1.
The process by which a cell divides to form two daughter cells, each of which contains the same genetic material as the original cell and roughly half of its cytoplasm.
Correct Answer
B. Cell division
Explanation
The given explanation describes the process of cell division, where a cell divides to form two daughter cells with the same genetic material as the original cell and approximately half of its cytoplasm. This process is known as cell division, as mentioned in the answer. The other options, cell cycle and sexual reproduction, do not specifically describe the process mentioned in the explanation.
2.
Any of the structures into which a chromosome divides during mitosis or meiosis
Correct Answer
C. Chromatid
Explanation
A chromatid is one of the structures into which a chromosome divides during mitosis or meiosis. During these processes, the chromosome replicates and forms two identical chromatids joined together at a region called the centromere. Each chromatid contains the same genetic information as the original chromosome. In prophase, the chromatids condense and become visible under a microscope. Cytokinesis is the final stage of cell division where the cytoplasm divides, resulting in two separate daughter cells. Therefore, the correct answer is chromatid.
3.
All body cells of an organism – apart from the sperm and egg cells, the cells from which they arise (gametocytes) and undifferentiated stem cells cells of internal organs, skin, bones, blood and connective tissues
Correct Answer
C. Somatic Cell
Explanation
The correct answer is somatic cell. Somatic cells are all the cells in an organism's body except for the sperm and egg cells, the cells from which they arise (gametocytes), and undifferentiated stem cells. Prophase and spindle are stages of cell division, but they do not specifically refer to somatic cells.
4.
The adaption of form or behaviour of an organism to changed conditions.
The power of a pregastrula stage to form a whole embryo from a part.
Correct Answer
A. Regulation
Explanation
Regulation refers to the ability of an organism to adapt its form or behavior in response to changes in its environment. This can involve various physiological and developmental processes that allow the organism to maintain homeostasis and function optimally. The given answer, "Regulation," aligns with the concept of adaptation and the ability of an organism to adjust to new conditions.
5.
A form of cell division happening in sexually reproducing organisms by which two consecutive nuclear divisions (meiosis I and meiosis II) occur without the chromosomal replication in between, leading to the production of four haploid gametes (sex cells), each containing one of every pair of homologous chromosomes (that is, with the maternal and paternal chromosomes being distributed randomly between the cells).
Correct Answer
B. Meiosis
Explanation
Meiosis is the correct answer because it is the form of cell division that occurs in sexually reproducing organisms. During meiosis, two consecutive nuclear divisions (meiosis I and meiosis II) occur without chromosomal replication in between. This process leads to the production of four haploid gametes, each containing one of every pair of homologous chromosomes. These chromosomes are randomly distributed between the cells, resulting in genetic variation.
6.
A large haploid cell produced at the second meiotic division that quickly becomes an egg cell
Correct Answer
A. Ootid
Explanation
An ootid is a large haploid cell that is formed during oogenesis, specifically at the second meiotic division. It quickly develops into an egg cell, also known as an ovum. This process occurs in the ovaries of females. Spermatogenesis, on the other hand, is the process of producing sperm cells in males. Therefore, the correct answer is ootid.
7.
The cells that results from the asymmetric division of an oocyte.
In animals and humans, polar bodies are produced every after meiotic division. They are relatively smaller in size due to less cytoplasm compared to the gametocyte that will become the ovum. This is essential so that much of the cytoplasm is available and the chromosomal content is halved at the time of fertilization. The polar bodies will eventually degenerate.
In plants, the polar bodies may also be fertilized by a sperm cell (aside from the ovum fertilized by another sperm cell). The fertilized polar bodies will develop and give rise to the endosperm while the fertilized ovum will become the plant embryo.
Correct Answer
C. Polar bodies
Explanation
Polar bodies are the cells that result from the asymmetric division of an oocyte. In animals and humans, polar bodies are produced after meiotic division and are smaller in size compared to the gametocyte that will become the ovum. This is important because it allows for more cytoplasm to be available in the ovum and ensures that the chromosomal content is halved at the time of fertilization. The polar bodies eventually degenerate. In plants, the polar bodies can also be fertilized by a sperm cell, and the fertilized polar bodies develop into the endosperm while the fertilized ovum becomes the plant embryo.
8.
