Trắc Nghiệm Sinh Học 12. Bài 4. Đột Biến Gen

The given answer is correct because it accurately describes genetic mutations as changes in the structure of genes. Genetic mutations can involve various types such as deletion, duplication, inversion, and translocation. It is important to note that not all genetic mutations are harmful, as some can have no effect or even be beneficial. Additionally, not all genetic mutations immediately manifest as visible traits.

The correct answer suggests that individuals carrying mutations will exhibit phenotypic changes in the body shape. This implies that the mutations affect the expression of genes related to the body shape in the individual.

The phenomenon described in the answer is albinism, a genetic condition characterized by a lack of melanin production in the body. This results in a person having white skin, white hair, and pink eyes. Albinism is a mutation that affects the pigmentation of the skin, hair, and eyes, leading to a lack of color in these features.

Thay thế 1 cặp nuclêôtit này bằng 1 cặp nuclêôtit khác xảy ra ở bộ ba mã hoá thứ ba của gen có thể làm thay đổi thàn phần 1 axit amin trong chuỗi polipeptit tương ứng. Mỗi bộ ba mã hoá trong gen xác định một axit amin cụ thể, do đó thay đổi cặp nuclêôtit trong bộ ba mã hoá sẽ dẫn đến thay đổi axit amin tương ứng trong chuỗi polipeptit. Tuy nhiên, số lượng axit amin trong chuỗi polipeptit không thay đổi vì mỗi axit amin được mã hoá bởi một bộ ba mã hoá duy nhất.

The correct answer is "Thay cặp nuclêôtit A-T bằng cặp G-X." This is because by replacing the A-T base pair with the G-X base pair, the number of hydrogen bonds in the gene will change. A-T base pairs form two hydrogen bonds, while G-X base pairs form three hydrogen bonds. Therefore, this mutation will alter the number of hydrogen bonds in the gene without changing the number of nucleotides.

The correct answer is "trong cấu trúc của gen, liên quan đến một hoặc một số cặp nuclêôtit tại một điểm nào đó trên ADN." This answer correctly states that gene mutations involve changes in the structure of a gene, specifically in the nucleotide pairs at a certain point on the DNA. Gene mutations can occur due to various factors such as exposure to certain chemicals, radiation, or errors during DNA replication. These mutations can result in changes to the genetic information and can have various effects on an organism's traits or health.

The occurrence of gene mutations depends on the intensity, dosage, type of mutagenic agent, and the stability of the gene structure. The environment in which the organism lives also plays a role. Mutations can involve the loss, addition, or substitution of a nucleotide pair. The quantity of nucleotides in a gene and the number of genes in a cell can also affect the occurrence of gene mutations.

The correct answer states that gene mutations can occur due to the influence of chemical agents, physical agents (such as radiation, ultraviolet rays), biological agents (such as viruses), or disruptions in cellular physiology and biochemistry. These factors can cause changes in the DNA sequence and lead to genetic mutations.

The correct answer is "Thêm hoặc mất 1 cặp nuclêôtit" because adding or deleting a pair of nucleotides can cause a frameshift mutation, which shifts the reading frame of the genetic code and leads to significant changes in the structure of the corresponding polypeptide chain. This type of mutation can result in the addition or removal of amino acids, leading to a completely different protein being synthesized.

The correct answer is "liên quan đến một cặp nucl trên gen" which means "related to a pair of nucleotides on a gene". This answer is chosen because it accurately describes the concept of a point mutation, which is a type of gene mutation that involves a change in a single nucleotide base pair in the DNA sequence of a gene. Point mutations can have various effects, ranging from no impact to significant consequences, depending on the specific change in the nucleotide sequence.

The correct answer is "xôma". This is because xôma is a genetic mutation that does not pass through sexual reproduction. It is a type of mutation that occurs in the somatic cells of an organism, which are not involved in the production of gametes. Therefore, xôma cannot be inherited by offspring.

The level of benefit or harm of genetic mutation depends on the combination of genes and environmental conditions. Different combinations of genes can interact with the mutated gene in different ways, influencing the outcome of the mutation. Additionally, the environmental conditions can also play a role in determining whether the mutation is beneficial or harmful. Therefore, the combination of genes and environmental conditions is crucial in determining the overall impact of a genetic mutation.

The correct answer is "Gen -> tiền đột biến gen -> đột biến gen". This sequence represents the mechanism of gene mutation, where a gene undergoes a precursor mutation before the actual mutation occurs.

The correct answer states that the mutation in soma can only be multiplied through the process of somatic reproduction, while the mutation in germ cells can be passed on to the next generation through sexual reproduction.

A gene mutation refers to a change in the DNA sequence of a gene. In this case, the correct answer states that the mutation can involve replacing a pair of nucleotides with a different pair in the last codon of the gene. This type of mutation is known as a substitution mutation. It can lead to a change in the amino acid sequence of the protein that the gene codes for, potentially affecting its structure and function.

