Microbiology Trivia Questions Quiz!

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1. Which are of microbiolgy studies fungi?

Explanation

Mycology is the branch of microbiology that specifically focuses on the study of fungi. Fungi are a diverse group of organisms that include yeasts, molds, and mushrooms. Mycologists study various aspects of fungi, including their classification, structure, reproduction, genetics, and ecological roles. They also investigate the interactions between fungi and other organisms, as well as the potential uses of fungi in various industries such as medicine, agriculture, and food production. Therefore, Mycology is the correct answer as it is the field that specifically deals with the study of fungi.

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About This Quiz
Microbiology Trivia Questions Quiz! - Quiz

The study of microbiology covers the area of science that deals with microscopic organisms, best defined as organisms so small that you typically cannot see them with the... see morenaked eye. Can you identify the different kinds of microorganisms out there – bacteria, fungi, protozoa, viruses – and tell us all about them and how they’re studied? Take the following quiz to find out just how much you know about them! Good luck!
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2. Which of the following statements about bacteria is not true?

Explanation

The statement "The only good bacterium is a dead bacterium" is not true. While some bacteria can cause diseases, many bacteria are beneficial and necessary for various ecological processes and human health. For example, bacteria help in digestion, produce vitamins, and play a crucial role in the nitrogen cycle. Therefore, it is incorrect to claim that the only beneficial bacterium is a dead one.

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3. At which growth temperture bacteria grow at the fastest rate?

Explanation

Bacteria grow at the fastest rate at their optimum temperature. This temperature is the ideal condition for their growth and metabolism. At this temperature, all the necessary enzymes and cellular processes occur at their maximum efficiency, allowing bacteria to multiply rapidly. Temperatures above or below the optimum can slow down or inhibit bacterial growth, as enzymes may become denatured or metabolic processes may become too slow. Therefore, the optimum temperature is where bacteria can grow at their fastest rate.

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4. Which of the following pairs is mismatched?

Explanation

The given pair "Koch - aseptic surgery" is mismatched because Robert Koch is known for his contributions to microbiology, particularly in the field of bacteriology. He developed techniques to isolate and identify bacteria, formulated Koch's postulates to establish the causative relationship between a microorganism and a disease, and discovered the bacteria responsible for diseases such as tuberculosis and cholera. Aseptic surgery, on the other hand, refers to the practice of performing surgical procedures in a sterile environment to prevent infection, which is not directly associated with Koch.

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5. Which of the following mechanisms requires energy?

Explanation

Active transport is the only mechanism among the options that requires energy. Active transport is the movement of molecules across a cell membrane against their concentration gradient, from an area of lower concentration to an area of higher concentration. This process requires the use of energy in the form of ATP (adenosine triphosphate) to pump the molecules against the concentration gradient. In contrast, simple diffusion, osmosis, and facilitated diffusion are all passive mechanisms that do not require energy as they involve the movement of molecules along their concentration gradient.

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6. The appearance of gram-negative bacteria after completing Gram stan is:

Explanation

After completing the Gram stain, gram-negative bacteria appear red. This is because the Gram stain procedure involves the use of crystal violet dye, iodine, alcohol, and safranin. Gram-negative bacteria have a thinner peptidoglycan layer in their cell walls, which allows the crystal violet dye to be easily washed away by the alcohol. As a result, the safranin counterstain is taken up by the gram-negative bacteria, causing them to appear red under a microscope.

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7. What color should a gram-positive organism appear after Gram stain

Explanation

Gram-positive organisms should appear purple after a Gram stain. This is because the Gram stain procedure involves the application of crystal violet dye, which stains the peptidoglycan layer in the cell wall of bacteria. Gram-positive bacteria have a thick peptidoglycan layer that retains the crystal violet dye, causing them to appear purple under a microscope.

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8. The most common solidifying agent added to culture media is:

Explanation

Agar is the most common solidifying agent added to culture media. Agar is a gelatinous substance derived from seaweed and has the ability to form a solid gel at a temperature range suitable for microbial growth. It is widely used in microbiology laboratories because it is inert, transparent, and can be easily sterilized. Agar provides a solid surface for the growth of microorganisms, allowing them to form distinct colonies, facilitating their isolation and identification. It also has the advantage of being resistant to degradation by most microorganisms, making it an ideal solidifying agent for culture media.

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9. Cocci are:

Explanation

Cocci are round to oval bacteria. The term "cocci" refers to a specific shape of bacteria, which is spherical or oval in appearance. This shape is characteristic of certain types of bacteria, such as Staphylococcus and Streptococcus. The other options mentioned in the question, such as rod bacteria, cylindrical shape bacteria, and bacillus type bacteria, do not accurately describe the shape of cocci bacteria. Spiral bacteria, on the other hand, have a corkscrew-like shape and are not considered cocci. Therefore, the correct answer is round to oval bacteria.

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10. You can find nucleotides in

Explanation

Nucleotides are the building blocks of DNA, which is a molecule that contains the genetic instructions for the development and functioning of all living organisms. DNA is made up of a long chain of nucleotides, each consisting of a sugar molecule, a phosphate group, and a nitrogenous base. Nucleotides are not found in amino acids, fatty acids, proteins, or carbohydrates.

