaginal yeast infection, caused by an overgrowth of Candida albicans, at some time in her life. Although uncomfortable due to irritation, itching, and vaginal discharge, the infection is easily treatable with antifungal medication in the form of creams, oral medications, or vaginal suppositories. The female reproductive system is quite amazing, and a very delicate balance is maintained within this environment. A small amount of C. albicans is nearly always present within the vagina, but its growth is limited by the acidic pH of the vaginal canal. Interestingly, the acid-producing bacteria also living within the vagina help to tightly control this pH level. When something disrupts the vaginal pH, C. albicanstakes the opportunity to proliferate, leading to an overgrowth of this microbe and in many cases to a subsequent yeast infection. But what causes disruption of the normal vaginal pH? Although pregnancy, diabetes, obesity, and monthly hormonal changes can cause pH levels to fluctuate, by far the most common cause that leads to the development of a yeast infection is antibiotic therapy. This is due to the fact that along with the pathogen it is really trying to target, the drug kills the protective bacteria (normal biota) of the vagina that help to keep yeast in check. So, Ladies, remember to eat your yogurt during and after antibiotic therapy, as the live active bacterial cultures within this fermented product may actually help to boost the levels of these beneficial bacteria within the vaginal canal. Inside the Clinic: Deadly Bite - Malaria Malaria is currently one of the world’s most dreaded diseases, affecting poor tropical countries most heavily. Around 220 million cases of malaria are diagnosed each year worldwide, with one child dying every minute of every day from this preventable disease. Almost all of the nearly 1,500 cases of malaria that occur in the United States yearly are acquired from foreign travel. Malaria is caused by parasitic protozoa of the genus Plasmodium. Malaria is contracted via the bite of the female Anopheles mosquito. The female mosquito passes the infectious parasites through its saliva to the host on which it is feeding. They enter the bloodstream of the host and eventually enter red blood cells, feeding on proteins and hemoglobin contained within the cells. The protozoa multiply rapidly within the red blood cells; these cells eventually burst and release toxins into the bloodstream, causing the symptoms associated with malaria. Symptoms occur in a cyclical nature every 48 or 72 hours (depending on species) and include joint and muscle aches, headache, malaise, and fever and chills. Anemia and jaundice may also occur due to destruction and hemolysis of red blood cells. Kidney failure, liver disease, coma, and death may occur with untreated disease, particularly with P. falciparum, the most deadly of the Plasmodium species. Nearly 90% of all malaria deaths today occur in rural sub-Saharan Africa. This is due to the biology of African mosquito species, the climate in this area, and low immunity to the pathogen in certain populations. Interestingly, the sickle-cell trait seen in many individuals within this region confers some immunity against malaria, particularly the P. falciparum form. Quinine has been the standard of treatment for many years, but resistance to the drug is a growing problem. Artesunate (artemesinin) is a newer drug in the fight against malaria, but its use in the United States is very limited and elsewhere in the world resistance to the drug has already appeared. Whether treatment is given on an outpatient or inpatient basis is dependent on the condition of the patient and the severity of the infection and availability of suitable medical facilities. Most people who receive adequate treatment will recover completely. Being simultaneously infected with HIV may complicate recovery from malaria, creating terrible problems in central and southern African countries where HIV/AIDS prevalence is especially high. Travelers should keep their skin covered as much as possible to prevent contracting malaria when traveling to countries where malaria is known to be endemic. Anopheles mosquitos are most active between the hours of dusk and dawn. Mosquito nets can diminish the risk of being bitten. Quinine and other drugs are sometimes recommended prophylactically for people traveling to countries where malaria is prevalent. Summary: 4.1 The History of Eukaryotes ● Eukaryotes are cells with a nucleus and organelles compartmentalized by membranes. They, like bacteria, originated from a primitive cell referred to as the last common ancestor.Eukaryotic cell structure enabled eukaryotes to diversify from single cells into a huge variety of complex multicellular forms. 