Bios 242 Week 1 Concepts: The Cell

Bacterium:

E.coli

Fungi and Protozoa are

Eukaryotic organisms

is the difference in the light intensity between the background and the object.

Staining of specimens increases the contrast or the difference in light intensity between the background and the object.

Scientific name is written as

Streptococcus pyogenes.

According to Binomial system the scientific name of any living organism has (select all that apply):

a combination of the generic (genus) and species name the genus name is always capitalized and the species name begins with a lower case letter both names should be italicized when in print or underlined when written by hand

What type of microscopy is used to produce image of the surface of the microbes?

electron

Does not have membrane bound cellular organelles and has cell wall made up of peptidoglycan:

Bacteria do not have membrane bound cellular organelle and has cell wall made up of peptidoglycan.

Biofilms:

Bacteria in some environments form into structures called biofilms. These attach to a surface, accumulate into complex layers, and are cemented by sugars, e.g., in diseases like ear infections, prostate infections, some lung infections.

While virus, viroids, and other infectious agents such as prions are also microscopic,

they are not considered living organisms because they are acellular (lacking a cell).

He was the first person to use swan neck flask to disapprove the theory of spontaneous generation:

was Louis Pasteur

Biochemical Identification - Types of Media Defined media - all chemical components are identified, and their precise concentrations are known. Complex media - contains a rich mixture of nutrient extracts or digestions, and the exact composition is not known. Examples include nutrient broth, blood agar, and MacConkey agar. Nutrient broth (liquid) and Nutrient agar (solid) are used extensively in the laboratory and this media supports the growth of a wide variety of microorganisms. Selective medi

(a) Mannitol salt agar is used to isolate members of the genus Staphylococcus. It is selective because Staphylococcus can grow in the presence of 7.5% sodium chloride, whereas many other species are inhibited by this high concentration. It contains a dye that also differentiates those species of Staphylococcus that produce acid from the fermentation of mannitol and turn the phenol red dye to a bright yellow. (b) MacConkey agar selects against gram-positive bacteria. It also differentiates between lactose-fermenting bacteria (indicated by a pink-red reaction in the center of the colony) and lactose-negative bacteria (indicated by an off-white colony with no dye reaction).

Visible light as source of illumination Bright-field Paramecium (230×)© Michael Abbey/Science Source

2,000×0.2 μm (200 nm)The bright-field microscope is the most widely used type of light microscope. Although we ordinarily view objects like the words on this page with light reflected off the surface, a bright-field microscope forms its image when light is transmitted through the specimen. The specimen, being denser and more opaque than its surroundings, absorbs some of this light, and the rest of the light is transmitted directly up through the ocular into the field. As a result, the specimen will produce an image that is darker than the surrounding brightly illuminated field. The bright-field microscope is a multipurpose instrument that can be used for both live, unstained material and preserved, stained material.

Dark-field Paramecium (230×)© Laguna Design/Science Source

2,000×0.2 μmA bright-field microscope can be adapted as a dark-field microscope by adding a special disc called a stop to the condenser. The stop blocks all light from entering the objective lens—except peripheral light that is reflected off the sides of the specimen itself. The resulting image is a particularly striking one: brightly illuminated specimens surrounded by a dark (black) field. The most effective use of dark-field microscopy is to visualize living cells that would be distorted by drying or heat or that cannot be stained with the usual methods.

Phase-contrast Paramecium (230×)© Michael Abbey/Science Source

2,000×0.2 μmIf similar objects made of clear glass, ice, cellophane, or plastic are immersed in the same container of water, an observer would have difficulty telling them apart because they have similar optical properties. Internal components of a live, unstained cell also lack contrast and can be difficult to distinguish. But cell structures do differ slightly in density, enough that they can alter the light that passes through them in subtle ways. The phase-contrast microscope has been constructed to take advantage of this characteristic. This microscope contains devices that transform the subtle changes in light waves passing through the specimen into differences in light intensity. For example, denser cell parts such as organelles alter the pathway of light more than less dense regions (the cytoplasm). Light patterns coming from these regions will vary in contrast. The amount of internal detail visible by this method is greater than by either bright-field or dark-field methods.