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11. Place the following steps in the correct sequence: 1 - Staining; 2- Making a smear; 3 - Fixing

Explanation

The correct sequence for the given steps is 2-3-1. First, making a smear is done to prepare a thin layer of the sample on a slide. Then, fixing is performed to kill the microorganisms and attach them to the slide. Finally, staining is carried out to enhance the visibility of the microorganisms and differentiate them from the background.

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12. Cell division occurs in prokaryotes by:

Explanation

Binary fission is the correct answer because it is the process of cell division in prokaryotes, such as bacteria. In binary fission, the parent cell divides into two identical daughter cells, each containing a copy of the parent's DNA. This process is different from meiosis, which is a type of cell division that occurs in eukaryotes and involves the formation of gametes. Budding is a form of asexual reproduction seen in some organisms, but it is not the primary method of cell division in prokaryotes. Mitosis is a type of cell division that occurs in eukaryotes and is not relevant to prokaryotes.

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13. Proteins are formed by amino acids connected by:

Explanation

Peptide bonds are formed between amino acids to create proteins. These bonds occur through a condensation reaction, where the carboxyl group of one amino acid reacts with the amino group of another amino acid, resulting in the formation of a peptide bond and the release of a water molecule. This process is repeated to form a chain of amino acids, which then folds and interacts with other molecules to create a functional protein. Peptide bonds are essential for the structure and function of proteins, as they determine the sequence and arrangement of amino acids in the protein chain.

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14. Which of the following is not a kingdom in the five-kingdom system?

Explanation

The five-kingdom system categorizes organisms into five kingdoms based on their characteristics and evolutionary relationships. The kingdoms are Animal, Fungi, Plant, Protista, and Monera. However, viruses are not considered as a kingdom in this system because they are not living organisms. Viruses are acellular and cannot carry out metabolic processes on their own. They require a host cell to reproduce and are considered as infectious agents rather than living organisms.

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15. These are the primary molecules making up plasma membrane in cells

Explanation

The primary molecules making up the plasma membrane in cells are lipids. Lipids are a diverse group of molecules that include fats, oils, and phospholipids. They are hydrophobic, meaning they repel water, which makes them ideal for forming the structure of the plasma membrane. The lipid bilayer is formed by two layers of phospholipids, with their hydrophilic heads facing the watery environment inside and outside the cell, and their hydrophobic tails facing each other in the middle. This arrangement provides a barrier that controls the movement of substances in and out of the cell, making lipids essential for maintaining cell integrity and function.

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16. This microscope is used to observe a specimen that emits light when illuminated with an ultra violet light and is an excellent diagnostic tool.

Explanation

A fluorescence microscope is the correct answer because it is specifically designed to observe specimens that emit light when illuminated with ultraviolet light. This type of microscope is commonly used in diagnostic applications because it allows for the visualization of fluorescently-labeled molecules or structures within the specimen. The emitted light provides valuable information about the presence and location of specific molecules or cellular components, making it an excellent tool for diagnostic purposes.

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17. Identify the FALSE statement.

Explanation

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18. This is not an internal structure of a bacteria

Explanation

Fimbriae are short, hair-like appendages found on the surface of some bacteria. They are used for attachment to surfaces, including host tissues, and are important for the bacteria to establish infections. In contrast, ribosomes are cellular structures responsible for protein synthesis, plasmids are small, circular DNA molecules that can be found in bacteria and often carry additional genetic information, and nucleoid refers to the region in a bacterial cell where the genetic material is located. Therefore, fimbriae are the only option that does not represent an internal structure of a bacteria.

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19. Which molecule is composed of a chain of amino acids?

Explanation

Proteins are composed of a chain of amino acids. Amino acids are the building blocks of proteins, and they are linked together through peptide bonds to form a long chain. This chain of amino acids then folds and twists into a unique three-dimensional structure, which determines the protein's function. Therefore, proteins are the molecules that are composed of a chain of amino acids.

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20. What is the purpose of buffer in culture media?

Explanation

The purpose of a buffer in culture media is to maintain the pH at a certain level. This is important because bacteria and other microorganisms have specific pH requirements for growth and survival. If the pH of the culture media fluctuates too much, it can negatively affect the growth of the microorganisms. Therefore, adding a buffer to the culture media helps to stabilize and maintain the pH at the desired level, providing optimal conditions for the growth and study of microorganisms.

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21. We discussed two processes for synthesizing ATP. Which process requires proton gradient across the membrane?

Explanation

Oxidative level phosphorylation requires a proton gradient across the membrane. During this process, electrons are transferred through the electron transport chain, which pumps protons from the matrix to the intermembrane space. This creates a proton gradient, and as the protons flow back into the matrix through ATP synthase, ATP is synthesized. Substrate level phosphorylation, on the other hand, involves the direct transfer of a phosphate group from a substrate molecule to ADP to form ATP, and does not require a proton gradient.

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22. This microscope achieves the highest magnification and greatest resolution.

Explanation

The electron microscope achieves the highest magnification and greatest resolution compared to the other types of microscopes listed. This is because it uses a beam of electrons instead of light to magnify and image the specimen. The shorter wavelength of electrons allows for higher resolution, enabling scientists to see smaller details and structures within the specimen.

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23. Nitrogen bases are building blocks of:

Explanation

Nitrogen bases are the building blocks of nucleotides. Nucleotides are the basic units that make up DNA and RNA molecules. They consist of a nitrogenous base, a sugar (deoxyribose or ribose), and a phosphate group. The nitrogen bases, including adenine, thymine, guanine, cytosine, and uracil, are responsible for the genetic code and the sequence of nucleotides in DNA and RNA. Therefore, the correct answer is nucleotides.

