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Microbiology Quiz: True/False & MCQs
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Microbiology Quiz: True/False & MCQs

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@PreeminentBliss

Questions and Answers

The procedures for culturing a microorganism require the use of a microscope.

True

Some microbes are not capable of growing on artificial media as pure cultures.

True

Mixed cultures are also referred to as contaminated cultures.

False

Bacterial cultures are easily identified from their microscopic appearance.

<p>False</p> Signup and view all the answers

A medium that is gel-like has less agar in it compared to a solid medium.

<p>True</p> Signup and view all the answers

A selective medium contains one or more substances that inhibit the growth of some microbes to facilitate the growth of other desired microbes.

<p>True</p> Signup and view all the answers

The bending of light rays as they pass from one medium to another is called refraction.

<p>True</p> Signup and view all the answers

A differential interference contrast microscope uses dyes to give colored, three-dimensional images.

<p>False</p> Signup and view all the answers

Following a properly performed Gram stain, gram-positive bacteria will appear as pink or red cells.

<p>False</p> Signup and view all the answers

A microbiologist inoculates Staphylococcus aureus into a culture medium. Following incubation, both Staphylococcus aureus and Staphylococcus epidermidis are determined to be growing in this culture. What is the most likely explanation?

<p>The culture was contaminated.</p> Signup and view all the answers

The bacterium Neisseria gonorrhoeae causes the sexually-transmitted infection gonorrhea. Although it can be isolated from the vagina, there are numerous normal biota in that location as well. To generate a pure culture of this pathogenic bacterium, the best choice is a/an ____.

<p>Selective medium</p> Signup and view all the answers

The term that refers to the purposeful addition of microorganisms into a laboratory nutrient medium is ______.

<p>Inoculation</p> Signup and view all the answers

Which of the following is not an inoculating tool?

<p>Petri dish</p> Signup and view all the answers

Which type of medium would be the best choice when shipping a sample of bacteria from a clinic to a laboratory for testing?

<p>Transport medium</p> Signup and view all the answers

Which type of microscopy transforms the subtle variations in cell density into differences in light intensity, allowing for increased internal detail without staining?

<p>Phase-contrast</p> Signup and view all the answers

Who invented the first crude microscope by grinding glass?

<p>Leeuwenhoek</p> Signup and view all the answers

A nutrient medium that contains at least one ingredient that is not chemically defined is termed ______.

<p>complex</p> Signup and view all the answers

Which type of medium distinguishes different types of microorganisms based on an observable change in the colonies or in the medium?

<p>Differential</p> Signup and view all the answers

Which of the following structures contribute to the ability of pathogenic bacteria to cause disease except?

<p>Inclusions</p> Signup and view all the answers

Magnetosomes are?

<p>Composed of magnetic iron oxide particles</p> Signup and view all the answers

Which of the following bacterial structures is incorrectly matched with a function?

<p>Plasmids - Contain genes essential for growth and metabolism</p> Signup and view all the answers

All bacterial cells have?

<p>A chromosome</p> Signup and view all the answers

The site for ATP synthesis in bacterial cells is the?

<p>Cell membrane</p> Signup and view all the answers

Which term refers to the presence of flagella all over the cell surface?

<p>Peritrichous</p> Signup and view all the answers

The transfer of genes during bacterial conjugation involves rigid, tubular appendages called?

<p>Sex pili</p> Signup and view all the answers

Which of the following properties are shared by both bacteria and archaea?

<p>Single, circular chromosome</p> Signup and view all the answers

The eukaryotic cell membrane is a bilayer of sterols.

<p>True</p> Signup and view all the answers

All fungi can form hyphae.

<p>False</p> Signup and view all the answers

A bacterial cell wall that has primarily peptidoglycan with small amounts of teichoic acid and lipoteichoic acid is?

<p>Gram-positive</p> Signup and view all the answers

What term refers to the enzyme that can hydrolyze the bonds in peptidoglycan?

<p>lysozyme</p> Signup and view all the answers

A scanning confocal microscope ______.

<p>Scans narrow planes and can build a three-dimensional image of the specimen</p> Signup and view all the answers

Which type of microscope does not use light in forming the specimen image?

<p>Electron</p> Signup and view all the answers

Which type of microscope achieves the greatest resolution and highest magnification?

<p>Electron</p> Signup and view all the answers

The purpose of staining cells on a microscope slide is to ______.

<p>Add contrast to see them better</p> Signup and view all the answers

The Gram staining procedure is best described as a ______ staining technique.

<p>Differential</p> Signup and view all the answers

What do the Gram stain, the acid-fast stain, and the endospore stain have in common?

<p>They are differential stains.</p> Signup and view all the answers

Basic dyes are ______.

<p>Attracted to the acidic surface of bacterial cells</p> Signup and view all the answers

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 ______.

<p>Simple staining</p> Signup and view all the answers

If you observe rod-shaped, pink cells on a slide that had just been Gram stained, you can assume that their cell envelope contains endotoxin.

<p>False</p> Signup and view all the answers

Archaea do not have the typical peptidoglycan structure found in bacterial cell walls.

<p>True</p> Signup and view all the answers

Endospores of certain bacterial species can enter tissues in the human body, germinate, and cause an infectious disease.

<p>True</p> Signup and view all the answers

Boiling water (100°C) can normally destroy endospores.

<p>False</p> Signup and view all the answers

Some bacteria have a cytoskeleton of sterols to help maintain their shape.

<p>False</p> Signup and view all the answers

What is the identity of the structure detected by chemical analysis in a bacterial cell that indicates it's an endospore?

<p>Dipicolinic acid</p> Signup and view all the answers

Endospores are ______.

<p>All of the choices are correct.</p> Signup and view all the answers

The presence of these endosymbiotic bacteria provided a cell with the advantage of ______.

