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MICROBIOLOGY EXAM 2025/2026 WK 1-
QUESTIONS AND ANSWERS GRADED A+ RIO
SALADO COLLEGE
All organisms are classified into three basic domains. What are the domains?
Bacteria, Archaea, and Eukarya.
Explain the importance of observations made by Hooke and van Leeuwenhoek.
Hooke discovery marked that beginning of cell theory - that all living things are composed of cells
VAm Leeu - observation of live microorganisms using his simple microscope
Compare the theories of spontaneous generation and biogenesis.
Spontaneous generation is that life could spontaneously generate
Biogenesis- the theory that living cells can arise only from preexisting living cells.
Identify the contributions to microbiology made by Needham, Spallanzani, Virchow, and Pasteur.
Needham claimed that microorganisms could arise spontaneously from heated nutrient broth
Spallanzani suggested needham results were due to microorganisms in the air that were entering his broth.
Virchow biogenesis
Pateur experiments that formed the basis for aseptic technique.
List several ways in which microbes affect our lives.
· Maintenance of an ecological balance on earth
Produce foods and chemical necessary for the survival of humans
Maintain health present on your skin, in your mouth, and in your stomach
Recognize the system of scientific nomenclature that uses genus and specific epithet names.
Designed by Carolus Linnaeus each living organism is assigned two names. The genus is the first name and is always capitalized. The species name follows and is not capitalized.
Differentiate among the major characteristics of each group of microorganisms.
Most common shapes of bacteria: Bacillius (rodlike); Coccus (spherical or ovoid); spiral (corkscrew or curved).
Identify the importance of Koch's postulates.
Proved that microorganisms caused disease
Explain how Pasteur's work influenced Lister and Koch.
Because he participated in the development of germ theory (idea that microorganisms might cause disease)Coined the term vaccine and that the protection from disease or recovery is called immunity, and discovered that avirulent bacteria can be used to cure fowl cholera
Identify the importance of Jenner's work.
He demonstrated that inoculation with cowpox material provided humans with immunity from small pox
Identify the contributions to microbiology made by Ehrlich and Fleming.
Ehrlich introduced an arsenic containing chemical called salvarsan to tx syphilis
Flemming observed that mold (penicillium) inhibited the growth of a bacterial culture.
Define bacteriology, mycology, parasitology, immunology, and virology.
Bacteriology: the study of bacteria
Mycology: the study of fungi
Parasitology: the study of parasitic protozoa and worms
Immunology: the study of immunity
Virology: study of viruses
Explain the importance of recombinant DNA technology.
bacteria can produce substances such as proteins, vaccines, and enzymes
List at least four beneficial activities of microorganisms.
Microorganisms degrade dead plants and animals and recycle chemical elements to be used by living plants and animals. Bacteria are used to decompose organic matter in sewage, and bioremediation processes use bacteria to clean up toxic wastes. Bacteria are being used to control insect populations, and microbes are commonly used to make products such as food and chemicals (called biotechnology).
List two examples of biotechnology that use genetic engineering and two examples that do not.
agriculture to protect plants from frost and insects and to improve the shelf life of products
patients recovered without complications. How was Lister influenced by Pasteur's work? Why was Koch's work still needed?
Pasteur was part of the discovery of disease caused by microorganisms, Lister then developed an antibacterial to help control disease in humans. Kochs work was still needed because he developed the structure for vaccines with his Koch Postucles.
Describe two events, discoveries, or inventions that were probably the most significant in the development of microbiology. Why are they considered significant to microbiology?
The discovery of microorganisims causing disease i would think is the most important. Without this discovery everything else wouldnt have been discovered. The second event would be the finding of Kock Postucles and being able to vaccinate again disease. This is significant in microbiology because it shows that microorganisms can be altered to prevent the disease they may have once started.
What is a microbe, and what are important contributions microorganisms make to the earth's ecosystems?
A microbes are microorganisms, they are the oldest life form on earth. They are too small to see with the naked eye. They help the ecosystem by keeping it in balance. Microbes are all around us, and without them humans wouldn't be able to survive. They help protect our bodies from foreign microbes that could cause disease, they also help with the breakdown of food, and keeping our immunity strong.
The invention of the microscope would have to be one of the most significant developments of microbiology. Without the microscope we would continue to not know about this whole world of minute living cells and structures. The microscope allows us to see thing unable to be seen with the naked eye.
The second significant event would be the discovery of pasteurization. Not only has it allowed beer and wine to travel and not spoil so quickly, it led to the germ theory of disease.