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24. Bacterial cell membrane DOES NOT contain:

Explanation

The bacterial cell membrane is composed of phospholipids, proteins, and lipids, which are essential components for its structure and function. Glycoproteins are also present in the membrane, serving various roles such as cell recognition and signaling. However, nucleic acids, which include DNA and RNA, are not typically found in the cell membrane. Nucleic acids are primarily located within the bacterial cell's cytoplasm and nucleus, where they play a crucial role in genetic information storage and protein synthesis.

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25. In the name of escherichia coli, coli is the:

Explanation

In the name of Escherichia coli, "coli" refers to the species. The species is the most specific taxonomic rank in the biological classification system. It represents a group of organisms that are closely related and can interbreed to produce fertile offspring. In this case, "Escherichia coli" is the specific species name for a type of bacteria commonly found in the intestines of humans and animals.

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26. Who proved that microorganisms cause disease?

Explanation

Koch proved that microorganisms cause disease. He was a German physician and microbiologist who developed the germ theory of disease. Koch's postulates, a set of criteria to establish a causal relationship between a microorganism and a disease, became the standard for identifying the causative agents of infectious diseases. Through his research on anthrax, tuberculosis, and cholera, Koch made significant contributions to the field of medical microbiology and laid the foundation for modern bacteriology.

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27. The type of bond holding Na+ and Cl- ions in NaCl is a(n):

Explanation

An ionic bond is formed between Na+ and Cl- ions in NaCl. In an ionic bond, one atom transfers electrons to another atom, resulting in the formation of oppositely charged ions. In this case, sodium (Na) loses an electron to become a positively charged ion (Na+), while chlorine (Cl) gains that electron to become a negatively charged ion (Cl-). The strong electrostatic attraction between these oppositely charged ions holds them together in a crystal lattice structure, forming an ionic bond.

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28. A chemical bond formed by two atoms when they share pairs of electrons to fill their outer shells is a/an:

Explanation

A covalent bond is formed when two atoms share pairs of electrons to fill their outer shells. In this type of bond, the electrons are shared between the atoms, creating a strong bond. This allows both atoms to achieve a stable electron configuration. Covalent bonds are typically formed between nonmetal atoms and are responsible for holding molecules together. Unlike ionic bonds, covalent bonds do not involve the transfer of electrons. Hydrophilic interaction, hydrogen bond, and ionic bond are not correct answers as they involve different types of bonding mechanisms.

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29. This microscope uses an ultraviolet light source.

Explanation

A fluorescence microscope is the correct answer because it uses an ultraviolet light source to excite fluorescent dyes or molecules in the sample. This causes them to emit light of a different wavelength, which can be captured and observed. This technique is commonly used in biological research to study specific molecules or structures within cells.

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30. Eukaryotes include all BUT

Explanation

Eukaryotes are organisms that have cells with a nucleus and other membrane-bound organelles. They include algae, fungi, plants, and animals. Bacteria, on the other hand, are prokaryotes, which means they lack a nucleus and membrane-bound organelles. Therefore, bacteria are not included in the category of eukaryotes.

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31. Which of the following pairs are mismatched?

Explanation

The given pair "Koch - aseptic surgery" is mismatched. Robert Koch was a German physician and microbiologist who is known for his contributions to the field of bacteriology, including his work on tuberculosis and the development of Koch's postulates. Aseptic surgery, on the other hand, refers to surgical techniques and practices aimed at preventing the introduction of microorganisms into a surgical wound. While Koch made significant contributions to the field of medicine, aseptic surgery is not one of them.

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32. Which of the following is a scientific name?

Explanation

Legionella Pneumophila is a scientific name because it follows the proper format for scientific naming, which consists of two parts: the genus name (Legionella) and the species name (Pneumophila). This naming system is used in biology to classify and categorize organisms. In contrast, the other options provided (Legionnaires' Disease, Legionnares' bacterium, Philadelphia fever) are not scientific names as they do not follow the proper naming conventions.

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33. Which of the following chemicals is found only in the outer membrane of Gram-negative bacteria?

Explanation

Lipopolysaccharide is a chemical found only in the outer membrane of Gram-negative bacteria. It is a unique component of the outer membrane and plays a crucial role in the structural integrity and protection of the bacteria. Lipopolysaccharide also acts as an endotoxin, triggering an immune response in the host organism. This chemical is not present in Gram-positive bacteria, making it a characteristic feature of Gram-negative bacteria.

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34. Which of the following statements are about a gram-negative cell wall is not true?

Explanation

Gram-negative cell walls do not have teichoic acids. Teichoic acids are a characteristic of gram-positive cell walls. Gram-negative cell walls contain lipopolysaccharides, which are responsible for the endotoxin activity. The outer membrane of gram-negative cell walls provides protection against osmotic lysis. The peptidoglycan layer in the cell wall helps maintain the shape of the cell.

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35. Which one makes the most ATP; aerobic respiration, anaerobic respiration or fermentation?

Explanation

Aerobic respiration is the process that produces the most ATP. During aerobic respiration, glucose is broken down in the presence of oxygen to produce a large amount of ATP. This process occurs in the mitochondria of cells and is the most efficient way to generate energy. Anaerobic respiration and fermentation also produce ATP, but in smaller amounts compared to aerobic respiration. Anaerobic respiration occurs in the absence of oxygen, while fermentation occurs in the absence of both oxygen and an electron transport chain. Both these processes are less efficient and produce fewer ATP molecules. Therefore, aerobic respiration is the most effective in generating ATP.

