MIC 205 Exam 1 (Chapters 1,3,4,5,11)

Explain the fluid mosaic model of membrane structure.

Describes our current understanding of membrane structure. Mosaic indicates that the membrane proteins are arranged in a way that resembles the tiles in a mosaic and the fluid indicates that the proteins and lipids are free to flow laterally within a membrane.

List the hierarchy of taxa from general to specific.

Domain Kingdom Phylum Class Order Family Genus Species

Describe the composition, function, and relevance to human health of glycocalyces.

A gelatinous, sticky substance that surrounds the outside of the cell. May be composed of polysaccharides, polypeptides, or both. Protect cells from desiccation (drying) and can also play a role in the ability of pathogens to survive and cause disease.

Compare and contrast eukaryotic cilia and flagella.

Cilia are shorter and more numerous than flagella. Beat rhythmically, coordinated beating propels single-celled eukaryotes through their environment. Also used within some multicellular eukaryotes to move substances in the local environment past the surface of the cell.

Define binomial nomenclature.

Two names for every organism, italicized.

Compare and contrast archaeal flagella with bacterial flagella.

-Archaeal flagella are 10-14 nm in diameter, which is about 1/2 the thickness of bacterial flagella. -Archaeal flagella are not hollow. -Archaeal flagella lack a central channel; therefore, they grow with the addition of subunits at the base of the filament rather than at the tip. -The proteins making up archaeal flagella share common amino acid sequences across archaeal species. These are very different from the amio acid sequences common to bacterial flagella. -Sugar molecules are attached to the filaments of many archaeal flagella, a condition that is rare in bacteria. -Archaeal flagella are powered with energy stored in molecules of ATP, whereas the flow of hydrogen ions across the membrane powers bacterial flagella. -Archaeal flagella rotate together as a bundle both when they rotate clockwise and when the rotate counterclockwise. In contrast, bacterial flagella operate independently when rotating clockwise.

Discuss regulation of metabolic activity.

-Cells synthesize or degrade channel and transport proteins to increase or decrease the concentration of chemicals in the cytosol or organelles. -Cells often synthesize the enzymes needed to catabolize a particular substrate only then that substrate is available. etc.

List 3 useful end products of fermentation and explain how fermentation reactions are used to identify bacteria.

-Ethanol (drinking alcohol) -Lactic acid (used in the production of cheese, sauerkraut, and pickles) -Nail polish remover Fermentation end products can be used to identify microbes.

List four steps in the scientific method of investigation.

1. A group of observations leads a scientist to ask a question about some phenomenon. 2. The scientist generates a hypothesis - that is, a potential answer to the question. 3. The scientist designs and conducts an experiment to test the hypothesis. 4. Based on the observed results of the experiment, the scientist either accepts, rejects, or modifies the hypothesis.

Describe 5 arrangements of prokaryotes.

1. Diplococci: cocci that remain attached in pairs 2. Streptococci: long chains of cocci 3. Tetrads: some cocci divide in two planes and remain attached 4. Sarcinae: other cocci divide in three planes to form cuboidal packets 5. Stapylococci: clusters, bunches of grapes

Name two scientists whose work with vaccines began the field of immunology.

1. Edward Jenner 2. Pasteur

Describe the four major processes of living cells.

1. Growth: Living things can grow and increase in size. 2. Reproduction: Organisms normally have the ability to reproduce themselves. An increase in number. Can be accomplished asexually or sexually. Increase in number. 3. Responsiveness: All living things respond to their environment. They have the ability to change themselves in reaction to changing conditions within or around them. many organisms have the ability to move toward or away from environmental stimuli. 4. Metabolism: Defined as the ability of organisms to take in nutrients from outside themselves and use them in a series of controlled chemical reactions to provide the energy needed to do the above 3 things.

List and answer four questions that propelled research in what is called the "Golden Age of Microbiology."

1. Is spontaneous generation of microbial life possible? No it is not. 2. What causes fermentation? Fermentation is caused by a metabolic process that converts sugar to acids, gases, or alcohol. It occurs in yeast and bacteria, and also in oxygen-starved muscle cells, as in the case of lactic acid fermentation. 3. What causes disease? Disease is caused by microorganisms and pathogens. 4. How can we prevent infection and disease? Antiseptic technique, cleanliness, immunology, etc.

List and describe four bacterial flagellar arrangements.

