Micro 223 Exam 1 Post Tests (Chapters 1-5) - SELU Bronwyn Duos
"The Golden Age of Microbiology" Monumental Achievements that followed into the 20th and 21st centuries
-1857-1914 -Germ theory of disease began to be accepted -Louis Pasteur developed a process we call pasteurization to kill bacteria in some alcoholic beverages. Today pasteurization is used extensively in the dairy and brewing industries. -Joseph Lister introduced the use of a disinfectant to clean wounds in order to control infection -Another milestone occurred when Edward Jenner demonstrated that it was possible to protect against smallpox by a procedure called vaccination. -Robert Koch established a sequence of experimental steps for directly relating a specific microbe to a specific disease. These steps are known as Koch's postulates.
What has biotechnology also been applied to?
-Agriculture -Ex. Genetically altered bacteria have been developed to protect fruit against frost damage and bacteria are being modified to control insects that damage crops. Bacteria have also been used to improve the appearance, flavor, and shelf life of fruits and vegetables.
The process of glycolysis is regulated at several steps by allosteric inhibition. Which of the following are features of allosteric inhibition?
-Allosteric inhibition can be reversed -Allosteric inhibition can be irreversible -The allosteric inhibitor binds to a site distinct from the active site resulting in decreased affinity of the enzyme for the substrate
Rank the following groups in the order that they contribute to the structure of a protein.
-Amino Acid sequence a-b-c-d-e -Alpha-helix or beta sheet -Helix-sheet-turn-helix -Polypeptide A joined to polypeptide B, which joins to polypeptide C
Three Common Bacterial Shapes
-Bacillus- Rodlike cell -Coccus- Spherical cell -Spiral- Corkscrew shaped or curved cell -Individual cells may form pairs, chains, or other groupings, which are usually the same within a species
Characteristics of Viruses
-Cannot survive outside a host cell -Can be seen only with an electron microscope
Indicate the bacterial structures that are likely to be antigens, to which host antibodies bind, marking the invader for phagocytosis.
-Capsule -Flagella -Fimbriae -Cell wall
Prokaryotic Cells
-Circular chromosome, not enclosed within a nuclear envelope -Peptidoglycan-containing cell wall -70s ribosomes -Flagella that rotate, composed of flagellin
Compare and contrast three metabolic pathways by choosing whether the statement applies to fermentation. Check all that apply.
-End products may include lactic acid or ethanol -The coenzyme NAD+ plays an important role in the pathway -Process includes glycolysis -Can generate ATP in the absence of O2 -A total of 2 ATP are produced per molecule of glucose input
Characteristics of Fungi
-Eukaryotic -Can be unicellular or multicellular
Membrane transport refers to the mechanisms by which solutes cross the plasma membrane, but there are additional prokaryotic cell structures through which a solute would pass when entering or exiting a cell. Sequence the path of a solute from the external environment to the cytoplasm of a prokaryotic cell.
-External Environment -Capsule cell wall -Plasma membrane -Cytoplasm
Consider the glycolysis pathway. Select all statements that correctly describe glycolysis.
-Glyceraldehyde 3-phosphate is oxidized, and NAD+ is reduced to NADH -Glucose is the original electron donor -The 6-carbon skeleton of glucose is enzymatically split into two 3-carbon compounds -More ATP is formed than is consumed in this process
Characteristics of Bacteria
-Have cell walls that contain petidoglycan -Derive nutrition from organic or inorganic sources or conduct photosythesis
Identify antibacterial strategies that would likely be selectively toxic for bacteria.
-Interfering with translation at 70s ribosomes -Inhibition of peptidoglycan synthesis -Inhibition of fimbriae synthesis
Biogenesis
-Life can arise as a result of microorganisms present in nonliving matter -Living cells can arise only from preexisting living cells -Microorganisms present in nonliving matter can lead to new microorganisms
Spontaneous Generation
-Life can arise spontaneously from nonliving matter -Vital forces in nonliving matter can lead to new life -Living cells can arise from nonliving matter under favorable conditions
Eukaryotic Cells
-Linear chromosomes enclosed within a nuclear envelope -Cellulose or chitin-containing cell wall -Flagella that wave, composed of microtubules -Golgi apparatus -Lysosomes -Mitochondria -80s ribosomes -Endoplasmic reticulum
What conclusions can be drawn from Pasteur's experiment involving the flasks with S-shaped necks?
-Microorganisms can be present in nonliving matter such as air, liquids, and solids -Microbes can be blocked from accessing favorable growth environments -Pasteur's observations support the theory of biogenesis -Microbial life can be destroyed by heat
Helminths
-Multicellular animal parasites -The flatworms and the roundworms. These parasitic worms are not themselves microscopic, although part of their life cycle involves microscopic forms. Identifying them requires many of the techniques used in identifying traditional microorganisms.
Characteristics of Archaea
-Not typically associated with human disease -Found in extreme environments
Select the structures below that are found in all bacterial cells.
-Nucleoid -Ribosomes -Cytoplasm -Plasma membrane
Put the following steps of the scientific method in order (from left to right) that should be followed to identify the virus that is causing this disease.
-Observe a natural phenomenon or reaction -Devise an explanation of what you have observed -Experiment to support or refute your explanation -Record the results of your experiments -Determine whether your results support or refute your explanation -Decide whether you need to rewrite your explanation or it has withstood testing
Biotechnology
-Practical applications of microbiology -Techniques have become much more advanced. These research techniques are required to develop vaccines, understand our immune system, identify viruses, and more.
Compare and contrast three metabolic pathways by choosing whether the statement applies to anaerobic respiration. Check all that apply.
-Process includes glycolysis -The coenzyme NAD+ plays an important role in the pathway -Much or most of the ATP produced is produced by oxidative phosphorylation -Can generate ATP in the absence of O2 -Between 2 and 38 ATP are produced per molecule of glucose input -Process involves electron transport and chemiosmosis -Process involves the Krebs cycle
Compare and contrast three metabolic pathways by choosing whether the statement applies to aerobic respiration. Check all that apply.
-Process involves the Krebs cycle -End products are CO2 and H2O -Process involves electron transport and chemiosmosis -A total of 38 ATP are produced per molecule of glucose input -Process includes glycolysis -The coenzyme NAD+ plays an important role in the pathway -Much or most of the ATP produced is produced by oxidative phosphorylation
How do microbes play a crucial role in our ecosystem to positively impact our lives and the world we live in?
-Recycling of Vital Elements- Microorganisms are responsible for converting the carbon, nitrogen, oxygen, sulfur, and phosphorus in the environment into forms usable by plants and animals. -Used in the Treatment of Sewage- Sewage treatment plants remove the undesirable materials by combining various physical and chemical processes with the action of beneficial microbes. -Another beneficial role for Bacteria is Bioremediation- Involves growing bacteria for the sole purpose of cleaning up pollutants and toxic wastes produced by various industrial processes.
What breaks in the S-neck flask would be most likely to allow microbial contamination of the sterile beef broth?
-Scenario A- Break near the mouth of the flask -Scenario B- Break before the first curve in the S-shaped neck
What impact do microbes have on our health?
-The bacteria that normally inhabit our bodies make up our normal microbiota or normal flora. They are harmless and in some cases, even beneficial. Unfortunately, under some circumstances, even normal flora can cause illness. There is a delicate balance between health and disease that depends on the body's immune system and the type of bacteria involved. Infectious diseases occur when the balance tips in favor of the bacteria. In spite of many effective chemotherapeutic drugs, infectious diseases not only are not disappearing, but seem to be reemerging and increasing. The breakdown of public health measures for previously controlled infections has resulted in the emergence of tuberculosis, whooping cough, and diphtheria. Antibiotic resistance is also adding to the problem of reemerging diseases. Emerging infectious diseases are diseases that are new or changing. The incidence of emerging infectious diseases is as people go to new geographic areas or travel from one part of the world to another and are exposed to unusual microbes. In addition, evolutionary changes in existing organisms have also contributed to the emergence of new diseases. -Examples of emerging diseases include the avian influenza A virus, severe acute respiratory syndrome (SARS), west nile virus, and AIDS.