<p>tolerance to oxygen</p> Signup and view all the answers

The endosymbiotic theory has been developed to explain the emergence of ______.

<p>eukaryotes</p> Signup and view all the answers

Biologists have found evidence that eukaryotic cells evolved from prokaryotic organisms by a process of intracellular ______.

<p>symbiosis</p> Signup and view all the answers

Select that statement that reflects evidence that directly supports the endosymbiotic theory.

<p>The electron transport system is located in the cell membrane in bacteria, while in eukaryotes it is located in the mitochondrial cristae.</p> Signup and view all the answers

Which of the following pairs is mismatched?

<p>Protozoa; multicellular</p> Signup and view all the answers

Protists include ______.

<p>algae and protozoa</p> Signup and view all the answers

Which of the following is found in eukaryotic cells but not in bacterial cells?

<p>All of the choices are correct.</p> Signup and view all the answers

You are observing an organism under the microscope and you note that it has a cell wall, no chloroplasts, and a nucleus. Your prediction would be that this organism is a/an ______.

<p>fungus</p> Signup and view all the answers

You are observing an organism under the microscope, and it is clearly multicellular with no cell walls. Your prediction is that this organism is a/an ______.

<p>helminth</p> Signup and view all the answers

Eukaryotic flagella differ from bacterial flagella because only eukaryotic flagella ______.

<p>contain microtubules</p> Signup and view all the answers

Cilia are exhibited by certain ______.

<p>protozoa</p> Signup and view all the answers

There are nine peripheral pairs and one central pair of _____ found inside eukaryotic flagella and cilia.

<p>microtubules</p> Signup and view all the answers

As part of their reproductive cycle, helminths produce egg and sperm cells. Both of these eukaryotic cell types have an outer surface composed of polysaccharides known as the ______.

<p>glycocalyx</p> Signup and view all the answers

The glycocalyx of a eukaryotic cell is ______.

<p>mostly polysaccharides</p> Signup and view all the answers

Which of the following is not a function of the eukaryotic glycocalyx?

<p>Movement</p> Signup and view all the answers

Which of the following organisms has a cell wall?

<p>Candida albicans</p> Signup and view all the answers

Cell walls are not typically possessed by ______.

<p>protozoa</p> Signup and view all the answers

Chitin is a chemical component of the cell walls of ______.

<p>fungi</p> Signup and view all the answers

The cell membranes of bacteria and eukaryotes are quite similar, differing only in ______.

<p>the presence of sterols</p> Signup and view all the answers

The eukaryotic cell membrane is composed of ______.

<p>sterols, proteins, and phospholipids</p> Signup and view all the answers

The site for ribosomal RNA synthesis is the ______.

<p>nucleolus</p> Signup and view all the answers

When a eukaryotic cell is not undergoing mitosis, the DNA and its associated proteins appear as a visible, thread-like mass called ______.

<p>chromatin</p> Signup and view all the answers

Histones are ______.

<p>proteins associated with DNA in the nucleus</p> Signup and view all the answers

The passageways in the nuclear envelope for movement of substances between the nucleus and cytoplasm are called nuclear ______.

<p>pores</p> Signup and view all the answers

In eukaryotic cells, which of the following organelles contain DNA?

<p>Nucleus, chloroplast, and mitochondrion</p> Signup and view all the answers

Which organelle is found in algae but not in protozoa or fungi?

<p>Chloroplasts</p> Signup and view all the answers

Chloroplasts are composed of membranous sacs called ______ that carry chlorophyll. Surrounding these sacs is a ground substance called ______.

<p>thylakoids; stroma</p> Signup and view all the answers

Pfiesteria is a/an ______ that produces a toxin harmful to humans.

<p>alga</p> Signup and view all the answers

A hypothesis must be tested many times before it can be considered a theory.

<p>True</p> Signup and view all the answers

Many chronic medical conditions have been found to be associated with microbial agents.

<p>True</p> Signup and view all the answers

All bacteria and archaea are microorganisms, but only some eukaryotes are microorganisms.

<p>True</p> Signup and view all the answers

The scientific method involves formulating a tentative explanation, called the hypothesis, to account for what has been observed or measured.

<p>True</p> Signup and view all the answers

Members of the same species share many more characteristics compared to those shared by members of the same kingdom.

<p>True</p> Signup and view all the answers

The names of the three proposed domains are: Bacteria, Protista, and Eukarya.

<p>False</p> Signup and view all the answers

Microorganisms are best defined as organisms that ______.

<p>are too small to be seen with the unaided eye</p> Signup and view all the answers

Which of the following are not considered microorganisms?

<p>Mosquitoes</p> Signup and view all the answers

Helminths are ______.

<p>parasitic worms</p> Signup and view all the answers

Among these types of microorganisms, the ______ are noncellular.

<p>viruses</p> Signup and view all the answers

Studies of the immune response to an infection caused by microorganisms would be performed by a/an _______.

<p>immunologist</p> Signup and view all the answers

Which of the following pairs of career descriptions and work tasks is not correctly matched?

<p>Industrial microbiologist -- manipulate bacterial strains to be less pathogenic</p> Signup and view all the answers

A scientist who studies the influence of microbes in the formation of caves is called a/an ______.

<p>geomicrobiologist</p> Signup and view all the answers

Astrobiology is considered a sub-discipline of microbiology because ______.

<p>life elsewhere in the universe is likely to be microbial</p> Signup and view all the answers

Which of the following does not indicate microbe involvement in energy and nutrient flow?

<p>Thermal hot springs warmed by heat from earth's interior</p> Signup and view all the answers

The microorganisms that recycle nutrients by breaking down dead matter and wastes are called ______.

<p>decomposers</p> Signup and view all the answers

The majority of oxygen in earth's atmosphere is a product of photosynthesis by ______.