Differential interference Paramecium (230×)© Gerd Guenther/Science Source

2,000×0.2 μmLike the phase-contrast microscope, the differential interference contrast (DIC) microscope provides a detailed view of unstained, live specimens by manipulating the light. But this microscope has additional refinements, including two prisms that add contrasting colors to the image and two beams of light rather than a single one. DIC microscopes produce extremely well-defined images that are vividly colored and appear three-dimensional.

A microbiologist inoculates Staphylococcus epidermidis and Escherichia coli into a culture medium both of which grow at 37oC. Following incubation, only the E. coli grows because _______________________________.

A microbiologist inoculates Staphylococcus epidermidis and Escherichia coli into a culture medium. Following incubation, only the E. coli grows because the media is selective.

A microbiologist makes a fixed smear of bacterial cells and stains it with methylene blue. All cells appear blue under the oil immersion lens. This is an example of ______.

A microbiologist makes a fixed smear of bacterial cells and stains it with methylene blue. All cells appear blue under the oil immersion lens. This is an example of simple staining

Biochemical Identification - Forms of Media Media is an important component of biochemical identification. The growth or lack of growth, color changes in the media, and color changes of the bacteria can help identify specific characteristics of each different type of bacteria. Media can be classified by: Physical State - liquid, semisolid, and solid. Liquid media is water based at room temperature. Semisolid has a clot-like consistency at room temperature. Solid had a firm consistency at room te

A) liquid media does not solidify at room temperature and provides for growth throughout the media (top to bottom). B) Semisolid media have more body than liquid media but less than solid media. This media has a soft consistency at room temperature. C) Solid media contains 1-5% agar. This media remains solid when tilted to the side.

Viruses

Acellular infectious agents, can infect bacteria or any other eukaryotic cells. Made up of nucleic acid (DNA or RNA) and protein coat only.

Prion and Viroids are

Acellular.

Historical Foundations of Microbiology The early years of microbiology brought the first observations of microscopic structures and microbial life that are invisible to the naked eye. The initial efforts were placed in organizing the microscopic organisms into logical classifications. Listed below are some key historical findings. Golden Age of Microbiology The Golden Age of Microbiology extended from the mid-19th to the early 20th century (1857-1907). Microbiologists competed to be the first to

Antoni van Leeuwenhoek, a Dutch merchant, made the first simple microscope with magnification of around 300x in order to examine the quality of cloth. His passion to view things under the microscope then extended to other things, including many microorganisms he called animalcules. He reported the existence of protozoa in 1674 and of bacteria a few years later. Leeuwenhoek's microscope. Transcript Link Carolus Linnaeus, a Swedish botanist, developed a taxonomic system for naming living organisms and grouping similar organisms together between the years of 1735-1760. Biologists still use a modification of Linnaeus's taxonomy and binomial nomenclature today.

Father of Microbiology who called microbes animalcules:

Antonie van Leeuwenhoek

The first microscope with magnification of around 300x was invented by this Dutch Tailor

Antonie van Leeuwenhoek used the microscope he made with magnification of around 300x to see the first microorganisms which he termed animicules. Louis Pasteur is known for pasteurization, Joseph Lister for antiseptic techniques in the operating room, and Robert Koch is known for his Koch's postulates.

Prokaryotes Prokaryotes are unicellular microbes that lack a true nucleus.

Bacteria: These are single-celled prokaryotes whose cell walls are composed of peptidoglycan (though some bacteria lack cell walls). They reproduce asexually. Most are beneficial, but some are pathogens that cause disease Archaea: Archaea are prokaryotes whose cell walls lack peptidoglycan and instead are composed of other polymers. They reproduce asexually. None are known to cause disease.

What type of microscopy would use stains to aid in the observation of these microbes against an illuminated background using visible light?

Bright Field

Protozoan:

Vorticella

medium distinguishes different types of microorganisms based on an observable change in the colonies or in the medium.