Examine the figure above depicting the preparatory step and the Krebs cycle, and identify statements that correctly describe these processes. Select all statements that correctly describe the preparatory step and the Krebs cycle.
-The equivalent of one ATP is made for each turn of the Krebs cycle -Carbons from pyruvic acid end up as CO2 -It takes two "turns" of the Krebs cycle to process the pyruvic acid molecules resulting from the glycolysis of one glucose molecule -The oxaloacetic acid that accepts the acetyl group is regenerated, enabling the cyclic nature of this process -There are five oxidation-reduction reactions depicted -The potential energy in the pyruvate is transferred to coenzymes NAD+ and FAD
Which of the following are limitations of antibiotics?
-Treatment with antibiotics can lead to the emergence of resistant strains -Antibiotics are not effective in treating viral infections -Antibiotics may be toxic
Bacteria
-Unicellular organisms whose genetic material is not enclosed inside a nucleus. For this reason, bacteria are called prokaryotes. Prokaryotes include both bacteria and the archaea. -Small, unicellular prokaryotic cells that divide by binary fission. They are nutritionally quite diverse.
Put the following descriptions in order for the staining reactions in the cells of a bacterial smear during the Gram staining procedure.
-Unstained cells (Start of process) -All cells are stained purple -Dye molecules are rendered insoluble in presence of mordant; dye is rinsed away -Cell wall of Gram-negative cells is broken down; Gram-positive cells remain intact -Clear cells are stained a red or pink whereas the color of other cells remains unchanged. -Stained cells (End of process)
Pasteur's experiments and observations provided the basis for developing aseptic techniques that prevent the introduction of unwanted microorganisms into controlled environments. Given what you have learned from the design of Pasteur's experiment, which of the following scenarios would be considered an aseptic technique?
-Wearing gloves when handling sterile lab equipment -Using a Bunsen burner to heat a wire inoculating loop prior to use -Taking steps to prevent contaminants from entering sterile solutions
All of the following are visible through a compound light microscope EXCEPT __________.
0.02-µm ribosome
A paramecium is approximately 150 micrometers in length. What is this measurement expressed in millimeters (mm)?
0.15 mm
The size of the smallest structure that can be clearly seen using light microscopy is __________.
0.2 um or 0.2 micrometers
In addition to knowing the names of the parts of the compound light microscope, you also need to know the functions of these parts. This activity asks you to match the appropriate function with each part of the microscope. Match each microscope part with its function.Drag the labels in the left column to indicate the microscope part that performs each function listed on the right.
1. Fine Focus Knob- Used after initial focusing to sharpen the image 2. Coarse Focus Knob- Used for initial focusing; should never be used when the high-power objective lens or oil immersion objective lens is in place 3. Diaphragm- Controls how much light from the illuminator reaches the specimen 4. Ocular Lens- Lens that you look through 5. Objective Lens- Lens that is closest to the slide and provides initial magnification of a specimen 6. Condenser Lens- Used to focus the light from the illuminator onto the slide 7. Stage- Platform on which the slide is placed for viewing
The pH of a solution reflects the hydrogen ion concentration. A change from pH 7 to pH 8 reflects a __________ change in hydrogen ion concentration.
10 fold
Consider an atom of sodium with an atomic number of 11 and an atomic weight of 23. How many neutrons are in this atom?
12
Streptococcus bacteria lack an electron transport chain. How many molecules of ATP can a Streptococcus cell net from one molecule of glucose?
2
What is the net number of ATP molecules produced during glycolysis?
2
When using a 10× ocular lens and a 20× objective, the total magnification achieved is __________.
200X
Chlamydia trachomatis elementary bodies measure approximately 0.25 micrometers in diameter. What is this measurement expressed in nanometers (nm)?
250 nm
Carbohydrates are made up of carbon, hydrogen, and oxygen with the ratio of hydrogen to oxygen atoms being __________.
2:1
For every NADH that is oxidized via the electron transport chain, __________ ATP(s) is/are formed.
3
Place these structures of the compound light microscope in the order that light passes through them on the way to the observer's eyes: (1) condenser, (2) ocular lens, (3) illuminator, (4) specimen, (5) objective lens.
3, 1, 4, 5, 2
Using the information in the figure above, calculate the molecular weight of ethanol, C2H5OH.
46
A sample of milk is tested for its bacterial content in a plate count assay. A one-milliliter sample of the milk is diluted in a 1:10 dilution series. One milliliter of the third dilution tube is plated in a pour plate. After incubation, the plate has 54 colonies, indicating that the original milk sample contained
54,000 cells
When observing a specimen in a microscope you are told that the total magnification of the specimen is 630x assuming you are using a standard occular lens with a magnification of 10x what is the magnification of the objective lens?
63X
In the figure above, which line best illustrates the growth of a facultative anaerobe incubated aerobically?
A
In the figure above, which line shows the growth of an obligate aerobe incubated anaerobically?
A
Which compound in the figure is an organic acid?
A
The figure above shows a typical bacterial growth curve with the x-axis indicating the log of the number of bacteria and the y-axis indicating time in culture. In the figure, which sections of the graph illustrate a logarithmic change in cell numbers?
A and D
Which of the following is true of biofilms?
A biofilm is a complex aggregation of microbes
What are bacteria enclosed within?
A cell wall that is largely composed of a molecule called peptidoglycan. Only bacteria contain peptidoglycan.
A prokaryotic cell may possess each of the following cellular components EXCEPT
A nucleus
The structure of an atom includes which of the following?
A nucleus with positively charged protons and uncharged neutrons, with orbiting negatively charged electrons
What could you conclude about an enzyme's activity?
A particular enzyme is very specific to the reaction it catalyzes
A reaction that involves the transfer of electrons from one molecule to another is referred to as
A redox reaction
During endospore formation, ________.
A thick spore coat forms around the forespore before the endospore is released into the environment
Which of the following regarding antimicrobial control agents is FALSE?
A true antimicrobial control agent is equally effective against both bacteria and viruses
At the completion of aerobic respiration, energy has been formed and stored in __________.
ATP
At the completion of aerobic respiration, energy has been formed. The energy from the oxidation of glucose is stored in __________.
ATP
Which of the following would you predict to be a feedback inhibitor of the glycolytic enzyme phosphofructokinase?
ATP
Which of the following statements about ATP is FALSE?
ATP represents an unlimited energy supply for cells
Which of the following processes occurs in bacterial plasma membranes but NOT in eukaryotic plasma membranes?
ATP synthesis
When stained, bacteria in the genus Mycobacterium are __________.
Acid-fast; 400X
A solution with a pH of 5 is __________.
Acidic
A population of bacterial cells has been placed in a very nutrient-poor environment with extremely low concentrations of sugars and amino acids. Which kind of membrane transport becomes crucial in this environment?
Active transport
Which of the following processes requires energy?
Active transport
In Pasteur's swan-neck flask experiment, the importance of the S-shaped curves in the flasks was twofold. The curves allowed entry of air but excluded __________.
Airborne bacteria
The cell theory states that __________ are made up of cells.
All living things
Choose the statement that does NOT pertain to amino acids.
Amino acids always contain a sulfur atom in their R-side group
Which of the following terms does NOT belong with the others?