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36. All of the following can be found in mitochondria except:

Explanation

Mitochondria are membrane-bound organelles found in eukaryotic cells and are responsible for producing energy in the form of ATP. They contain their own circular DNA, which is distinct from the linear DNA found in the cell nucleus. Mitochondria also have ribosomes, which are responsible for protein synthesis. The ATP-generating mechanism and the electron transport system are both crucial components of mitochondrial function. However, mitochondria do not have a cell wall. Cell walls are typically found in prokaryotic cells, such as bacteria, and some eukaryotic cells, such as plant cells.

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37. Loss of electrons means:

Explanation

Oxidation refers to the loss of electrons from a substance. In this context, when a substance loses electrons, it is undergoing oxidation. Phosphorylation, on the other hand, refers to the addition of a phosphate group to a molecule, and reduction involves the gain of electrons. Therefore, the correct answer is oxidation as it directly relates to the loss of electrons.

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38. The best definition of biotechnology is:

Explanation

Biotechnology refers to the use of living organisms to create useful products. This can involve various techniques such as genetic engineering, fermentation, and cell culture. By harnessing the capabilities of living organisms, biotechnology allows for the production of a wide range of products including medicines, vaccines, biofuels, and agricultural crops. It also plays a crucial role in improving the efficiency and sustainability of various industrial processes. Therefore, the best definition of biotechnology is the use of living organisms to make desired products.

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39. The idea of spontaneous generation postulated that:

Explanation

The idea of spontaneous generation postulated that living organisms could arise from non-living material. This theory was widely believed in ancient times, with people thinking that maggots could spontaneously generate from decaying meat or mice could be born from piles of dirty clothes. However, this idea was later disproven by experiments conducted by Louis Pasteur in the 19th century, which showed that living organisms only arise from preexisting living organisms through reproduction. This discovery led to the development of the theory of biogenesis, which states that life can only come from life.

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40. By which of the following mechanisms can a cell transport a substance from a lower to a higher concentration?

Explanation

Active transport is the mechanism by which a cell can transport a substance from a lower to a higher concentration. Unlike passive transport mechanisms like simple diffusion and facilitated diffusion, active transport requires the cell to expend energy in the form of ATP to move molecules against their concentration gradient. This allows the cell to accumulate substances in higher concentrations than their surroundings, which is essential for various cellular processes such as nutrient uptake and ion regulation. Extracellular enzymes, on the other hand, are not involved in the transport of substances across the cell membrane.

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41. Bioremediation refers to:

Explanation

Bioremediation refers to the use of microbes to clean up pollution. Microbes, such as bacteria and fungi, are used to break down and remove pollutants from contaminated soil, water, and air. These microbes have the ability to metabolize and degrade various pollutants, including oil spills, heavy metals, pesticides, and organic compounds. Bioremediation offers a cost-effective and environmentally friendly approach to remediate polluted environments, as it harnesses the natural abilities of microbes to degrade and detoxify harmful substances.

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42. S-S agar inhibits gram-positive bacteria. On this medium, bacteria that ferment lactose to produce red colonies, and bacteria that do not ferment lactose to produce colorless colonies. This medium is:

Explanation

S-S agar is both selective and differential. It is selective because it inhibits the growth of gram-positive bacteria, allowing only gram-negative bacteria to grow. It is differential because it allows for the differentiation of bacteria based on their ability to ferment lactose. Bacteria that ferment lactose produce red colonies, while bacteria that do not ferment lactose produce colorless colonies. Therefore, S-S agar serves as a selective medium by inhibiting certain bacteria and a differential medium by allowing for the differentiation of bacteria based on their lactose fermentation abilities.

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43. Which of the following chemical bonds is the strongest?

Explanation

Covalent bonds are the strongest type of chemical bonds. In a covalent bond, two atoms share electrons, creating a strong bond between them. This sharing of electrons results in a stable configuration for both atoms, making the bond difficult to break. Ionic bonds, on the other hand, involve the transfer of electrons from one atom to another, resulting in a weaker bond. Hydrogen bonds are even weaker than both ionic and covalent bonds, as they are formed between a hydrogen atom and an electronegative atom, such as oxygen or nitrogen. Therefore, the correct answer is covalent bond.

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44. Which of the following statements is true?

Explanation

Endospores are specialized structures produced by certain bacteria in response to unfavorable environmental conditions. These structures are highly resistant to heat, radiation, chemicals, and desiccation. Endospores allow the bacterial cell to enter a dormant state, protecting its genetic material until conditions become favorable again. This enables the cell to survive harsh conditions such as extreme temperatures, lack of nutrients, or exposure to toxic substances. Therefore, the statement "endospores allow cell to survive environmental changes" is true.

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45. This is not a major bioelement

Explanation

Magnesium is not considered a major bioelement because it is not required in large quantities by living organisms. Major bioelements, such as carbon, hydrogen, oxygen, nitrogen, phosphorus, and sulfur, are essential for life and make up the majority of an organism's composition. While magnesium is still important for various biological processes, it is needed in smaller amounts compared to the major bioelements.

