1.
The following illustration depicts which stage of mitosis.
Correct Answer
A. Metaphase
Explanation
The correct answer is Metaphase because in this stage of mitosis, the chromosomes align themselves along the equatorial plane of the cell. This alignment is clearly depicted in the illustration, where the chromosomes are seen arranged in a single line at the center of the cell. This stage is crucial for ensuring that each daughter cell receives the correct number of chromosomes during cell division.
2.
What type of bonds hold the DNA strands together?
Correct Answer
A. Hydrogen Bonds
Explanation
Hydrogen bonds hold the DNA strands together. These bonds form between the nitrogenous bases of the DNA strands. Specifically, hydrogen bonds form between adenine (A) and thymine (T), and between guanine (G) and cytosine (C). These bonds are relatively weak, allowing the DNA strands to separate during replication and transcription processes. However, they are strong enough to maintain the stability and integrity of the DNA double helix structure.
3.
Which of the following is not part of interphase, which is the longest phase of the cell cycle?
Correct Answer
A. G0
Explanation
G0 is the correct answer because it is not part of interphase. Interphase is the longest phase of the cell cycle and consists of three stages: G1, S-Phase, and G2. G0, also known as the resting phase, is a stage where cells temporarily or permanently stop dividing and do not actively participate in the cell cycle. It is a quiescent phase where cells may exit the cell cycle and enter a non-dividing state, such as neurons and muscle cells.
4.
Which process produces gametic (sex) cells?
Correct Answer
A. Meiosis
Explanation
Meiosis is the process that produces gametic (sex) cells. During meiosis, a single cell divides twice, resulting in four daughter cells, each with half the number of chromosomes as the parent cell. These daughter cells are the gametes, such as sperm and eggs, which are necessary for sexual reproduction. In contrast, mitosis is the process of cell division that produces identical copies of cells for growth, repair, and asexual reproduction. Therefore, the correct answer is Meiosis.
5.
Which process produces somatic (body/diploid) cells?
Correct Answer
A. Mitosis
Explanation
Mitosis is the process that produces somatic (body/diploid) cells. During mitosis, a single cell divides into two identical daughter cells, each containing the same number of chromosomes as the parent cell. This process is responsible for growth, repair, and maintenance of the body's tissues and organs. Meiosis, on the other hand, produces gametes (sex cells) with half the number of chromosomes, which are involved in sexual reproduction. Therefore, the correct answer is Mitosis.
6.
Which process produces diploid cells (2n)?
Correct Answer
A. Mitosis
Explanation
Mitosis is the process that produces diploid cells (2n). During mitosis, a single cell divides into two identical daughter cells, each containing the same number of chromosomes as the parent cell. This results in the preservation of the original chromosome number, making the daughter cells diploid. In contrast, meiosis is the process that produces haploid cells (n), as it involves two rounds of cell division, resulting in the formation of four non-identical daughter cells with half the number of chromosomes as the parent cell.
7.
Which process produces haploid cells (n)?
Correct Answer
A. Meiosis
Explanation
Meiosis is the process that produces haploid cells (n). During meiosis, a diploid cell undergoes two rounds of division, resulting in four haploid cells. This process is essential for sexual reproduction as it ensures the correct number of chromosomes in the offspring. Mitosis, on the other hand, produces identical diploid cells (2n) and is involved in growth, repair, and asexual reproduction.
8.
Which biomolecule is made of subunits that contain a phosphate, sugar, and nitrogen base?
Correct Answer
A. Nucleic Acid
Explanation
Nucleic acids are biomolecules made of subunits called nucleotides, which consist of a phosphate group, a sugar molecule (ribose or deoxyribose), and a nitrogenous base (adenine, thymine, cytosine, guanine, or uracil). These subunits are joined together to form DNA and RNA, which play crucial roles in storing and transmitting genetic information. Carbohydrates, proteins, and lipids do not contain these specific subunits and therefore are not the correct answer.
9.
Which of the following has the steps of mitosis in the correct order?
Correct Answer
A. Prophase, Metaphase, Anaphase, Telophase
Explanation
The correct order of the steps in mitosis is 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 align along the equator of the cell. Anaphase follows, where the sister chromatids separate and move towards opposite poles of the cell. Finally, during Telophase, the chromosomes reach the poles, the nuclear membrane reforms, and the cytoplasm begins to divide. Therefore, the correct answer is Prophase, Metaphase, Anaphase, Telophase.
10.
Before DNA replication it has to unzip then unwind with the help of enzymes.
Correct Answer
A. True
Explanation
DNA replication is the process by which a cell makes an identical copy of its DNA. Before replication can occur, the DNA molecule needs to unzip and unwind, which is facilitated by enzymes. This allows the DNA strands to separate and serve as templates for the synthesis of new complementary strands. Therefore, the statement that before DNA replication it has to unzip and unwind with the help of enzymes is true.
11.
Meiosis produces-
Correct Answer
A. 4 Genetically Different Haploid Sex Cells
Explanation
Meiosis is a specialized cell division process that occurs in sexually reproducing organisms. It involves two rounds of division, resulting in the production of four haploid cells. These cells are genetically different from each other and from the parent cell. The term "haploid" refers to having half the number of chromosomes as the parent cell. These haploid cells are also known as sex cells or gametes, which are involved in sexual reproduction. Therefore, the correct answer is "4 Genetically Different Haploid Sex Cells."