Amino group
What is one type of protozoan?
Amoebas
The proton motive force is __________.
An electrochemical gradient formed across a membrane
You find colorless areas in cells in a gram-stained smear. What should you apply next?
An endospore stain
Which of the following is NOT a domain in the three-domain system?
Animalia
Microbes are NOT responsible for __________.
Antibody production
Who is credited with first observing microorganisms?
Anton van Leeuwenhoek
Why is a specimen smaller than 200 nm not visible with a light microscope?
Anything smaller than 200nm cannot interact with visible light
A new microorganism has been isolated from hot springs in Yellowstone National Park. It consists of single cells, which appear to lack a nucleus. Chemical analysis shows the presence of both DNA and RNA in the cytoplasm and pseudomurein in the cell wall. In which of the following groups will this organism be classified?
Archaea
An organism is found in a deep-sea vent where the temperature is very high and the mineral content very unusual. The organism is unicellular, has no apparent nucleus, and has a cell wall but no peptidoglycan. This organism would be classified as which of the following types of organisms?
Archaea
Bacillus anthracis causes the deadly disease anthrax. Organisms of the genus Bacillus may form endospores. This bacterium would be suitable for biological warfare because endospores __________.
Are resistant to high temperatures, UV light, and desiccation
Laboratory methods that prevent contamination of materials by unwanted microbes are called __________ techniques.
Aseptic
Which type of microscope uses a metal and diamond probe that is gently forced down along the surface of a specimen?
Atomic force
Different functional groups confer different properties on organic molecules. For example, the hydroxyl group of alcohol is hydrophilic and thus __________.
Attracts water to it
In the figure above, which line best depicts a facultative anaerobe in the absence of O2?
B
All of the following are eukaryotes EXCEPT __________.
Bacteria
Which of the following is characteristic of bacteria?
Bacteria lack a membrane-bound nucleus
All of the following are examples of biotechnology EXCEPT __________.
Bacteria that cause disease
All living organisms can be classified into three domains: __________.
Bacteria, archaea, eukarya
What are the major groups in microbiology?
Bacteria, archaea, fungi, protozoa, algae, viruses, and some stages of the lifecycle of helminths
You would expect a fluid with a pH of 10 to be called __________.
Base
How do bacteria generally reproduce?
Binary fission, with one cell dividing into two equal cells
A complex community of microorganisms that may form a slimy layer on surfaces is known as a __________.
Biofilm
The theory of spontaneous generation has been disproven and replaced with the concept that living cells arise only from preexisting cells. This is the concept of __________.
Biogenesis
Arsenic is a relatively common hazardous waste generated by smelting processes and can contaminate soil and water surrounding smelting facilities. A bioprocess using naturally occurring bacteria to remove arsenic has been developed. This process is an example of __________.
Bioremediation
Which of the following disinfectants acts by disrupting the plasma membrane?
Bisphenols
Which of the following properties are true of both bacteria and viruses?
Both use a molecule of nucleic acid to determine heredity
Microbes are responsible for __________.
Breaking down wastes, synthesis of vitamins, synthesis of acetone and alcohol, oxygen generation via photosynthesis
Which type of light microscopy is used to visualize stained specimens?
Brightfield
Enzymes are important in living organisms because they __________.
Bring together reactants or properly orient a molecule for a reaction
How do protozoa generally move around?
By using appendages like pseudopods, flagella, or cilia
In the figure above, which line best depicts an obligate anaerobe in the presence of O2?
C
In the figure, which is an alcohol?
C
The figure above shows a typical bacterial growth curve with the x-axis indicating the log of the number of bacteria and the y-axis indicating time in culture. In the figure, which section (or sections) shows a growth phase where the number of cells dying equals the number of cells dividing?
C
At the completion of the Krebs cycle, the carbons from glucose are in __________. (Name the molecule.)
CO2
Which of the following is an example of anabolism?
CO2 and H2O to glucose
Viruses are not considered living organisms because they
Cannot reproduce by themselves
A well-organized glycocalyx that is firmly attached to the cell wall is called a(n) __________.
Capsule
Many pathogenic (Disease-producing) bacteria produce a(n) __________ that protects them from phagocytosis by host cells.
Capsule
Many pathogenic (Disease-producing) bacteria have __________ that protect them from phagocytosis by host cells.
Capsules
Which type of molecule is composed of (CH2O) units?
Carbohydrate
Nitrogen is found in all of the following cell components EXCEPT __________.
Carbohydrates
Which of the following statements is true regarding carbohydrates?
Carbohydrates, such as glycogen and starch, are composed of carbon, hydrogen, and oxygen and function as important energy sources
Organic molecules always contain __________.
Carbon and hydrogen
Which of the following statements concerning carbon and bonding is FALSE?
Carbon is most commonly found in nature as carbon-14
The formal system for classifying and naming organisms was developed by
Carolus Linnaeus
Only a small percentage of microbes __________.
Cause disease
Robert Koch's studies on Bacillus anthracis established a sequence of experimental steps to prove that microbes __________.
Cause disease
Robert Hooke's observation of the individual units in thin layers of cork tissue led to the development of __________ theory.
Cell
The primary function of lipids in biology is the formation of __________ that enclose cells.
Cell membranes
Compared to other bacteria, mycoplasmas are somewhat atypical because they do NOT have a(n) __________.
Cell wall
Gram-positive and gram-negative bacteria react differently in the Gram stain because of differences in their __________ structure.
Cell wall
An abundant polysaccharide that is found in plant cell walls is __________.
Cellulose
Scientists working in the field of biology called genetic engineering or recombinant DNA technology can alter microbes to produce proteins that they normally would not make. What do these substances include?
Cellulose, digestive aids, drain cleaner and many important therapeutic substances such as insulin and growth hormone
All atoms with the same number of protons behave the same way chemically and are classified as the same __________.
Chemical element
When an atom's outer electron shell is only partially filled, the atom is considered __________.
Chemically unstable
A Thiobacillus bacterium uses the Calvin-Benson cycle to reduce CO2 and the oxidation of sulfide ions for energy. This organism is a __________.
Chemoautotroph
Organisms that use carbon dioxide as a carbon source and ammonia or hydrogen sulfide as energy sources are called __________.
Chemoautotrophs
An organism uses glucose as energy source and requires O2. This organism is known as a(n) __________.
Chemoheterotroph
Which type of metabolic diversity contains most pathogens?
Chemoheterotroph
In cyclic photophosphorylation, electrons released from excited chlorophyll molecules eventually return to __________.
Chlorophyll
Which of the following is NOT a structure of prokaryotic cells?
Chloroplast
In the capsule stain using India ink, capsules are distinguished as __________ surrounding cells.
Clear halos
The morphology of bacterial cells that are circular is referred to as __________.
Cocci or coccus or a coccus
Competitive inhibition of enzyme action involves __________.
Competition with the substrate for binding at the active site
__________ involves an inhibitor that fills the active site of an enzyme and competes with the normal substrate for the active site. (Two words)
Competitive inhibition
Which of the following statements regarding competitive inhibitors is true?
Competitive inhibitors decrease the rate of enzyme activity
What enables competitive inhibitors to bind to a specific enzyme?
Competitive inhibitors have structures that resemble the enzyme's substrate
Small organic molecules are joined to form macromolecules through __________ reactions.
Condensation
The __________ of a compound light microscope focuses light from the light source on the specimen.
Condenser
Short, prokaryotic appendages made up of pilin are called pili. Special pili involved in the transfer of DNA from one cell to another are called __________.
Conjugation pili
Archae
Consist of prokaryotic cells, but if they have cell walls, the walls do not contain peptidoglycan
The nuclear area of the bacterial cell __________.