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46. All of the following organisms are eukaryotes except:

Explanation

Archaea are prokaryotes, not eukaryotes. Eukaryotes are organisms that have cells with a nucleus and other membrane-bound organelles, while prokaryotes lack a nucleus and organelles. Plants, protozoa, and fungi are all eukaryotes because they have cells with a nucleus and organelles. However, archaea are prokaryotes, meaning they do not have a nucleus or organelles. Therefore, the correct answer is archaea.

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47. Which of the following is not a kingdom in the five-kingdom system?

Explanation

Algae is not a kingdom in the five-kingdom system. The five-kingdom system categorizes living organisms into five kingdoms: Monera, Protista, Fungi, Plantae, and Animalia. Algae is a diverse group of photosynthetic organisms that can be found in various kingdoms, including Protista and Plantae, depending on their characteristics. However, it is not considered a separate kingdom in this classification system.

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48. Which of the following is not part of the cell membrane?

Explanation

Nucleic acids are not part of the cell membrane. The cell membrane is primarily composed of lipids, such as fatty acids, which form a lipid bilayer. Sugars are also present in the form of glycolipids and glycoproteins, while amino acids are found in integral membrane proteins. However, nucleic acids, which include DNA and RNA, are not directly involved in the structure or function of the cell membrane. They are primarily responsible for storing and transmitting genetic information within the cell.

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49. Who disproved the theory of spontaneous generation?

Explanation

Pasteur disproved the theory of spontaneous generation. He conducted experiments in the mid-19th century where he showed that microorganisms do not arise spontaneously from non-living matter, but rather from pre-existing microorganisms. His experiments involved using swan-necked flasks to prevent dust particles and microorganisms from entering the flask, and he observed that no growth occurred in the broth within the flask, thus refuting the theory of spontaneous generation.

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50. The difference between simple diffusion and facilitated diffusion is that facilitated diffusion:

Explanation

Facilitated diffusion is a type of passive transport that requires transporter proteins or carriers to move materials across the cell membrane. These transporter proteins facilitate the movement of specific molecules or ions by binding to them and helping them cross the membrane. Unlike active transport which requires ATP energy, facilitated diffusion does not require ATP as it relies on the concentration gradient to move materials from an area of higher concentration to an area of lower concentration. Therefore, the correct answer is that facilitated diffusion requires transporter proteins (carriers).

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51. Assume you have bacterial culture that requires teichoic acid in its growth medium. If teichoic acid is not provided, the bacteria will not be able to make:

Explanation

Teichoic acid is a crucial component of the bacterial cell wall. It provides structural integrity and stability to the cell wall, allowing the bacteria to maintain its shape and protect itself from external stresses. Without teichoic acid, the cell wall would be weakened and unable to function properly. This would compromise the overall integrity of the bacterial cell and its ability to survive and grow.

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52. The fluid mosaic model describes

Explanation

The fluid mosaic model describes the structure and organization of the cell membrane. According to this model, the cell membrane is composed of a phospholipid bilayer with embedded proteins, creating a fluid-like structure. The phospholipids have hydrophilic heads that face the aqueous environment inside and outside the cell, while the hydrophobic tails face each other in the interior of the membrane. This model also recognizes the presence of various proteins within the membrane that have different functions, such as transport, signaling, and cell adhesion. Overall, the fluid mosaic model explains the dynamic nature of the cell membrane and its ability to regulate the movement of substances in and out of the cell.

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53. Which of the following scientists and their discoveries is not correctly matched?

Explanation

The statement "Lister-antibiotics" is not correctly matched because Joseph Lister is known for his contributions to antiseptic surgery, not antibiotics. Lister introduced the use of carbolic acid to sterilize surgical instruments and clean wounds, which significantly reduced the risk of infection during surgeries. Antibiotics, on the other hand, were discovered by Alexander Fleming in 1928 with the discovery of penicillin.

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54. Which forces/bonds are involved in quaternary structure of proteins?

Explanation

The quaternary structure of proteins is determined by the interactions between multiple protein subunits. These interactions include hydrogen bonds, which form between the polar amino acid residues of different subunits, and disulfide (S-S) bridges, which covalently link cysteine residues. Van der Waals forces, which are weak attractions between nonpolar amino acid residues, also contribute to the stability of the quaternary structure. Additionally, peptide bonds, which form between the amino acids within a single polypeptide chain, are essential for the overall structure of the protein. Finally, hydrophobic interactions, which occur between nonpolar amino acids in an aqueous environment, play a crucial role in the folding and assembly of protein subunits.

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55. Cells containing the peptidoglycan layer are susceptible to penicillin. Which part of this molecule does this antibiotic affect?

Explanation

Penicillin affects the formation of the peptide bridge in the peptidoglycan layer of bacterial cells. The peptidoglycan layer is a crucial component of the cell wall in bacteria, providing structural support and protection. Penicillin interferes with the enzymes involved in the formation of the peptide bridge, which is essential for the cross-linking of peptidoglycan strands. By inhibiting this process, penicillin weakens the cell wall and ultimately leads to the lysis and death of the bacterial cell.

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56. What is/are the important biological function(s) of polysaccharides? a. energy storage b. structural support c. enzymatic activity d. information change

Explanation

Polysaccharides have important biological functions in energy storage and structural support. They serve as a source of energy for cells and organisms, as they can be broken down into glucose molecules through hydrolysis. Additionally, polysaccharides like cellulose and chitin provide structural support to plant cell walls and the exoskeleton of arthropods, respectively. Therefore, the correct answer is a and b.

