1.
What must cells do in order to survive?
Correct Answer
E. All of above
Explanation
Cells must obtain and process energy in order to carry out their functions and survive. This energy is necessary for various cellular processes such as growth, reproduction, and maintaining homeostasis. Additionally, cells need to convert genetic information into proteins through the process of gene expression. Proteins perform various important functions in the cell, including enzymatic reactions, structural support, and cell signaling. Furthermore, cells must keep certain biochemical reactions separate from one another to ensure proper functioning and prevent interference between different processes. Therefore, cells must do all of the above in order to survive.
2.
The surface area-to-volume ratio of an object can be decreased by:
Correct Answer
D. Making it sperical
Explanation
Making an object spherical decreases its surface area-to-volume ratio. This is because a sphere has the smallest surface area for a given volume compared to any other shape. By making an object spherical, the surface area decreases while the volume remains the same, resulting in a lower surface area-to-volume ratio.
3.
Members of the domains Bacteria and Archaea:
Correct Answer
D. Are prokaryotes
Explanation
The correct answer is "are prokaryotes". This is because members of the domains Bacteria and Archaea are both prokaryotes, which means they lack a nucleus and other membrane-bound organelles. Prokaryotes are single-celled organisms that do not have a true nucleus, unlike eukaryotes. Therefore, they do not have nuclei, chloroplasts, or flagella. Additionally, they are typically unicellular, although some species may form colonies or biofilms.
4.
Which of the following is not a characteristic of a prokaryotic cell?
Correct Answer
B. A nuclear envelope
Explanation
A prokaryotic cell does not have a nuclear envelope, which is a characteristic of eukaryotic cells. Prokaryotic cells have a nucleoid region instead, where the genetic material is located. The nucleoid is not enclosed by a membrane like the nucleus in eukaryotic cells. Prokaryotic cells do have a plasma membrane, ribosomes, and enzymes.
5.
Which of the following is (are) found in prokaryotic cells?
Correct Answer
D. Ribosomes
Explanation
Ribosomes are found in prokaryotic cells. Prokaryotic cells are simple, single-celled organisms that lack a nucleus and membrane-bound organelles. Ribosomes are the cellular structures responsible for protein synthesis, and they are found in both prokaryotic and eukaryotic cells. Therefore, ribosomes are the only option listed that can be found in prokaryotic cells.
6.
What is the major distinction between a prokaryotic and a eukaryotic cell?
Correct Answer
A. A prokaryotic cell does not have a nucleus, whereas a eukaryotic cell does
Explanation
The major distinction between a prokaryotic and a eukaryotic cell is that a prokaryotic cell does not have a nucleus, whereas a eukaryotic cell does. Prokaryotic cells are simpler in structure and do not have a membrane-bound nucleus, while eukaryotic cells have a distinct nucleus that houses their genetic material. This difference in cellular organization has significant implications for the complexity and functionality of these cells.
7.
A prokaryotic cell does not have a _____ or _____
Correct Answer
A. Nucleus; organelles
Explanation
A prokaryotic cell does not have a nucleus or organelles. Prokaryotic cells are simple cells that lack a membrane-bound nucleus and other membrane-bound organelles found in eukaryotic cells. Instead, their DNA is found in the cytoplasm, floating freely. Prokaryotic cells also lack membrane-bound compartments such as mitochondria, endoplasmic reticulum, and Golgi apparatus, which are present in eukaryotic cells.
8.
How does the surface area-to-volume ratio of a 1-mm cube compare to the surface area-to-volume ratio of a 3-mm cube?
Correct Answer
D. The ratio decreases as the cube becomes larger
Explanation
As the cube becomes larger, the volume increases at a faster rate compared to the surface area. This is because the volume of a cube is determined by the length of its sides cubed, while the surface area is determined by the length of its sides squared. Therefore, as the cube grows in size, the volume increases more rapidly than the surface area, causing the surface area-to-volume ratio to decrease.
9.
You would not expect to find RNA in which of the following structures?
Correct Answer
C. Vacuole
Explanation
RNA is typically found in structures involved in protein synthesis, such as the nucleus, mitochondrion, ribosome, and prokaryotic cell. Vacuoles, on the other hand, are storage structures responsible for storing water, ions, and other molecules. While they may contain some RNA, it is not primarily their function, so you would not expect to find a significant amount of RNA in vacuoles.
10.
The DNA of prokaryotic cells is found in the
Correct Answer
D. Nucleoid region
Explanation
In prokaryotic cells, the DNA is found in the nucleoid region. Unlike eukaryotic cells, prokaryotic cells do not have a true nucleus. The nucleoid region is a region within the cytoplasm where the DNA is located. It is not enclosed by a membrane like a nucleus, but rather the DNA is organized and compacted within this region. The nucleoid region plays a vital role in controlling the cell's activities and contains all the genetic information necessary for the cell's functioning.
11.
Ribosomes are not visible under a light microscope, but they can be seen with an electron microscope because:
Correct Answer
C. Electron microscopes have more resolving power than light microscopes
Explanation
Electron microscopes have more resolving power than light microscopes. Resolving power refers to the ability of a microscope to distinguish between two closely spaced objects as separate entities. Electron microscopes use a beam of electrons instead of light to create an image, which allows for much higher magnification and resolution. The shorter wavelength of electrons compared to light enables electron microscopes to visualize smaller structures, such as ribosomes, that are not visible under a light microscope. Therefore, electron microscopes are able to provide a more detailed and clear image of ribosomes.
12.