The man-operated process of extracting dna from a host cell and implanting it to function in another type of cell.
Correct Answer
C. Cloning
Explanation
Cloning refers to the process of extracting DNA from a host cell and then implanting it into another type of cell, which is typically done by humans. This allows the DNA to function in the new cell, essentially creating a genetic copy of the original organism. Therefore, cloning is the correct answer in this context.
9.
____________begins soon after fertilization, as primordial germ cells travel from the yolk sac to the gonads, where they begin to proliferate mitotically. The germ cells multiply from only a few thousand to almost 7 million. They become oocytes once they enter the stages of meiosis several months after birth. Now called primordial follicles, they are made up of oogenic cells from the primordial germ cells surrounded by follicle cells from the somatic line. The oocyte is then arrested in the first meiotic prophase until puberty
Correct Answer
B. Oogenesis
Explanation
Oogenesis is the correct answer because the given passage describes the process of oogenesis, which is the development and maturation of oocytes (eggs) in the female reproductive system. It explains how primordial germ cells travel to the gonads and undergo mitotic proliferation, eventually becoming oocytes. These oocytes then enter meiosis and become primordial follicles, where they are arrested in the first meiotic prophase until puberty. Therefore, the passage provides an explanation of the process of oogenesis.
10.
A reproductive cell or sex cell that contains the haploid set of chromosomes, e.g. spermatozoon or sperm cell (male reproductive cell) and egg cell or ovum (female reproductive cell).
Correct Answer
C. Gamete
Explanation
A gamete is a reproductive cell or sex cell that contains a haploid set of chromosomes. It can be either a spermatozoon or sperm cell in males or an egg cell or ovum in females. Gametes are involved in sexual reproduction and combine during fertilization to form a zygote with a complete set of chromosomes.
11.
- A self-replicating, small, fibrous, cylindrical-shaped organelle, typically located in the cytoplasm near the nucleus in cells of most animals. It is involved in the process of nuclear division.
Correct Answer
A. Centrioles
Explanation
Centrioles are small, fibrous, cylindrical-shaped organelles that are typically found near the nucleus in animal cells. They are involved in the process of nuclear division, specifically in the formation of the spindle apparatus during cell division. The spindle apparatus is responsible for separating the duplicated chromosomes during mitosis or meiosis. Therefore, centrioles play a crucial role in the process of nuclear division.
12.
1. one of a pair of chromosomes
2. a chromosome with the same gene sequence as another
Supplement
In a biological cell, a chromosome pairs with another chromosome during meiosis. This pairing (synapsis) happens between two chromosomes that are homologous, i.e. chromosomes having the same genes at the same loci but possibly different alleles. For example, two chromosomes may have genes encoding eye color, but one may code for brown eyes, the other for blue.
Correct Answer
B. Homologous chromosomes
Explanation
Homologous chromosomes are a pair of chromosomes that have the same gene sequence. During meiosis, these chromosomes pair up and undergo a process called synapsis. This pairing allows for the exchange of genetic material between the chromosomes, leading to genetic variation. The example given in the supplement further explains that homologous chromosomes can have different alleles for the same genes. Therefore, the correct answer is homologous chromosomes.
13.
For the first phase of mitosis or of one of the divisions of meiosis. During this phase the chromosomes condense and become visible. It is the first stage of meiosis. The initial stage in nuclear Division (meiosis and mitosis), where there are two prophase stages in the meiosis process.
Correct Answer
C. PropHase
Explanation
Prophase is the correct answer because it is the initial stage of both meiosis and mitosis. During prophase, the chromosomes condense and become visible, preparing for the subsequent stages of cell division. This phase is crucial for the proper separation of genetic material and the formation of daughter cells.
14.
The sequence of growth and division of a cell
Correct Answer
A. Cell cycle
Explanation
The correct answer is "Cell cycle" because it refers to the sequence of growth and division of a cell. The cell cycle consists of interphase, where the cell grows and prepares for division, followed by mitosis or meiosis, where the cell divides into two daughter cells. The cell cycle is crucial for the growth, development, and reproduction of organisms.
15.
The final stage of mitosis or meiosis, when chromosome separation is completed. The final stage of mitosis.The final stage of meiosis when the chromosomes move toward opposite ends of the nuclear spindle.A stage of nuclear Division in meiosis and mitosis, occurring once in mitosis and twice in meiosis.