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57. All of the following statements are true of gram-positive cells except which one?

Explanation

Gram positive cells do not have endotoxin. Endotoxin is a component of the outer membrane of gram-negative bacteria, not gram-positive bacteria. Gram-positive cells have a thick layer of peptidoglycan, making them more susceptible to the action of penicillin. Additionally, gram-positive cells retain the crystal violet stain and do not get decolorized by alcohol-acetone during the Gram staining process.

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58. These molecules are the primary building blocks of the plasma membrane in cells

Explanation

Lipids are the primary building blocks of the plasma membrane in cells. They form a lipid bilayer, which acts as a barrier to protect the cell and regulate the movement of molecules in and out of the cell. Lipids are hydrophobic, meaning they repel water, making them ideal for creating a barrier. Additionally, lipids are responsible for cell signaling, energy storage, and insulation. Therefore, lipids play a crucial role in maintaining the structure and function of the plasma membrane in cells.

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59. A protein's function depends upon its unique conformation. Which level of protein folding achieves this conformation?

Explanation

The tertiary structure of a protein is responsible for achieving its unique conformation. This level of protein folding involves the overall three-dimensional arrangement of the protein's secondary structures, such as alpha helices and beta sheets. The tertiary structure is determined by various interactions, including hydrophobic interactions, hydrogen bonding, disulfide bonds, and electrostatic interactions. These interactions help to stabilize the protein's structure and enable it to carry out its specific function. Therefore, the tertiary structure is crucial for determining a protein's overall conformation and functionality.

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60. Cells are made of mostly

Explanation

Cells are made up of various molecules, including lipids, proteins, RNA, DNA, and carbohydrates. However, proteins play a crucial role in the structure and function of cells. They are involved in various cellular processes such as metabolism, signaling, transportation, and cell division. Proteins are responsible for carrying out most of the cell's activities and are essential for the growth, repair, and maintenance of cells. Therefore, the correct answer is proteins.

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61. A medium having higher concentration of solutes than interior of the cell is a ______ ______, which causes cell to _________

Explanation

A hypertonic solution refers to a medium that has a higher concentration of solutes compared to the interior of the cell. When a cell is exposed to a hypertonic solution, water molecules tend to move out of the cell in an attempt to balance the concentration of solutes. As a result, the cell loses water and shrinks, causing it to shrivel.

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62. Robert koch established his postulates using the disease

Explanation

Robert Koch established his postulates using anthrax. The postulates are a set of criteria used to determine the causative agent of a disease. Koch successfully applied these postulates to anthrax, which helped him identify the specific bacterium responsible for the disease. By isolating and studying the bacterium, Koch was able to establish a direct link between the presence of the bacterium and the occurrence of the disease. This groundbreaking work laid the foundation for the field of medical microbiology and greatly advanced our understanding of infectious diseases.

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63. Which of the following organelles most closely resembles a prokaryotic cell?

Explanation

The correct answer is mitochondrion. Mitochondria are double-membraned organelles that have their own DNA and ribosomes, similar to prokaryotic cells. They also have the ability to replicate independently, just like prokaryotic cells. This resemblance suggests that mitochondria may have originated from a symbiotic relationship between an ancestral prokaryote and a eukaryotic cell.

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64. A molecule that contains both hydrophobic and hydrophilic groups is called:

Explanation

An amphipathic molecule is one that has both hydrophobic (water-repelling) and hydrophilic (water-attracting) groups. This dual nature allows it to interact with both water and nonpolar substances. The term "amphipathic" is derived from the Greek words "amphi" meaning "both" and "pathos" meaning "feeling". This property is important in biological systems, as it allows amphipathic molecules such as phospholipids to form the basis of cell membranes, with their hydrophobic tails facing inward and hydrophilic heads facing outward.

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65. Which of the following mechanisms generate ATP using an electron transport chain?

Explanation

Oxidative phosphorylation is the correct answer because it is the process by which ATP is generated using an electron transport chain. During oxidative phosphorylation, electrons are transferred through a series of protein complexes in the inner mitochondrial membrane, creating a proton gradient. This proton gradient is then used by ATP synthase to produce ATP. Fermentation, glycolysis, substrate level phosphorylation, and the Krebs cycle do not involve an electron transport chain and therefore do not generate ATP through oxidative phosphorylation.

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66. The most important environmental factor affecting growth is:

Explanation

Temperature is the most important environmental factor affecting growth because it directly influences the rate of biochemical reactions within an organism. As temperature increases, the rate of these reactions also increases up to a certain point, known as the optimum temperature. Beyond this point, the rate of reactions decreases. Different organisms have different temperature ranges in which they can grow optimally. Therefore, temperature plays a crucial role in determining the growth and development of organisms.

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67. The best use of a negative stain is:

Explanation

A negative stain is a staining technique that stains the background of a specimen, leaving the cells unstained. This allows for a clear visualization of the cell shape and morphology. By using a negative stain, the cells appear as colorless against a stained background, making it easier to observe their size, arrangement, and overall shape. Therefore, the best use of a negative stain is to determine the cell shape.

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68. An example of bioremediation is the use of:

Explanation

Bioremediation is the use of living organisms to remove or neutralize pollutants from a contaminated environment. Pseudomonas, a type of bacteria, can be used in bioremediation to remove uranium from oil at weapons depots. This bacterium has the ability to break down and metabolize uranium, converting it into a less harmful form. By utilizing Pseudomonas, the uranium contamination can be effectively reduced or eliminated, making the environment safer.

