1.
A typical virus consits of...
Correct Answer
C. A protein core and a nucleic acid core
Explanation
A typical virus consists of a protein core and a nucleic acid core. This means that viruses have genetic material (nucleic acid) surrounded by a protein coat. The nucleic acid can be either DNA or RNA, depending on the type of virus. The protein coat, also known as the capsid, protects the genetic material and helps the virus attach to host cells. Some viruses may also have additional structures, such as an envelope derived from the host cell membrane. However, the essential components of a virus are the protein and nucleic acid cores.
2.
A virus that has been genetically altered to reduce its virulence is known as a (n)
Correct Answer
B. Annenuated virus
Explanation
An attenuated virus is a virus that has been genetically altered to reduce its virulence. This means that the virus is less harmful or less likely to cause disease compared to its original form. Attenuated viruses are often used in vaccines as they can still stimulate an immune response without causing severe illness. By reducing the virulence of the virus, it allows for safer and more controlled administration of the vaccine.
3.
Bacterial cells...
Correct Answer
C. Have both a cell membrane and a cell wall
Explanation
Bacterial cells have both a cell membrane and a cell wall. The cell membrane acts as a barrier, controlling the movement of substances in and out of the cell. It also contains various proteins and enzymes necessary for cellular processes. The cell wall, located outside the cell membrane, provides structural support and protection to the cell. It helps maintain the shape of the cell and prevents it from bursting when exposed to changes in osmotic pressure. Therefore, bacterial cells possess both a cell membrane and a cell wall to maintain their integrity and functionality.
4.
Viruses...
Correct Answer
B. Reproduce only in living cells
Explanation
Viruses are considered non-living entities because they lack the characteristics of cellular organisms. They are unable to reproduce on their own and instead rely on living cells to replicate. This process involves the virus injecting its genetic material into a host cell, taking over the cell's machinery, and using it to produce more viruses. Therefore, the statement "reproduce only in living cells" accurately describes the reproductive mechanism of viruses.
5.
When a virus transfers a gene to a bacterium, it is called:
Correct Answer
D. Transduction
Explanation
Transduction is the correct answer because it refers to the process in which a virus transfers genetic material from one bacterium to another. During transduction, the virus infects a bacterium and incorporates its own genetic material into the bacterium's DNA. When the bacterium replicates, it also replicates the viral DNA, allowing it to be transferred to other bacteria. This process plays a significant role in horizontal gene transfer and the spread of antibiotic resistance genes among bacteria.
6.
Algae are different the other protists because algae are:
Correct Answer
D. pHotoautotropHs
Explanation
Algae are different from other protists because they are photoautotrophs. This means that they can produce their own food through photosynthesis, using sunlight as their energy source. Unlike prokaryotic organisms, algae have a nucleus and other membrane-bound organelles, making them eukaryotic. Ingestive heterotrophs obtain their food by consuming other organisms, while absorptive heterotrophs absorb nutrients from their environment. Algae, on the other hand, are able to use light energy to convert carbon dioxide and water into organic compounds, making them unique among protists.
7.
The process by which bacteria reproduce is known as:
Correct Answer
D. Binary fission
Explanation
Binary fission is the correct answer because it is the process by which bacteria reproduce. In binary fission, a single bacterium divides into two identical daughter cells. This process allows bacteria to rapidly increase in population and is essential for their survival and spread. Mitosis is a form of cell division that occurs in eukaryotic cells, not bacteria. Sexual reproduction involves the fusion of gametes from two parents, which is also not the method used by bacteria.
8.
It is important to distinguish between Gram-negative and Gram-positive bacteria in diagnosing a bacterial infection because:
Correct Answer
A. Gram-negative and Gram-positive bacteria respond to different antibiotics
Explanation
Gram-negative and Gram-positive bacteria respond to different antibiotics. This is important in diagnosing a bacterial infection because it helps determine the most effective treatment. Gram-negative bacteria have an outer membrane that makes them more resistant to antibiotics, while Gram-positive bacteria have a thicker peptidoglycan layer that makes them more susceptible to certain antibiotics. Therefore, knowing whether the bacteria are Gram-negative or Gram-positive allows healthcare professionals to prescribe the appropriate antibiotics to target the specific type of bacteria causing the infection.
9.
Bacteria whose cells are rod shaped are classified as:
Correct Answer
B. Bacilli
Explanation
Rod-shaped bacteria are classified as bacilli. This is because the term "bacilli" specifically refers to bacteria that have a rod-like shape. Cocci, on the other hand, are bacteria that have a spherical shape, while spirilli are bacteria that have a spiral or helical shape. Therefore, the correct classification for bacteria with rod-shaped cells is bacilli.
10.
Bacteria whose cells are round/spherical are classified as:
Correct Answer
A. Cocci
Explanation
Bacteria whose cells are round/spherical are classified as cocci. Cocci are a type of bacteria that have a spherical shape. This shape is due to the presence of a cell wall that is rigid and maintains the round structure. Cocci can occur in various arrangements, such as in pairs (diplococci), in chains (streptococci), or in clusters (staphylococci). This classification is based on the shape and arrangement of the cells, which helps in identifying and categorizing different types of bacteria. Bacilli, on the other hand, are rod-shaped bacteria, and spirilli are spiral-shaped bacteria.
