1.
All members of which biological group require a host cell to reproduce?
Correct Answer
D. Viruses
Explanation
Viruses require a host cell to reproduce. Unlike other biological groups, viruses cannot reproduce on their own. They invade host cells and use the host's machinery to replicate themselves. They attach to the host cell, inject their genetic material, and take over the cell's functions to produce more viruses. This process eventually leads to the death or lysis of the host cell, releasing newly formed viruses to infect other cells. Therefore, viruses are dependent on host cells for their reproduction.
2.
Which group(s) contain organisms that can be classified as autotrophs?
Correct Answer
C. Bacteria and protists
Explanation
Bacteria and protists can both be classified as autotrophs. Autotrophs are organisms that are able to produce their own food using energy from the environment, such as sunlight or inorganic compounds. Bacteria and protists have the ability to perform photosynthesis or chemosynthesis, allowing them to produce their own energy and nutrients. Viruses, on the other hand, are not considered living organisms and do not possess the ability to produce their own food. Therefore, the correct answer is bacteria and protists.
3.
Alec studied an unknown microscopic organism and recorded this information:
- It contains DNA.
- It has a cell wall, but no nucleus.
What is Alec most likely studying?
Correct Answer
A. Bacterium
Explanation
Alec is most likely studying a bacterium. Bacteria are microscopic organisms that contain DNA and have a cell wall, but no nucleus. Fungi, protists, and viruses do not fit all the criteria mentioned by Alec.
4.
Bacterial cells
Correct Answer
C. Have both a cell membrane and cell wall.
Explanation
Bacterial cells have both a cell membrane and a cell wall. The cell membrane is a thin, flexible layer that surrounds the cell and acts as a barrier, controlling the movement of substances in and out of the cell. The cell wall, located outside the cell membrane, provides structural support and protection for the cell. It helps maintain the shape of the cell and prevents it from bursting under osmotic pressure. Therefore, bacterial cells possess both a cell membrane and a cell wall to perform these essential functions.
5.
Structures found in a protist but not in a bacterium are
Correct Answer
D. All of the answers
Explanation
Protists are eukaryotic organisms, which means they have a true nucleus enclosed within a nuclear membrane. Bacteria, on the other hand, are prokaryotic organisms and lack a true nucleus. Therefore, the presence of cell nuclei is a structure found in protists but not in bacteria. Additionally, protists can have multiple chromosomes, whereas bacteria usually have a single circular chromosome. Lastly, protists possess membrane-bound organelles such as mitochondria, Golgi apparatus, and endoplasmic reticulum, while bacteria lack these organelles. Hence, all of the given answers are structures that are found in protists but not in bacteria.
6.
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 simple organisms that do not have a defined nucleus and their genetic material is not enclosed in a membrane. They also lack other membrane-bound organelles such as mitochondria or chloroplasts. Instead, their genetic material is found in the cytoplasm in a region called the nucleoid. Bacteria are unicellular organisms that reproduce through binary fission and are found in various environments.
7.
Which structure would NOT be found in a bacterial cell?
Correct Answer
B. Chloroplast
Explanation
Chloroplasts are organelles found in plant cells and some protists, but they are not present in bacterial cells. Bacterial cells have a cell wall, DNA, and ribosomes, which are essential structures for their survival and function. The absence of chloroplasts in bacterial cells is due to the fact that they do not perform photosynthesis, unlike plants and some other organisms.
8.
Viruses are considered nonliving because
Correct Answer
D. All of the answers
Explanation
The correct answer is "All of the answers." This is because all three statements provided in the options support the idea that viruses are considered nonliving. Viruses cannot reproduce by themselves, as they require a host cell to replicate. They are not made up of cells, unlike living organisms. Additionally, viruses cannot carry out metabolism independently, as they rely on host cells for energy and other metabolic processes. Therefore, all of these statements contribute to the understanding that viruses are nonliving entities.
9.
All viruses have
Correct Answer
D. A protein coat.
Explanation
All viruses have a protein coat. This is a distinguishing feature of viruses, as they are composed of genetic material (DNA or RNA) surrounded by a protein coat called a capsid. The protein coat provides protection to the viral genetic material and helps in the attachment of the virus to host cells. Additionally, some viruses may also have an outer envelope made up of lipids. However, not all viruses have cytoplasm, ribosomes, or mitochondria as these are cellular components found in living organisms.
10.
Refer to the illustration above. Which structure could possibly be made of RNA?
Correct Answer
B. Structure 3
Explanation
Based on the illustration, structure 3 appears to be a single-stranded molecule with a ribose sugar backbone and nitrogenous bases. This suggests that it could be RNA, as RNA is typically single-stranded and contains ribose sugar. Structures 2, 4, and 5 seem to have a double-stranded nature, which is more characteristic of DNA rather than RNA.
11.
Refer to the illustration above. Which structure is found outside the cell after the cell is infected?
Correct Answer
A. Structure 1
12.
Viruses
Correct Answer
B. Reproduce only in living cells.
Explanation
Viruses are considered non-living entities because they lack the cellular machinery necessary for independent reproduction. Instead, they rely on infecting living cells and hijacking their cellular machinery to replicate themselves. This process is known as viral replication. Once inside a host cell, viruses use the host's resources to produce more viral particles, which can then go on to infect other cells. Therefore, the correct answer is that viruses reproduce only in living cells.
13.
All protists
Correct Answer
B. Have a true nucleus.
Explanation
The correct answer is "have a true nucleus." This is because protists are eukaryotic organisms, meaning they have a true nucleus enclosed within a membrane. Unlike prokaryotes, which lack a true nucleus, protists have a well-defined nucleus that contains their genetic material. This characteristic distinguishes protists from other types of microorganisms and is essential for their complex cellular functions and processes.
14.
Algae are:
Correct Answer
C. AutotropHic protists.
Explanation
Algae are autotrophic protists, meaning they are capable of producing their own food through photosynthesis. They can be found in various environments, including freshwater, marine habitats, and even on land. While some algae species are unicellular, others can be multicellular. Therefore, the correct answer is that algae are autotrophic protists, encompassing all of the given statements.
15.
This is an organism that must obtain energy from the food it consumes.
Correct Answer
C. HeterotropH
Explanation
A heterotroph is an organism that must obtain energy from the food it consumes. Unlike autotrophs, which can produce their own energy through photosynthesis or other means, heterotrophs rely on external sources for energy. They obtain nutrients by consuming other organisms or organic matter. The other options, such as capsid, prokaryote, and eukaryote, do not directly relate to the organism's energy source and are therefore not the correct answer.
16.
This is the outer protein coat of a virus.
Correct Answer
A. Capsid
Explanation
The outer protein coat of a virus is called a capsid. The capsid is responsible for protecting the genetic material of the virus and helps in attaching to host cells. It is composed of individual protein subunits called capsomeres, which come together to form the overall structure of the capsid. The capsid provides structural stability to the virus and plays a crucial role in the viral replication cycle.
17.
Any organism whose cell(s) contain a nucleus is called a _____.
Correct Answer
E. Eukaryote
Explanation
An organism whose cell(s) contain a nucleus is called a eukaryote. Eukaryotes are characterized by having a well-defined nucleus that houses their genetic material, such as DNA. This distinguishes them from prokaryotes, which do not have a nucleus. Eukaryotes include a wide range of organisms, such as plants, animals, fungi, and protists.