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69. Which of the following is not a product of TCA cycle?

Explanation

Acetyl-CoA is not a product of the TCA cycle, but rather a reactant that enters the cycle. In the TCA cycle, acetyl-CoA combines with oxaloacetate to form citrate, which then undergoes a series of reactions to produce CO2, NADH, GTP (ATP), and FADH. Acetyl-CoA is generated from the breakdown of glucose or fatty acids and serves as the starting point for the TCA cycle. Therefore, it is not a product but an important molecule that fuels the cycle.

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70. Which of the following is not related to bacterial cell wall

Explanation

All of the given options are related to the bacterial cell wall. The cell wall of bacteria is made of peptidoglycan, which provides structural support and helps maintain the shape of the bacteria. It also plays a role in controlling the water balance within the cell. Although not all bacteria have a cell wall, for those that do, these functions are essential for their survival and protection. Therefore, all of the options listed are related to the bacterial cell wall.

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71. All of the following statements about cellulase are true except which one?

Explanation

All of the given statements about cellulase are true except for the statement that it is a carbohydrate. Cellulase is an enzyme that is used to degrade cellulose, which is a complex carbohydrate found in plant cell walls. It is produced by some bacteria and fungi. However, cellulase itself is not a carbohydrate, but rather a protein enzyme that catalyzes the breakdown of cellulose into smaller sugar molecules.

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72. Which of the following compounds has the greatest amount of energy for a cell?

Explanation

Glucose has the greatest amount of energy for a cell compared to the other compounds listed. Glucose is a carbohydrate that is broken down through cellular respiration to produce ATP, the main source of energy for cells. ATP is a high-energy molecule that stores and releases energy as needed by the cell. O2 and CO2 are involved in cellular respiration but do not directly provide energy. Pyruvate is an intermediate product of glucose metabolism and does not contain as much energy as glucose.

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73. You have isolated a cell that lacks a membrane enclosed nucleus. You would find all of the following structures except  which one?

Explanation

The correct answer is "A lysosome". Lysosomes are membrane-bound organelles found in eukaryotic cells, but since the cell in question lacks a membrane-enclosed nucleus, it is most likely a prokaryotic cell. Prokaryotic cells, such as bacteria, do not possess lysosomes. Ribosomes, chromosomes, and peptidoglycan are all commonly found in prokaryotic cells.

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74. Name the two macromolecules that are considered essence of life

Explanation

Nucleic acids and proteins are considered the essence of life because they play crucial roles in the functioning and structure of living organisms. Nucleic acids, such as DNA and RNA, carry genetic information and are responsible for transmitting hereditary traits. Proteins are involved in almost all cellular processes and perform a wide range of functions, including catalyzing chemical reactions, providing structural support, and transporting molecules. Together, nucleic acids and proteins are essential for the growth, development, and maintenance of life.

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75. A denatured protein maintains its:

Explanation

When a protein is denatured, it loses its secondary, tertiary, and quaternary structures. However, the primary structure of the protein remains intact. The primary structure refers to the linear sequence of amino acids that make up the protein. This sequence is determined by the DNA sequence of the gene encoding the protein. Therefore, even though a denatured protein may no longer be able to perform its specific function, its primary structure remains unchanged.

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76. A peptide bond: (1) is a covalent bond (2) holds the primary structure of protein together (3) is between two hydrogen groups (4) is between carbon and nitrogen (5) is between two sugar molecules

Explanation

A peptide bond is a covalent bond that holds the primary structure of a protein together. It is formed between the carboxyl group of one amino acid and the amino group of another amino acid. Therefore, the correct answer is 1 2 4.

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77. All of the following are true about starch and cellulose except they are:

Explanation

Starch and cellulose are both polymers of glucose, produced by plants, and can be digested by many bacteria and fungi. However, they cannot be digested by animals. Animals lack the necessary enzymes to break down the beta-linkages present in starch and cellulose, making them indigestible for animals.

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78. Which of the following is not a characteristic of cell membrane

Explanation

The cell membrane is responsible for maintaining the shape of the cell by providing structural support and preventing the cell from collapsing or bursting. It is composed of a phospholipid bilayer, which gives it flexibility and allows for selective permeability. The cell membrane also contains proteins that perform various functions such as transport, signaling, and cell adhesion. Therefore, "Maintain cell shape" is not a characteristic of the cell membrane.

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79. Which of the following does not contribute to the hydrophobic interaction?

Explanation

Ionic interactions between hydrophobic molecules do not contribute to the hydrophobic interaction. The hydrophobic interaction is a phenomenon where nonpolar molecules or groups cluster together in an aqueous environment to minimize their contact with water. This occurs due to the exclusion of water molecules from the hydrophobic region, which leads to an increase in entropy. Proximity of hydrophobic molecules also contributes to the hydrophobic interaction as it allows for the formation of hydrophobic clusters. However, ionic interactions involve charged molecules and are not directly related to the hydrophobic interaction.

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80. Eukarya

Explanation

Eukarya have a membrane around their DNA. This is because eukaryotic cells, which belong to the domain Eukarya, have a well-defined nucleus that contains their DNA. The nucleus is surrounded by a double membrane called the nuclear envelope, which acts as a barrier between the DNA and the rest of the cell. This membrane helps protect and organize the DNA, allowing for more complex cellular functions to occur within the eukaryotic cell. Therefore, the statement "Eukarya have a membrane around their DNA" is correct.

