STEM Mitosis And Mitosis Quiz 2014

Cytokinesis in plant cells occurs when a new cell wall is formed. During cytokinesis, the cytoplasm divides to form two separate daughter cells. In plant cells, a new cell wall called the cell plate forms between the two daughter cells. This cell plate is made up of cellulose and other materials, and it eventually develops into the primary cell wall of the two daughter cells. The formation of this new cell wall is a crucial step in the completion of cell division in plant cells.

When two parent cells join together to form offspring, it is considered sexual reproduction. This is because sexual reproduction involves the fusion of gametes from two parents, resulting in offspring with a combination of genetic material from both parents. In contrast, asexual reproduction involves the creation of offspring without the involvement of gametes or the fusion of genetic material from two parents. Meiosis is a type of cell division that occurs during sexual reproduction, but it is not the correct answer in this context.

Chromatids are duplicate halves of a chromosome. During cell division, a chromosome replicates and each copy is called a chromatid. The two chromatids are held together by a structure called the centromere. When the cell divides, each chromatid is pulled to opposite ends of the cell, ensuring that each new cell receives a complete set of genetic information. Eventually, the chromatids separate and become individual chromosomes in the newly formed cells.

The stage of the cell cycle that occupies most of the cell's life is G1, S, and G2. This is because these three stages, collectively known as interphase, are responsible for cell growth, DNA replication, and preparation for cell division. During interphase, the cell spends a significant amount of time carrying out its normal functions and preparing for division. In contrast, the M phase, which includes mitosis and cytokinesis, is a relatively short stage where the actual division of the cell occurs. Therefore, G1, S, and G2 collectively occupy the majority of the cell's life.

Metaphase is the correct answer because it is the phase of mitosis where all the chromosomes align themselves along the equator of the cell. In this phase, the spindle fibers attach to the centromeres of the chromosomes and exert tension to position them in a single plane. This alignment is crucial for the equal distribution of chromosomes to the daughter cells during cell division.

A human egg cell is a haploid cell, meaning it contains half the number of chromosomes as a diploid cell. Since the diploid number of chromosomes in a human skin cell is 46, the haploid number of chromosomes in a human egg cell is 23.

In anaphase of mitosis, the chromatids separate at the centromere and move towards opposite poles of the cell, while in anaphase I of meiosis, the homologous chromosomes separate and move towards opposite poles of the cell. Therefore, the statement "chromatids do not separate at the centromere in anaphase I" is correct as it accurately describes the difference between anaphase of mitosis and anaphase I of meiosis.

Crossing over occurs during prophase I of meiosis. This is the phase where homologous chromosomes pair up and exchange genetic material through a process called recombination. Crossing over increases genetic diversity by creating new combinations of alleles on the chromosomes. It plays a crucial role in the formation of gametes and contributes to genetic variation in sexually reproducing organisms.

Homologous chromosomes are pairs of chromosomes that have the same genes and structures, are the same size, and have the same shape. They are inherited from each parent and contain similar genetic information. During meiosis, homologous chromosomes pair up and exchange genetic material through a process called recombination, which contributes to genetic diversity. Therefore, homologous chromosomes play a crucial role in genetic inheritance and variation.

Crossing over is the correct answer because it is a process that occurs during meiosis, not mitosis. During crossing over, genetic material is exchanged between homologous chromosomes, resulting in genetic diversity among offspring. This process is responsible for the differences in traits between siblings and contributes to genetic variation within a population.

Meiosis is a type of cell division that occurs in sexually reproducing organisms to produce gametes (sperm and egg cells). The process involves two rounds of division, resulting in the formation of four daughter cells. These daughter cells are genetically different from the parent cell and from each other. Additionally, each daughter cell has half the number of chromosomes as the parent cell. This is because during meiosis, the chromosomes pair up and exchange genetic material, a process known as crossing over, which leads to genetic variation. Therefore, the correct answer is "4 daughter cells with half the number of chromosomes as parent cells."

A protein disk that attaches two chromatids to each other in a chromosome is called a centromere. This structure plays a crucial role in cell division, specifically during the process of mitosis and meiosis. The centromere helps to ensure that the replicated DNA strands are properly distributed to daughter cells by facilitating the attachment of spindle fibers. Without the centromere, the chromatids would not be able to separate correctly, leading to errors in chromosome distribution and potential genetic abnormalities.

The chromosomes in your body exist in 23 pairs, which means there are a total of 46 chromosomes. This includes two sex chromosomes, which determine the individual's biological sex (XX for females and XY for males). The remaining 44 chromosomes are called autosomes, and they carry genes responsible for various traits and characteristics. Therefore, the statement "all of the above" is correct as it encompasses the fact that chromosomes exist in 23 pairs, include two sex chromosomes, and include 44 autosomes.

A diploid cell is one that has two homologues of each chromosome, meaning it has two copies of each chromosome, one inherited from each parent. It is designated by the symbol 2n, indicating that it has a double set of chromosomes. Additionally, diploid cells have chromosomes found in pairs, where each member of the pair is a homologue. Therefore, all of the given options are correct explanations of a diploid cell.

Oogenesis refers to the process of formation and development of ova (eggs) in the female reproductive system. It involves the maturation of ova from primordial germ cells through meiosis, resulting in the production of mature eggs. This process is specific to females and is essential for sexual reproduction. Gametogenesis, on the other hand, is a broader term that encompasses the development of both male and female gametes. Fertilization refers to the fusion of a sperm and an egg, while spermatogenesis is the process of producing sperm cells in males. Therefore, oogenesis is the correct term for the making of ova.

During meiosis I, homologous chromosomes separate. This is because meiosis I is the first division of meiosis, where the homologous chromosomes pair up and exchange genetic material through a process called crossing over. This genetic recombination results in the shuffling of genes between the homologous chromosomes. After crossing over, the homologous chromosomes then separate and move to opposite poles of the cell, ensuring that each resulting gamete receives one copy of each homologous chromosome. Therefore, meiosis I is the correct answer as it specifically involves the separation of homologous chromosomes.

A karyotype is a visual representation of the chromosomes in an individual's cells, arranged in pairs according to size, shape, and other characteristics. By studying a karyotype, a student can determine the number of chromosomes present in a body cell. This can provide important information about genetic disorders and abnormalities, as well as help identify any chromosomal abnormalities or variations that may be present in an individual. Therefore, studying a karyotype can provide insights into the number of chromosomes present in a body cell.

After mitosis and cytokinesis, each of the two new cells formed from the original cell will have a complete set of 46 chromosomes. This is because during mitosis, the chromosomes are replicated, and each of the resulting daughter cells receives an identical copy of the original cell's chromosomes. Therefore, both new cells will have the same number of chromosomes as the original cell, which is 46.

Each sex cell, also known as a gamete, contains only 23 single chromosomes, not pairs. This is because during the process of fertilization, when the gametes combine, the resulting zygote will have a total of 46 chromosomes, with 23 pairs. Therefore, the statement that each sex cell contains 23 pairs of chromosomes is incorrect.