Correct Answer
C. TelopHase
Explanation
Telophase is the final stage of both mitosis and meiosis, where chromosome separation is completed. In telophase, the chromosomes move towards opposite ends of the nuclear spindle. It is a stage of nuclear division that occurs once in mitosis and twice in meiosis. Chromatid and diploid are unrelated terms and do not refer to the final stage of mitosis or meiosis.
16.
A small, nonstaining structure, usually near the center of a chromosome to which the spindle fiber attaches during mitosis
Correct Answer
B. Centromere
Explanation
A centromere is a small structure located near the center of a chromosome. It is responsible for attaching the spindle fibers during mitosis, which is the process of cell division. The centromere plays a crucial role in ensuring that the chromosomes are properly divided and distributed to the daughter cells.
17.
Having twice the number of chromosomes normally occurring in a mature germ cell: most somatic
Correct Answer
C. Diploid
Explanation
Diploid refers to having two sets of chromosomes, which is the normal condition in most somatic cells. This means that a diploid cell contains twice the number of chromosomes compared to a haploid cell, which only has one set of chromosomes. Mitosis is a type of cell division that produces two identical diploid cells, while haploid refers to having only one set of chromosomes. Therefore, the correct answer is diploid.
18.
The stage of mitosis (and meiosis) following prophase and preceding anaphase.
an imaginary plane located between the poles of a dividing cell, while the microtubules formed during prophase would then attach themselves to kinetochores.
Correct Answer
A. MetapHase
Explanation
During metaphase, the chromosomes align themselves along an imaginary plane called the metaphase plate, which is located between the poles of the dividing cell. The microtubules that were formed during prophase then attach themselves to the kinetochores of the chromosomes. This alignment and attachment of the chromosomes ensure that they are properly separated during the subsequent phase of anaphase. Therefore, metaphase is the correct answer as it describes the stage of mitosis (and meiosis) that follows prophase and precedes anaphase.
19.
1) A collection of minute fibers composed of microtubules, which are prominent during cell division, (2) A specialized innervated muscle structure involved in the reflex action and in proprioception,
Correct Answer
B. Spindle
Explanation
The correct answer is "Spindle". A spindle is a collection of minute fibers composed of microtubules that are prominent during cell division. It plays a crucial role in separating chromosomes during mitosis and meiosis. The spindle fibers attach to the chromosomes and help pull them apart, ensuring that each daughter cell receives the correct number of chromosomes.
20.
The stage of mitosis or meiosis beginning with the separation of sister chromatids (or homologous chromosomes) followed by their movement towards the poles of the spindle.
Correct Answer
C. AnapHase
Explanation
Anaphase is the correct answer because it is the stage of mitosis or meiosis where the sister chromatids (or homologous chromosomes) separate and move towards opposite poles of the spindle. This is a crucial step in cell division as it ensures that each daughter cell receives the correct number of chromosomes.
21.
Mode of reproduction involving the fusion of female gamete (ovum) and male gamete (spermatozoon), which forms a zygote that potentially develops into genetically distinct offspring.
Correct Answer
A. Sexual reproduction
Explanation
Sexual reproduction involves the fusion of a female gamete (ovum) and male gamete (spermatozoon), resulting in the formation of a zygote. This zygote has the potential to develop into genetically distinct offspring. This process introduces genetic variation into the population, as the offspring inherit a combination of genetic material from both parents. Asexual reproduction, on the other hand, does not involve the fusion of gametes and does not result in genetically distinct offspring. Cancer is a disease characterized by the uncontrolled growth and division of abnormal cells and is not related to the given description.
22.
A form of reproduction that does not involve meiosis, ploidy reduction or fertilization, and the offspring is a clone of the parent organism.
Correct Answer
B. Asexual reproduction
Explanation
Asexual reproduction is a form of reproduction that does not involve meiosis, ploidy reduction, or fertilization. In this process, the offspring is a clone of the parent organism, meaning it is genetically identical to the parent. This type of reproduction is commonly observed in many organisms, such as bacteria, fungi, and plants, where a single parent can produce offspring without the need for a mate. It allows for rapid population growth and the preservation of favorable traits, but it lacks genetic diversity compared to sexual reproduction.