11.
Protists are different from bacteria because protists:
Correct Answer
C. Have eukaryotic cells
Explanation
Protists are different from bacteria because they have eukaryotic cells. Eukaryotic cells are more complex than prokaryotic cells, which bacteria have. Eukaryotic cells have a true nucleus, membrane-bound organelles, and other complex structures, while prokaryotic cells lack these features. Therefore, the presence of eukaryotic cells is what sets protists apart from bacteria.
12.
Animal-like protists are animal like because animal-like protists are:
Correct Answer
B. Ingestive heterotropHs
Explanation
Animal-like protists are referred to as ingestive heterotrophs because they obtain their nutrients by ingesting other organisms or organic matter. Unlike photoautotrophs, which can produce their own food through photosynthesis, animal-like protists rely on consuming other organisms for their energy and nutrients. This characteristic sets them apart from prokaryotes, which are single-celled organisms lacking a nucleus, and absorptive heterotrophs, which obtain nutrients by absorbing them from their surroundings.
13.
The prokaryotic organisms that are most similar to the first life on Earth are the:
Correct Answer
C. Archaebacteria
Explanation
Archaebacteria are the most similar prokaryotic organisms to the first life on Earth because they are ancient and have unique characteristics that resemble the conditions of early Earth. They thrive in extreme environments like hot springs, deep-sea hydrothermal vents, and salt flats, which are similar to the harsh conditions that existed billions of years ago. Archaebacteria also have a different cell wall structure and genetic makeup compared to other prokaryotes, making them more primitive and similar to the first life forms on Earth.
14.
Amoeba is a member of:
Correct Answer
D. Kingdom Protista
Explanation
Amoeba is a member of Kingdom Protista because it is a single-celled organism that lacks specialized tissues and organelles found in higher organisms. Kingdom Protista is a diverse group of eukaryotic microorganisms that includes various types of unicellular organisms, such as amoebas, as well as some multicellular algae. Amoebas are characterized by their ability to move and feed by extending pseudopods, which are temporary projections of their cell membrane. They are commonly found in freshwater environments and play important roles in nutrient cycling and food chains.
15.
A substance that kills bacteria that interferes with their cellular functions is a(n):
Correct Answer
A. Antibiotic
Explanation
An antibiotic is a substance that kills bacteria by interfering with their cellular functions. It targets specific processes or structures within the bacterial cells, such as inhibiting protein synthesis or disrupting cell wall formation. Antibiotics are commonly used to treat bacterial infections in humans and animals. They can be produced naturally by microorganisms or synthesized in the laboratory. Antibiotics are not effective against viruses or other types of microorganisms, and their misuse or overuse can lead to the development of antibiotic resistance.
16.
Bacteria whose cells are arranged into grape-like clusters are classified as:
Correct Answer
D. StapHlo-
Explanation
Bacteria whose cells are arranged into grape-like clusters are classified as "staphlo-". This is because the term "staphlo-" is used to describe bacteria that form clusters or groups. The arrangement of cells in grape-like clusters is a characteristic feature of Staphylococcus bacteria, which belong to the staphylo- group.
17.
Bacteria that stain purple and have a thick cell wall of peptidoglycan are the:
Correct Answer
B. Gram-positive bacteria
Explanation
Gram-positive bacteria are the correct answer because they are characterized by their ability to retain the purple stain when subjected to the Gram staining procedure. This is due to the thick cell wall of peptidoglycan that they possess. Archaebacteria and Gram-negative bacteria do not have this specific characteristic.
18.
Bacteria lack a true nucleus and membrane-bound organelles; therefore, they are classified as:
Correct Answer
A. Prokaryotes
Explanation
Bacteria are classified as prokaryotes because they lack a true nucleus and membrane-bound organelles. Prokaryotes are single-celled organisms that do not have a well-defined nucleus or other complex membrane-bound structures found in eukaryotes. Bacteria have a simple cell structure with a single circular DNA molecule and lack membrane-bound organelles like mitochondria or chloroplasts. This classification distinguishes them from eukaryotes, which have a true nucleus and membrane-bound organelles.
19.
Bacteria whose cells are arranged into straight chains or filaments are classified under:
Correct Answer
C. Strepto-
Explanation
Bacteria whose cells are arranged into straight chains or filaments are classified under "strepto-". This prefix indicates that the cells are arranged in a linear pattern, forming a chain or filament-like structure. It is important to note that "strepto-" is different from "staphylo-", which refers to bacteria arranged in clusters or groups.
20.
Which of the following groups of algae has the most characteristics in common with plants?