Contains the bacterial chromosome
All of the following are required for the generation of ATP by chemiosmosis EXCEPT __________.
Conversion of pyruvic acid to lactic acid
What is the type of bond holding hydrogen and oxygen atoms in the H2O molecule?
Covalent bond
What is the type of bond holding hydrogen and oxygen atoms together in a single H2O molecule?
Covalent bond
What is the type of strong chemical bond between carbon, hydrogen, and oxygen atoms in a single organic molecule?
Covalent bond
Which type of bond holds C and H atoms in glucose?
Covalent bond
Which of the following chemical bonds is the strongest?
Covalent bonds
An exposure to __________ protects against infection with smallpox.
Cowpox
The structural framework in a cell is the
Cytoskeleton
Which microscope uses two beams of light to produce a three-dimensional color image?
DIC microscope
Application of heat to living cells can result in all of the following EXCEPT
Damage to nucleic acids
The equation below is what type of reaction? Molecule AB → Molecule A + Molecule B
Decomposition reaction
What kind of chemical reaction is involved when bacteria are used for the bioremediation of a petroleum spill?
Decomposition reaction
Amino acids are joined together in a specific type of dehydration synthesis reaction that results in the formation of a peptide bond. This bond links the carboxyl group of one amino acid to the amino group of another amino acid. The formation of a peptide bond to link two amino acids together is a special type of __________. Choose from the following the answer that best finishes this statement.
Dehydration synthesis reaction that removes a hydroxyl group from the carboxyl end of the amino acid and reforms the bond with the nitrogen from the amino group that has lost a hydrogen atom
Biological oxidations are also called __________ reactions.
Dehydrogenation
The tests for these uncommon pathogens are similar to the ones that have already been performed for the common viruses, but in this case, you will try to identify the DNA or proteins of specific viruses that are not often seen in clinics or hospitals in that area of the country. Each region of the country has certain viral pathogens that are spread throughout the human population that live in that area. When one of these viruses spreads to a new area, we consider it to be "emerging" in this new population of people. Some detective work and deductions will be required. By applying the scientific method, you can focus and refine your list of possible viral pathogens to experimentally test for. You'll begin your investigation by reviewing the patient's history and symptoms and formulating a hypothesis for possible causative agents. Based on what you know of the scientific method, what would you like to do next?
Design and run some tests or experiments
The __________ is the part of the microscope that controls the amount of light entering the condenser.
Diaphragm
A culture medium consisting of agar, peptone, and beef heart is a
Differential medium
An agent used to reduce the number of bacteria on a toilet would most accurately be called a(n)
Disinfectant
Lister knew that carbolic acid (phenol) kills bacteria. He used it as the first __________.
Disinfectant
Which of the following is NOT a type of a compound microscope?
Electron microscope
Within an atom, electrons of differing energy levels are arranged in different __________.
Electron shells
A coenzyme assists an enzyme by accepting or donating matter. What does NAD+ transfer?
Electrons
An atom is composed protons, neutrons, and electrons. Which of these components contributes the negative change to an atom?
Electrons
Every atom has a centrally located nucleus and __________ that move around the nucleus.
Electrons
All of the following steps are involved in the aerobic electron transport chain. Which step happens last?
Electrons are transferred to O2
Aseptic technique is a standard lab practice that includes all of the following EXCEPT __________.
Elimination of all oxygen during any processes to prevent contamination
Increased human exposure to new and unusual infectious agents in areas that are undergoing ecologic changes accounts for the __________.
Emergence of new infectious disease
When essential nutrients are depleted, some strains of bacteria form __________, dormant structures that form within cells.
Endospores
Which of the following statements is true?
Endospores are extremely durable structures that can survive high temperatures
Why do all enzymatic reactions need activation energy?
Energy is required to disrupt a substrate's stable electron configuration
Commercial utilization of microbial products has become increasingly popular due to their environmentally friendly nature. Removal of these products from the environment typically utilizes
Enzymes
Why are enzymes important to biological systems?
Enzymes decrease the amount of activation energy required for chemical reactions to occur
What is meant by the statement "Enzymes are biological catalysts"?
Enzymes speed up the chemical reactions in living cells
Fungi
Eukaryotes, which means they have a nucleus containing the cell's DNA. Organisms in this group are either unicellular, like yeast, or multicellular, like mushrooms.
Where are archae often found?
Extreme environments such as in the hot springs at Yellowstone National Park or in extremely salty places such as the Dead Sea, in Israel
A molecule of ADP would have more energy than a molecule of ATP.
False
A solution with a pH of 2 would be considered very basic.
False
Acid-fast bacteria demonstrate unique staining properties because of a special protein layer found in their cell walls.
False
Anaerobic respiration is another name for fermentation.
False
Bacteria do NOT have chloroplasts and therefore CANNOT perform photosynthesis.
False
Bacterial motility and flagellar movement can readily be viewed using transmission electron microscopy.
False
Bacterial smears must be heat-fixed before all staining procedures.
False
Both DNA and RNA are required for protein synthesis.
False
Compounds with the general formula R—OH are called acids.
False
Covalent bonds are formed by attraction between atoms that have lost or gained electrons.
False
DNA and RNA are primarily composed of amino acids.
False
Disaccharides are formed when two monosaccharide molecules bond in a hydrolysis reaction.
False
E. coli O157:H7 is part of the normal microbiota in the human large intestine.
False
Epulopiscium fishelsoni is 0.5 mm in diameter. It contains NO nucleus and has peptidoglycan. Because of the size of this cell, it should be classified as a eukaryote.
False
Feedback inhibition generally acts on the last enzyme in an anabolic pathway.
False
Glycolysis produces ATP through oxidative phosphorylation.
False
Ionization is the separation of molecules into elements.
False
Lipids, proteins, and sugars all may serve as substrates of glycolysis.
False
Magnification is the quality of the microscope that allows one to distinguish between two points that are very close together.
False
Penicillin is more effective against gram-negative bacteria than against gram-positive bacteria because it specifically interferes with the synthesis of lipopolysaccharides.
False
Stains used in electron microscopy increase the contrast between specimen and background by colorizing the internal structures differently.
False
The Golden Age of Microbiology began with the work of Louis Pasteur and ended with the discovery of HIV.
False
The avian influenza A virus is transmitted only between birds.
False
The cell walls of bacteria and eukaryotes are very similar.
False
The theory of biogenesis is the same as the theory of spontaneous generation.
False
The vast majority of microbes are harmful to humans or plants.
False
Treatments that affect the secondary structure of the protein and leave the primary structure intact will not affect the function of the protein.
False
Vaccines were invented by Paul Ehrlich in 1920
False
When the bond of ATP's terminal phosphate group is hydrolyzed, energy is required.
False
You inoculated an unknown strain of E. coli into a medium containing sorbitol. Your test is positive for sorbitol fermentation. You conclude that your strain is the pathogenic strain E. coli O157.
False
Which of the following bacterial structures are necessary for chemotaxis?
Flagella
Which of the following are correctly matched?
Fleming and antimicrobials
Which of the following types of microscopy can be used to specifically identify pathogens (Such as Mycobacterium tuberculosis or rabies virus) in specimens?
Fluorescence
Where is algae found?
Fresh or salt water
Which of the following is true of functional groups?
Functional groups confer different properties, such as hydrophobia, on organic molecules
Which of the following could be used to sterilize plastic Petri plates in a plastic wrapper?
Gamma radiation
What is a very exciting and important outcome of recombinant DNA techniques?