<p>microorganisms</p> Signup and view all the answers

The three cell types discussed, eukaryotes, archaea, and bacteria, all derived from ______.

<p>a common ancestral cell</p> Signup and view all the answers

The first cells appeared about _____ billion years ago.

<p>4</p> Signup and view all the answers

Which area of biology states that living things undergo gradual structural and functional changes over long periods of time?

<p>Evolution</p> Signup and view all the answers

When humans manipulate the genes of microorganisms, the process is called ______.

<p>genetic engineering</p> Signup and view all the answers

Which activity is an example of biotechnology?

<p>Escherichia coli producing human insulin</p> Signup and view all the answers

Which of the following is a traditional human use of microorganisms?

<p>Baking bread</p> Signup and view all the answers

Using microbes to detoxify a site contaminated with heavy metals is an example of ______.

<p>bioremediation</p> Signup and view all the answers

Disease-causing microorganisms are called ______.

<p>pathogens</p> Signup and view all the answers

The number one worldwide infectious diseases are ______.

<p>respiratory diseases</p> Signup and view all the answers

The incidence of deaths from communicable disease is ______ in the United States compared to the entire world.

<p>less</p> Signup and view all the answers

In which way are bacteria and eukaryotes the same?

<p>Possess a cell membrane</p> Signup and view all the answers

In which way are archaea and eukaryotes the same?

<p>Have similar ssu rRNA sequences</p> Signup and view all the answers

Which of the following is a unique characteristic of viruses that distinguishes them from the other major groups of microorganisms?

<p>Lack cell structure</p> Signup and view all the answers

Which group of microorganisms is composed only of hereditary material wrapped in a protein covering?

<p>Viruses</p> Signup and view all the answers

Eukaryotic cells are larger than bacterial or archaeal cells; all cells are larger than macromolecules. Where do viruses fit on this scale?

<p>Viruses are smaller than bacterial or archaeal cells, but larger than macromolecules.</p> Signup and view all the answers

In general, eukaryotic cells are about ______ times larger than bacterial or archaeal cells.

<p>10</p> Signup and view all the answers

Archaeal cells are about ______ bacterial cells.

<p>the same size as</p> Signup and view all the answers

Which of the following historical microbiologists is incorrectly paired with his contribution to the science?

<p>Louis Pasteur: demonstrated that anthrax was caused by a bacterium</p> Signup and view all the answers

In the experiments constructed by Pasteur to disprove spontaneous generation, swan-necked flasks were used. Why was this shape of flask used in this experiment?

<p>The glass necks needed to be open to the air, yet constructed so that bacteria would settle in the lowest part of the neck.</p> Signup and view all the answers

Koch's postulates are criteria used to establish that ______.

<p>a specific microbe is the cause of a specific disease</p> Signup and view all the answers

Which of the following is NOT a recent discovery that has had a huge impact on the understanding of microbiology?

<p>All are significant discoveries.</p> Signup and view all the answers

The sum total of all the microbes in a certain environment is termed the ______.

<p>microbiome</p> Signup and view all the answers

Which of the following is not a process in the scientific method?

<p>Belief in a preconceived idea</p> Signup and view all the answers

Experimentation ______.

<p>provides a means to gather objective data</p> Signup and view all the answers

The scientific method includes all of the following except ______.

<p>publication</p> Signup and view all the answers

Caring for patients infected with a new virus requires safety precautions for medical personnel. Choosing appropriate procedures is an example of a/an ______ process.

<p>deductive</p> Signup and view all the answers

Sterile is best described as ______.

<p>absence of any life forms and viral particles</p> Signup and view all the answers

Taxonomy does not involve ______.

<p>a common name</p> Signup and view all the answers

Which scientific field is involved in the identification, classification, and naming of organisms?

<p>Taxonomy</p> Signup and view all the answers

The orderly arrangement of organisms into a hierarchy of taxa is called ______.

<p>classification</p> Signup and view all the answers

Which of the following is a taxon that contains all the other taxa listed?

<p>Kingdom</p> Signup and view all the answers

The smallest and most significant taxon is a ______.

<p>species</p> Signup and view all the answers

Select the correct descending taxonomic hierarchy (left to right).

<p>Family, genus, species</p> Signup and view all the answers

A mnemonic for remembering the taxonomic levels from Domain to Species is 'Dear King Phillip Came Over for Good Soup.' The word 'came' here is a reminder of the taxonomic level of ______.

<p>class</p> Signup and view all the answers

Which of the following is a scientific name?

<p>Streptococcus pyogenes</p> Signup and view all the answers

When assigning a scientific name to an organism, _______.

<p>both genus and species names are italicized or underlined</p> Signup and view all the answers

Which scientific name is written correctly?

<p>Staphylococcus aureus</p> Signup and view all the answers

A diagram of the three domains (Bacteria, Archaea, Eukarya) proceeding from the Last Common Ancestor would show Archaea _______.

<p>branching off the Domain Bacteria</p> Signup and view all the answers

Analysis of the small subunit rRNAs from all organisms in the three current domains suggests that _______.

<p>all modern and extinct organisms on earth arose from a common ancestor</p> Signup and view all the answers

The study of evolutionary relationships among organisms is called ______.

<p>phylogeny</p> Signup and view all the answers

A scientist studying the sequence of nucleotides in the rRNA of a bacterial species is working on _______.

<p>determining evolutionary relatedness</p> Signup and view all the answers

Trees of life that illustrate the phylogenetic relationships of all organisms were traditionally based on ______; newer methods for determining phylogeny rely on ______.

<p>morphology; nucleic acid sequences</p> Signup and view all the answers

Electrons that participate in chemical bonding are typically located closest to the nucleus.