1. Peritrichous: Cover the surface of the cell. 2. Polar: Only at the ends of the cell. 3. Endoflagella: Form an axial filament that wraps around the cell between its cytoplasmic membrane and an outer membrane. 4. Lophotrichous: Having two or more flagella at one or both ends.

Describe 5 procedures taxonomists use to identify and classify organisms.

1. Physical Characteristics 2. Biochemical Tests 3. Serological Tests 4. Phage Typing 5. Analysis of Nucleic Acids

Describe the formation and function of endospores.

A vegetative cell normally transforms itself into an endospore when one or more nutrients are in limited supply. The process of endospore formation is called sporulation and it requires 8-10 hours and it takes 8 steps. Endospores are extremely resistant to drying, heat, radiation, and lethal chemicals. In a state of suspended animation and germinate only when conditions improve. The most resistant and enduring cells. (anthrax, tetanus, gangrene)

Describe interrelationships between catabolism and anabolism in terms of ATP and substrates.

ATP molecules produced by catabolism are used to drive anabolic reactions. Second catabolic pathways produce precursor metabolites to use as substrates for anabolic reactions. Additionally, most metabolic pathways are amphibolic; they function as part of either catabolism or anabolism as needed.

Compare and contrast the cell walls of acid-fast bacteria with typical Gram + cell walls.

Acid Fast Bacteria: Gram positive cell walls that contain large amounts of waxy lipids. Gram +: Do not contain large amounts of waxy lipids.

Contrast electron transport in aerobic and anaerobic respiration.

Aerobic Respiration: In some organisms, the final electron acceptors are oxygen atoms, which, with the addition of hydrogen ions, generate H2O; these organisms are called aerobes. Anaerobic Respiration: Use other inorganic molecules instead of oxygen as the final electron acceptor and are called aerobes.

List three types of common reproduction in prokaryotes.

All prokaryotes reproduce asexually; none reproduce sexually. 1. Binary fission 2. Snapping division: occurs in some Gram + bacilli, only the inner portion of the cell wall is deposited across the dividing cell 3. Budding: outgrowth of the original cell (a bud) receives a copy of the genetic material and enlarges.

Compare the structure and function of archaeal and bacterial fimbriae.

Archaeal Fimbriae: Composed of protein and anchor the cells to one another and to environmental surfaces.

Compare the structure and chemistry of archaeal and bacterial glycocalyces.

Archaeal Glycocalyces: Gelatinous, sticky, extracellular structures composed of polysaccharids, polypeptides, or both. Function at a minimum in the formation of biofilms - adhering cells to one another, to other types of cells, and to nonliving surfaces in the environment. Bacterial Glycocalyces: Often associated with disease.

Contrast types of archaeal cell walls with each other and with bacterial cell walls.

Archael Cell Walls: Composed of specialized proteins or polysaccharides. In some species, the outermost protein molecules form an array that coats the cell like chain mail. All archaeal walls lack peptidoglycan, which is common to all bacterial cell walls. Gram - Archaeal Cell Walls: Thick, Gram stains purple. Bacterial Cell Walls: Have peptidoglycan within.

Compare and contrast the cytoplasm of archaea with that of bacteria.

Archael Cytoplasm: The ribosomes of archarea have proteins different from those of the ribosomes of bacteria; indeed, archaeal ribosomal proteins are similar to those of eukaryotes. They use different metabolic enzymes to make RNA and use a genetic code more similar to the code used by eukaryotes.

Describe bacterial cytoplasm and its basic components.

Bacterial Cytoplasm: The general term used to describe the gelatinous material inside a cell. It is semitransparent, fluid, elastic, and aqueous. Composed of cytosol, inclusions, ribosomes, and (in many cells) a cytoskeleton.

Explain why Pasteur may be considered the Father of Microbiology.

Because of his many, varied, and significant accomplishments in working with microbes.

Compare and contrast bright-field microscopy, dark-field microscopy, and phase microscopy.

Bright-Field Microscopy: Two basic types: simple and compound microscopes. Dark-Field Microscopy: Pale objects are best observed with these. These microscopes utilize a dark-field stop in the condenser that prevents light from directly entering the objective lens. Instead, light rays are reflected inside the condenser, so that they pass into the slide at such an oblique angle that they miss the objective lens. This increases contrast and enables observation of more details than are visible in bright-field microscopy. Phase Microscopy: Used to examine living microorganisms or specimens that would be damaged or altered by attaching them to slides or staining them. Basically, phase microscopes treat one set of light rays differently from another set of light rays.