23.
A process occurring during meiosis wherein two chromosomes pair up and exchange segments of their genetic material.
This occurs at the stage when chromatids of homologous chromosomes pair up during synapsis, forming X-structure (chiasma). The chromatids break into segments (of matching regions), which are then exchanged with one another.
Correct Answer
A. Crossing over
Explanation
During meiosis, crossing over occurs when two chromosomes pair up and exchange segments of their genetic material. This process happens during synapsis, when the chromatids of homologous chromosomes align and form an X-shaped structure called a chiasma. The chromatids break into segments with matching regions, and these segments are then exchanged between the chromosomes. This genetic exchange leads to genetic diversity in the resulting gametes.
24.
____________pertains to the structure formed by the synapsis of homologous chromosomes during the prophase I of meiosis.
Correct Answer
C. Tetrad
Explanation
During prophase I of meiosis, homologous chromosomes pair up and undergo synapsis, forming a structure called a tetrad. This structure consists of two pairs of sister chromatids, with each pair coming from one homologous chromosome. The tetrad allows for the exchange of genetic material between the homologous chromosomes through a process called crossing over. This genetic recombination is important for increasing genetic diversity in offspring. Therefore, the correct answer is tetrad.
25.
An unspecialized cell characterized by the ability to self-renew by mitosis while in undifferentiated state, and the capacity to give rise to various differentiated cell types by cell differentiation.
Correct Answer
A. Stem cell
Explanation
The given definition describes a stem cell, which is an unspecialized cell that can divide through mitosis while maintaining its undifferentiated state. These cells have the unique ability to differentiate into various specialized cell types through the process of cell differentiation. Spermatogenesis and oogenesis, on the other hand, refer to the processes of sperm and egg cell production respectively, and do not encompass the full characteristics of a stem cell. Therefore, the correct answer is stem cell.
26.
The process where a single cell divides resulting in generally two identical cells, each containing the same number of chromosomes and genetic content as that of the original cell.
Correct Answer
C. Mitosis
Explanation
Mitosis is the correct answer because it is the process of cell division where a single cell divides into two identical cells. During mitosis, the chromosomes are duplicated and then separated into two sets, resulting in two cells with the same genetic content as the original cell. This process is essential for growth, repair, and maintenance of the body's tissues. Anaphase and metaphase are stages within mitosis, but they do not encompass the entire process of cell division.
27.
The stage of the cell or nucleus when it is not in mitosis, hence comprising most of the cell cycle.
Correct Answer
B. InterpHase
Explanation
Interphase is the correct answer because it is the stage of the cell cycle when the cell or nucleus is not in mitosis. During interphase, the cell prepares for division by growing, replicating its DNA, and carrying out normal cellular functions. It is the longest phase of the cell cycle and comprises about 90% of the total cell cycle time. Prophase and metaphase are stages of mitosis, which occur after interphase.
28.
Having the full number of chromosomes normally occurring in the mature germ cell, or half the number in the usual somatic cell
Correct Answer
B. Haploid
Explanation
Haploid refers to having half the number of chromosomes in a somatic cell. In contrast to diploid cells, which have the full set of chromosomes, haploid cells only have one set of chromosomes. This is typically seen in mature germ cells, such as eggs and sperm, where the number of chromosomes is reduced by half through a process called meiosis. Haploid cells are important for sexual reproduction as they combine with another haploid cell during fertilization to form a diploid zygote.
29.
The process occurring in the male gonad of sexually reproducing organism wherein the undifferentiated male germ cells develop into spermatocytes
Correct Answer
A. Spermatogenesis
Explanation
Spermatogenesis is the correct answer because it is the process that occurs in the male gonad (testes) of sexually reproducing organisms. During spermatogenesis, undifferentiated male germ cells called spermatogonia undergo a series of divisions and differentiations to form spermatocytes, which eventually develop into mature sperm cells. This process is essential for the production of male gametes and is responsible for the continuous production of sperm throughout the reproductive lifespan of males. Oogenesis, on the other hand, is the process that occurs in the female gonad (ovaries) and involves the development of ova (eggs). Tetrad refers to a group of four chromatids that are formed during meiosis.