1.
Define what is meant by emerging and remerging disease OR state Koch's postulates.
2.
List two differences between optical light microscope and electron microscope OR differentiate between negative and positive staining using examples
3.
Define glycocalyx and describe its different forms OR list and briefly describe two basic layers that make up cell envelope
4.
List the mechanisms by which an enzyme lowers the activation energy and brings on the transition state OR what are holoenzymes and give examples.
5.
List and briefly describe the events in nitrogen cycle OR describe life cycle of endospore forming bacteria, including formation and germination of endospores
6.
Contrast the major structure of gram-positive and gram-negative cell wall OR what is competitive and noncompetitive inhibition
7.
Disease-causing microorganisms are called
Correct Answer
C. Pathogens
Explanation
Pathogens are disease-causing microorganisms. They are able to invade and multiply within the host, causing various infections and diseases. Pathogens can be bacteria, viruses, fungi, or parasites. They have specific mechanisms and virulence factors that allow them to evade the host's immune system and cause harm. Identifying and understanding pathogens is crucial in the field of medicine to develop effective treatments and preventive measures against infectious diseases.
8.
The microorganisms that recycle nutrients by breaking down dead matter and wastes are called
Correct Answer
A. Decomposers
Explanation
Decomposers are microorganisms that play a crucial role in ecosystems by breaking down dead matter and wastes. They break down organic material into simpler forms, releasing nutrients back into the environment. This process, known as decomposition, is essential for nutrient cycling and the overall health of the ecosystem. Prokaryotes are a type of microorganism that lack a nucleus, but not all prokaryotes are decomposers. Fermenters are microorganisms that carry out fermentation, a metabolic process that does not involve oxygen, but they are not specifically involved in nutrient recycling. Pathogens are microorganisms that cause diseases and are not involved in the decomposition process.
9.
The microorganisms that do not have a nucleus in their cell wall are called
Correct Answer
B. Prokaryotes
Explanation
Prokaryotes are microorganisms that do not have a nucleus in their cell wall. They are single-celled organisms that lack membrane-bound organelles, including a nucleus. Prokaryotes include bacteria and archaea. They have a simple cellular structure and are capable of various functions such as decomposition, nitrogen fixation, and photosynthesis. Unlike eukaryotes, which have a nucleus and other membrane-bound organelles, prokaryotes have their DNA floating freely in the cytoplasm. Therefore, prokaryotes are the correct answer to the question.
10.
Which activity is an example of biotechnology?
Correct Answer
C. Humans using yeast to make beer and wine
Explanation
Using yeast to make beer and wine is an example of biotechnology because it involves the use of living organisms, in this case yeast, to produce a desired product. Biotechnology refers to the use of biological systems, organisms, or their components to develop or create useful products or processes. In this case, yeast is used to ferment sugars and produce alcohol, which is then used to make beer and wine.
11.
The Dutch merchant who made and used quality magnifying lenses to see and record microorganisms was
Correct Answer
B. A. Leeuwenhoek
Explanation
Leeuwenhoek is the correct answer because he was a Dutch merchant who made and used quality magnifying lenses to see and record microorganisms. He is considered one of the pioneers of microbiology and is known for his meticulous observations and accurate drawings of microorganisms, which he made using his handmade lenses. His discoveries greatly contributed to the understanding of the microscopic world and laid the foundation for the field of microbiology.
12.
Spontaneous generation is the belief that
Correct Answer
D. Living things arise from nonliving matter
Explanation
The belief of spontaneous generation states that living organisms can arise from nonliving matter. This theory was widely accepted in the past, as people observed the apparent emergence of organisms from decaying matter or stagnant water. However, this belief was later disproven by experiments conducted by Louis Pasteur and others, which demonstrated that living organisms only arise from preexisting living organisms through processes such as reproduction or germination.
13.