<p>False</p> Signup and view all the answers

Water molecules are nonpolar molecules.

<p>False</p> Signup and view all the answers

Polar molecules have more reactivity compared to nonpolar molecules.

<p>True</p> Signup and view all the answers

A covalent bond is formed between an anion and a cation.

<p>False</p> Signup and view all the answers

The concentration of a solution expresses the amount of solvent present.

<p>False</p> Signup and view all the answers

If solution A has a lower pH compared to solution B, then solution A is more acidic than solution B.

<p>True</p> Signup and view all the answers

The only part of an amino acid that differs from other amino acids is its R group.

<p>True</p> Signup and view all the answers

All proteins are enzymes.

<p>False</p> Signup and view all the answers

Nucleic acids have primary, secondary, tertiary, and quaternary levels of organization.

<p>True</p> Signup and view all the answers

What is the most important outcome of polypeptide intrachain bonding and folding?

<p>The unique shape of the protein.</p> Signup and view all the answers

A new organism was identified that contained arsenic in place of phosphate in its DNA double helix structure. Based upon this information alone, it can be determined that this change will greatly alter the information encoded by this genetic material.

<p>True</p> Signup and view all the answers

An atom has gained an electron; it has been ______.

<p>Reduced</p> Signup and view all the answers

Anything that occupies space and has mass is called ______.

<p>Matter</p> Signup and view all the answers

The electrons of an atom are _______.

<p>Moving in pathways called orbitals</p> Signup and view all the answers

All of the following pertain to the atom Carbon-14 except it _______.

<p>Has 14 neutrons</p> Signup and view all the answers

The subatomic particles that surround the nucleus are the ______.

<p>Electrons</p> Signup and view all the answers

What is the maximum number of electrons in the second energy shell of an atom?

<p>8</p> Signup and view all the answers

What is the maximum number of electrons in the first energy shell of an atom?

<p>2</p> Signup and view all the answers

Protons and neutrons make up the atom's central core, which is referred to as its ______.

<p>Nucleus</p> Signup and view all the answers

The valence number is the _______.

<p>Number of electrons in the outermost orbital</p> Signup and view all the answers

Two or more atoms bonded together are called a(n) ______.

<p>Molecule</p> Signup and view all the answers

What would be the valence number of electrons in the sulfur (S) atom? Its atomic number is 16.

<p>6</p> Signup and view all the answers

Polar molecules _______.

<p>Have an unequal charge distribution</p> Signup and view all the answers

Organic chemicals always have a basic framework of the element _____ bonded to other atoms.

<p>Carbon</p> Signup and view all the answers

C6H12O6 + C6H12O6 → C12H22O11 + H2O represents _______.

<p>A dehydration synthesis</p> Signup and view all the answers

Substances that release ions when dissolved in water and conduct electricity are ______.

<p>Electrolytes</p> Signup and view all the answers

A capillary tube is used to acquire a small blood sample for CBC (complete blood count) analysis. Suction is not required to transfer the blood from the fingertip prick to the tube in part due to _______.

<p>Adhesive forces between the water molecules and the glass particles of the tube</p> Signup and view all the answers

Polar molecules are composed of covalently bonded _______.

<p>Atoms of different electronegativity</p> Signup and view all the answers

Covalent bonds _______.

<p>Result from sharing electrons</p> Signup and view all the answers

Cations are _______.

<p>Capable of forming ionic bonds with anions</p> Signup and view all the answers

A reaction where an electron is lost is called ______.

<p>Oxidation</p> Signup and view all the answers

Ionic bonds _______.

<p>Result from transferring electrons</p> Signup and view all the answers

Hydrogen bonds _______.

<p>Result from attractive forces between molecules with polar covalent bonds</p> Signup and view all the answers

Atoms that gain or lose electrons become charged particles called ______.

<p>Ions</p> Signup and view all the answers

Which of the following represents a synthesis reaction?

<p>A + B → AB</p> Signup and view all the answers

Which of the following represents a reversible reaction?

<p>AB + XY ↔ AY + XB</p> Signup and view all the answers

Ionic compounds _______.

<p>Are hydrophilic</p> Signup and view all the answers

The important solvent associated with living things is ______.

<p>Water</p> Signup and view all the answers

In the cell cytoplasm, molecules of ATP are a ______.

<p>Solute</p> Signup and view all the answers

Burning coal produces sulfur dioxide in the atmosphere. When combined with rain that falls into bodies of water, this leads to _______.

<p>A decrease in the pH level of the water</p> Signup and view all the answers

Compared to a solution of pH 9, a solution of pH 7 ______.

<p>Has more H+ ions</p> Signup and view all the answers

Compared to a solution of pH 9, a solution of pH 7 is ______.

<p>100 times more acidic</p> Signup and view all the answers

One technique for staining bacteria for viewing under the microscope is called the Gram stain. In this technique, alcohol is used as a decolorizer because it degrades the outer membrane found in some bacteria. What chemical component of the cell does alcohol affect?

<p>Lipid</p> Signup and view all the answers

What type of bond is formed by dehydration synthesis between two amino acids?

<p>Peptide</p> Signup and view all the answers

The purine ______ always hydrogen bonds with the pyrimidine ______ in double-stranded DNA.

<p>Guanine; cytosine</p> Signup and view all the answers

In what way would life be different if the element carbon was absent?

<p>There would be no organic compounds.</p> Signup and view all the answers

A student forgot to label a beaker containing a DNA solution and a beaker containing a glucose solution. If chemical analysis was performed to identify the contents of each beaker, which of the following would be found in the beaker of DNA but not in the beaker with glucose?

<p>Nitrogen and phosphorus</p> Signup and view all the answers

Which of the following functional groups is mismatched to the organic compound in which it is typically found?