Identify the scientist whose experiments led to the field of biochemistry and the study of metabolism.

Eduard Buchner

Describe the formation and function of bacterial endospores.

Endospores constitute a defensive strategy against hostile or unfavorable conditions. The process of endospore formation is called sporulation.

Identify the field of microbiology that studies the role of microorganisms in the environment.

Environmental Microbiology

List and describe the three domains proposed by Carl Woese.

Eukarya: Includes all eukaryotic cells, all of which contain eukaryotic rRNA sequences. Bacteria: Include all prokaryotic cells. At least 50 kingdoms. Archaea: Include all prokaryotic cells. 3 kingdoms.

In general terms, describe the three stages of aerobic glucose metabolism (glycolysis, the Krebs cycle, and electron transport chain), including their substrates, products, and net energy production.

Glycolysis First step in the catabolism of glucose via both respiration and fermentation. Occurs in most cells, involves the splitting of a 6-carbon glucose molecule into 2 3-carbon sugar molecules. When these 3 carbon molecules are oxidized to pyruvic acid, some of the energy released is stored in molecules of ATP and NADH. Occurs in the cytosol. 1. Energy-investment stage (1-3) 2. Lysis Stage (4-5) 3. Energy-conserving stage (6-10) The Kreb's Cycle A circular series of 8 enzymatically catalyzed reactions that transfer must of this stored energy to coenzymes NAD+ and FAD). The two carbon atoms in acetate are oxidized, and then coenzymes are reduced. Occurs in the cytosol of prokaryotes and in the matrix of mitochondria in eukaryotes. Also known as the TCA cycle. 1. Anabolism: of citric acid (1) 2. Isomerization (2) 3. Redox reactions (3-4, 6, 8) 4. Decarboxylations (3 &4) 5. Substrate-level phosphorylation (5) 6. Hydration (7) Electron Transport Chain The most significant production of ATP occurs through this series of redox reactions. Electrons pass sequentially from one membrane-bound carrier molecule to another, each time losing some energy. Eventually, they pass to a final acceptor molecule. The electrons' energy is used to pump protons across the membrane. Located in the inner mitochondrial membranes of eukaryotes and in the cytoplasmic membranes of prokaryotes.

Compare and contrast the cell walls of Gram + and Gram - bacteria in terms of structure and Gram staining.

Gram +: Have a relatively thick layer of peptidoglycan that also contains unique chemicals called teichoic acids. The thick cell wall of a Gram + bacterium retains the crystal violet dye used in a Gram staining procedure. They appear purple. Gram -: Have only a thin layer of peptidoglycan, but outside this layer is another, outer bilayer membrane composed of two different layers. The inner layer of the outer membrane is composed of phospholipids and proteins but the outer layer is composed of lipopolysaccharides (LPS). Appears pink in a Gram staining procedure.

Describe the contribution of Gram to the field of microbiology.

Hans Christian Gram created a series of dies that help determine is a group of cells is Gram + or Gram -. The Gram stain is still the most widely used staining technique, it is one of the first steps carried out when bacteria are being identified.

Identify the scientists who argued in favor of spontaneous generation.

John T Needham was the only scientist noted to argue in favor of spontaneous generation.

List the four steps that must be taken to prove the cause of an infectious disease.

Koch's Postulates: 1. The suspected causative agent must be found in every case of the disease and be absent from healthy hosts. 2. The agent must be isolated and grown outside the host. 3. When the agent is introduced to a healthy, susceptible host, the host must get the disease. 4. The same agent must be found in the diseased experimental host.

Describe the clinical implications of the structure of the Gram - cell wall.

LPS is a union of lipids and sugar known as lipid A. A dead cell releases lipid A when the outer membrane disintegrates and that may trigger a fever, vasodilation, inflammation, shock, and blood clotting in humans. Because killing large numbers of Gram - bacteria with antimicrobial drugs releases large amounts of lipid A, any internal infection by Gram - bacteria is a cause for concern.

Define microbes in the words of Leeuwenhoek and as we know them today.

Leeuwenhoek named the bacteria he saw under the microscope microorganisms and today we call them microbes. He described microorganisms as a "quantity of matter no bigger than 1/100 part of a grain of sand.

Describe biosynthesis of lipids.

Lipids are synthesized through a variety of routes. For example, fats are synthesized in anabolic reactions that are the reverse of their catabolism - cells polymerize glycerol and three fatty acid.

Describe the structure and function of hami.