Koch's postulates are criteria used to establish that
Correct Answer
B. A specific microbe is the cause of a specific disease
Explanation
Koch's postulates are criteria used to establish that a specific microbe is the cause of a specific disease. These postulates were developed by Robert Koch and are still widely used in microbiology to determine the causative agent of a disease. According to Koch's postulates, the microbe must be present in all cases of the disease, it must be isolated from the diseased individual and grown in pure culture, it should cause the same disease when inoculated into a healthy individual, and it must be re-isolated from the newly infected individual. These steps help establish a causal relationship between a specific microbe and a specific disease.
14.
Which scientist discovered heat resistant bacterial spores
Correct Answer
C. F. Cohn
Explanation
Ferdinand Cohn is credited with discovering heat resistant bacterial spores. He was a German biologist and botanist who made significant contributions to the field of microbiology. Cohn conducted extensive research on bacteria and was the first to describe and classify bacterial endospores, which are highly resistant to heat and other adverse conditions. His work on spore formation and resistance laid the foundation for understanding the survival mechanisms of bacteria and their ability to withstand extreme environments.
15.
The rash and/or hemorrhage associated to Rocky Mountain spotted fever and Typhus occur when this bacterium targets the endotheilal cells that line blood vessels
Correct Answer
Rickettsia
Explanation
Rickettsia is a bacterium that causes diseases such as Rocky Mountain spotted fever and Typhus. These diseases are characterized by a rash and/or hemorrhage. The explanation for the correct answer is that Rickettsia specifically targets the endothelial cells that line the blood vessels. This leads to damage and inflammation of the blood vessels, resulting in the symptoms observed in patients with these diseases.
16.
This bacterium has a life cycle that includes elementary and reticulate bodies
Correct Answer
Chlamydia
Explanation
Chlamydia is the correct answer because it is a bacterium that has a unique life cycle involving two distinct forms: elementary bodies and reticulate bodies. The elementary bodies are the infectious form that can survive outside the host, while the reticulate bodies are the replicative form that multiply within host cells. This life cycle allows Chlamydia to successfully infect and reproduce in various host organisms, causing a range of diseases such as sexually transmitted infections and respiratory tract infections.
17.
This bacterium is a member parasite that adheres to and damages the mucous membrane of the respiratory, urinary, and reproductuve tracts
Correct Answer
Mycoplasma
Explanation
Mycoplasma is a bacterium that is known to be a member parasite, as it adheres to and causes damage to the mucous membranes of various tracts in the body, including the respiratory, urinary, and reproductive tracts. This bacterium lacks a cell wall, which allows it to attach to and invade the host's cells, leading to infection and subsequent damage. Mycoplasma infections can result in a range of symptoms depending on the affected tract, including respiratory issues, urinary tract infections, and reproductive problems.
18.
This bacterium causes a commonly acquired sexually transmitted bacterial disease and Trachoma, the most common cause of blindness
Correct Answer
Chlamydia
Explanation
Chlamydia is the correct answer because it is a bacterium that is known to cause both a commonly acquired sexually transmitted bacterial disease and Trachoma, which is the most common cause of blindness. Chlamydia is transmitted through sexual contact and can cause infections in the genital tract, leading to symptoms such as discharge, pain, and infertility. Additionally, if left untreated, Chlamydia can spread to the eyes and cause Trachoma, a chronic infection that can lead to blindness. Therefore, Chlamydia fits the description provided in the question.
19.
Which bacterium was the first organisms to produce oxygen as a byproduct of photosynthesis
Correct Answer
Cyanobacteria
Explanation
Cyanobacteria were the first organisms to produce oxygen as a byproduct of photosynthesis. They are a group of bacteria that are capable of photosynthesis and have the ability to convert sunlight into energy. Through this process, they release oxygen into the atmosphere, which played a crucial role in the evolution of life on Earth. Cyanobacteria are often referred to as blue-green algae, but they are not true algae. They are found in various environments, including freshwater, marine, and terrestrial habitats.
20.
If microbiologist is studying a specimen at a total mag of 950x, what is the magnifying power of the objective lens if the ocular lens is 10x
Correct Answer
D. 95x
Explanation
The magnifying power of a microscope is determined by multiplying the magnification of the objective lens by the magnification of the ocular lens. In this case, the ocular lens has a magnification of 10x. Since the total magnification is given as 950x, we can divide 950 by 10 to find the magnification of the objective lens. This gives us a magnifying power of 95x for the objective lens.