4.2 Structures of the Eukaryotic Cell ● The cell structures common to most eukaryotes are the cell membrane, nucleus, vacuoles, mitochondria, endoplasmic reticulum, Golgi apparatus, and a cytoskeleton. Cell walls, chloroplasts, and locomotor organs are present in some eukaryote groups. ● Microscopic eukaryotes use locomotor organs such as flagella or cilia for moving themselves or their food. ● The glycocalyx is the outermost boundary of most eukaryotic cells. Its functions are protection, adherence, and reception of chemical signals from the environment or from other organisms. The glycocalyx is supported by either a cell wall or a cell membrane. ● The cell membrane of eukaryotes is similar in function to that of bacteria, but it differs in composition, possessing sterols as additional stabilizing agents. ● Fungi have a cell wall that is composed of glycans and chitin or cellulose. ● The genome of eukaryotes is located in the nucleus, a spherical structure surrounded by a double membrane. The nucleus contains the nucleolus, the site of ribosome synthesis. DNA is organized into chromosomes in the nucleus. ● The endoplasmic reticulum (ER) is an internal network of membranous passageways extending throughout the cell. ● The Golgi apparatus is a packaging center that receives materials from the ER and then forms vesicles around them for storage or for transport to the cell membrane for secretion. ● The mitochondria generate energy in the form of ATP to be used in numerous cellular activities. ● Chloroplasts, membranous packets found in plants and algae, are used in photosynthesis. ● Ribosomes are the sites for protein synthesis present in both eukaryotes and bacteria. ● The cytoskeleton maintains the shape of cells and produces movement of cytoplasm within the cell, movement of chromosomes at cell division, and, in some groups, movement of the cell as a unit. 4.3 The Fungi ● The fungi are a nonphotosynthetic species with cell walls. They are either saprobes or parasites and may be unicellular, colonial, or multicellular. ● There are two categories of fungi that cause human disease: the primary pathogens, which infect healthy persons, and the opportunistic pathogens, which cause disease only in compromised hosts. ● All fungi are heterotrophic. ● Fungi use both asexual and sexual reproductive strategies. ● Fungi can produce asexual spores called sporangiospores and conidiospores. ● Fungal sexual spores enable the organisms to incorporate variations in form and function. 4.4 The Protozoa ● Protozoa are mostly unicellular eukaryotes that lack specialized tissues. ● Disease-causing protozoa are typically heterotrophic and usually display some form of locomotion. All have a trophozoite form, and many produce a resistant stage, or cyst. 4.5 The Helminths ● The kingdom Animalia has only one group that contains members that are studied in microbiology. These are the helminths, or worms. Parasitic members include flatworms and roundworms that are able to invade and reproduce in human tissues. 1 Pseudopodia are used for motility by a helminths. b protozoa. c fungi. d algae. 2 The Golgi apparatus a receives vesicles from the mitochondrion. b packages products into transitional vesicles. c modifies proteins. d synthesizes proteins and sterols. 3 Yeasts are fungi, and molds are fungi. a macroscopic; microscopic b unicellular; filamentous c motile; nonmotile d water; terrestrial 4 Fungi produce which structures for reproduction and multiplication? a endospores b cysts c spores d eggs 5 The protozoa that cause malaria belong to the following group: a Sarcodina b Ciliophora c Mastigophora d Sporozoa 6 Parasitic helminths reach adulthood and mate within a a intermediate host. b temporary host. c definitive host. d multiplicative host. 7 Mitochondria likely originated from a archaea. b invaginations of the cell membrane. c bacteria. d chloroplasts. 