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81. Peptidoglycan is made of mostly:

Explanation

Peptidoglycan is a major component of the cell wall in bacteria and is primarily composed of carbohydrates. It consists of long chains of sugar molecules, specifically N-acetylglucosamine and N-acetylmuramic acid, which are cross-linked by short peptide chains. This structure provides strength and rigidity to the bacterial cell wall. Proteins, lipids, and nucleic acids are also present in the cell wall, but they are not the main constituents of peptidoglycan.

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82. All of the following statements are true about the plasma membrane except which?

Explanation

The plasma membrane is a selectively permeable barrier that regulates the movement of substances in and out of the cell. The given answer states that small ions can easily cross the membrane, which is incorrect. Small ions, such as sodium and potassium, require specific protein channels or transporters to cross the membrane. These channels facilitate the movement of ions across the membrane by creating a passageway. Therefore, the statement contradicts the nature of the plasma membrane's selective permeability and the need for specialized proteins to transport small ions.

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83. Bacterial cell wall is made of:

Explanation

Murein is the correct answer because it is a major component of bacterial cell walls. Also known as peptidoglycan, murein is a complex molecule composed of sugars and amino acids that provides structural support and protection to the bacterial cell. It forms a mesh-like network that surrounds the cell membrane, giving the cell its shape and rigidity. Murein is unique to bacterial cells and is not found in other organisms, making it a distinguishing feature of bacterial cell walls.

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Which are of microbiolgy studies fungi?
Which of the following statements about bacteria is not true?
At which growth temperture bacteria grow at the fastest rate?
Which of the following pairs is mismatched?
Which of the following mechanisms requires energy?
The appearance of gram-negative bacteria after completing Gram stan...
What color should a gram-positive organism appear after Gram stain
The most common solidifying agent added to culture media is:
Cocci are:
You can find nucleotides in
Place the following steps in the correct sequence: 1 - Staining; 2-...
Cell division occurs in prokaryotes by:
Proteins are formed by amino acids connected by:
Which of the following is not a kingdom in the five-kingdom system?
These are the primary molecules making up plasma membrane in cells
This microscope is used to observe a specimen that emits light when...
Identify the FALSE statement.
This is not an internal structure of a bacteria
Which molecule is composed of a chain of amino acids?
What is the purpose of buffer in culture media?
We discussed two processes for synthesizing ATP. Which process...
This microscope achieves the highest magnification and greatest...
Nitrogen bases are building blocks of:
Bacterial cell membrane DOES NOT contain:
In the name of escherichia coli, coli is the:
Who proved that microorganisms cause disease?
The type of bond holding Na+ and Cl- ions in NaCl is a(n):
A chemical bond formed by two atoms when they share pairs of electrons...
This microscope uses an ultraviolet light source.
Eukaryotes include all BUT
Which of the following pairs are mismatched?
Which of the following is a scientific name?
Which of the following chemicals is found only in the outer membrane...
Which of the following statements are about a gram-negative cell wall...
Which one makes the most ATP; aerobic respiration, anaerobic...
All of the following can be found in mitochondria except:
Loss of electrons means:
The best definition of biotechnology is:
The idea of spontaneous generation postulated that:
By which of the following mechanisms can a cell transport a substance...
Bioremediation refers to:
S-S agar inhibits gram-positive bacteria. On this medium, bacteria...
Which of the following chemical bonds is the strongest?
Which of the following statements is true?
This is not a major bioelement
All of the following organisms are eukaryotes except:
Which of the following is not a kingdom in the five-kingdom system?
Which of the following is not part of the cell membrane?
Who disproved the theory of spontaneous generation?
The difference between simple diffusion and facilitated diffusion is...
Assume you have bacterial culture that requires teichoic acid in its...
The fluid mosaic model describes
Which of the following scientists and their discoveries is not...
Which forces/bonds are involved in quaternary structure of proteins?
Cells containing the peptidoglycan layer are susceptible to...
What is/are the important biological function(s) of polysaccharides?...
All of the following statements are true of gram-positive cells except...
These molecules are the primary building blocks of the plasma membrane...
A protein's function depends upon its unique conformation. Which level...
Cells are made of mostly
A medium having higher concentration of solutes than interior of the...
Robert koch established his postulates using the disease
Which of the following organelles most closely resembles a prokaryotic...
A molecule that contains both hydrophobic and hydrophilic groups is...
Which of the following mechanisms generate ATP using an electron...
The most important environmental factor affecting growth is:
The best use of a negative stain is:
An example of bioremediation is the use of:
Which of the following is not a product of TCA cycle?
Which of the following is not related to bacterial cell wall
All of the following statements about cellulase are true except which...
Which of the following compounds has the greatest amount of energy for...
You have isolated a cell that lacks a membrane enclosed nucleus. You...
Name the two macromolecules that are considered essence of life
A denatured protein maintains its:
A peptide bond: (1) is a covalent bond (2) holds the primary structure...
All of the following are true about starch and cellulose except they...
Which of the following is not a characteristic of cell membrane
Which of the following does not contribute to the hydrophobic...
Eukarya
Peptidoglycan is made of mostly:
All of the following statements are true about the plasma membrane...
Bacterial cell wall is made of:
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