1.
Prokaryotic cells have
Correct Answer
A. A circular chromosome.
Explanation
Prokaryotic cells have a circular chromosome because they lack a nucleus and their genetic material is present in the cytoplasm. The circular shape of the chromosome allows for efficient packing of the DNA within the cell. This is in contrast to eukaryotic cells, which have linear chromosomes enclosed within a nucleus. The presence of a circular chromosome is a defining characteristic of prokaryotic cells.
2.
Which of the following would have cells that would undergo binary fission?
Correct Answer
C. Bacteria
Explanation
Bacteria would have cells that undergo binary fission. Binary fission is a form of asexual reproduction in which a single organism divides into two identical daughter cells. Bacteria are unicellular organisms that reproduce through binary fission, making them capable of rapidly multiplying and colonizing various environments. In contrast, potato plants, human bodies, and insects are multicellular organisms that reproduce through sexual reproduction or other methods, not binary fission.
3.
How many copies of each chromosome are made during the first stage of a eukaryotic cell cycle?
Correct Answer
B. 2
Explanation
During the first stage of a eukaryotic cell cycle, known as the S phase, the DNA is replicated. This means that each chromosome is duplicated, resulting in two identical copies of each chromosome. Therefore, the correct answer is 2.
4.
____ ensures that each new eukaryotic cell receives a copy of each chromosome.
Correct Answer
A. Mitosis
Explanation
Mitosis is the correct answer because it is the process by which eukaryotic cells divide and ensure that each new cell receives an identical copy of each chromosome. During mitosis, the chromosomes are replicated and then separated into two daughter cells, resulting in the distribution of genetic material. Osmosis, endocytosis, and exocytosis are not related to the distribution of chromosomes during cell division.
5.
Mitosis is usually divided into ____ stage(s).
Correct Answer
D. 4
Explanation
Mitosis is usually divided into four stages: prophase, metaphase, anaphase, and telophase. During prophase, the chromatin condenses into chromosomes, the nuclear membrane breaks down, and the spindle fibers form. In metaphase, the chromosomes line up at the center of the cell. Anaphase is characterized by the separation of sister chromatids, which are pulled to opposite ends of the cell by the spindle fibers. Finally, during telophase, the nuclear membrane reforms, the chromosomes decondense, and the cell begins to divide into two daughter cells. Therefore, the correct answer is 4.
6.
Which of the following would NOT undergo mitosis?
Correct Answer
B. Prokaryotic cell
Explanation
Prokaryotic cells do not undergo mitosis because they lack a nucleus and other membrane-bound organelles. Mitosis is a process of cell division that occurs in eukaryotic cells, such as human cells, plant cells, and fungi cells, where the nucleus divides to produce two identical daughter cells. In prokaryotic cells, replication of genetic material occurs through binary fission, a simpler form of cell division. Therefore, prokaryotic cells do not undergo mitosis.
7.
Once mitosis is complete, the splitting of the cytoplasm or ____ occurs.
Correct Answer
B. Cytokinesis
Explanation
Cytokinesis is the process that occurs after mitosis, where the cytoplasm of a cell is divided into two daughter cells. During cytokinesis, the cell membrane pinches inward, forming a cleavage furrow in animal cells or a cell plate in plant cells. This division of the cytoplasm allows for the complete separation of the genetic material and other organelles, ensuring that each daughter cell receives a complete set of cellular components. Therefore, cytokinesis is the correct answer to the question.
8.
A difference in cell division between animal cells and plant cells occurs during
Correct Answer
C. Cytokinesis.
Explanation
Cytokinesis is the process in which the cytoplasm of a single cell divides into two daughter cells. This process is different in animal cells and plant cells. In animal cells, cytokinesis occurs through the formation of a cleavage furrow, which pinches the cell membrane inward until the cell is divided. In contrast, plant cells form a cell plate during cytokinesis, which eventually develops into a new cell wall that separates the two daughter cells. Therefore, the difference in cell division between animal cells and plant cells is observed during cytokinesis.
9.
What condenses into an "X" shape before mitosis?
Correct Answer
A. Chromatids
Explanation
Before mitosis, the replicated DNA molecules condense into X-shaped structures called chromatids. These chromatids are attached at the centromere and are the result of DNA replication during the S phase of the cell cycle. During mitosis, the chromatids separate and move to opposite poles of the cell, ensuring that each daughter cell receives a complete set of chromosomes. Therefore, chromatids are the correct answer to the question.
10.
The cell cycle includes__________.