8 Helminths a are unicellular animals. b are all parasitic. c can be hermaphroditic. Chapter 5 Viruses are considered a ‘unique group of biological entities’ in that they are: o Extremely abundant = 1 billion/ml of human feces o Capable of infecting all types of cells including algae, animals, bacteria, fungi, plants, and protozoa o Non-cellular particles of a definitive size, shape, and chemical composition o Subject to being grown (cultured) in a laboratory setting o Capable of fulfilling roles which we ‘cant even guess about’ o Incapable of multiplying outside a host cell (leading some scientists to suggest they be classified as infection molecules instead of generally called living things o Unable to exhibit most cellular life processes, they can definitively impact/ Directly them (leading some scientists to suggest they are by no means “inert and lifeless” entities. o Essential in the development of cells and other life forms in that their ability to infect other cells and in so doing impact their genetic makeup, they actually have “shaped” the way bacteria, plants, animals, ect. have developed to their current form o Capable of permanently “incorporating their genetic material into human DNA o Most accurately classified as OIP (obligate intercellular parasites) per their inability to multiply without invading a specific HC host cell and instructing it to make and release new viruses o Are numerically dwarfed by their host cells, more than 2,000 bacterial viruses comprise an average bacterial cell and more than 50 million polioviruses can be present in an average single human cell o Of varied sizes ranging in diameter from .02 micrometers to as large as the size of a typical bacterial cell, 1 micrometer. Lewis Pasteur- the scientist credited with the term ‘virus’, who developed in 1884 the first vaccine for rabies and who postulated that this disease was caused by living things smaller than bacteria Whereas viruses possess only the genes needed to invade host cells and redirect their activity, o Bacteria to include E. coli have 4,000 genes and a human cell has 20-30,000 genes, thereby permitting cells to fulfill all activities essential to life 5 segments of a typical Animals Virus Life Cycle 1. Adsorption: adsorb/ attaches to host cell membrane 2. Penetration & uncoating: cell takes in virus 3. Synthesis (replication & protein production): virus’s nucleic acids make protein for new viruses. 4. Assembly: mature virus components are formed 5. Release: virus departs host cell Provirus- host cells were being eaten by unseen parasite Lysogeny- bacterial cell retains the viral DNA & passes it to the offspring Family Genus Common Name Chickenpox/ Shingles Herpesuiridae Varicellovirus Varicella Zoster Virus Warts Papovaviridae Papillomavirus HPV Common Cold Picornaviridae Rhinovirus Human Rhinovirus West Nile Fever Flaviviridae Flavivirus West Nile Fever virus Flu Orthomyxoviridae Influenza A virus Influenza virus, type A (Asian, Hong Kong, & swine influenza viruses) Mumps Paramyxoviridae Respirovirus, Rubulavirus Mumps virus Measles Paramyxoviridae Morbillivirus Measles virus AIDS Retroviridae Lentivirus HIV Yellow Fever Flavivridae Flavivirus Yellow fever virus Smallpox Poxviridae Orthopoxvirus Variola & Vaccinia Cold Sores Hepessuiridae Simplexvirus Herpes simplex 1 virus Medical Moment Why Antibiotics Are Ineffective Against Viruses Many people mistakenly believe that they can take an antibiotic to cure a viral infection, such as the common cold. Why are antibiotics ineffective against viruses? To understand why antibiotics do not work on viral infections, we need to think about what antibiotics do, as well as the properties of viruses that make them unique (see table 5.1). Most antibiotics target specific functions or processes within bacteria. Antibiotics may inhibit cell wall synthesis, protein synthesis, nucleic acid synthesis, or the synthesis of specific proteins required for the bacteria to survive and reproduce. They may also cause injury to the cytoplasmic membrane. Viruses lack cytoplasmic membranes, are unable to synthesize proteins and contain either DNA or RNA (but not both). Viruses can only reproduce by hijacking their host’s genetic material to create new viruses. Antibiotics cannot alter functions or processes that do not exist in viruses. This is why antibiotics are not helpful for viral infections. Inside the Clinic: Shingles Shingles is an example of a disease caused by a virus that remains in the body in a chronic latent state, only to reappear years later. The disease is caused by the varicella zoster virus, the same virus that causes chickenpox. Once an individual has recovered from chickenpox, the virus can “hide” in the nerves for