Correct Answer
C. Green algae
Explanation
Green algae has the most characteristics in common with plants. This is because both green algae and plants contain chlorophyll, which allows them to photosynthesize and convert sunlight into energy. Additionally, green algae and plants both have cell walls made of cellulose, and they share similar reproductive structures, such as the presence of multicellular reproductive organs. These similarities suggest a close evolutionary relationship between green algae and plants.
21.
One difference between the archaebacteria and eubacteria is that the archaebacteria:
Correct Answer
B. Don't have peptidoglycan in their cell walls
Explanation
Archaebacteria don't have peptidoglycan in their cell walls. Peptidoglycan is a polymer that provides structural support to the cell walls of most bacteria. Eubacteria, on the other hand, do have peptidoglycan in their cell walls. This difference in cell wall composition is one of the key distinguishing features between these two groups of bacteria.
22.
In which type of cell cycle(s) does viral DNA become integrated into the host cell's DNA?
Correct Answer
B. Lysogenic
Explanation
Viral DNA becomes integrated into the host cell's DNA in the lysogenic cell cycle. In this cycle, the viral DNA is inserted into the host cell's genome and becomes a part of it. This integration allows the viral DNA to be replicated along with the host cell's DNA during cell division. The lysogenic cycle is characterized by a period of viral dormancy, where the viral DNA remains integrated in the host cell's genome without causing immediate harm.
23.
When bacteria reproduce:
Correct Answer
A. They divide into two identical cells
Explanation
When bacteria reproduce, they divide into two identical cells. This process is known as binary fission, where a single bacterium splits into two daughter cells that are genetically identical to the parent cell. This type of reproduction ensures that the genetic material is passed on accurately and maintains the same characteristics as the parent bacterium.
24.
Protists are different from animals, plants and the fungi because protists are:
Correct Answer
A. Relatively simple
Explanation
Protists are different from animals, plants, and fungi because they are relatively simple. Unlike animals, plants, and fungi, protists do not have specialized tissues or organs. They are typically single-celled organisms or multicellular organisms with simple structures. This simplicity allows protists to carry out basic functions such as reproduction, feeding, and movement. In contrast, animals, plants, and fungi have more complex cellular structures and specialized functions.
25.
The archae that thrive in hot acidic environments are the:
Correct Answer
A. ThermoacidopHiles
Explanation
Thermoacidophiles are a type of archaea that thrive in hot acidic environments. They are able to survive and grow in extreme conditions of high temperature and low pH levels. These organisms have adapted to these harsh environments by developing unique biochemical and physiological mechanisms. Thermoacidophiles are found in places such as hot springs, volcanic vents, and acidic soils. They play an important role in the ecosystem by contributing to nutrient cycling and biogeochemical processes.
26.
When two bacteria connect using a pilli, and genes are transferred from one bacterium to another, it is called:
Correct Answer
A. Conjugation
Explanation
Conjugation is the correct answer because it refers to the process in which two bacteria connect using a pilus and exchange genetic material, such as plasmids, through a conjugation bridge. This allows for the transfer of genes from one bacterium to another, increasing genetic diversity and potentially providing new traits or resistance to antibiotics. Transformation refers to the uptake of foreign DNA from the environment, while transduction involves the transfer of genetic material via bacteriophages. Binary fission, on the other hand, is the process of a bacterial cell dividing into two identical daughter cells.
27.
When a bacterial cell absorps a gene from the environment, it is called:
Correct Answer
B. Transformation
Explanation
Transformation is the correct answer because it refers to the process in which a bacterial cell absorbs genetic material from its environment. This can occur when free DNA is released by other bacteria and taken up by a recipient cell. The absorbed DNA can then be incorporated into the recipient cell's genome and potentially alter its characteristics. Conjugation involves the transfer of genetic material between bacteria through direct cell-to-cell contact, transduction involves the transfer of genetic material through a viral vector, and binary fission is the process by which bacteria reproduce by dividing into two identical daughter cells.
28.
The capsid of a virus is the
Correct Answer
A. Protective outer coat
Explanation
The capsid of a virus refers to the protective outer coat that surrounds the genetic material of the virus. It acts as a shield, providing protection to the genetic material from the external environment, such as enzymes or the host's immune system. The capsid is made up of protein subunits called capsomeres, which come together to form the outer coat. This outer coat plays a crucial role in the virus's ability to infect host cells and replicate.
29.
What is the organism that causes malaria?
Correct Answer
A. Plasmodian
Explanation
Plasmodian is the correct answer because it is the organism that causes malaria. Malaria is a mosquito-borne infectious disease that is caused by the Plasmodium parasite. The parasite is transmitted to humans through the bite of infected female Anopheles mosquitoes. Once inside the human body, the parasite multiplies and infects red blood cells, leading to the characteristic symptoms of malaria. Therefore, Plasmodian is the organism responsible for causing malaria.
30.
Which of the following is an example of how microogranisms DO NOT benefit humans?
Correct Answer
D. Algae creates algo-blooms and red-tides, which harm bodies of water
Explanation
Algae creating algo-blooms and red-tides that harm bodies of water does not benefit humans.