Correct Answer
A. Mitosis, cytokinesis, and interpHase
Explanation
The cell cycle is a series of events that occur in a cell leading to its division and duplication. It consists of multiple phases, including interphase, mitosis, and cytokinesis. Interphase is the longest phase where the cell grows and prepares for division. Mitosis is the phase where the cell's nucleus divides into two identical nuclei. Cytokinesis is the final phase where the cell's cytoplasm divides, resulting in two separate daughter cells. Therefore, the correct answer is mitosis, cytokinesis, and interphase.
11.
As the cell grows larger, ___________.
Correct Answer
D. Greater demands on the DNA and the less efficient diffusion of nutrients and waste.
Explanation
As the cell grows larger, there are greater demands placed on its DNA because the larger size requires more genetic material to control and regulate the cell's functions. Additionally, the diffusion of nutrients and waste becomes less efficient in larger cells because the distance that molecules have to travel within the cell increases, making it harder for them to reach their intended destinations. Therefore, the correct answer is that there are greater demands on the DNA and the less efficient diffusion of nutrients and waste in larger cells.
12.
___________ reproduction allows for diversity among offspring.
Correct Answer
B. Sexual
Explanation
Sexual reproduction allows for diversity among offspring because it involves the fusion of two gametes (sperm and egg) from two different parents. This process leads to the mixing of genetic material from both parents, resulting in offspring that inherit a unique combination of traits. This genetic variation increases the chances of survival and adaptation to changing environments. In contrast, asexual reproduction involves the production of genetically identical offspring, limiting diversity and adaptability.
13.
The result of mitotic division is two ___________ cells.
Correct Answer
A. Daughter
Explanation
During mitotic division, a parent cell divides into two identical daughter cells. The daughter cells have the same genetic information as the parent cell and are genetically identical to each other. Therefore, the correct answer is "daughter."
14.
________ is the complex made of DNA and proteins.
Correct Answer
B. Chromatin
Explanation
Chromatin is the complex made of DNA and proteins. It is the material that makes up chromosomes. Chromatin is composed of DNA molecules tightly coiled around proteins called histones. This coiling allows for the packaging of DNA into a compact and organized structure. During cell division, chromatin condenses further to form visible chromosomes. Therefore, chromatin is the correct answer to the question.
15.
Binary fission is a form of _________ reproduction.
Correct Answer
B. Sexual
Explanation
Binary fission is a form of asexual reproduction where a single organism divides into two identical offspring. In this process, the parent organism replicates its genetic material and then divides into two equal halves, each containing a complete set of genetic material. This results in the formation of two genetically identical offspring. Therefore, the correct answer is asexual.
16.
DNA is doubled during _______ phase.
Correct Answer
C. S
Explanation
DNA is doubled during the S phase of the cell cycle. This phase is also known as the synthesis phase. During this phase, the cell replicates its DNA in preparation for cell division. The DNA is unwound and each strand serves as a template for the synthesis of a new complementary strand. This results in the formation of two identical copies of the DNA molecule. Once the DNA replication is complete, the cell proceeds to the next phase of the cell cycle, which is the G2 phase.
17.
Cell division occurs during ____ phase.
Correct Answer
D. M
Explanation
During the M phase, or the mitotic phase, cell division occurs. This phase includes both mitosis, where the nucleus divides, and cytokinesis, where the cytoplasm divides. The other options mentioned - G1 and S phases - are not involved in cell division. G1 is the first gap phase where the cell grows and prepares for DNA replication, while S phase is the synthesis phase where DNA replication occurs. Therefore, the correct answer is M.
18.
Most of a eukaryotic cell’s growth occurs during ____ phase.
Correct Answer
A. G1
Explanation
During the G1 phase, a eukaryotic cell grows in size and carries out its normal metabolic activities. This phase is also known as the first gap phase. It is during this phase that the cell prepares for DNA replication and checks for any damage or errors in the DNA. Once the cell completes the G1 phase, it enters the S phase where DNA synthesis occurs. Therefore, most of a eukaryotic cell's growth occurs during the G1 phase.
19.
Which phase is the shortest in interphase?
Correct Answer
C. G2
Explanation
G2 is the shortest phase in interphase. Interphase is the longest phase of the cell cycle, consisting of G1, S, and G2 phases. G2 follows the S phase, during which DNA replication occurs, and precedes the M phase, where cell division takes place. G2 is relatively short as it mainly involves preparation for cell division, such as growth and synthesis of proteins and organelles.
20.