Made up of some unique proteinaceous, fimbriae- like archaea structures. More than 100 may radiate from the surface of a single archaeon. Each hamus is a helical filament with tiny prickles sticking out at regular intervals much like barbed wire. Function to securely attach archaea to surfaces.

Distinguish among metabolism, anabolism, and catabolism.

Metabolism: All of the chemical reactions in an organism. Can be divided into two major classes of reactions, anabolism and catabolism. A series of such reactions is called a pathway. Cells have catabolic pathways, which break larger molecules into smaller products, and anabolic pathways, which synthesize large molecules from the smaller products of catabolism.

Describe common shapes and arrangements of bacterial cells.

Most are surrounded by a cell wall that provides structure and shape and protection from osmotic forces. Some are spherical (cocci) and may appear in chains (streptococci) or clusters (staphylococci) or cuboidal packets (sarcinae). Some are rod shaped (bacilli) and may appear singly or in chains. Bacterial cells walls are composed of peptidoglycan, a meshlike complex polysaccharide.

Describe the structure and function of cilia.

Motile, internal, hair-like structures. Extend the surface of the cell and are shorter and more numerous than flagella. No prokaryotic cells have cilia. Composed primarily of tubulin microtubules. A single cell may have hundreds or even thousands.

Describe biosynthesis of nucleotides.

Nucleotides are produced from precursor metabolites of glycolysis and the Kreb's cycle.

Explain why protozoa, algae, and nonmicroblal parasitic worms are studied in microbiology.

Protozoa and nonmicroblal parasitic worms are studied in microbiology because they can cause disease. Algae is studied in microbiology because it provides most of the world's oxygen as a by-product of photosynthesis and it is used in agar as a solidifying agent in laboratories.

Compare and contrast the investigations of Redi, Needham, Spallanzani, and Pasteur concerning spontaneous generation.

Redi was responsible for the decaying meat/flies/maggots experiment. Needham argued that spontaneous generation was legit because he boiled sealed beef and plant matter in vials and organisms survived. Spallanzani disproved Needham's findings when he repeated the same experiment and no organisms survived. Pasteur, using swan neck flasks, proved that spontaneous generation is not possible.

Define microscopy.

Refers to the use of light or electrons to magnify objects.

Describe the structure and function of ribosomes and the cytoskeleton.

Ribosomes: The sites of protein synthesis in cells. The approx size is determined by their sedimentation rate - the rate at which they move to the bottom of a test tube during centrifugation. Prokaryotic ribosomes are 70S (30S and 50S) and eukaryotic ribosomes are 80S. All ribosomes are composed of 2 subunits each of which is composed of polypeptides and molecules of RNA called ribosomal RNA (rRNA). Cytoskeleton: The cell's internal scaffolding. Composed of three or four types of protein fibers. One type of cytoskeleton fiber wraps around the equator of a cell and constricts, dividing the cell into 2. Another forms a helix down the length of some cells.

Describe a few modifications of the Linnaean system of taxonomy.

Scientists sometimes use additional categories such as tribes, sections, subfamilies, and sub species. Based on five kingdoms: anamalia, plantae, fungi, protista, and prokaryotae.

Contrast simple and compound microscopes.

Simple Microscopes: Contains a single magnifying lens, is more similar to a magnifying class than to a modern microscope. Compound Microscopes: Uses a series of lenses for magnification. Magnification is achieved as light rays pass through a specimen and into an objective lens, which is the lens immediately above the object being magnified. An objective lens is really a series of lenses that not only create a magnified image but also are engineered to reduce aberrations in the shape and color of the image.

Describe the simple, Gram, acid-fast, and endospore staining procedures.

Simple: Composed of a single basic dye, such as crystal violet, safranin, or methylene blue. Gram: Differentiates between Gram + and - bacterial cells. Gram + = purple/Gram - = pink. Acid-Fast: Differential stain. Results in pink acid-fast cells which can be differentiated from blue non acid-fast cels, including human cells and tissue. Endospore: Cannot be stained with normal staining procedures because their walls are practically impermeable. Uses heat to drive the primary stain, Malachite green, into the endospore. After cooled, the slide is decolorized with water and counterstained with safranin. Results in green-stained endospores and red-stained vegetative cells.

Explain the purposes of a smear, heat fixation, and chemical fixation in the preparation of a specimen for microscopic viewing.