21.
Which microscope achieves the greatest resolution and highest magnification
Correct Answer
D. Electron
Explanation
The electron microscope achieves the greatest resolution and highest magnification among the options given. Unlike light microscopes, which use visible light to magnify and resolve images, electron microscopes use a beam of electrons. Electrons have a much shorter wavelength than visible light, allowing for higher resolution and greater magnification. This enables electron microscopes to visualize extremely small structures and details that would be impossible to see with other types of microscopes.
22.
Which microscope bombard a whole, metal-coated specimen with electrons moving back and forth over it
Correct Answer
C. Scanning electron
Explanation
A scanning electron microscope (SEM) bombards a whole, metal-coated specimen with electrons moving back and forth over it. SEMs use a focused beam of electrons to scan the surface of a sample, creating detailed images of the specimen's surface morphology. The electrons interact with the atoms in the sample, producing signals that can be detected and used to create an image. This technique is particularly useful for studying the surface features of materials and provides high-resolution images with great depth of field.
23.
The primary purpose of staining cells on a microscope slide is to
Correct Answer
D. Add contrast in order to see them better
Explanation
Staining cells on a microscope slide is done to add contrast, which helps in visualizing the cells better. By using specific dyes or stains, the cells can be highlighted and differentiated from their surroundings, making it easier to observe their structure, morphology, and any abnormalities. This contrast enhancement enables researchers and scientists to study and analyze cells more effectively under a microscope.
24.
A microbiologist makes a fixed smear of bacterial cells and stains them with methylene blue. all the cells appear blue under the oil lens. this is an example of
Correct Answer
C. Simple staining
Explanation
In this scenario, the microbiologist made a fixed smear of bacterial cells and stained them with methylene blue. The fact that all the cells appear blue under the oil lens suggests that the stain is uniformly coloring the cells, without any contrast or differentiation. This indicates that the staining technique used is simple staining, where a single dye is used to color all the cells in a sample.
25.
Why is immersion oil often used when viewing specimens under the microscope
Correct Answer
D. To increase the resolution
Explanation
Immersion oil is often used when viewing specimens under the microscope to increase the resolution. Immersion oil has a similar refractive index as glass, which reduces the amount of light that is scattered or refracted as it passes through the specimen and the microscope lens. This reduction in scattering and refraction allows more light to be collected by the lens, resulting in a clearer and more detailed image. By using immersion oil, the resolution of the microscope is improved, allowing for better visualization and analysis of the cells or organisms being observed.
26.
Spirochetes have a twisting and flexing locomotion due to
Correct Answer
D. Periplasmic flagella
Explanation
Periplasmic flagella allow spirochetes to have a twisting and flexing locomotion. Unlike external flagella or cilia, periplasmic flagella are located within the periplasmic space, which is between the cell membrane and the outer membrane of spirochetes. This unique arrangement enables spirochetes to move in a corkscrew-like motion, propelling themselves forward and allowing them to navigate through various environments. The presence of periplasmic flagella is a distinguishing characteristic of spirochetes and contributes to their motility.
27.
Magnification is achieved in a compound microscope through the initial magnification of the specimen by the ______ lens. This image is then projected to the _________ lens that will further magnify the specimen to form a virtual image received by the eye
Correct Answer
Objective; Ocular
Explanation
In a compound microscope, magnification is achieved through two lenses: the objective lens and the ocular lens. The objective lens initially magnifies the specimen, creating an image. This image is then projected to the ocular lens, which further magnifies the specimen to form a virtual image that is received by the eye. Therefore, the correct answer is objective for the first lens and ocular for the second lens.
28.
The transfer of genes during bacterial conjugation involve rigid, tubular appendages called
Correct Answer
D. Sex pili
Explanation
Bacterial conjugation is a process where genetic material is transferred between bacterial cells through direct contact. During this process, the transfer of genes is facilitated by the presence of rigid, tubular appendages called sex pili. These sex pili help in establishing physical contact between the donor and recipient bacterial cells, allowing for the transfer of genetic material. Flagella are whip-like structures used for bacterial movement, cilia are short hair-like structures used for movement or sensing, and fimbriae are short, hair-like appendages used for attachment to surfaces. None of these structures are directly involved in the transfer of genes during bacterial conjugation.