A general function of all cellular membranes is to
Correct Answer
A. Regulate which materials can cross the membrane
Explanation
Cellular membranes play a crucial role in regulating the movement of materials in and out of the cell. They act as selective barriers, allowing certain substances to pass through while preventing others from doing so. This regulation is essential for maintaining the cell's internal environment and ensuring proper functioning. The other options, such as supporting the cell, producing energy or proteins, and moving the cell, are not general functions of all cellular membranes.
13.
The cytosol:
Correct Answer
C. Is composed largely of water
Explanation
The cytosol is the liquid component of the cytoplasm, which fills the interior of the cell. It is composed largely of water, making up the majority of the cell's volume. This aqueous solution provides a medium for many cellular processes to occur, such as metabolic reactions and protein synthesis. Additionally, the cytosol also contains various ions, small molecules, and proteins that contribute to its overall composition and function within the cell.
14.
A specialized structure found in some prokaryotes is the:
Correct Answer
A. Cell wall
Explanation
The correct answer is cell wall. The cell wall is a specialized structure found in some prokaryotes, such as bacteria. It is a rigid layer that surrounds the cell membrane and provides support and protection to the cell. The cell wall is composed of peptidoglycan, a unique molecule that is not found in eukaryotic cells. It helps maintain the shape of the cell and prevents it from bursting or collapsing under osmotic pressure. The cell wall also acts as a barrier, preventing the entry of harmful substances and protecting the cell from mechanical damage.
15.
Specialized cellular appendages of prokaryotes that help bacteria adhere to one another when they exchange genetic material are called:
Correct Answer
D. Pili
Explanation
Pili are specialized cellular appendages of prokaryotes that help bacteria adhere to one another when they exchange genetic material. Unlike cilia and flagella, which are involved in movement, pili play a crucial role in bacterial conjugation, a process where genetic material is transferred between bacterial cells. Pili are hair-like structures that extend from the bacterial surface and allow the bacteria to attach to surfaces or other bacteria, facilitating the exchange of genetic material.
16.
In some prokaryotic organisms the plasma membrane folds to form an internal membrane system that is able to:
Correct Answer
A. Carry on pHotosynthesis
Explanation
In some prokaryotic organisms, the plasma membrane folds to form an internal membrane system that is able to carry on photosynthesis. This is known as the thylakoid membrane system, which contains pigments and enzymes necessary for the process of photosynthesis. The folding of the plasma membrane increases the surface area available for the reactions involved in photosynthesis, allowing the organism to capture sunlight and convert it into energy. This adaptation is found in certain prokaryotes, such as cyanobacteria, which are capable of performing photosynthesis.
17.
17. Some bacteria are able to propel themselves through liquid by means of a structure called the
Correct Answer
A. A. flagellum.
Explanation
Some bacteria are able to propel themselves through liquid by means of a structure called the flagellum. The flagellum is a long, whip-like appendage that rotates like a propeller, allowing the bacteria to move in a directed manner. This structure is found in many different types of bacteria and is essential for their motility. The flagellum is composed of a protein called flagellin, which forms a helical structure that can rotate when powered by a motor protein. This rotation creates a whipping motion that propels the bacteria through their environment.
18.
18. If you removed the pili from a bacterial cell, which of the following would you expect to happen?
Correct Answer
B. B. The bacterium would not adhere to other cells as well.
Explanation
If the pili, which are hair-like structures on the surface of bacterial cells that help them adhere to surfaces, are removed from a bacterial cell, it would be expected that the bacterium would not adhere to other cells as well. Pili play a crucial role in bacterial adhesion, allowing the bacteria to stick to surfaces and other cells. Without pili, the bacterium would lose this ability to adhere effectively, reducing its ability to form biofilms or interact with other cells.
19.
19. Why are prokaryotic cells generally smaller than eukaryotic cells?
Correct Answer
E. E. Eukaryotes have compartmentalization, which allows for specialization.
Explanation
Eukaryotic cells have a compartmentalization system, such as membrane-bound organelles, that allows for specialization and division of labor within the cell. This allows eukaryotic cells to perform a wide range of functions efficiently. In contrast, prokaryotic cells lack this compartmentalization, which limits their ability to specialize and perform complex functions. Therefore, prokaryotic cells are generally smaller in size compared to eukaryotic cells.
20.
20. The membrane surrounding each organelle
Correct Answer
B. B. regulates traffic into and out of the cell.
Explanation
The correct answer is b. The membrane surrounding each organelle regulates traffic into and out of the cell. This is because the organelle membrane acts as a barrier, controlling the movement of substances in and out of the organelle. It allows for selective transport, ensuring that only specific molecules are allowed to enter or exit the organelle. This regulation is crucial for maintaining the internal environment and functions of the organelle.
21.
21. Which statement about the nuclear envelope is true?
Correct Answer
D. D. Both a and b
Explanation
The correct answer is d. Both a and b. This means that both statements a and b are true. Statement a states that the nuclear envelope contains pores for the passage of large molecules, which is true. Statement b states that the nuclear envelope is composed of two membranes, which is also true. Therefore, both of these statements are correct, making option d the correct answer.
22.
22. The roles of biological membranes in eukaryotic cells include which of the functions listed below?
Correct Answer
E. E. All of the above
Explanation
Biological membranes in eukaryotic cells serve multiple functions. They separate the cell from its environment, acting as a barrier that controls the movement of substances in and out of the cell. They also play a role in selecting what molecules are allowed to pass through the membrane. Additionally, these membranes help maintain a constant internal environment by regulating the concentration of ions and other molecules inside the cell. Furthermore, they facilitate communication between adjacent cells through the exchange of signaling molecules. Therefore, option e, "All of the above," is the correct answer as it encompasses all the mentioned functions of biological membranes in eukaryotic cells.