Smear: The thin film or organisms on a slide. Firmly attach microorganisms to a slide for viewing. Heat Fix: A form of fixating the microorganism on the slide. Chemical Fix: Involves applying a chemical such as methyl alcohol to the smear for one minute. Desiccation (drying) and fixation kill the microorganisms, attaching them firmly to the slide, and generally preserve their shape and size.

Describe the composition, function, and importance of eukaryotic glycocalyces.

Sticky, anchored to its cytoplasmic membrane via covalent bonds to membrane proteins and lipids. The functions, which are not as structurally organized as prokaryotic capsules, include helping to anchor animal cells to eachother, strengthening the cell surface, providing some protection against dehydration, and functioning in cell-to-cell recognition and communication.

Discuss the structure and function of bacterial flagella.

Structure: Long structures that extend beyond the surface of a cell and its glycocalyx and propel the cell through its environment. Not all bacteria have flagella. Composed of three parts: a long, hollow filament, a hook, and a basal body. The filament is a long hollow shaft, about 20 nm in diameter, that extends our into the cell's environment. It is composed of many identical globular molecules of a protein called flagellin, it lengthens by growing at its tip. At its base, a filament inserts into a curved structure, the hook which is composed of a different protein. The basal body is composed of a different protein as well and it anchors the filament and hook to the cell wall and cytoplasmic membrane by means of a rod and four rings of integral proteins. Function: They rotate 360 by boat propellors rather than whipping fro side to side. Move by a series of runs and tumbles. Runs: Counterclockwise flagellar rotation produces movements of a cell in one direction for some time. Tumbles: Result from clockwise flagellar rotation where each flagellum rotates independently. Both occur in response to stimuli.

Compare and contrast 3 types of ATP phosphorylation.

Substrate-Level Phosphorylation: Involves the transfer of phosphate to ADP from another phosphorylated organic compound. GLYCOLYSIS Oxidative Phosphorylation: Energy from redox reactions of respiration is used to attach inorganic phosphate to ADP. Photophosphorylation: Light energy is used to phosphorylate ADP with inorganic phosphate.

Describe the structure and formation of a archaeal flagella.

Superficially similar to a bacterial flagellum: it consists of a basal body, hook, and filament, each composed of protein. The flagellum extends outside the cell and is not covered by a membrane. The basal body anchors the flagellum in the cell wall and cytoplasmic membrane. (Bacterial flagella rotate like propellers.)

Compare and contrast the cytoplasm of prokaryotes and eukaryotes.

The cytoplasm of eukaryotic cells is more complex than that of either bacteria or archaea. The most distinctive difference is the presence of numerous membranous organelles in eukaryotes.

Describe the functions of a cytoplasmic membrane as they relate to permeability.

The cytoplasmic membrane controls the passage of substances into and out of the cell. Nutrients are brought into the cell and wastes are removed. It is selectively permeable, it allows some substances to cross while preventing others from crossing. Phospholipid bilayers are naturally impermeable to most substances. However, cytoplasmic membranes contain proteins that allow substances to cross the membrane by functioning as pores, channels, or carriers.

Compare and contrast prokaryotic and eukaryotic cell walls and cytoplasmic membranes.

The eukaryotic cells of fungi, algae, and plants have cell walls. (Glycocalyces are absent from eukaryotes with cell walls.) The cell wall provides shape and support against osmotic pressure. The walls of plant cells are composed of cellulose, a polysaccharide that is familiar as dietary fiber. All eukaryotic cells have cytoplasmic membranes. Channel proteins for facilitated diffusion are more common in eukaryotes than in prokaryotes.

Describe the reactants and products of the Calvin-Benson cycle.

The key reaction of the light-independent pathway of photosynthesis is carbon fixation by the Calvin-Benson cycle which involves the attachment of molecules of CO2 to molecules of a 5-carbon organic compound called ribulose. 1. Fixation of CO2 2. Reduction 3. Regeneration of RuBP. Essentially, ADP and NADPH from the light-dependent reactions drive the synthesis of glucose from CO2 in the light-independent reactions of the Calvin-Benson cycle.

Describe the quest for a "magic bullet."

The search for chemicals that would destroy pathogens while remaining nontoxic to humans.

Explain relevance of electromagnetic radiation to microscopy.

Visible light is one part of a spectrum of electromagnetic radiation that includes X rays, microwaves, and radio waves. Note that beams of radiation may be referred to as either rays or waves. These various forms of radiation differ in wavelength - the distance between two corresponding parts of a wave. Electrons are negatively charged particles that orbit the nuclei or an atom. Moving electrons act as waves, with wavelengths dependent on the voltage of an electron beam.