29.
The term that refers to the presence of flagella all over the cell surface is
Correct Answer
D. Peritrichous
Explanation
Peritrichous refers to the presence of flagella all over the cell surface. This means that the flagella are distributed evenly around the cell, allowing it to move in any direction. Amphitrichous refers to the presence of flagella at both ends of the cell, atrichous refers to the absence of flagella, and monotrichous refers to the presence of a single flagellum. Therefore, peritrichous is the correct term to describe the presence of flagella all over the cell surface.
30.
The outcome of the gram stain is based on differences in cell's
Correct Answer
C. Cell wall
Explanation
The outcome of the gram stain is based on differences in the cell wall. Gram staining is a technique used to differentiate bacteria into two groups: Gram-positive and Gram-negative. Gram-positive bacteria have a thick peptidoglycan layer in their cell wall, which retains the crystal violet stain, giving them a purple color. On the other hand, Gram-negative bacteria have a thinner peptidoglycan layer and an outer membrane, which does not retain the stain, resulting in a pink color. Therefore, the cell wall plays a crucial role in determining the outcome of the gram stain.
31.
The most immediate result of destruction of a cell's ribosomes would be
Correct Answer
B. Protein synthesis would stop
Explanation
If a cell's ribosomes are destroyed, the most immediate result would be that protein synthesis would stop. Ribosomes are responsible for translating the genetic information from DNA into proteins, so without functioning ribosomes, the cell would not be able to produce proteins.
32.
A prokaryotic cell wall that is primarily peptidoglycan with small amounts of teichoic acid and lipoteichoic acid is
Correct Answer
B. Gram-positive
Explanation
A prokaryotic cell wall that is primarily composed of peptidoglycan with small amounts of teichoic acid and lipoteichoic acid is classified as gram-positive. Gram-positive bacteria have a thick layer of peptidoglycan in their cell walls, which retains the crystal violet stain during the Gram staining process, causing them to appear purple under a microscope. Teichoic acid and lipoteichoic acid are unique components found in the cell walls of gram-positive bacteria, further supporting this classification. Gram-negative bacteria, on the other hand, have a thinner layer of peptidoglycan and an outer membrane, which makes them appear pink after the Gram staining process. Archaea have a different cell wall composition and structure compared to bacteria, and spheroplasts are bacterial cells that have had their cell walls partially or completely removed.
33.
Endospores are
Correct Answer
E. All of the choices are correct
Explanation
Endospores are a unique form of bacterial survival structures that are metabolically inactive, meaning they are not actively carrying out any metabolic processes. They are also highly resistant to heat, chemical destruction, and radiation. This allows them to withstand harsh environmental conditions such as extreme temperatures, exposure to chemicals, and high levels of radiation. Therefore, the correct answer is that all of the choices are correct.
34.
What is the correct sequence for gram stain?
Correct Answer
C. Crystal violet, gran's iodine, alcohol, safranin
Explanation
The correct sequence for the gram stain is crystal violet, gram's iodine, alcohol, safranin. This staining technique is used to differentiate bacteria into two groups: gram-positive and gram-negative. Crystal violet is the primary stain that colors all bacteria purple. Gram's iodine is the mordant that forms a complex with crystal violet, making it more resistant to decolorization. Alcohol is the decolorizing agent that removes the crystal violet-iodine complex from gram-negative bacteria, leaving them colorless. Safranin is the counterstain that stains gram-negative bacteria pink, allowing them to be differentiated from the gram-positive bacteria.
35.
All of the following are correct about slime layer, except
Correct Answer
D. It plays a roll in cell motility
Explanation
The slime layer is a type of glycocalyx that surrounds the cell and protects it from the loss of water and nutrients. It forms a sticky layer that can be difficult to wash off the cell. However, it does not play a role in cell motility.
36.