years. When the virus is triggered again, perhaps by changes in immunity, it becomes active and causes the disease known as shingles. In some people, emotional or physical stress seems to trigger reactivation. Shingles occurs most commonly in older people who had chickenpox at some point in their lives, usually during childhood. Most people experience shingles only once, but a few unlucky people may suffer from shingles more than once. A person who has shingles can pass the virus on to someone who has never had it, but that person will get chickenpox, not shingles. Shingles initially causes a tingling, burning, or painful sensation. Discomfort precedes the rash, which starts as reddened areas on the skin that eventually form small blisters. The blisters eventually break and crusted areas of skin remain, which are shed in 2 to 3 weeks. The rash usually follows dermatomes, areas of the skin supplied by sensory fibers of the spinal cord. Typically, the rash starts on the back and extends around to the skin on the chest or abdomen on one side of the body. The pain of shingles can sometimes be severe. Some people develop postherpetic neuralgia, resulting from damage to the nerves, which causes chronic pain. Other symptoms associated with shingles include fever, headache, malaise, abdominal pain, and joint pain. Shingles affecting the eye or ear may result in vision or hearing loss. The diagnosis can usually be made based on the appearance of the rash. Leukocytosis (an elevated white blood cell count) and antibodies to the chickenpox virus can help to confirm the virus when there is any doubt as to the cause of the rash. Most of the time, however, the appearance of the rash is enough to make the diagnosis. Antiviral drugs may be used; although they can’t cure shingles, they may shorten the course of the disease. However, antivirals need to be started within 72 hours of the start of symptoms and preferably before the blisters that accompany the rash appear. Acyclovir, famciclovir, and valacyclovir are the antivirals typically used. They are given in higher doses than would typically be used for herpes simplex or genital herpes. Antiviral medications may be given intravenously to people who are immunocompromised or at risk for disseminated disease. It is important for individuals to visit their physician immediately upon noticing symptoms of shingles so that antiviral therapy can be commenced. A live vaccine, called Zostavax, is now recommended in the United States for adults aged 50 and older who have had chickenpox. The vaccine has been shown to prevent up to 50% of cases of shingles and has also been shown to reduce the occurrence of postherpetic neuralgia, which can be very debilitating and can lead to lifelong pain that is very difficult to treat. Summary: 5.1 The Position of Viruses in the Biological Spectrum ● Viruses are noncellular entities whose properties have been identified through technological advances in microscopy and tissue culture. ● Viruses are infectious particles that invade every known type of cell. They are not alive, yet they are able to redirect the metabolism of living cells to reproduce virus particles. ● Viruses have a profound influence on the genetic makeup of the biosphere. ● The International Committee on the Taxonomy of Viruses oversees naming and classification of viruses. Viruses are classified into orders, families, and genera. ● Viruses are grouped in various ways. This textbook uses their structure, genetic composition, and host range to categorize them. 5.2 The General Structure of Viruses ● Virus size range is from 20 to 450 nm (diameter). Viruses are composed of an outer protein capsid enclosing either DNA or RNA plus a variety of enzymes. Some viruses also exhibit an envelope around the capsid. ● Spikes on the surface of the virus capsid or envelope are critical for their attachment to host cells. 5.3 Modes of Viral Multiplication ● Viruses go through a multiplication cycle that generally involves adsorption, penetration (sometimes followed by uncoating), viral synthesis and assembly, and viral release by lysis or budding. ● These events turn the host cell into a factory solely for making and shedding new viruses. This results in the ultimate destruction of the cell. ● Animal viruses can cause acute infections or can persist in host tissues as chronic latent infections that can reactivate periodically throughout the host’s life. Some persistent animal viruses can cause cancer. ● Bacteriophages vary significantly from animal viruses in their methods of adsorption, penetration, site of replication, and method of exit from host cells. ● Lysogeny is a condition in which viral DNA is inserted into the bacterial chromosome and remains inactive for an extended period. The viral DNA is replicated with the chromosome every time the bacterium divides. ● Some bacteria express virulence traits that are coded for by the bacteriophage DNA in their chromosomes. This phenomenon is called lysogenic conversion. 