How did the theory of biogenesis lead the way for the germ theory of disease?
The theory of biogenesis came first and started the golden age of microbiology. Through the process of trying to prove that biogenesis was correct Louis Pasteur discovered that microorganisms are the reason why things spoil or turn bad. These findings led to the theory of germ disease which states microorganisms may be the reason for disease.
What is a microbe, and what are important contributions microorganisms make to the earth's ecosystems?
Microbes are minute living things that individually are usually too small to be seen with the unaided eye. Microbes help the ecosystem work. They are used as the basic foundations of food chains in the oceans, lakes and rivers. They are responsible for digestion and synthesis of vitamins in the human intestines.
The antibiotic (antimicrobial) amphotericin B causes leaks in cells by combining with sterols in the plasma membrane. Would you expect to use amphotericin B
The domains are: archaea, bacteria, eukarya
regarding Pasteurs experiments with the s-neck flask; which of the following statements is true?
All;
There was air involved, there was a food source involved , any possibility of contamination was removed, all microorganisms were killed before beginning
the concept that living cells can arise only from other living cells is called
biogenesis
Whose experiments did Lazaro Spallanazni repeat to disprove and suggest spontaneous generation of microorganisms was incorrect
John Needham
What are the keys in Koch's postulates used for?
To relate a specific microbe to a specific disease
which molecules consist of nucleotides?
Nucleic acids
Starch, dextran, glycogen, and cellulose are polymers of..?
glucose
the antimicrobial drug imidazole inhibits sterol synthesis. This would most likely interfere with...
eukaryotic plasma membranes
the smallest unit of matter is
an atom
all atoms with the same number of protons that behave the same way are classified as
chemical elements
the valence shell of an atom is
multicellular animal parasite
helminths
what bond is formed when opposite charges come together
ionic
these kind of bonds share electrons
covalent bonds
identify the large and diverse group of organic compounds that includes sugars and starches
carbohydrates
this microscope contained an opaque disc that blocks light that would normally enter the objective lens directly
darkfield
this technique permits detailed examination of internal structures in living organisms
phase-contrast
you would view a gram stained specimen using this microscope
brightfield
Compounds
molecules consisting of at least two different kind of atoms
molecules
made up of two or more atoms
atoms from molecules
in order to fill their outermost electron shellsq
mole
Describe the structure of a simple lipid.
also called fats or triglycerides contain an alcohol called glycerol and a group of compounds known as fatty acids.
the primary function of lipids is the formation of plasma membranes that enclose cells.
saturated is when it has no double bonds saturated chains become solid more easily because they are relatively straight and are able to pack together moe closely than unsaturated chains
unsaturated fats have double bonds and they create kinks in the chain which keep the chains apart from one another.
Special properties of water
ice being less dense which means less hydrogen molecules the ice of lakes serves as a insulating layer to the underlying organisms
solvent properties
water is a key reactant to digestion by larger molecules are broken down into smaller molecules; water is important source of the hydrogen and oxygen that are incorporated into numerous organic compounds in living cells
temperature buffer - water moe easily maintains a content temp than other solvents and protect cell from fluctuations in environments due to its strong hydrogen bonding in water molecules
acid
dissociates into H+and anions
base
dissociates into OH- and cations
total magnification
multiplying the objective lens by the ocular lens
dark field microscope
examining live microorganisms - that are invisible in ordinary light microscope, cannot be stained by standard methods, or are distorted by normal staining
scanning
to study the surface features of cell sand viruses
Compound light microscope
examine very small specimens and some of their fine detail.
can not resolve structures smaller than 0.2um
How does light pass through a microscope
illuminatior - light source --- condenser; lens that direct the light rays through the specimen --- objective lenses; light passes through here this is the lens closest to the specimen --- the imagine is magnified again by the ocular lens
stains
salts composed of positive and negative ion one of which is colored and is known as chromophore
basic dye - positive ion
acidic - negative ion
negative staining
preparing colorless bacteria against a colored background - usually with acidic dyes
Gram staining steps
heat fixed smear is covered with a basic purple dye
purple dye is washed off ad the smear is covered with iodine - mordant (both gram
- and gram - appear purple in this step)
the slide is washed with alcohol this decolorizes
alcohol is rinsed off and the slide is stained with another basic dye that is red
smear is washed again and dried then examined.
Why does gram staining work?
because the crystal violet and the iodine can enter the cell. the primary dye stays or leaves based on the cell wall of the bacteria. is negative cells the lipopolysaccharide layer allows the color to leave