Gene Therapy- When scientists insert a missing gene or replace a defective gene in human cells. This therapy has been used to treat some diseases such as cystic fibrosis and Duchenne's muscular dystrophy, but the results are still being evaluated. Someday, many diseases may be treated with gene therapy.
__________ involves the ability afforded by genetic engineering to insert a missing gene or replace a defective gene in a human cell.
Gene therapy
Pick the area of biology that studies DNA and chromosomes.
Genetics
In the scientific name Escherichia coli, Escherichia is the __________.
Genus name
Pasteur, Koch, and Lister made discoveries showing the relationship between microbes and diseases. These discoveries led to the __________.
Germ theory
Which one molecule could provide the carbon source, the energy source, and the electron source for a chemoheterotroph?
Glucose
One of the most common energy sources used by bacteria is glucose. Why is glucose such a good source of energy for bacteria?
Glucose is a highly reduced compound, containing many carbon-hydrogen bonds and a lot of potential energy
Oxidizing agents include all of the following EXCEPT
Glutaraldehyde
Which of the following terms does NOT belong with the others?
Glycerol
In fermentation, ATP is generated only in __________. (Name the pathway)
Glycolysis
The complete oxidation of glucose in aerobic and anaerobic respiration involves which three stages?
Glycolysis, Krebs cycle, and the electron transport chain
Which of the following is part of the endomembrane system?
Golgi apparatus
Following an endospore stain, an endospore would appear __________ under the microscope.
Green
Slime Molds
Have characteristics of both fungi and amoebas
Your lab partner tells you the bacteria are moving in his Gram-stained smear. You can conclude that __________.
He didn't properly fix the smear
Which of the following steps is common to both the Gram stain and the acid-fast stain?
Heat fixation of the smear before staining
Pasteur discovered that microbes can cause food spoilage. His solution to protect wine from spoiling was a process called pasteurization, which is based on what principle?
Heating beer and wine just enough to kill those organisms causing the spoilage
One of the sites of allosteric regulation of the Krebs cycle is the conversion of pyruvic acid to acetyl CoA. Which of the following conditions would you expect to inhibit the conversion of pyruvic acid to acetyl CoA?
High ATP and high NADH
In DNA, the two strands of the double helix are held together by __________ bonds.
Hydrogen
Which of the following is the type of bond between molecules of water in a beaker of water?
Hydrogen bond
Which of the following contributes to the secondary structure of a protein?
Hydrogen bonding
Which of the following statements is true regarding the principles of osmosis?
If a cell is in a hypertonic solution, water leaves the cell in an attempt to balance to concentration of solutes and reach equilibrium
The protection from disease provided by vaccination is called __________.
Immunity
In the Gram stain, crystal violet remains in gram-positive cells after treatment with alcohol because crystal violet-iodine (CV-I) complexes are trapped __________.
In thick layers of peptidoglycan
Polyphosphate (Volutin), carboxysomes, and magnetosomes are examples of __________.
Inclusion bodies
__________ disease is one in which pathogens invade a susceptible host.
Infectious
Which of the following cellular functions is NOT attributed to proteins?
Inheritance
S. aureus has been isolated from George's infected wound. To satisfy Koch's postulates, what would George's doctor need to do with the isolated S. aureus?
Inject the S. aureus into an animal, observe whether the animal gets an infection similar to George's, and isolate the same strain of S. aureus from the infection
Hydrogen bonds are important in the formation of __________.
Interactions between complex molecules, such as nucleic acids and proteins
A negatively or positively charged atom is called a/an __________.
Ion
Which type of bond is found in Na+ and Cl- ions in NaCl?
Ionic Bond
Which of the following is a limitation of the autoclave?
It cannot be used with heat-labile materials
Which of the following is NOT true of the gram-negative outer membrane?
It contains enzymes for energy synthesis
The plasma membrane is considered a barrier to the environment because __________.
It controls the passage of molecules into the cell
Which of the following statements about the atom 12 6 C is FALSE?
It has 12 neutrons in its nucleus
Which of the following statements about the atom 12^6 C is FALSE?
It has 12 neutrons in the nucleus
Which of the following statements about a gram-negative cell wall is NOT true?
It has teichoic acids
What is meant by light rays being divergent?
It is spreading out
Oleic acid is in the cis configuration. What does this mean?
It is unsaturated at carbon atoms 9 and 10 and the hydrogen atoms are on the same side of the hydrocarbon chain
Chemiosmosis in prokaryotes, unlike that in eukaryotes, has which of the following characteristics?
It occurs at the plasma membrane and not the mitochondria
A strain of Streptococcus pneumoniae is no longer able to synthesize its capsular polysaccharide. What is a likely outcome?
It will be readily phagocytized upon entering the host
A strain of Neisseria gonorrhoeae has been genetically altered and can no longer produce fimbriae. What is a likely outcome?
It will be unable to adhere to host tissue and establish infection
Which of the following describes organic molecules?
Large, complex molecules containing carbon and hydrogen bonded together by covalent bonds
The antibiotic polymyxin B combines with phospholipids. This will cause __________.
Leakage of cell contents
Which of the following is a scientific name?
Legionella pneumophila
As photosynthesizes, what does algae need?
Light, water, and carbon dioxide for growth
All of the following are found in the cell walls of gram-positive bacteria EXCEPT __________.
Lipid A
The lipid protein in the gram-negative outer membrane that causes fever and shock in humans is called __________.
Lipid A
Which are the primary molecules making up plasma membranes in cells?
Lipids
Which of the following organelles breaks down worn-out organelles?
Lysosomes
Further characterization of the S. aureus isolated from George's wound reveals that the strain is MRSA. Why is George's doctor concerned that MRSA has been identified as the causative agent of George's infection?
MRSA is transmissible
Ehrlich searched for a/an __________ that would destroy a pathogen without harming the infected host.
Magic bullet
The purpose of the ocular lens is to
Magnify the image from the objective lens
Antacids neutralize acid by the following reaction. Identify the salt in the following equation: Mg(OH)2 + 2HCl → MgCl2 + H2O
MgCl2
A __________ is equal to 0.000001 meter.
Micrometer
Which of the following is the most convenient and appropriate unit for expressing the size of an average bacterial cell?
Micrometer
Where in a cell is ATP made?
Mitochondria
What are the most typical kind of fungi and form visible masses called mycelia?
Molds
Flagella are too thin to be seen with the light microscope without adding a __________.
Mordant
Chemotaxis refers to the ability of microorganisms to __________.
Move toward or away from chemical stimuli
Fungi are a food source. What would a food source consist of?
Mushrooms
Which of the following is a likely outcome, based on the unique cell structure of members of the genus Mycoplasma?
Mycoplasma species have very flexible cells that can pass through bacteriologic filters
During glycolysis, electrons from the oxidation of glucose are transferred to __________.
NAD+
In an enzymatic reaction involving oxidation of a substrate, which of the following would be required?
NAD+
In fermentation, the electrons from __________ are passed to pyruvic acid to form reduced organic molecules.
NADH
A negative stain differs from a Gram stain because the background is stained in a __________ stain.
Negative
Are archaeology known to cause disease in humans?
No
All of the following factors contribute to hospital-acquired infections EXCEPT
None of the answers is correct; all of these factors may contribute to hospital-acquired infection
Which of the following statements about normal microbiota found on the human body is FALSE?
Normal microbiota commonly overcome our defenses and produce disease
Viruses
Not cellular in their structure, and contain a single type of nucleic acid surrounded by a protein coat. Sometimes the virus coat is encased in an envelope.
What do genes consist of?
Nucleic acids
Where is the genetic information of the cell stored?
Nucleus
Gastric juices have a pH of 1 or 2. This would indicate which of the following?