5.4 Techniques in Cultivating and Identifying Animal Viruses ● Animal viruses must be studied in some sort of living cell or tissue. ● Viruses are grouped in various ways. This textbook uses their structure, genetic composition, and host range to categorize them. ● Cell and tissue cultures are cultures of host cells grown in special sterile chambers using aseptic techniques to exclude unwanted microorganisms. ● Virus growth in cell culture and bacteriophage growth on bacterial lawns are detected by the appearance of plaques. 5.5 Other Noncellular Infectious Agents ● Other noncellular agents of disease are the prions, which are not viruses at all but protein fibers; viroids, extremely small lengths of naked nucleic acid; and satellite viruses, which require the presence of larger viruses to cause disease. 5.6 Viruses and Human Health ● Viruses are easily responsible for several billion infections each year. It is conceivable that many chronic diseases of unknown cause will eventually be connected to viral agents. ● Viral infections are difficult to treat because the drugs that attack viral replication also cause side effects in the host. 1 When phage nucleic acid is incorporated into the nucleic acid of its host cell and is replicated when the host DNA is replicated, this is considered part of which cycle? a lytic cycle b virulence cycle c lysogenic cycle d cell cycle e multiplication cycle 2 A virus that undergoes lysogeny is a/an a temperate phage. b intemperate phage. c T-even phage. d animal virus. e DNA virus. 3 The nucleic acid of a virus is a DNA only. b RNA only. c both DNA and RNA. d either DNA or RNA. 4 The general steps in a viral multiplication cycle are a adsorption, penetration, synthesis, assembly, and release. b endocytosis, uncoating, replication, assembly, and budding. c adsorption, uncoating, duplication, assembly, and lysis. d endocytosis, penetration, replication, maturation, and exocytosis. 5 A prophage is an early stage in the development of a/an a bacterial virus. b poxvirus. c lytic virus. d enveloped virus. 6 In general, RNA viruses multiply in the cell , and DNA viruses multiply in the cell . a nucleus; cytoplasm b cytoplasm; nucleus c vesicles; ribosomes d endoplasmic reticulum; nucleolus 7 Viruses cannot be cultivated in a tissue culture. b bird embryos. c live mammals. d blood agar. 8 Clear patches in cell cultures that indicate sites of virus infection are called a plaques. b pocks. c colonies. d prions. Chapter 6 Functions of the following minerals re’ microbial growth o Calcium- stabilizer to cell wall o “zinc fingers” binding factors that help enzymes attach to DNA o Potassium- protein synthesis o Sodium- cell transport Despite containing 5000 different compounds, bacterial cells utilize only 10 types of nutrients to fulfill their life/growth functions, which include: o Glucose o Potassium o Water o Salt o Iron chloride o Calcium phosphate o Ammonium sulfate Essential nutrients- those needed by microbes to live/ grow Micronutrients- those responsible for enzymatic and protein functions and are commonly referred to as trace elements Macronutrients- those required in large amounts for the cell’s structure and metabolism needs Carbon- one primary entity which distinguishes microbes’ nutritional classification Autotrophs- “self- feeder”, those that breakdown inorganic CO2 into organic compounds Heterotrophs- those who must obtain carbon in an organic form Energy- another key entity which distinguishes microbes’ Chemotrophs- gain energy from chemical compounds Phototrophs- get energy through photosynthesis Water- the predominant components of microbes Accounts for 70% of their structure Secondly protein 6 elements comprise 96% of microbes’ dry cell weight: o Nitrogen o Sulfur o Phosphate o Oxygen o Carbon o Hydrogen Photoheterotrophs- gets energy from sun Chemoheterotrophs- get energy from inorganic compounds Obligate- the inability of