Differential

Eukaryotes Eukaryotes are organisms whose cells contain a nucleus composed of genetic material surrounded by a distinct membrane.

Fungi: Fungi are relatively large microscopic eukaryotes and include multicellular molds and single-celled yeasts. These organisms obtain their food from other organisms and have cell walls made of a polymer called chitin. Protozoa: Protozoa are single-celled eukaryotes that are similar to animals in their nutritional needs and cellular structure. Most are capable of locomotion, and some are pathogens that cause disease. Algae: Algae are plantlike eukaryotes that are photosynthetic; that is, they make their own food from carbon dioxide and water, using energy from sunlight. The algae include multicellular and unicellular organisms. Parasitic Worms: Parasitic worms are invertebrate worm like animals that cause several infectious diseases. They range in size from microscopic forms to adult tapeworms several meters in length. Acellular infectious agents- Viruses, viroids and prions are so small that they were hidden from microbiologists until the invention of the electron microscope i

Structural genes code for

Genes code for cellular proteins some of which are enzymes used in metabolic processes.

Acellular agents include viruses, viroids, and prions. These do not have cells and are not considered living.​ Prokaryotes include bacteria and archaea, which are unicellular and 10x smaller than eukaryotes. Only bacteria are pathogens.​ Eukaryotes include fungi such as yeast, protozoa, photosynthetic algae, and parasitic worms/helminths.

Helminths are parasitic worms.

Virus:

Herpes simplex

Thymine always pairs with adenine in DNA. In DNA guanine always pairs with cytosine.

In RNA, Adenine is complimentary to Uracil. Cytosine is complimentary to Guanine in RNA.

Industrial Microbiology - This branch safeguards our food and water, and includes biotechnology, the use of microbial metabolism to arrive at a desired product, ranging from bread making to gene therapy. Microbes can be used to create large quantities of substances such as amino acids, beer, drugs, enzymes, and vitamins. Figure D. Scientists use a multispectral imaging system for inspection of chickens. USDA-ARS/tephen R Ausmus Agricultural Microbiology - This branch is concerned with the rela

Industrial microbiologists safeguard our food and water, and includes biotechnology,

In this module, we will learn the 5-step approach used by microbiologists to grow and identify microorganisms. Scientists use a combination of different growth techniques, microscopy and biochemical methods to grow and identify microorganisms. This approach is called the Five I's. The five I's include: Inoculation Incubation Isolation Inspection Identification You will learn in detail about these methods in the lesson ahead. The Five I's of Microbiology: Inoculation, Incubation, Isolation, Inspe

Inoculation: Sample is placed into a petri dish or container of growth medium. Incubation: Proper growth conditions like temperature and gas requirements are maintained inside an incubator. Isolation: Cultures are isolated, re-inoculated and re-incubated to obtain a single species sample. Inspection: The microbial colony is jammed both macroscopically and microscopically, often with the use of staining. Identification: The identity of the microbe is determined, usually to the species level. Additional biochemical tests, immunological tests, and genetic analysis may be needed.

Antoni van Leeuwenhoek - First to make a microscope with magnification of around 300x and called microorganisms animalcules. Joseph Lister - Introduced use of aseptic techniques to disinfect both hands and air inside surgical theaters. Robert Koch - Postulates to identify causative microorganism. Louis Pasteur - Experiments using swan-necked flasks.

Koch's postulates are criteria used to establish that a specific microbe is the cause of a specific disease.

In order to identify a microorganism, we must first grow the organism on

Microorganisms are grown on various types of media in the laboratory.

The purpose of staining is to

Microorganisms are small and colorless which makes them hard to see. Staining increases resolution and contrast.

While most microbes are useful and harmless, a small number of microbes called pathogens can cause damage and are capable of producing infections. They are called pathogens and are of immense importance in human health.

Photosynthetic microorganisms (bacteria and algae) account for more than 70% of the earth's photosynthesis, contributing the majority of the oxygen to the atmosphere.