List six groups of microorganisms.

1. Bacteria 2. Archaea 3. Fungi 4. Protozoa 5. Algae 6. Viruses

Identify six health care practitioners who did pioneering research in the areas of public health microbiology and epidemiology.

1. Semmelweis - believed that women giving birth were dying of disease and advised washing hands in chlorinated lime water 2. Lister - created antiseptic technique 3. Nightingale - introduced cleanliness into nursing practice 4. Snow - his study was the foundation of infection and control and epidemiology, studied cholera spread in England through the waterways 5. Jenner - discovered cowpox can prevent small pox infection, completed cow/little boy experiment 6. Ehrlich - theorized that chemicals could be used to kill microorganisms differently, searched for the "magic bullet"

List at least seven contributions made by Koch to the field of microbiology.

1. Simple staining techniques for bacterial cells and flagella 2. The first photomicrograph of bacteria 3. The first photograph of bacteria in diseased tissue 4. Techniques for estimating the number of bacteria in a solution based on the number of colonies that form after inoculation onto a solid surface 5. The use of steam to sterilize growth media 6. The use of Petri dishes to hold solid growth media 7. Laboratory techniques such as transferring bacteria between media using a metal wire that has been heat-sterilized in a flame 8. Elucidation of bacteria as distinct species

List and explain two factors that determine resolving power.

1. The wavelength of the electromagnetic radiation. 2. The numerical aperture of the lens, which refers to the ability of a lens to gather light. Resolving power = 0.61 x wavelength / numerical aperture. 1. Modern microscopes use shorter wavelength radiation, such as blue light or electron beams. 2. Modern microscopes have lenses with larger numerical apertures.

List four major questions that drive microbiological investigations today.

1. What are the basic chemical reactions of life? 2. How do genes work? 3. What roles do microorganisms play in the environment? 4. How do we defend against disease?

Name the fastest-growing scientific disciplines in microbiology today.

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Describe the world-changing scientific contributions of Leeuwenhoek.

A Dutch tailor, merchant, and lens grinder, and the man who discovered the bacterial world. He made his own magnifying lenses - simple microscopes - and observed many things in close detail. He discovered the microbial world and bacteria.

Distinguish capsules from slime layers.

Capsules: When the glycocalyx of a bacterium is composed of organized repeating units of organic chemicals FIRMLY ATTACHED to the cells's surface. Slime Layers: A loose, water-soluble glycocalyx. Often sticky and provide one means for bacteria to attach to surfaces as biofilms, which are aggregates of many bacteria living together on a surface. LOOSELY ATTACHED

Define photosynthesis.

Captured light energy from the sun to be used to drive the synthesis of carbohydrates from CO2 and H2O.

Describe biosynthesis of amino acids.

Cells synthesize amino acids from precursor metabolites derived from glycolysis, the Krebs cycle, and the pentose-phosphate pathway snd from other amino acids. Precursor metabolites are converted to amino acids by the addition of an amine group.

Discuss the purposes of classification and identification of organisms.

Classification: Brings a sense of order and organization to the variety and diversity of living things, enhances communication, makes predictions about the structure and function of similar organisms, and to uncover the understated potential evolutionary connections. Taxonomy is the science of classifying and naming organisms. Identification: An essential part of taxonomy because it enable scientists to communicate effectively and be confident that they are discussing the same organism. Oftentimes essential for treating groups of diseases.

Contrast the archaeal cytoplasmic membrane with that of bacteria.

Composed of lipids that lack phosphate groups and have branched hydrocarbons linked to glycerol by either linkages rather than ester linkages seen in bacterial membranes Either linkages are stronger in many ways than ester linkages, allowing archaea to live in extreme environments. Maintains electrical and chemical gradients in the cell. Functions to control the import and export of substances from the cell using membrane proteins as ports and pumps just like in bacterial cytoplasmic membranes.

Describe the sugar and peptide portions of peptidoglycan

Composed of two types of regularly alternating sugar molecules, NAG and NAM which are structurally similar to glucose. Millions of NAG and NAM molecules are covalently linked in chains in which they are alternating. These chains are the "glycan" portion of peptidoglycan. Chains of NAG and NAM are attached to other chains by crossbridges of four amino acids (tetrapeptides). These peptide crossbridges are the "peptido" portion of peptidoglycan.

Discuss the relationship between contrast and staining microscopy.