parasites to grow outside a living host Organisms which cause leprosy and syphilis What are the functions of the following essential nutrients for microbes: a) Sulfur: shape and structure of proteins b) Nitrogen: structure of DNA, RNA, ATP, and proteins c) Phosphate: genetics of cells and viruses d) Oxygen: enzymatic and structural cellular functions e) Hydrogen: energy for respiration and maintenance of cell’s ph f) Carbon: provision of energy through proteins, carbs, nucleic acids, and lipids Biofilm- “Mixed Communities” of varying free-living synergistic bacteria that together attach to the surface of teeth and together body components Quorum Sensing- a method to monitoring biofilm accumulation with other microbes Biofilm-containing microbes function differently from non-attached (free floating or planktonic state) microbes and are not capable of being destroyed by common organism-specific methods Binary Fission- the process in which one cell develops into two daughter cells Binary Fission process o Patent cell gets bigger o Parent cell duplicates chromosomes o Parent cell pulls cell envelope to center of cell o Cell walls forms new entity (septum forms) o Two daughter cells are developed Generation or Doubling Time- the time taken for one cell to become two cells; the amount of time between birth and the production of offspring Growth Time- how fast a microbe grows (determined by generation times) o Shortest in minutes being 10-12 o Average being 30-60 minutes Two bacteria known to have short GT: o Salmonella enteritidis o Staphylococcus aureus ▪ Both are pathogens that grow best at room temperatures causing Food-Borne Illnesses (FBI) Temperature Danger Zone (TDZ)- 40 F- 140 F o It is critical to keeps food out of TDZ Bacterial growth pattern is considered to be exponential o The number cells as well as corresponding “exponents” increase by one in each generation The preferred method to graph bacterial growth is logarithmically opposed to arhythmically as logarithmic graphs provide for easier reads especially during the early growth phase Nt=(Ni)2n- calculate the size of a population Nt= total cells at a given time Ni= # of cells at prep time 2n= 2 to the # of minutes in TDZ divided by generation time 5 steps for observing the population growth pattern: 1. Put a small # of cells into sterile broth 2. Incubate culture for several hours 3. Sample broth at regular periodic intervals 4. Plate each sample on solid media 5. Incubate again 6. Count # of colonies Colony Forming Unit- a colony present on a media- provided plate represents one cell from the original sample To estimate the total population size at a given point in time, multiply the volume of the container by the number of colonies in a single sample Due to growth limiting factors associated with Closed Systems (referred to in microbiology as Batch Culture) bacteria do not maintain their potential growth rate nor do their ability to double their numbers Per the growth curve, indicate the population of the given bacterium in 10 hours 104 and 35 hours 108. Paraphrase the importance of the growth curve as regards infection stages: o More pathogens are present thus more spreadable in the early and mid-time of pathogens Direct Cell Count- actual counting of cells using a guided microscope slide called cytometer Flow Cytometer- distinguishes live and dead cells Turbidity- simplest way to approximate a population in a liquid substance Medical Moment Osmosis and IV Fluids The provision of intravenous (IV) solutions is a very common practice in medicine. Keeping in mind that the osmotic movement of water occurs as the body attempts to create a balance between the different solute concentrations that exist on either side of a semipermeable membrane, let’s look at different types of IV solutions commonly used in medicine. Isotonic solutions have a tonicity that is the same as the body’s plasma. When isotonic solutions are administered, there will be very little movement, if any, between the cells and the blood vessels. Hypertonic solutions have a tonicity that is higher than the body plasma. Administering hypertonic solutions will cause water to shift from the extravascular spaces into the bloodstream to increase the intravascular volume. This is how the body attempts to dilute the higher concentration of electrolytes in the IV fluid. Hypotonic solutions have a tonicity that is lower than the body plasma, causing water to shift from the intravascular