<p>Phosphate - carbohydrates</p> Signup and view all the answers

Most biochemical macromolecules are polymers, which are chains of ______.

<p>Repeating monomers</p> Signup and view all the answers

All of the following are monosaccharides except ______.

<p>Glycogen</p> Signup and view all the answers

Which of the following would have glycosidic bonds?

<p>Polysaccharides</p> Signup and view all the answers

Starch is the primary storage food for all of the following except ______.

<p>Animals</p> Signup and view all the answers

Select the statement that most accurately reflects the process of plant material digestion in humans.

<p>It is a process that is dependent upon enzyme (cellulase) production by gut microbiota.</p> Signup and view all the answers

All of the following are lipids except ______.

<p>Starch</p> Signup and view all the answers

What part of a phospholipid comprises the hydrophobic tail?

<p>Fatty acids</p> Signup and view all the answers

A fat is called _______ if all carbons of the fatty acid chain are single-bonded to 2 other carbons and 2 hydrogens.

<p>Saturated</p> Signup and view all the answers

The building blocks of an enzyme are ______.

<p>Amino acids</p> Signup and view all the answers

An amino acid contains all of the following except a/an ______.

<p>Phosphate</p> Signup and view all the answers

An example of an amphipathic molecule found in living cells is ______.

<p>Phospholipid</p> Signup and view all the answers

The lipid group that serves as energy storage molecules is the ______.

<p>Triglycerides</p> Signup and view all the answers

All of the following are polysaccharides except ______.

<p>Sterols in cell membranes</p> Signup and view all the answers

The lipid group that is the major component of cell membranes is the ______.

<p>Phospholipids</p> Signup and view all the answers

Which of the following statements is incorrect regarding protein structure?

<p>The interaction between various R groups of amino acids determines the primary structure of a protein.</p> Signup and view all the answers

Which of the following is not true about enzymes?

<p>Enzymes have high-energy bonds between phosphates.</p> Signup and view all the answers

The alpha (α) helix is a type of _____ protein structure.

<p>Secondary</p> Signup and view all the answers

ATP differs from the nucleotides found in DNA in the _______.

<p>Sugar portion of the molecule</p> Signup and view all the answers

One nucleotide contains one _______.

<p>All of the choices are correct.</p> Signup and view all the answers

Purines and pyrimidines are components in the building block units of all ______.

<p>Nucleic acids</p> Signup and view all the answers

Which of the following is not a pyrimidine?

<p>Adenine</p> Signup and view all the answers

Which pertains to DNA but not to RNA?

<p>Contains thymine</p> Signup and view all the answers

Which of the following is a correct description of a component of the ATP molecule?

<p>Sugar: ribose</p> Signup and view all the answers

ATP is best described as _______.

<p>The energy molecule of cells</p> Signup and view all the answers

A culture of an organism believed to cause intestinal symptoms is viewed under the microscope, and the microbiologist observes a cell membrane, flagella, mitochondria, and some dark unrecognizable structures within each cell. The microbiologist notes that the cells are eukaryotic because _______.

<p>Only eukaryotic cells have mitochondria</p> Signup and view all the answers

NASA has published a list of criteria for identifying fossil bacteria in samples from Mars, as part of a search for evidence of life. Which of the following is good evidence for the presence of bacterial cells?

<p>Cell size of 0.5 to 2 microns</p> Signup and view all the answers

Characteristics shared by all cells include _______.

<p>All of the choices are correct.</p> Signup and view all the answers

All cells contain _______.

<p>Genetic information</p> Signup and view all the answers

Which of the following statements is true regarding differential media?

<p>They contain indicators that reveal differences between microorganisms.</p> Signup and view all the answers

An example of a medium that is both selective and differential is:

<p>MacConkey agar</p> Signup and view all the answers

The specimen preparation that is best for viewing cell motility is the:

<p>Hanging drop</p> Signup and view all the answers

Which of the following is not an optical microscope?

<p>Electron microscope</p> Signup and view all the answers

What is the primary purpose of staining cells on a microscope slide?

<p>To see them better</p> Signup and view all the answers

A pure culture contains:

<p>Only one species of microorganism</p> Signup and view all the answers

Which type of media would be the best choice when shipping a sample of bacteria to a laboratory?

<p>Transport media</p> Signup and view all the answers

Basic dyes are characterized by their:

<p>Ability to bind to nucleic acids</p> Signup and view all the answers

What substances primarily characterize a reducing medium?

<p>Substances that remove oxygen</p> Signup and view all the answers

Which medium is specifically designed to assess bacterial motility?

<p>Sulfur Indole Motility (SIM)</p> Signup and view all the answers

When a microscope boasts a resolving power of 0.2 µm, what does this indicate?

<p>The microscope can differentiate two points that are less than 0.2 µm apart</p> Signup and view all the answers

What type of microscope allows for the observation of brightly illuminated specimens against a black background?

<p>Dark-field microscope</p> Signup and view all the answers

For effective focusing under a microscope, which initial approach is recommended?

<p>Low power objective and coarse adjustment</p> Signup and view all the answers

Which type of microscopy allows the viewer to observe a specimen in three dimensions?

<p>Confocal microscopy</p> Signup and view all the answers

What term describes the intentional introduction of microorganisms into a nutrient medium?

<p>Inoculation</p> Signup and view all the answers

What is referred to as a nutrient medium containing at least one ingredient that is not chemically definable?

<p>Complex</p> Signup and view all the answers

What is the primary purpose of a differential stain?

<p>Differentiate between various bacterial types</p> Signup and view all the answers

Which of the following statements about selective media is incorrect?

<p>A medium must be either selective or differential.</p> Signup and view all the answers

In microbiology, what best explains why both Staphylococcus aureus and Staphylococcus epidermidis grew in a culture medium inoculated with Staphylococcus aureus?