Enzymes are
Correct Answer
B. Proteins and some are RNA that function as catalysts
Explanation
Enzymes are proteins and some are RNA that function as catalysts. Proteins and RNA can both act as enzymes, facilitating and speeding up chemical reactions. Enzymes work by lowering the activation energy required for a reaction to occur, thereby increasing the rate of the reaction. They are not used up in the reactions they catalyze and can be reused multiple times. Therefore, the correct answer is that enzymes can be proteins and some are RNA that function as catalysts.
37.
Important components of coenzymes are
Correct Answer
A. Vitamins
Explanation
Coenzymes are organic molecules that work alongside enzymes to facilitate various biochemical reactions in the body. They are derived from vitamins, which are essential nutrients that the body needs in small amounts for proper functioning. Vitamins are important components of coenzymes because they provide the necessary chemical groups or functional units that are required for the coenzymes to carry out their specific roles in enzymatic reactions. Metallic ions, active sites, and substrates are also important in enzymatic reactions, but they are not the primary components of coenzymes.
38.
Metabollic pathways that regenerate their starting point is called _____ pathways.
Correct Answer
D. Cyclic
Explanation
Cyclic pathways are metabolic pathways that regenerate their starting point. In these pathways, the initial substrate is converted into intermediate products, which are then further metabolized to regenerate the starting substrate. This creates a circular flow of metabolites within the pathway. Unlike linear pathways, where the end product is different from the starting substrate, cyclic pathways maintain the same starting point throughout the process. Bi-directional pathways allow for reversible reactions, but they do not necessarily regenerate the starting point. Convergent pathways involve multiple substrates converging into a common intermediate, but they do not necessarily regenerate the starting point.
39.
Glycolysis
Correct Answer
D. Uses 2 ATP, produces 4 ATP, without oxygen
Explanation
Glycolysis is the metabolic pathway that breaks down glucose into pyruvate. It occurs in the cytoplasm of cells and is the first step in both aerobic and anaerobic respiration. During glycolysis, 2 ATP molecules are used to initiate the process. However, it produces 4 ATP molecules through substrate-level phosphorylation, resulting in a net gain of 2 ATP molecules. In the absence of oxygen, glycolysis can still occur, but the end product, pyruvate, is converted into either lactate or ethanol, depending on the organism. Therefore, the correct answer is "uses 2 ATP, produces 4 ATP, without oxygen."
40.
Substrate level phosphorylation in
Correct Answer
C. Glycolysis + krebs cycle
Explanation
Glycolysis is the initial step in cellular respiration where glucose is broken down into pyruvate, producing a small amount of ATP through substrate-level phosphorylation. The pyruvate molecules then enter the Krebs cycle, a series of reactions that occur in the mitochondria. In the Krebs cycle, more ATP is produced through substrate-level phosphorylation, as well as the release of high-energy electrons. These electrons are then transferred to the electron transport chain (ETC), where they combine with oxygen to produce a large amount of ATP through oxidative phosphorylation. Therefore, the correct answer is glycolysis + Krebs cycle, as both processes involve substrate-level phosphorylation.
41.
The majority of reduced NAD/NADH is produced in
Correct Answer
B. Krebs cycle
Explanation
The Krebs cycle, also known as the citric acid cycle, is a series of chemical reactions that occur in the mitochondria of cells. This cycle is an essential part of cellular respiration, which is the process by which cells convert glucose into energy. During the Krebs cycle, reduced NADH is produced through the oxidation of glucose and other molecules. This reduced NADH carries high-energy electrons that are used in the electron transport chain (ETC) to generate ATP, the main energy currency of the cell. Therefore, the majority of reduced NAD/NADH is produced in the Krebs cycle.
42.
In bacterial cells, the ETC is located in
Correct Answer
A. Cell membrane
Explanation
In bacterial cells, the electron transport chain (ETC) is located in the cell membrane. The cell membrane of bacteria serves as the site for various metabolic processes, including the ETC. The ETC is responsible for the transfer of electrons and the generation of a proton gradient, which is used to produce ATP. The location of the ETC in the cell membrane allows for efficient electron transfer and ATP synthesis. Unlike eukaryotic cells, bacteria lack mitochondria and chloroplasts, which are the organelles where the ETC is located in eukaryotic cells. Ribosomes, on the other hand, are responsible for protein synthesis and are not directly involved in the ETC.