The correct answer is "những lần nguyên phân đầu tiên của hợp tử, trong giai đoạn 2 – 8 tế bào." This means that somatic mutations occur during the initial cell divisions of an organism, specifically during the 2nd to 8th cell divisions. These mutations can lead to genetic variations within the organism.

The correct answer states that a substitution mutation can lead to either no change in the protein structure, replacement of the amino acid with a different one, or disruption of the translation process resulting in no protein synthesis.

In order for a new recessive mutation to be expressed as a phenotype in a mating population, it is necessary for many individuals in the population to also undergo random mutations that result in the same recessive gene. This recessive gene then mutates back to become a dominant gene. The time it takes for the number of heterozygous individuals with that recessive mutation to increase in the population through mating is what leads to the appearance of the recessive homozygous gene type. Therefore, the correct answer is that the time it takes for the number of heterozygous individuals with the recessive mutation to increase in the population through mating is necessary for the appearance of the recessive homozygous gene type.

The correct answer is that point mutations usually occur on one strand as a precursor mutation, which can either revert back to the original form or form a mutation in subsequent rounds of replication under the action of error-correcting enzymes.

The correct answer is "tế bào sinh dưỡng." This is because "tế bào sinh dưỡng" refers to the cells responsible for providing nourishment and support to the organism. These cells do not participate in reproduction or the formation of gametes. Therefore, mutations occurring in these cells would not be passed on to future generations.

The given correct answer states that the substitution of nucleotides in a gene can potentially result in the gene becoming longer or shorter compared to the original gene, or it may not change the length at all. This is because the substitution can alter the sequence of nucleotides, which can affect the coding region of the gene and potentially lead to changes in the length of the gene. However, it is also possible that the substitution occurs in a non-coding region of the gene, which would not affect the gene's length. Therefore, the length of the gene can vary depending on the specific nucleotide substitution that occurs.

The correct answer is "Nhiều bộ ba khác nhau cùng mã hoá cho một loại axit amin." This means that multiple codons can code for the same amino acid. This is because the genetic code is degenerate, meaning that there is redundancy in the code, and different combinations of nucleotides can still result in the same amino acid being produced. Therefore, even if there is a substitution mutation in the gene, the same amino acid can still be encoded by a different codon.

The correct answer is "mất, thêm, thay thế 1 cặp nuclêôtít." This is because the given statement lists various types of mutations that can occur, including the loss, addition, or substitution of a nucleotide pair.

The correct answer is "Biến đổi trình tự các nuclêôtit của gen cấu trúc -> biến đổi trình tự các ribônuclêôtit của mARN -> biến đổi trình tự các axitamin trong chuỗi pôlypeptit -> biến đổi tính trạng." This sequence accurately represents the central dogma of molecular biology, which states that genetic information flows from DNA to RNA to protein. The first step involves transforming the nucleotide sequence of a gene into the nucleotide sequence of mRNA. Next, the ribonucleotide sequence of mRNA is translated into the amino acid sequence of a polypeptide chain. Finally, this sequence of amino acids determines the characteristics and functions of the protein.

The correct answer is "thay thế một cặp nuclêôtit này bằng một cặp nuclêôtit khác." This is because the disease mentioned, hồng cầu hình lưỡi liềm, is caused by a mutation in which a pair of nucleotides is replaced by another pair of nucleotides.

If a pair of nucleotides is lost from the second position since the beginning of the gene structure, it can lead to the inability to synthesize the polypeptide chain.

Mutation in meiosis will enter the gametes and be passed on to the next generation through sexual reproduction.

The correct answer is "when in the homozygous state". This means that the gene mutation is present in both copies of the gene in an individual. In the homozygous state, the mutated gene is expressed and can result in a visible phenotype or trait.

The correct answer is "thay thế một cặp G - X bằng một cặp A - T." This is because the question states that the mutated gene has the same length but has an increased hydrogen bond. The only option that involves a substitution of nucleotides is "thay thế một cặp G - X bằng một cặp A - T." Therefore, this is the most logical explanation for the given answer.

This answer suggests that the condition known as "tay 6 ngón, ngón tay ngắn" (six-fingered hand with short fingers) is caused by certain prominent mutations in humans. It is a physical abnormality characterized by the presence of an extra finger and shorter fingers.

The given answer states that both somatic mutations and germ line mutations can be passed on to future generations through sexual reproduction. This means that the mutations can be inherited and expressed in the offspring. The other statements in the question provide additional information about the characteristics of these mutations, such as somatic mutations being immediately expressed in the body and dominant mutations being expressed in a part of the body. However, the main point emphasized by the given answer is the ability of both types of mutations to be transmitted through sexual reproduction.