12.
Crossing over between non-sister chromatids during meiosis is significant in heredity. This process most likely leads to an increase in which of the following?
Correct Answer
A. Genetic variation
Explanation
Crossing over between non-sister chromatids during meiosis is significant in heredity because it promotes genetic variation. This is because crossing over involves the exchange of genetic material between homologous chromosomes, leading to the creation of new combinations of alleles. These new combinations result in offspring that have different genetic traits than their parents, increasing genetic diversity within a population. Therefore, the correct answer is genetic variation.
13.
The diagram below shows the process of meiosis.The segregation that occurs during meiosis results in a-
Correct Answer
A. Reduction in the number of chromosomes per cell.
Explanation
During meiosis, the process of cell division in reproductive cells, the chromosomes are divided and distributed equally between the resulting cells. This results in a reduction in the number of chromosomes per cell, as each new cell will have half the number of chromosomes compared to the parent cell. This reduction is important for sexual reproduction as it ensures that when the egg and sperm combine during fertilization, the resulting offspring will have the correct number of chromosomes. Therefore, the correct answer is reduction in the number of chromosomes per cell.
14.
The sequence of nitrogen bases in DNA varies. The sequence of the bases in DNA is most important for which of the following?
Correct Answer
A. Providing the instructions for traits of an organism
Explanation
The sequence of nitrogen bases in DNA is most important for providing the instructions for traits of an organism. This is because the sequence of bases determines the order of amino acids in a protein, which in turn determines the structure and function of the protein. These proteins are responsible for carrying out various biological processes and traits in an organism.
15.
All of the following are true EXCEPT-
Correct Answer
A. In animal cells the division of the cytoplasm does not occur.
Explanation
In animal cells, the division of the cytoplasm does occur during cell division, which is known as cytokinesis. Cytokinesis is the process where the cytoplasm is divided into two daughter cells after the nuclear division (mitosis) has taken place. This is achieved through the formation of a contractile ring that contracts and pinches the cell membrane inward, leading to the separation of the cytoplasm. Therefore, the statement "In animal cells the division of the cytoplasm does not occur" is incorrect.
16.
Which statement applies to meiosis?
Correct Answer
A. Four Daughter cells are haploid and genetically different
Explanation
Meiosis is a type of cell division that occurs in sexually reproducing organisms. It involves two rounds of division, resulting in the formation of four daughter cells. These daughter cells are haploid, meaning they have half the number of chromosomes as the parent cell. Additionally, during meiosis, genetic recombination occurs, leading to the genetic diversity of the daughter cells. Therefore, the statement "Four Daughter cells are haploid and genetically different" accurately describes the process of meiosis.
17.
What structure allows the chromosomes to split during cell division?
Correct Answer
A. Spindle Apparatus
Explanation
During cell division, the spindle apparatus is responsible for ensuring that chromosomes are properly separated. It is a structure made up of microtubules that attach to the chromosomes and pull them apart. The spindle apparatus forms during prophase and metaphase of cell division and helps to ensure that each daughter cell receives the correct number of chromosomes. Without the spindle apparatus, chromosomes would not be able to properly split and distribute to the daughter cells, resulting in genetic abnormalities. Therefore, the spindle apparatus is the correct answer to the question.
18.
Which statement best describes the DNA molecules made from this process?
Correct Answer
A. The two new DNA strands are identical with one strand from the original and one new strand.
Explanation
The given answer states that the two new DNA strands produced in this process are identical, with one strand being from the original DNA and the other being a newly synthesized strand. This suggests that the process being described is DNA replication, where a DNA molecule is duplicated to produce two identical copies. During replication, the original DNA strands act as templates for the synthesis of new complementary strands, resulting in two identical DNA molecules.
19.
In which of the following statements does meiosis play a more significant role than mitosis?
Correct Answer
A. In genetic variation.
Explanation
Meiosis plays a more significant role than mitosis in genetic variation. During meiosis, the genetic material is shuffled and recombined through processes such as crossing over and independent assortment, leading to the creation of genetically diverse gametes. In contrast, mitosis is responsible for the formation of genetically identical cells. Therefore, meiosis is crucial for generating genetic diversity, which is essential for evolution and adaptation.
20.
What is the differene between the cells at the start of the s-phase and ones at G2
Correct Answer
A. The cells in G2 will have double the amount of DNA.
Explanation
During the S-phase of the cell cycle, DNA replication occurs, resulting in the duplication of the cell's DNA. This means that the cells at the start of the S-phase will have a certain amount of DNA. However, by the time the cells reach the G2 phase, they will have completed DNA replication and will have double the amount of DNA compared to the cells at the start of the S-phase. Therefore, the correct answer is that the cells in G2 will have double the amount of DNA.
21.
The following image depicts what phase of mitosis?
Correct Answer
A. Anaphase
Explanation
The image shows the separation of sister chromatids, with each chromatid moving towards opposite poles of the cell. This is a characteristic feature of anaphase in mitosis, where the chromosomes are pulled apart by spindle fibers. In telophase, the chromosomes have already reached the poles and are starting to decondense. In metaphase, the chromosomes are aligned along the equator of the cell. In prophase, the chromosomes are condensing and the nuclear envelope is breaking down.