<p>The culture is contaminated.</p> Signup and view all the answers

Bacteria that reproduce by dividing in multiple planes and form clusters resembling grapes are known as:

<p>Staphylococci</p> Signup and view all the answers

Which method is considered most effective for isolating pure cultures from mixed cultures?

<p>Streak plate method</p> Signup and view all the answers

Which media type is utilized for differentiating various bacterial species based on their colony morphology?

<p>Differential media</p> Signup and view all the answers

What is the primary use of the spread plating technique?

<p>Spreading the inoculum evenly over the surface of the agar plate.</p> Signup and view all the answers

What component in a light microscope increases the light intensity passing through the specimen?

<p>Condenser</p> Signup and view all the answers

Which microscope utilizes two sets of lenses to magnify a specimen?

<p>Compound microscope</p> Signup and view all the answers

Which organism type requires a living host for growth?

<p>Obligate intracellular parasite</p> Signup and view all the answers

Which microscope uses a probe to scan a specimen's surface?

<p>Scanning electron microscope</p> Signup and view all the answers

Which statement accurately describes electron microscopy?

<p>Focuses electrons with electromagnetic lenses</p> Signup and view all the answers

In dark-field microscopy, what is a primary application?

<p>Observing live, unstained cells</p> Signup and view all the answers

What does the term 'culture' signify in microbiology?

<p>Growth of microorganisms in a controlled environment</p> Signup and view all the answers

To view specimens that glow under ultraviolet light, which microscope would be used?

<p>Fluorescence microscope</p> Signup and view all the answers

The primary function of a decolorizer in Gram staining is to:

<p>Remove the primary stain from gram-negative bacteria</p> Signup and view all the answers

Which stain is used as the primary stain in the Gram staining procedure?

<p>Crystal violet</p> Signup and view all the answers

What purpose does immersion oil serve in microscopy?

<p>To increase resolution</p> Signup and view all the answers

Which term describes the ability of a microscope to distinguish two points as separate?

<p>Resolution</p> Signup and view all the answers

Which type of bacteria features a thick peptidoglycan layer in its cell wall?

<p>Gram-positive bacteria</p> Signup and view all the answers

What is the function of crystal violet in the Gram staining procedure?

<p>Primary stain to visualize Gram-positive bacteria</p> Signup and view all the answers

Study Notes

True/False Statements

  • A hypothesis requires extensive testing before qualifying as a theory.
  • Chronic medical conditions often relate to microbial agents.
  • All bacteria and archaea are classified as microorganisms; some eukaryotes are not.
  • The scientific method includes formulating a hypothesis based on observations.
  • Species within the same category share more characteristics than those within a kingdom.
  • The three domains of life are Bacteria, Archaea, and Eukarya, not Protista.

Multiple Choice Insights

  • Microorganisms are defined as organisms too small to be seen without a microscope (option D).
  • Mosquitoes are not categorized as microorganisms (option A).
  • Helminths refer to parasitic worms (option D).
  • Viruses are the noncellular microorganisms (option A).
  • Immunologists study immune responses to infections by microorganisms (option C).
  • Incorrectly matched career description: Industrial microbiologist does not primarily manipulate bacterial strains to reduce pathogenicity (option A).
  • A geomicrobiologist studies microbial effects on cave formation (option A).
  • Astrobiology focuses on microbial life possibilities elsewhere in the universe (option A).
  • Microbes play key roles in energy and nutrient flow, except in thermal springs related to Earth's heat (option A).
  • Decomposers recycle nutrients by breaking down dead matter (option A).
  • Microorganisms produce the majority of atmospheric oxygen through photosynthesis (option A).
  • All cell types (eukaryotes, archaea, bacteria) evolved from a common ancestral cell (option A).
  • First cells appeared approximately 4 billion years ago (option B).
  • Evolution explains gradual changes in living organisms over time (option C).
  • Human manipulation of microorganism genes is termed genetic engineering (option B).
  • Example of biotechnology: E. coli producing human insulin (option D).
  • Traditional use of microorganisms includes bread baking (option A).
  • Using microbes to clean heavy metal sites demonstrates bioremediation (option B).
  • Disease-causing microorganisms are referred to as pathogens (option C).
  • Worldwide, respiratory diseases are the most common infectious diseases (option E).
  • Death rates from communicable diseases are lower in the U.S. compared to global averages (option A).
  • Bacteria and eukaryotes both possess a cell membrane, which is a similarity (option B).
  • Archaea and eukaryotes share similar small subunit rRNA sequences (option B).
  • Unique characteristic of viruses: they lack a cellular structure (option E).
  • Viruses are smaller than both bacterial and archaeal cells, yet larger than macromolecules (option C).
  • Eukaryotic cells are generally 10 times larger than bacterial or archaeal cells (option B).
  • Archaeal cells are about the same size as bacterial cells (option A).
  • Incorrect pairing: Louis Pasteur did not demonstrate anthrax was caused by a bacterium (option C).
  • Pasteur used swan-necked flasks in experiments to keep bacteria from entering while allowing air contact (option A).
  • Koch's postulates help link a specific microbe to a particular disease (option B).
  • Recent microbiology discoveries impacting understanding: all listed options are significant (option E).
  • The microbiome represents the total microbial composition in a specific environment (option A).
  • A preconceived belief is not part of the scientific method (option A).
  • Experimentation collects objective data to support or refute hypotheses (option D).
  • Scientific method elements exclude publication (option D).
  • Determining safety protocols for new virus patients involves a deductive approach (option A).
  • Sterility is the absence of all forms of life, including viruses (option C).
  • Taxonomy does not include the use of common names (option D).
  • Taxonomy involves identifying, classifying, and naming organisms (option B).
  • Organisms structured in a hierarchy of taxa exemplify classification (option A).
  • The kingdom is a taxon that encompasses all others listed (option C).
  • The species taxon ranks smallest yet is critically important (option B).
  • Correct descending hierarchy: Family, genus, species (option B).
  • In taxonomy, "came" corresponds to class (option A).
  • Scientific naming includes both italicizing genus and species (option E).
  • Correct format for scientific names: Genus capitalized followed by species (option A).
  • Archaea stemmed from original cells according to phylogenetic diagrams (option A).
  • Analysis of rRNA suggests all organisms share a common ancestor (option C).
  • Phylogeny studies evolutionary relationships among organisms (option D).
  • Sequencing nucleotides in rRNA helps determine evolutionary connections (option A).
  • Traditional phylogenetic trees relied on morphology; modern methods focus on genetic sequences (option A).