Contrast Microscopy: Refers to differences in intensity between two objects or between and object and its background. Important in determining resolution. Staining Microscopy: A way to increase contrast between microorganisms and their background.

Describe the role of pseudopods in eukaryotic cells.

False feet. Surround a substance, bringing it into the cell.

Describe fermentation and contrast it with respiration.

Fermentation is the partial oxidation of sugar (or other metabolites) to release energy using an organic molecule from within the cell as the final electron acceptor. Fermentation pathways are metabolic reactions that oxidize NADH and NAD+ while reducing cellular organic molecules. In contrast, respiration reduces externally acquired substances - oxygen in aerobic respiration and, in anaerobic respiration, some other inorganic chemical such as sulfate and nitrate or (rarely) an organic molecule. Essentially, fermentation is the regeneration of NAD+ for glycolysis so that ADP molecules can be phosphorylated to ATP. Fermentation pathways are not as energetically efficient as respiration. The major benefit is that it allows ATP production to continue in the absence of cellular respiration.

Compare and contrast the structures and functions of fimbriae, pili, and flagella.

Fimbriae: Rodlike proteinaceous extensions. Sticky, bristlelike projections adhere to one another and to substances in the environment. May be hundreds per cell and are shorter than flagella. Some carry enzymes that render soluble, toxic metal ions to insoluble, nontoxic forms. May be used to move across a surface via a process similar to pulling an object with a rope. An important function of biofilms. Some act as electrical wires, conducting electrical signals among cells in a biofilm. Pili: Special type of fimbriae. Longer than fimbriae but usually shorter than flagella. Typically only have one to a few per cell in bacterial cells that have them. Cells use pili to transfer DNA from one cell to another via conjugation. Flagella: Long structures that extend beyond the surface of a cell and its glycocalyx and propel the cell through its environment.

Compare and contrast the structure and function of prokaryotic and eukaryotic flagella.

Flagella of eukaryotes differ structurally and functionally from flagella of prokaryotes. First, eukaryotic flagella are within the cytoplasmic membrane; they are internal structures that push the cytoplasmic membrane out around them. Their basal bodies are in the cytoplasm. Second, the shaft of a eukaryotic flagellum is composed of molecules of a globular protein called tubulin arranged in chains to form hollow microtubules. The filaments of eukaryotic flagella are anchored in the cytoplasm by a basal body , but no hook connects the two parts, as in prokaryotes. The flagella of eukaryotes also move differently than those of prokaryotes. Rather than rotating like prokaryotic flagella, those of eukaryotes undulate rhythmically. Some eukaryotic flagella push the cell through the medium whereas others pull.

Compare and contrast fluorescence and confocal microscopes.

Fluorescence Microscopes: Use an ultraviolet (UV) light source to fluoresce objects. UV light increases resolution because it has a shorter wavelength than visible light, and contrast is improved because fluorescing structures are visible against a black background. Confocal Microscopes: Also use fluorescent dyes or fluorescent antibodies, but these microscopes use ultraviolet lasers to illuminate the fluorescent chemicals in only a single plane that is no thicker than 1 um; the rest of the specimen remains dark and out of focus.

Define inclusion, and give two examples.

Inclusion: Deposits often found within bacterial cytosol. May include reserve deposits of lipids, starch, or compounds containing nitrogen, phosphate, or sulfur. Example 1: Gas vesicles that store gases in protein sacs. The gases buoy the cells to the surface and into the light needed for photosynthesis. Example 2: Small crystals of magnetite stored by magnetobacteria.

Discuss the function of each of the following membranous organelles: nucleus, endoplasmic reticulum, Golgi body, lysosome, peroxisome, vesicle, vacuole, mitochondrion, and chloroplast.

Nucleus: Control center of the cell. Absent in all prokaryotes and present in all eukaryotes. Endoplasmic Reticulum: Transport within the cell and lipid synthesis . Absent in all prokaryotes and present in all eukaryotes. Golgi Body: Exocytosis, secretion. Absent in all prokaryotes and present in some eukaryotes. Lysosome: Breakdown of nutrients, self-destruction of damaged or aged cells. Absent in all prokaryotes and present in some eukaryotes. Peroxisome: Neutralization of toxins. Absent in all prokaryotes and present in some eukaryotes. Vesicle: Storage, digestion, transport. Absent in all prokaryotes and present in all eukaryotes. Vacuole: Storage. Absent in all prokaryotes and present in some eukaryotes. Mitochondrion: Aerobic ATP production. Absent in all prokaryotes and present in most eukaryotes. Chloroplast: Photosynthesis. Absent in all prokaryotes and present in plants and algae.