Bacteria and Archaea are

Prokaryotic organisms

Public Health Microbiology and Epidemiology - These branches monitor and control the spread of diseases in communities. Institutions involved in this work are the U.S. Public Health Service (USPHS) with its main agency, the Centers for Disease Control and Prevention (CDC) located in Atlanta, Georgia, and the World Health Organization (WHO), the medical limb of the United Nations. Figure B. Two epidemiologists conducting interviews as part of the effort to curb the cholera epidemic in Haiti. Pho

Public Health Microbiology and Epidemiology - Monitor and control the spread of diseases in communities

Which field of microbiology monitors and controls the spread of diseases in communities?

Public Health Microbiology and Epidemiology monitors and controls the spread of diseases in communities.

RNA molecules differ from DNA molecules because only RN

RNA contains the nucleotides Adenine, Guanine, Cytosine, and Uracil. DNA contains the nucleotides Adenine, Guanine, Cytosine, and Thymine.

refers to the microscope's ability to show two separate objects as discrete and distinct.

Resolution refers to the microscope's ability to show two separate objects as discrete and distinct.

Many microorganisms are capable of photosynthesis and generate organic compounds that can be metabolized to produce energy.

Some bacteria and fungi are capable of decomposition and play a crucial role in recycling nutrients in nature. Microbes are diverse in their metabolic capabilities and this potential of microbes is used in the science of bioremediation to stabilize the environment. Using microbes to clean the environment of toxic chemicals is an example of bioremediation.

Taxonomy Taxonomy is involved in the identification, classification, and naming of organisms. Nomenclature The assignment of scientific names to the various taxonomic categories and individual organisms is called phyologeny. The understanding and appreciation of microorganisms is improved by learning a few general rules about how they are named. From most general to most specific: Domain Kingdom Phylum or Division Class Order Family Genus Species Sample Taxonomy Binomial System A combination o

Taxonomy is involved in the identification, classification, and naming of organisms.

The most common student microscope is the

The bright-field microscope, also known as a light microscope, is the least expensive microscope and typically used by students. A darkfield microscope is more narrow in scope while the electron and fluorescent microscope can cost over $100,000 and requires a large floor space.

The bacteria and archae are prokaryotes that do not have a nucleus or membrane-bound organelles but are cellular microorganisms.

The eukaryotes will have a nucleus, mitochondria, etc. The viruses do not have cells and include AIDS virus and bacterial viruses.

The magnification of the objective lens with a total magnification of 1000X and an ocular magnification of 10X is____________.

The total magnification = ocular X objective. We are given the total magnification and we are given the ocular. We must determine the objective. After rearranging the variables we have 1000X/10X = 100X for the objective lens

Eukaryotic Organisms

Unicellular or Multicellular; membrane bound organelles like nucleus, mitochondria, golgi complex; bigger in size. Include fungi, protozoa, algae and helminthes.

Prokaryotic Organisms

Unicellular; contain no membrane bound organelles; have simple structures; are 10 times smaller than eukaryotes. Include archaea and bacteria. Only bacteria are pathogenic

Viruses belong to the _______________ category of microorganisms.

Viruses are acellular infectious agents that are made up of nucleic acid (DNA or RNA) and protein coat only and lack organization of a true cell.

An instrument called a _____________ is needed to magnify the image of the microorganisms to observe them

microscope

Unicellular organisms (prokaryotes and eukaryotes) and many multicellular organisms (eukaryotes) are

microscopic living organisms.

Microorganisms are classified in various taxonomic categories: they can be prokaryotic (bacteria and archaea);

or eukaryotic (animals, plants, protists, fungi).

The three physical forms of laboratory media are ______, ______, and ______.

solid, semisolid, and liquid

Electron beam forms image of specimen Transmission electron microscope (TEM) Coronavirus, causative agent of many respiratory infections (100,000×)© Billy Curran, Department of Veterinary Science. Queen's University Belfast 100,000,000×0.5 nmTransmission electron microscopes are the instruments of choice for viewing the detailed structure of cells and their organelles and viruses. This microscope produces its image by transmitting electrons through the specimen.Because electrons cannot readi

surface or microb