Additional True/False Statements

  • Electrons involved in chemical bonding are located further from the nucleus, not closer.
  • Water molecules are polar, not nonpolar.
  • Polar molecules often exhibit greater reactivity than nonpolar molecules.
  • Covalent bonds form between atoms of equal charge, not anions and cations.
  • Concentration refers to the solute, not the solvent in a solution.
  • A lower pH indicates increased acidity.
  • Amino acids differ only in their R groups.
  • Not every protein functions as an enzyme.
  • Nucleic acids exhibit multiple levels of organization.
  • Polypeptide bonding and folding determine protein structure significantly.
  • Arsenic replacing phosphate in DNA may disrupt genetic information encoding.

Additional Multiple Choice Insights

  • An atom gaining an electron reflects reduction (option B).
  • Matter is defined as anything occupying space and possessing mass (option C).
  • Electrons orbit the nucleus in defined pathways or orbitals (option E).
  • Electrons correlate to the atomic number, matching the number of protons (option D).
  • Carbon-14, an isotope, has 6 protons, 6 electrons, and 8 neutrons (option C).
  • Electrons surrounding the nucleus are identified as the electrons (option A).
  • The second energy shell can host a maximum of 8 electrons (option C).
  • The first energy shell can hold 2 electrons.### Atomic Structure and Chemical Bonds
  • Protons and neutrons form the atom's nucleus, which is the central core.
  • The valence number refers to the number of electrons in the outermost orbital; in sulfur (atomic number 16), this number is 6.
  • Molecules are two or more atoms bonded together.
  • Polar molecules have an unequal charge distribution, critical for molecular interactions.

Organic Compounds and Reactions

  • Organic chemicals primarily consist of carbon, which forms the backbone of organic compounds.
  • The reaction represented by ( C_6H_{12}O_6 + C_6H_{12}O_6 \rightarrow C_{12}H_{22}O_{11} + H_2O ) is known as dehydration synthesis, a process to form polysaccharides.
  • Electrolytes are substances that release ions in water and conduct electricity.

Intermolecular Forces

  • Hydrogen bonds result from attractive forces between polar molecules, influencing the properties of water and biological molecules.
  • Covalent bonds are formed by sharing electrons and can be either polar or nonpolar.

Ions and Chemical Reactions

  • Cations are positively charged ions formed by losing electrons, while anions are negatively charged ions formed by gaining electrons.
  • Oxidation is a reaction where an electron is lost, while reduction is the gain of an electron.
  • Ionic bonds result from transferring electrons, leading to charge attraction between ions.

Acidity and pH Levels

  • pH scale quantifies acidity; a solution of pH 7 has more ( H^+ ) ions than one of pH 9, which is 100 times more acidic.
  • Sulfur dioxide from burning coal can lower the pH of water, making it more acidic.

Cell Biology and Microscopy

  • Eukaryotic cells are identified by their cell membranes and organelles like mitochondria.
  • Gram staining requires fixed smears. Gram-positive bacteria appear purple after staining, while Gram-negative appear pink.

Chemical Structures and Functional Groups

  • Nucleotide structures comprise a phosphate, a pentose sugar, and a nitrogen base; ATP differs from DNA nucleotides by having ribose instead of deoxyribose.
  • Phospholipids are amphipathic molecules, crucial for cell membrane structure, where glycerol and fatty acids make up the hydrophobic tail.

Biochemical Macromolecules

  • Monosaccharides include glucose, fructose, and deoxyribose; glycogen is not a monosaccharide but a polysaccharide.
  • Proteins are composed of amino acids, with the peptide bond formed during dehydration synthesis.

Enzymes and Digestive Processes

  • Enzymes, which are catalysts in biochemical reactions, can be denatured by factors such as high temperature.
  • The human digestive system relies on gut microbiota for the digestion of complex plant materials, showcasing the importance of microbial interactions.

Key Functional Groups

  • Functional groups, including amino, carboxyl, and hydroxyl, define the properties of organic compounds. Mismatches exist, like phosphates typically being associated with nucleic acids rather than carbohydrates.

Structural Features of RNA and DNA

  • DNA contains thymine, while RNA includes uracil; both have unique structural properties important for their functions in genetics.

Bacterial Culturing Techniques

  • Selective media inhibit the growth of undesired microbes, aiding in the isolation of specific bacteria like Neisseria gonorrhoeae.
  • Complex media contain unspecified nutrients, allowing various microorganisms to grow based on their nutritional needs.### Microscopy and Magnification
  • Leeuwenhoek's microscope achieved a maximum magnification of 300X.
  • Poliovirus (30 nm) would be invisible using Leeuwenhoek's microscope, as it is smaller than the microscope's capability.
  • Staphylococcus aureus cells are cocci with a diameter of about 1 μm.
  • An image of S.aureus measuring 1 cm at 1 μm size indicates a magnification of 10,000X.
  • Paramecium is typically magnified to 230X, and actual size can be determined from image size.