Numerous H+ ions and a low pH
With a light microscope, which of the following would allow discrimination between eukaryotes and prokaryotes?
Observation of nuclei
Hooke and van Leeuwenhoek helped to create the basis of the cell theory by __________.
Observing and documenting cells using microscopes to visualize the invisible structure of living things
Unlike chemiosmosis in eukaryotes, prokaryotes chemiosmosis __________.
Occurs at the plasma membrane and not the mitochondria
Which of the following is a difference between gram-positive and gram-negative cells?
Only gram-negative cells have a lipopolysaccharide (LPS) layer
Which of the following pairs is NOT correctly matched?
Oxidation; reaction in which electrons are gained
In the generation of ATP, energy is released when electrons are passed to a series of electron acceptors and finally to oxygen or another inorganic compound. What is this process called?
Oxidative phosphorylation
NADH molecules formed during glycolysis and in the Krebs cycle are __________.
Oxidized when electrons are passed to the electron transport chain
In noncyclic photophosphorylation, __________ is/are produced as water is oxidized.
Oxygen
What is the final electron acceptor in the membrane?
Oxygen
You have just started brewing beer at home, and your first batch is now ready. You used the yeast Saccharomyces cerevisia, which can perform both aerobic cellular respiration and fermentation. When you test the beer, you determine that the alcohol content is almost zero. What could have been present in the fermentation reaction apparatus that caused this problem?
Oxygen
What does algae produce?
Oxygen and carbohydrates that other organisms use. As a result, they play an important role in the balance of nature.
If high amounts of sulfanilamide are in the presence of an enzyme whose substrate is PABA, what outcome is expected?
PABA will not be catalyzed
Which of the following fields of study and its example are NOT correctly matched?
Parasitology--study of HIV
Which of the following were instrumental in DISPROVING spontaneous generation?
Pasteur's experiments using a specialized swan-necked flask that prevented microbes from entering flasks open to the air
The term used to describe a disease-causing microorganism is
Pathogen
20th Century
Paul Ehrlich speculated about a "magic bullet" that could hunt down and destroy a pathogen without harming the infected host. He found salvarsan, which was used to treat syphilis. This was the beginning of modern day chemotherapy- The treatment of disease with chemicals. Some chemicals are called antibiotics when made naturally by bacteria and fungi. The first antibiotic discovered was penicillin in 1928 by Alexander Fleming. Since then, many other antibiotics and chemotherapeutic drugs have been discovered.
Why is penicillin selectively toxic to bacterial cells but harmless to human cells?
Penicillin specifically weakens peptidoglycan, which is found only in bacterial cells
Heterotrophs use organic molecules as energy and carbon sources. To produce five-carbon intermediates needed for synthesis of nucleic acids, the cell utilizes the __________.
Pentose phosphate pathway
The bond between two amino acids in a peptide is called a __________ bond.
Peptide
Disinfection of water is achieved by all of the following EXCEPT
Peracetic acid
The term describing bacteria with flagella distributed over the entire surface of the cell is __________.
Peritrichous
A eukaryotic cell can ingest a prokaryotic cell by __________.
Phagocytosis
Which of the following types of microscopy is most useful for viewing the internal structures of unstained specimens?
Phase contrast
Which type of microscopy-brightfield, darkfield, or phase-contrast-yields the best view of internal structures?
Phase contrast
You isolated an unknown that uses CO2 as carbon source and also uses H2O to reduce CO2. The organism is a(n) __________.
Photoautotroph
Which organism is NOT correctly matched to its energy source?
Photoautotroph; CO2
Algae
Photosynthetic eukaryotes that have cell walls that contain cellulose, like plants
Which of the following is NOT a functionally analogous pair?
Pili; centrioles
Which of the following statements is false?
Plant cells do not have mitochondria
Detergents emulsify lipid molecules. Which part of a cell would you therefore expect detergents to damage?
Plasma membrane
What structure acts as a selective barrier, regulating the traffic of materials into and out of the cell?
Plasma membrane
In a phospholipid bilayer, water interacts with the __________ of the phospholipid molecules.
Polar heads or hydrophilic heads
The __________ charge of a basic dye adheres to the __________ charge of bacterial cell surfaces.
Positive and negative
All of the following describe a major feature used to classify organisms into to three domains (Bacteria, Archaea, and Eukarya) EXCEPT __________.
Presence or absence of DNA
The steps outlined in the figure above disprove the theory of spontaneous generation. How was Pasteur's experiment able, once and for all, to disprove this theory?
Previous experimenters excluded air from the sterile broth. Pasteur's approach excluded particles in the air from reaching the broth, but still allowed air to reach the broth.
Which of the following is true about antibiotics?
Previously treatable microbes have become resistant to some antibiotics
The __________ structure of proteins is the unique sequence of amino acids linked together.
Primary
In the Gram stain, crystal violet is the __________.
Primary stain
Mad cow disease is caused by a prion, which is an infectious __________.
Protein
The relationship between a nucleotide and a nucleic acid is similar to the relationship between an amino acid and a __________.
Protein
Which type of molecule contains -NH2 groups?
Protein
Which of the following statements about the cellular functions of proteins is INCORRECT?
Proteins function in genetic inheritance
A base can be defined as a __________.
Proton acceptor
The __________ are unicellular, eukaryotic microbes that move by pseudopods, flagella, or cilia.
Protozoa
Which of the following types of microorganism and its description are NOT correctly matched?
Protozoa--small animals
In Pasteur's experiment, what was the purpose of the beef broth?
Provided a nutritious environment to support microbial growth
In Pasteur's experiment, what was the purpose of the air?
Provided a source of potential external microbial contaminants
In Pasteur's experiment, what was the purpose of the Bunsen burner?
Provided heat that destroyed microorganisms already present in the beef broth
In Pasteur's experiment, what was the purpose of the flask with S-shaped neck?
Provided the physical conditions for trapping airborne contaminants and preventing microorganisms from entering the flask
In the Gram stain, if the decolorizing step is NOT performed, gram-negative cells will appear __________ at the completion of the staining procedure.
Purple
In the Gram stain, if the decolorizing step is deleted, gram-negative cells will appear ________ at the completion of the staining procedure.
Purple
All of the following are potential end-products of fermentation EXCEPT __________.
Pyruvic acid
At the completion of glycolysis, the carbons from glucose are in __________. (Name the molecule)
Pyruvic acid
Which of the following is NOT a characteristic of RNA?
RNA is most often arranged in a double helix
Placing the DNA from an animal cell into the genome of a bacterium will allow the bacterium to produce an animal product. This new piece of DNA is referred to as __________.
Recombinant DNA
Which of the following processes are beneficial activities of microorganisms?
Recycling elements in the environment, decomposing sewage, producing foods and chemicals
Which of the following statements regarding redox reactions is true?
Redox reactions involve an oxidation reaction coupled with a reduction reaction
In microscopy, the term resolution
Refers to the ability to distinguish fine structure and detail in a specimen
Which is NOT a characteristic of the normal microbiota?
Regularly associated with disease symptoms
Choose the mismatched pair.
Ribonucleic acid; steroid
One of the ways smooth endoplasmic reticulum (ER) differs from rough endoplasmic reticulum is that rough ER is covered by
Ribosomes
Which of the following pairs is MISMATCHED?
Ribosomes; storage
Gram-negative cells contain a periplasmic space that is __________.
Rich in degradative enzymes
A student from one of the research labs is having trouble preparing a slide for examination and photographing. The bacterial slide that he has brought to you was prepared using a commercially purchased stain. He has asked for your help in determining what he is doing wrong so that he can change the lab protocols and continue on with his project. After examining the slide under oil immersion, you determine that no bacteria are present even though the student is able to show you the culture he used to make that slide that has visible growth in the liquid medium. Which of the following statements does NOT explain the fact that there are no bacteria present on the student's slide? Select all that apply.