to the extravascular space, and eventually into the cells of the tissues. In this case, the body moves water from the intravascular space to the cells in order to dilute the electrolytes in the solution. Inside the Clinic: Fever - To Treat or Not to Treat? Our immune system helps to protect us from invading microorganisms. One manner in which our body protects itself is by mounting a fever in response to microbes present in the body (body temperature can also rise in response to inflammation or injury). The hypothalamus, located in the brain, serves as the temperature-control center of the body. Fever occurs when the hypothalamus actually resets itself at a higher temperature. The hypothalamus raises body temperature by shunting blood away from the skin and into the body’s core. It also raises temperature by inducing shivering, which is a result of muscle contraction and serves to increase temperature. This is why people experience chills and shivering when they have a fever. Once the new, higher temperature is reached (warmer blood reaches the hypothalamus), the hypothalamus works to maintain this temperature. When the “thermostat” is reset once again to a lower level, the body reverses the process, shunting blood to the skin. This is why people become diaphoretic (sweaty) when a fever breaks. When microorganisms gain entrance to the body and begin to proliferate, the body responds with an onslaught of macrophages and monocytes, whose purpose is to destroy microorganisms. This immune response induces fever. Fever is often one of the first symptoms a patient with an illness will experience, prompting the individual with fever to take stock of his or her symptoms. Many people, including physicians, routinely treat fever with fever-reducing agents such as acetaminophen or other NSAIDs (nonsteroidal anti-inflammatory drugs). Is it a good idea to reduce fever if fever is a normal response to an abnormal process occurring in the body, such as an infection? Not all experts agree. We know that microorganisms thrive at different temperatures (see “Environmental Factors That Influence Microbes”). For example, rhinoviruses, responsible for causing the common cold, thrive at temperatures slightly below normal human body temperature. If this is the case, fever can be seen as the body’s attempt to make the internal environment less hospitable to the virus, and lowering body temperature may allow the virus to proliferate. Therefore, fever can be seen as a natural and useful method of curbing the growth of microorganisms. For most people, fever is not harmful. It may cause unpleasant symptoms such as chills, headache, and muscle and joint pain, which is why people tend to want to treat it. A small segment of the population may experience adverse effects of a high fever, for example, children who experience febrile seizures; however, most people tolerate fever well without any ill effects. Because a high fever may sometimes be caused by serious illness, the following guidelines regarding fever should be kept in mind: ● Children under the age of 6 months should be examined by a physician if they develop a high fever. ● Fever should be treated if it rises to 40°C/104°F, regardless of age. ● A patient of any age who has neck stiffness, difficulty breathing or labored/rapid breathing, altered level of consciousness (i.e., confusion), persistent/severe abdominal pain, or severe headache with photophobia (aversion to light) or who experiences a febrile seizure should be seen by a physician, as these symptoms may be indicative of a serious illness. 1. An organism that can synthesize all its required organic components from CO2 using energy from the sun is a a. Photoautotroph b. Photoheterotroph c. Chemoautotroph d. Chemoheterotroph 2. Which of the following is not one of the 6 major elements microbes need to survive, grow, and reproduce? a. Oxygen b. Calcium c. Sulfur d. Nitrogen e. Carbon 3. A microbe that does not require oxygen for metabolism but will use it if available is a/an a. Microaerophile b. Facultative anaerobe c. Obligate anaerobe d. Aerotolerant anaerobe e. Obligate 4. A pathogen would most accurately be described as a a. Parasite b. Commensal c. Saprobe d. Symbiont 5. Which of the following is true of passive transport? a. It requires a gradient b. It uses the cell wall c. It includes endocytosis d. It only moves water 6. A cell exposed to a hypertonic environment will _ by osmosis a. Gain water b. Lose