BÀi 6 - ĐỀ 1

The correct answer is n=9 & là tam bội. This is because the given equation states that the number of chromosomes in a banana plant is 3n = 27. By solving for n, we find that n=9. The term "tam bội" refers to a multiple of 3, indicating that the number of chromosomes is a multiple of 3. Therefore, the correct answer is n=9 & là tam bội.

Cônsixin (colchicine) is commonly used to induce polyploidy in plants. Polyploidy refers to the condition where an organism has more than two complete sets of chromosomes. Colchicine disrupts the normal process of cell division, leading to the formation of cells with double or multiple sets of chromosomes. This can result in the development of new plant varieties with desirable traits, such as larger flowers or higher fruit yields.

The term "thể dị bội" refers to the condition where a cell has an abnormal number of chromosomes, either more or less than the normal diploid number (2n). This can occur due to errors during cell division or genetic mutations. In this case, the cell has an extra or missing copy of one or more chromosomes, leading to an abnormal chromosome number.

The given passage describes a species with a diploid chromosome number of 2n. During meiosis, the chromosomes of the germ cells do not undergo segregation, resulting in gametes that contain 2n chromosomes. When fertilization occurs, the fusion of these 2n gametes with normal gametes (1n) results in a triploid individual. Therefore, the correct answer is "thể tam bội" which means triploid.

The correct answer is "Người nữ mắc hội chứng Tớcnơ". This is because the question states that there are 45 chromosomes, and one of them is a sex chromosome (X). This indicates that the person is female, as males typically have one X and one Y chromosome. Additionally, the mention of "Tớcnơ" suggests that the person has Turner syndrome, which is a genetic condition that affects females and is characterized by the absence of all or part of one X chromosome.

The correct answer is "Bộ NST tăng lên theo bội số của n và > 2n". This means that the number of chromosomes in a polyploid individual increases in multiples of n, where n is the basic number of chromosomes in the species, and the number of chromosomes is greater than 2n. This is a characteristic of polyploidy, where there are multiple sets of chromosomes in an organism.

The correct answer is "Cản trở sự hình thành thoi vô sắc" because it refers to the mechanism by which the chemical colchicine causes polyploidy in plants. Colchicine inhibits the formation of the spindle fibers, which are responsible for separating the chromosomes during cell division. This leads to the formation of cells with multiple sets of chromosomes, resulting in polyploidy.

The correct answer states that the formation of a triploid body (3n) occurs due to a disruption in the meiotic division of the entire set of chromosomes (NST) during which phase. This implies that during the process of meiotic division, either the male or female germ cells experience a disorder, leading to the formation of a triploid body.

The statement "Trong thể đa bội, bộ nhiễm sắc thể của tế bào sinh dưỡng có số lượng nhiễm sắc thể là 2n + 2" is incorrect. In polyploidy, the number of chromosomes in the somatic cells is a multiple of the haploid number, which is denoted as 2n. Therefore, the correct statement should be that the number of chromosomes in the somatic cells is 2n, not 2n + 2.

The correct answer is 4n = 28 NST. This is because in the given question, it is mentioned that there is a disorder in the distribution of chromosomes during cell division. The normal number of chromosomes in a cell is 2n = 14. In this case, 4n represents the total number of chromosomes in a cell, which is 28. Therefore, the correct answer is 4n = 28 NST.