Rinsing with alcohol during the washing step stripped the bacteria off the glass slide
Who is credited with first observing cells?
Robert Hooke
Endoplasmic reticulum that has ribosomes attached to its outer surface is referred to as __________.
Rough ER
You are studying a cell structure that is approximately 100 nm in size. Which of the following provides the lowest magnification you can use to see this structure?
Sanning electron microscope
Which of the following types of microscopy is used to study the structure of the slimy accumulation of bacteria on an IV catheter tip?
Scanning acoustic
Which microscope is best used for observing the surfaces of intact cells and viruses?
Scanning electron microscope
Which of the following kinds of microscopy would be most appropriate for viewing the shape and arrangement of pili or fimbriae on the surface of a bacterial cell?
Scanning electron microscopy
If you viewed one single protein using a microscope, you would observe multiple __________ structures.
Secondary
Overuse and misuse of antibiotics has __________.
Selected for antibiotic-resistant strains of bacteria and increased their frequency in both the hospital environment and the community
How do algae reproduce?
Sexually and asexually
How do protozoa reproduce?
Sexually or asexually
Consider a gram-positive cell in a hypertonic medium. If the peptidoglycan in the cell wall were damaged, the cell would __________.
Shrink or plasmolyze or collapse
When one pair of electrons is shared between atoms, this is called a __________ covalent bond.
Single
A __________ is a thin layer of cells used for microscopic examination.
Smear
Microorganisms are involved in each of the following processes EXCEPT
Smog production
Where are lipids made in the cell?
Smooth endoplasmic reticulum (ER)
How are bacteria diverse in nutrition?
Some use organic chemicals and others use photosynthesis. Still others can derive nutrition from inorganic substances.
A student is looking at a bacterial specimen using the oil immersion lens, but has forgotten to put immersion oil on the slide. The specimen will appear
Somewhat fuzzy and have poor resolution
In the name Staphylococcus aureus, aureus is the
Specific name
Pasteurization was first developed to kill __________ in wine.
Spoilage bacteria
Spherical bacteria that divide and remain attached in chainlike patterns are called __________.
Streptococci
For which of the following can Koch's postulates be used to identify the organism causing the disease?
Streptococcus pyogenes, the organism that causes strep throat, which can be cultured on blood agar in the laboratory
Which of the following mechanisms does NOT generate ATP using an electron transport chain?
Substrate-level phosphorylation
How would you recognize an antibiotic-producing soil bacterium on a plate crowded with other bacteria? The bacterial colony producing the antibiotic would be __________.
Surrounded by a clear area
Consider the following reaction. A + B → AB What kind of chemical reaction does this illustrate?
Synthesis reaction
The equation below is what type of reaction? Molecule A + Molecule B → Molecule AB
Synthesis reaction
Which of the following statements regarding protein structure is FALSE?
Tertiary structures are formed only from covalent bond
The overall equation for cell respiration is shown below. Why do NAD+ and FAD NOT appear in the overall equation? C6H12O6 + 6O2 + 38ADP + 38Pi → 6CO2 + 6H2O + 38ATP
The NAD+ and FAD are initially reduced then oxidized to their original state, so they do not appear in the net equation
In 1861, Pasteur conducted his now-famous experiments using flasks with long necks bent into an S-shape. Imagine that you are a scientist working in Pasteur's lab at this time. You decide to tip the flasks so that broth enters the long S-shaped neck. You then return the flask to its upright position. Predict the most likely outcome of tipping one of Pasteur's S-necked flasks.
The broth would become contaminated with microbes because they were trapped in the neck
What will occur if a bacterial cell with a weakened or damaged cell wall is placed in pure water?
The cell will swell and burst
You perform a Gram stain, and upon completion of the procedure, the cells are colorless. Which of the following possibilities best explain your results?
The cells are gram-negative, and you forgot to use the safranin
Assume you are growing a bacterial culture in a glucose medium. Your lab partner adds more glucose in hopes of speeding up the experiment. The bacteria suddenly die. The best explanation for this result is that __________.
The cells plasmolyzed
During which growth phase will gram-positive bacteria be most susceptible to penicillin?
The culture is equally susceptable during all phases
During an oxidation reaction,
The donor molecule loses an electron and becomes oxidized
Why is reduction the term used to describe the gain of an electron?
The electron acceptor's net charge decreases
The usefulness of antibiotics is hampered by __________.
The emergence of antibiotic-resistant bacteria
During a chemical reaction, an enzyme functions as a biological catalyst and lowers the activation energy. How does an enzyme lower the activation energy of a reaction?
The enzyme increases the effectiveness of reactant collisions thereby increasing the number of reactant molecules that reach activation energy
In a typical brightfield microscope (Seen in the animation), at which point does magnification begin?
The objective lens
Predict which of the following is most likely to occur as a result of the switch from aerobic to anaerobic metabolism.
The organisms will grow more slowly because they will produce less ATP compared to aerobic metabolism
What statement most accurately describes the structure of the plasma membrane?
The plasma membrane is a phospholipid bilayer with the hydrophilic phosphate groups oriented toward the inside and outside of the cell
Water is an excellent solvent as well as an effective temperature buffer. This is because of __________.
The polar nature of water
You volunteer to help the student with his fixation technique and in choosing a proper stain for the project he is working on. After watching and helping the student correct any problems with his fixation technique, you now need to determine which stains to use. The single criterion for the project is to be able to determine cell shape and size in a pure broth culture after some treatments. No differentiation between cell types is required (i.e., Gram-positive or Gram-negative), so you want to convince the student that a simple stain would be his best option. The charged dyes used in simple staining will penetrate the bacterial cell and will be retained after rinsing the slide with water to remove surplus dye. Which staining procedure would be best to use to stain the slides required for this student's project? Why?
The positively charged methylene blue will be attracted to the negatively charged components of the cell wall and will be retained
In the Gram-stain procedure, a clear oval in the center of a cell could indicate __________.
The presence of an endospore
Protein structure is directly related to the diverse functions of proteins. Which of the following is an accurate description of the level of structure in a protein?
The primary structure of a protein is the unique sequence of amino acids linked together
One of the first set of experiments to refute spontaneous generation was done in 1688 by Francesco Redi. Which of the following statements regarding Francesco Redi's experiments is true?
The results of his experiment demonstrated that living organisms are derived from other living organisms
Which of the following is true of scientific names assigned to living organisms?
The scientific name is always underlined or italicized
Which of the following statements is NOT true for both TEM and SEM?
The specimen must be sectioned before viewing
Koch's postulates are the essential foundation for which of the following?
The steps that relate a specific microbe to a specific disease (Etiology)
You are viewing a sputum smear that has been stained with an acid-fast stain. On this smear you see 5-micrometer-long red cells. You can conclude that __________.
There are acid-fast bacteria in the specimen
Which of the following pairs is mismatched?
Thermophile-growth at 37°C
Which of the following treatments is the most effective for controlling microbial growth?
They are equivalent treatments
Our world is filled with microbes. Where are they and how do they affect our lives?
They are in the air we breathe, the food we eat, and inside our bodies. They affect our lives both positively and negatively.
What happens to the light rays when they hit the specimen?
They are reflected, refracted, or absorbed by the specimen
How does a competitive inhibitor slow enzyme catalysis?
They compete with the substrate for the enzyme's active site
Fungi do not use photosynthesis. What do they use?
They obtain nourishment by absorbing organic material from their environment
Flagella are too __________ to be seen with the light microscope without adding a mordant and carbolfuchsin.