Define osmosis, and distinguishing among isotonic, hypertonic, and hypotonic solutions.

Osmosis: The diffusion of water across a semipermeable membrane - that is across a membrane that is permeable to water molecules but not to most solutes that are present, such a proteins, amino acids, salts, or glucose. SOLVENT Isotonic Solutions: When solutions on either side of a selectively permeable membrane have the same concentration of solutes. Hypertonic Solutions: When the concentrations of solutions are unequal, the solution with the higher concentration of solutes. SOLUTE Hypotonic Solutions: The solution with a lower concentration of solutes. SOLUTE

Contrast reduction and oxidation reactions.

Oxidation-reduction reactions (redox reactions) are when an electron acceptor is said to be reduced. Electron acceptors are reduced because their gain in electrons reduces their overall electric charge. Molecules that lose electrons are said to be oxidized because frequently their electrons are donated to oxygen atoms. OXIDATION INVOLVES LOSS/REDUCTION INVOLVES GAIN.

Compare and contrast the passive and active processes by which materials cross a cytoplasmic membrane.

Passive: Do not require the expenditures of a cell's metabolic energy store. The electrochemical gradient provides the source of energy; the cell does not expend its energy reserve. Includes diffusion, facilitated diffusion, and osmosis. Active: Requires the expenditure of cellular energy (ATP), either directly or indirectly. Moves materials across the cytoplasmic membrane against their electrochemical gradient.

Discuss the significance of Pasteur's fermentation experiments in our world today.

Pasteur's discovery that anaerobic bacteria fermented grape juice into acids suggested a method for preventing the spoilage of wine. His name became a household word when he developed pasteurization, a process of heating the grape juice just enough to kill most contaminating bacteria w/o changing the juice's basic qualities so that yeast could be added to ensure alcohol fermentation.

Compare and contrast prokaryotic and eukaryotic cells.

Prokaryotic: They can make proteins simultaneously to reading their genetic code because they do not have a membrane surrounding their genetic material (DNA). They typically don't have a nucleus. Typically lack various types of internal structures bound with membranes. Eukaryotic: Have a membrane called a nuclear envelope surrounding their DNA, forming a nucleus. Have numerous other internal membranes that compartmentalize cellular functions. These compartments are membrane-bound organelles - specialized structures that act like tiny organs to cary out the various functions of the cell.

Diagram a phospholipid bilayer and explain its significance in reference to a cytoplasmic membrane.

The structure of a cytoplasmic membrane. It is bipolar, two ends of the molecule are different. They are attracted to water at the two surfaces of the membrane.

Discuss the roles of acetyl-CoA, the Krebs cycle, and electron transport in carbohydrate catabolism.

Three stages of cellular respiration include: 1. Synthesis of Acetyl-CoA: Before pyruvic acid (generated by glycolysis or an alternate pathway) can enter the Kreb's cycle for respiration it must first be converted to acetyl-coenzyme A. Enzymes remove one carbon from pyrivuc acid as a CO2 and join the remaining 2 carbon acetate to coenzyme A with a high-energy bond. 2. The Kreb's Cycle:" " 3. Electron Transport Chain:" "

Contrast transmission electron microscopes with scanning electron microscopes in terms of how they work, the images they produce, and the advantages of each.

Transmission Electron Microscopes: (TEM) Generates a beam of electrons that ultimately produces an image on a fluorescent screen. The path of electrons is similar to the path of light in a light microscope. From their source, the electrons pass through the specimen, through magnetic fields, that manipulate the focus of the beam, and then onto a fluorescent screen that absorbs electrons, thereby changing some of their energy into visible light. Produce TEM images, these can be colorized to emphasize certain features. Can't be used to study living organisms because of the vacuum and the slicing required to operate. Scanning Electron Microscopes: (SEM) Uses magnetic fields within a vacuum tube to manipulate a beam of electrons, called primary electrons. However, rather than passing electrons through a specimen, the SEM rapidly focuses them back and forth across the specimen's surface, which has previously been coated with a metal such a platinum or gold. The primary electrons knock electrons off the surface of the coated specimen, and these scattered secondary electrons pass through a detector and a photomultiplier, producing an amplified signal that is displayed on a monitor. An advantage of the scanning microscope over is transmission microscope is that whole specimens can be observed because slicing is not required. Can be beautifully realistic and 3D.