43.
What chemical causes death in many eukaryotes because it blocks cytochrome c oxidase?
Correct Answer
C. Cyanide
Explanation
Cyanide is a chemical that blocks cytochrome c oxidase, an enzyme involved in cellular respiration. This enzyme is responsible for the final step in the electron transport chain, which generates ATP, the energy currency of the cell. By blocking cytochrome c oxidase, cyanide prevents the production of ATP, leading to cellular dysfunction and ultimately death. This effect is observed in many eukaryotes, including humans, making cyanide a potent and lethal poison.
44.
When humans manipulate the genes of microorganisms the process is called
Correct Answer
B. Genetic engineering
Explanation
Genetic engineering refers to the process of manipulating the genes of microorganisms, plants, or animals to produce desired traits or characteristics. This can involve inserting, deleting, or modifying specific genes to enhance their functions or create new ones. Bioremediation, on the other hand, is the use of microorganisms to clean up pollutants in the environment. Epidemiology is the study of diseases and their patterns, while immunology focuses on the immune system and its response to diseases. Therefore, genetic engineering is the correct answer as it specifically relates to the manipulation of genes in microorganisms.
45.
Microorganisms are best defined as organisms that
Correct Answer
D. Are too small to be seen with the unaided eye
Explanation
Microorganisms are best defined as organisms that are too small to be seen with the unaided eye. This definition encompasses a wide range of microscopic organisms such as bacteria, viruses, fungi, and protozoa. These organisms play a crucial role in various ecosystems and have both beneficial and harmful effects on human health and the environment.
46.
Organisms called parasites are
Correct Answer
B. Maybe harmful to their host
Explanation
Parasites are organisms that live in or on another organism (host) and obtain nutrients from the host, often causing harm in the process. They rely on the host for survival and reproduction, which can lead to negative effects on the host's health and well-being. Therefore, parasites may be harmful to their host.
47.
All of the following are correct about prokaryotes, except
Correct Answer
D. They have organelles
Explanation
Prokaryotes are single-celled organisms that lack a nucleus and membrane-bound organelles. They are generally smaller and less complex than eukaryotes. However, prokaryotes do not have organelles. Organelles are specialized structures within a cell that perform specific functions, such as mitochondria or chloroplasts in eukaryotic cells. Prokaryotes, on the other hand, have simpler internal structures and lack these membrane-bound organelles.
48.
The fossil record has est. that prokaryotes existed on earth for approx 2 billion years before eukaryotes appeared
Correct Answer
A. True
Explanation
The explanation for the given correct answer is that the fossil record, which consists of preserved remains or traces of organisms from the past, has provided evidence that prokaryotes, which are single-celled organisms without a nucleus, existed on Earth for approximately 2 billion years before eukaryotes, which are organisms with a nucleus, appeared. This evidence supports the statement that the given statement is true.
49.
CO2 IS
Correct Answer
E. All of the above
Explanation
The correct answer is "all of the above". This means that CO2 is removed from the atmosphere during photosynthesis, it is a source of carbon, it is returned to the atmosphere during respiration and fermentation, and it is used by marine organisms to make limestone for their hard shells.
50.
The conversion of gaseous nitrogen (N2) to ammonium (NH4+) occurs during
Correct Answer
B. Nitrogen fixation
Explanation
Nitrogen fixation is the process in which gaseous nitrogen (N2) is converted into ammonium (NH4+). This process is carried out by certain bacteria, either free-living or symbiotic, which have the ability to convert atmospheric nitrogen into a form that can be used by plants and other organisms. Ammonification, on the other hand, is the process of converting organic nitrogen into ammonium, while nitrification is the process of converting ammonium into nitrate (NO3-). Photosynthesis is the process by which plants convert sunlight into energy, and it does not involve the conversion of nitrogen. Therefore, the correct answer is nitrogen fixation.