The shortest phase of mitosis is _______.
Correct Answer
C. MetapHase
Explanation
Metaphase is the shortest phase of mitosis because it is a brief stage where the chromosomes align themselves along the equatorial plane of the cell. During metaphase, the spindle fibers attach to the centromeres of the chromosomes and align them in a single file line at the center of the cell. Once this alignment is achieved, the cell can proceed to the next phase, anaphase, where the chromosomes are separated and pulled towards opposite poles of the cell. Compared to prophase, anaphase, and telophase, which involve more complex processes, metaphase is relatively quick and straightforward.
21.
Chromatin condenses down into ________ during prophase.
Correct Answer
B. Chromosomes
Explanation
During prophase, chromatin, which is the loosely packed form of DNA, condenses down into chromosomes. This condensation allows the DNA to become more compact and organized, making it easier for the cell to divide and ensure that each daughter cell receives the correct amount of genetic material. Chromosomes are made up of two identical sister chromatids, which are held together by a centromere. Centrioles, on the other hand, are involved in the formation of the spindle fibers that help separate the chromosomes during cell division.
22.
Animal cells have ______, which are located at the poles during mitosis and may play an important role spindle formation.
Correct Answer
B. Centrioles
Explanation
Centrioles are small structures found in animal cells that play a crucial role in cell division. During mitosis, centrioles migrate to opposite poles of the cell and help in the formation of the spindle fibers, which are responsible for separating the chromosomes. Therefore, centrioles are located at the poles during mitosis and are important for spindle formation.
23.
The mitotic spindle attaches to the _______ of sister chromatids during metaphase.
Correct Answer
D. Centromeres
Explanation
During metaphase, the mitotic spindle attaches to the centromeres of sister chromatids. The centromere is a specialized region of the chromosome that holds the two sister chromatids together. The attachment of the mitotic spindle to the centromeres is essential for the proper alignment and separation of the sister chromatids during cell division. This ensures that each daughter cell receives an equal and complete set of chromosomes.
24.
The nuclear membrane and nucleolus disintegrate during _______. They return during _____.
Correct Answer
A. PropHase, telopHase
Explanation
During prophase of mitosis, the nuclear membrane and nucleolus disintegrate. This is because the cell is preparing for cell division and needs to condense its genetic material. The disintegration of the nuclear membrane allows the chromosomes to be more easily accessible for separation. On the other hand, during telophase, the nuclear membrane and nucleolus reform. This is because the cell division process is almost complete and the daughter cells need to establish their own nuclear envelopes and nucleoli to resume normal cellular functions.
25.
Chromosomes begin to relax and unwind during _______.
Correct Answer
C. TelopHase
Explanation
During telophase, the final stage of mitosis, the chromosomes begin to relax and unwind. This is because the process of cell division is almost complete, and the genetic material needs to return to its more extended and less condensed form in order to be properly distributed to the daughter cells. In telophase, the nuclear envelope reforms around the separated chromosomes, and the spindle fibers disappear. This allows the chromosomes to decondense and return to their interphase state, preparing for the next cell cycle.
26.
______ are proteins that seem to regulate the timing of the cell cycle.
Correct Answer
B. Cyclins
Explanation
Cyclins are proteins that regulate the timing of the cell cycle. They control the progression of the cell cycle by binding to and activating cyclin-dependent kinases (CDKs), which are enzymes that drive the cell cycle forward. The levels of cyclins fluctuate throughout the cell cycle, with different cyclins being expressed at different stages. This regulation ensures that each phase of the cell cycle is completed before moving on to the next, preventing errors and maintaining the proper timing and order of events in cell division.
27.
_______ regulators originate from outside the cell to control a cell’s cycle.
Correct Answer
A. External
Explanation
External regulators originate from outside the cell to control a cell's cycle. These regulators can include signals from neighboring cells, growth factors, or hormones. They play a crucial role in regulating the progression of the cell cycle by influencing the activation or inhibition of specific proteins involved in cell division. By responding to external signals, the cell can ensure that it only divides when necessary and in response to appropriate cues from its environment.
28.
Programmed cell death is a process known as ______.
Correct Answer
B. Apoptosis
Explanation
Apoptosis is a programmed cell death process that occurs in multicellular organisms. It is a natural and controlled mechanism by which cells undergo self-destruction. This process plays a crucial role in maintaining tissue homeostasis, eliminating damaged or infected cells, and regulating cell populations during development. Cancer, tumors, and regulation are not accurate descriptions of programmed cell death.