water c. Neither gain nor lose water d. Burst 7. Psychrophiles would be expected to grow a. In hot springs b. On the human body c. At refrigeration temperatures d. At low pH 8. In a viable plate count, each represents a from the sample populations a. Cell; colony b. Colony; cell c. Hour; generation d. Cell; generation Chapter 7 Anabolism- “biosynthesis”, building up compounds Catabolism- breaking of bonds Three metabolic accomplishments o Assembles smaller molecules into lager macromolecules needed for the cell via ATP o Break-down of larger molecules into smaller there by releasing energy o Stores energy in the form of ATP 6 classes of enzymes o Oxidoreductases- transfer electrons from one substrate to another, and dehydrogenases transfer a hydrogen from one compound to another o Transferases- transfer functional groups form one substrate to another o Hydrolases- cleave bonds on molecules with the addition of water o Lyases- add groups to or remove groups from double-bonded substrates o Isomerases- change a substrate into its isomeric form o Ligases- catalyze the formation of bonds with the input of ATP and the removal of water Major ways bacterial cells directly influence enzymes o Competitive inhibition- the mimic is competing with the substrate for the binding site o Noncompetitive inhibition- the regulator molecule does not bind in the same site as the substrate Metabolic Role of ATP o ATP must be replaced in cycles when involved in chemistry reactions cycling occurs catabolically or anabollically ▪ Glucose-> glucose 6 phosphate (anabolic) ▪ Glucose 6 phosphate -> glucose (catabolic) Aerobic respiration o Converts glucose to co2 and allows the cell to recover Anaerobic respiration o Does not use oxygen as the final electron acceptor and other oxidized compounds are utilized Fermentation- partial oxidation of glucose w/out oxygen yielding ATP Facultative- adjusts to oxygen Krebs Cycle TCA- Tri Carboxylic Acid Series of chemical reactions used by all aerobic microbes to generate energy in form of ATP Centered on the processing of pyruvic acid Anabolic pathways Glycolysis- splitting of glucose and forming of protein from amino acids Catabolic pathways Break-down of protein to amino acids Assembly of the Cell- Binary- Fission The combination of anabolic and catabolic processing of nutrients into enough macromolecules to support two cells Amphibolism- the ability of a system to integrate catabolic and anabolic pathways to improve cell efficiency Medical Moment Muscle Metabolism The burning sensation felt in the muscles during intense exercise has always been blamed on the buildup of lactic acid in the muscles. It has been thought for many years that when muscles deplete their supply of oxygen during exercise, they convert pyruvic acid to lactic acid so that production of ATP can continue to proceed for a short period of time. As the level of lactic acid builds, muscle pain and fatigue are experienced. New research has suggested that lactic acid may have gotten a bad rap all these years. Instead of being viewed as the cause of muscle pain, it is now thought that lactic acid may be simply another fuel source. Lactic acid is created from glucose and is used by the muscles as another energy source, particularly during high-intensity exercise. It is now thought that the body creates additional proteins whose role is to convert lactic acid into energy. If this is indeed the case, what is to blame for the muscle pain we have all experienced during bouts of intense exercise? Some experts now state that muscle pain is simply the result of microscopic tears and muscle trauma. Vitamin D Deficiency Vitamins are required for normal metabolism. Many vitamins cannot be synthesized in the human body or are synthesized in inadequate amounts; therefore, they must be obtained from the diet. Vitamins are necessary because many coenzymes are derived from vitamins. Inadequate intake of a vitamin can lead to a deficiency state, in which the complete holoenzyme (the combination of a protein apoenzyme plus one or more cofactors) is prevented from forming. Vitamin D has been studied extensively in recent years. Deficiency of vitamin D has been linked to multiple sclerosis (MS), cancer, hypertension, autoimmune disease, Alzheimer’s disease, dementia, premature labor, and certain infectious diseases. Deficiency has long been known to predispose to rickets in children and to osteomalacia, osteoporosis, and bone fractures