Microscopy Resolution and Contrast

  • A microscope with a resolving power of 0.15 μm will produce fuzzy images of cocci measuring 0.1 μm.
  • Visual manipulation on an iPad can improve the apparent size but does not enhance resolution or contrast.

Media and Culturing Microorganisms

  • Agar provides a solid surface for bacterial growth and is not inherently a source of carbon.
  • The Five I's of studying microorganisms include inoculation, incubation, isolation, and identification, excluding infection.
  • Inoculation refers to the intentional introduction of microorganisms to a nutrient medium.

Culture Characteristics

  • A pure culture contains only one identified species of microorganism.
  • The sample used to create a culture is called an inoculum.
  • Streak plate methodology is the most effective for colony isolation in labs.

Microbiological Techniques

  • Mannitol salt agar selects for Staphylococcus.
  • A reducing medium contains substances that remove oxygen, helping to culture anaerobic organisms.
  • Differential media result in observable characteristics, such as color changes in colonies.

Types of Microscopy

  • Different microscopy types include bright-field (shows cells against a white background) and phase-contrast (allows visualization of internal details without staining).
  • Scanning electron microscopy (SEM) involves bombarding a metal-coated specimen with electrons for surface detail.
  • Transmission electron microscopy (TEM) provides internal details of cells and subcellular structures.

Staining Techniques

  • The purpose of staining is to enhance visibility by adding contrast to cells.
  • Gram staining is a differential technique utilized to differentiate between gram-positive and gram-negative bacteria.
  • Basic dyes are attracted to the acidic surfaces of bacterial cells, allowing for effective staining.

Bacterial Cell Structure

  • Gram-positive bacteria have a thicker cell wall compared to gram-negative bacteria.
  • Endospores can survive extreme conditions and may enter tissues to cause infections.
  • Bacterial cell membranes are vital sites for metabolic reactions and enzyme functions.

Miscellaneous Facts

  • A slime layer can enhance the pathogenicity of bacteria compared to a capsule.
  • The term "diplococcus" describes pairs of spherical bacteria, not irregular clusters.

Tools of the Laboratory

  • Differential media contain indicators that reveal differences between microorganisms.
  • An example of media that is both selective and differential is MacConkey agar.
  • Transport media is the best choice for shipping bacterial samples.
  • Hanging drop method is ideal for viewing cell motility.
  • Electron microscope is not an optical microscope.
  • Pure cultures consist of only one species of microorganism.
  • The primary purpose of staining is to enhance visibility of cells under a microscope.
  • Reducing media contain substances that remove oxygen.
  • Sulfur Indole Motility (SIM) media can determine bacterial motility.
  • Phase-contrast microscopes allow observation of live specimens and internal structures.
  • Resolving power of 0.2 µm means two points can be distinguished if they are at least that far apart.
  • Dark-field microscopy features brightly illuminated specimens against a black background.
  • Focus a microscope starting with a low power objective and coarse adjustment.
  • Inoculation refers to the purposeful introduction of microorganisms into a culture medium.
  • A medium may be selective, differential, or both.
  • Contamination of culture is likely if both Staphylococcus aureus and Staphylococcus epidermidis are present.
  • Differential media differentiate bacteria based on colony morphology.
  • Spread plating is used to evenly distribute inoculum over agar surfaces.
  • Obligate intracellular parasites require a living host for growth.
  • Atomic force microscopes utilize a probe to scan surfaces of specimens.
  • Dark-field microscopy is commonly used for visualizing live, unstained cells.
  • Fluorescence microscopy visualizes specimens that emit light under ultraviolet illumination.
  • Electron microscopes produce high-resolution images using electron beams.
  • Immersion oil enhances resolution by reducing light scattering.
  • Stage clips hold slides in place on a microscope stage.
  • Selective media enable the growth of specific bacteria while inhibiting others.
  • Light microscopy paths typically follow the route: illuminator, condenser, specimen, objective lens, ocular lens.
  • Transmission electron microscopes provide the highest resolution, exceeding 100,000 times magnification.
  • Confocal microscopy allows three-dimensional specimen visualization.
  • Complex media contain at least one non-chemically definable ingredient.
  • Differential stains help differentiate types of bacteria and highlight specific structures.
  • Staphylococci are bacteria that divide in multiple planes, forming grape-like clusters.
  • Biochemical testing, serological testing, DNA analysis, colony morphology, and Gram staining are methods for identifying bacteria.
  • Streak plate methods effectively isolate pure cultures from mixed samples.
  • Condensers in light microscopes increase light passing through specimens.
  • Compound microscopes have two sets of lenses for magnification.
  • Electron microscopy provides higher resolution than light microscopy using electromagnetic lenses.
  • The term "culture" refers to the controlled growth of microorganisms.
  • The streak plate method's objective is to isolate individual colonies.
  • Bacterial reproduction occurs through binary fission.
  • Refractive index defines how light bends as it passes through substances.
  • Scanning electron microscopes excel at detailed surface imaging of bacteria and viruses.
  • Total magnification is calculated by multiplying ocular lens and objective lens magnifications.
  • Resolution ability determines if two objects can be distinguished as separate.
  • Axial filament refers to the structure spirochetes use for movement.
  • Gram staining is a differential technique that identifies bacteria retaining crystal violet.
  • Gram-positive bacteria have a thick peptidoglycan layer in their cell walls.
  • The decolorizer in Gram staining primarily removes the primary stain from gram-negative bacteria.
  • Crystal violet serves as the primary stain in the Gram staining technique.
  • Fixed smears on slides before staining can be achieved through heat fixation, chemical fixation, or air drying.

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Test your knowledge on microorganisms with this quiz featuring true/false statements and multiple-choice questions. Topics include the classification of bacteria and archaea, the scientific method, and the roles of various microorganisms. Perfect for students studying microbiology or related fields.

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