Thin
What is the role of the ocular lens?
To recreate the image in the viewer's eye
What is the purpose of fermentation?
To regenerate NAD+ from NADH
Which microscope is used to observe viruses and the internal structure of thinly sectioned cells?
Transmission electron microscope
Which type of molecule NEVER contains a phosphate group?
Triglycerides
A disease that has increased in incidence or could increase in incidence in the near future is called an emerging infectious disease.
True
A mordant may be used to improve the bonding between a primary stain and the specimen.
True
Anton van Leeuwenhoek was the first to observe microbes.
True
Bacterial smears should be fixed to the slide before all staining procedures.
True
Biochemical tests for the identification of bacteria involve testing fermentation products or amino acid catabolism.
True
Endospores can remain dormant for thousands of years. Once this dormant structure is provided appropriate nutrients and growth conditions, it will germinate to form a viable bacterial cell.
True
Enzymes work most effectively at their optimal temperature and pH.
True
Examples of fungi include the yeasts, molds, and mushrooms.
True
Flagella are appendages that allow locomotion in bacteria.
True
Fluorescent-dye-labeled antibodies allow specific recognition of one bacterium in a mixed culture of bacteria.
True
Glycolysis produces ATP through substrate-level phosphorylation.
True
Gram-positive bacteria retain the primary stain after the decolorizing step in the Gram stain.
True
Immersion oil acts to decrease refraction of light rays and thus increase resolution.
True
In the nomenclature system designed by Carl Linnaeus, each living organism is assigned two names.
True
Metabolic pathways that function in both anabolism and catabolism are called amphibolic pathways.
True
Mucous membranes provide a barrier to infectious disease.
True
NADPH produced in noncyclic photosynthesis is used to provide electrons for the fixation of CO2 in the Calvin-Benson cycle.
True
Nigrosin staining-not safranin staining-of Klebsiella pneumoniae will allow for the visualization of the cell shape and the determination of the presence of a capsule.
True
Phase-contrast microscopy is an especially useful type of microscopy because it permits detailed examination of internal structures in living microorganisms.
True
Saturated fats have only single bonds between carbons in the hydrocarbon chains.
True
The Gram stain is important in medical microbiology because the results help medical professionals select appropriate antibiotics for treatment.
True
The cell membrane is a fluid structure that allows membrane proteins to move freely within the membrane.
True
The cell membrane is a fluid structure that allows membrane proteins to move freely.
True
The endosymbiotic theory states that eukaryotic organelles evolved from symbiotic prokaryotes living within other prokaryotes.
True
The following bacterial structures increase the likelihood that bacteria will be associated with disease: Capsules, fimbriae, and LPS.
True
The hydrogen bonding pattern in ice makes ice less dense than water, so ice floats on the surfaces of lakes and streams.
True
The oxidase test is commonly used to identify aerobic microorganisms.
True
The plane in which a bacterial cell divides determines the arrangement of cells.
True
The synthesis of sugars by using carbon atoms from CO2 gas is called carbon fixation.
True
Water molecules are polar molecules with the oxygen region of the molecule having a slight negative charge and the hydrogen regions of the molecule having a slight positive charge.
True
Jenner's work with vaccinations depended on which of the following?
Trusting that the body produced agents that effectively overcame a disease-causing microbe
The motility of bacteria with flagella occurs through a series of "runs" and __________.
Tumbles
Which microscope is used to see intracellular detail in a living cell?
Two-photon microscope
This activity asks you to sort items according to the most appropriate method for viewing. For each of the following items, indicate which viewing method is most appropriate-the unaided eye, light microscopy, scanning electron microscopy, or transmission electron microscopy-by dragging it into the correct bin.
Unaided eye -Examining your cat for the presence of fleas Light Microscope -Examining a clinical specimen, such as a sputum smear, for the presence of bacteria -Examining a blood smear for the presence of malarial parasites Scanning Electron Microscope -Viewing the three-dimensional shape of a protozoan and the arrangement and distribution of cilia on its surface -Determining the three-dimensional shape and arrangement of bacterial cells Transmission Electron Microscope -Confirming the 9 + 2 microtubule arrangement in a eukaryotic flagellum -Viewing ribosomes (20 nm) within a bacterial cell -Viewing a cross-section of poliovirus (30 nm) -Viewing the layers of the gram-negative cell wall in cross section
Protozoa
Unicellular eukaryotic microbes
Bacterial cells have an overall negative charge on their surface. If a bacterial smear is stained by a pink, acidic, water-soluble stain and then washed with water, which of the following describes the result that will be observed when viewing the stained slide under a microscope?
Unstained cells with no background
In a negative staining procedure, the bacterial cells would appear __________ when viewed under a microscope.
Unstained in a colored background
A scientist wants to perform a test that will indicate whether a nucleic acid sample is composed of RNA or DNA. Testing for the presence of which of the following is most appropriate in this situation?
Uracil
Which of the following best describes gene therapy?
Use of a harmless virus to insert a gene in a host cell
Which one of the following is an example of bioremediation?
Use of pseudomonas to remove uranium from soil at weapons depots
Choose from the following statements the one that best describes the reactions illustrated in the figure above.
Using energy, an enzyme removes a hydroxyl group from the carboxyl group of one amino acid and a hydrogen atom from the amino group of another amino acid to join the amino acids in a dehydration synthesis reaction that releases water. Alternatively, another enzyme breaks the peptide bond and uses a water molecule to join a hydroxyl group to the carboxyl group of one amino acid and a hydrogen atom to the amino group of another amino acid in a hydrolysis reaction.
All of the following factors contribute to the threat of emerging infectious diseases (EIDs) EXCEPT __________.
Vaccinations against various types of childhood diseases
What type of microorganisms are only visible with an electron microscope?
Viruses
Which quality of water accounts for its characteristic role as a reactant or product in many chemical reactions?
Water can split into a hydrogen ion and a hydroxide ion
Which characteristic of water accounts for its excellent solvent properties?
Water has a negatively charged portion and a positively charged portion
Which of the following statements is true about water?
Water is removed during biological synthesis reactions
Resolution is very good when using an electron microscope because the __________ of the electron beam is much shorter than that of visible light.
Wavelength
Acid-fast mycobacteria differ from non-acid-fast bacteria by the presence of __________. In the decolorizing step of the acid-fast stain, __________ is used.
Waxy material in their cell walls; acid-alcohol
Acid-fast Mycobacteria differ from non-acid-fast bacteria by the presence of __________.
Waxy materials in their cell walls
The valence of oxygen is 2. This means that oxygen __________.
Will form up to two bonds
When placed in water, phospholipids will orient themselves __________.
With phosphates associated with water and lipids clustered away from the water
What are some diseases that fungi can cause?
Yeast infections in humans
Are viruses living?
Yes, in a sense, because they can multiply when inside another living cell. On the other hand, they are often considered nonliving because they are inert outside of a living host.
A chemical indicator called phenol red is typically used in microbiology labs. At pH 8, it appears fuchsia; at neutral, it appears red; and at pH 6, it is yellow. If this indicator were incorporated into a medium with a sugar and turned from red to yellow after bacteria grew on the medium for 24 hours, what could you conclude?
You could deduce that the bacteria created acids in the medium
In the late 1800s, a researcher by the name of Robert Koch developed a series of postulates (Guidelines) that can be used to prove that a given pathogen is the true cause of a 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 Which of the following steps does NOT follow one of Koch's postulates?
You give a patient an antibiotic to treat an infection
What carries instructions for making proteins from the nucleus into the cytoplasm?
mRNA
The amount of H+ ions in a solution is represented by the __________ of the solution.
pH
