OAT Biology - Problem Drill 20: Chromosomes and Genetic Technology Question No. 1 of 10 Instructions: (1) Read the problem and answer choices carefully, (2) Work the problems on paper as needed, (3) Pick the answer, and (4) Review the core concept tutorial as needed. 1. Which of the following statements about Mendel s Laws is true? Question #01 (A) His studies led to the formation of two main ideas, collectively known as Mendel s Laws of Inheritance: (1) Law of Segregation and (2) Law of Independent Assortment. (B) His studies led to the formation of two main ideas, collectively known as Mendel s Laws of Inheritance: (1) Law of Aggregation and (2) Law of Independent Assortment. (C) Second Law: Law of Dependent Assortment the sorting of genes for different traits is dependent on one another in the formation of gametes. (D) Second Law: Law of Independent Assortment - Genes for similar traits sort independently of one another in the formation of gametes. (E) Gregor Mendel was a scientist and a priest who studied the inheritance of traits in tissue culture cells. A. Correct! His studies using pea plants led to the formation of two main ideas, collectively known as Mendel s Laws of Inheritance: (1) Law of Segregation and (2) Law of Independent Assortment. His studies using pea plants led to the formation of two main ideas, collectively known as Mendel s Laws of Inheritance: (1) Law of Segregation and (2) Law of Independent Assortment. Second Law: Law of Independent Assortment - Genes for different traits sort independently of one another in the formation of gametes. Second Law: Law of Independent Assortment - Genes for different traits sort independently of one another in the formation of gametes. Gregor Mendel was a scientist and a priest who studied the inheritance of traits in pea plants. Gregor Mendel was a scientist and a priest who studied the inheritance of traits in in pea plants. Later in the 20th century, his results were part of the foundation of the discipline of genetics. His studies using pea plants led to the formation of two main ideas, collectively known as Mendel s Laws of Inheritance: (1) Law of Segregation and (2) Law of Independent Assortment. Law of Segregation, which is Mendel s First Law. During gamete formation, the two alleles of one gene segregate independently without mixing with each other. For example, yellow color of a pea seed is controlled by allele Y and green by y. When a YY yellow seed is crossed by yy green seed, the only gamete type YY can produce is Y, and only gamete type yy can produce is yy. These two gametes combine during pollination and produce Yy offspring. These Yy seed will exhibit yellow phenotype, not any intermediated color between yellow and green. This is the Law of Segregation. The correct answer is (A).
Question No. 2 of 10 Instructions: (1) Read the problem and answer choices carefully, (2) Work the problems on paper as needed, (3) Pick the answer, and (4) Review the core concept tutorial as needed. 2. Which of the following statements about a codominance is true? Question #02 (A) When two alleles are co-dominant, the phenotype of each allele is not masked by the presence of the other alleles. (B) When two alleles are co-dominant, the phenotype of one allele is masked by the presence of the other allele. (C) Sickle cell anemia is an example of co-dominant alleles. Only a single phenotype is expressed. (D) For example, sickle cell anemia allele HbS can be co-dominant with normal hemoglobin allele Hbb. In a heterozygous patient, all of the red blood cells will exhibit the sickle cell phenotype. (E) For example, sickle cell anemia allele HbS can be co-dominant with normal hemoglobin allele Hbb. In a heterozygous patient, all of the red blood cells will cells will be normal. A. Correct! When two alleles are co-dominant, the phenotype of each allele is not masked by the presence of the other alleles. When two alleles are co-dominant, the phenotype of each allele is not masked by the presence of the other alleles. Sickle cell anemia is an example of co-dominant alleles. Both phenotypes are expressed. For example, sickle cell anemia allele HbS can be co-dominant with normal hemoglobin allele Hbb. In a heterozygous patient, both alleles are expressed and about half of the red blood cells will exhibit the sickle cell phenotype, half of the blood cells will be normal. For example, sickle cell anemia allele HbS can be co-dominant with normal hemoglobin allele Hbb. In a heterozygous patient, both alleles are expressed and about half of the red blood cells will exhibit the sickle cell phenotype, half of the blood cells will be normal. When two alleles are co-dominant, the phenotype of each allele is not masked by the presence of the other alleles. In some cases, both allele can be expressed when they are present, i.e., the phenotype of each allele is not masked by the presence of the other alleles. This is called co-dominance. For example, sickle cell anemia allele HbS can be co-dominant with normal hemoglobin allele Hbb. In a heterozygous patient, both alleles are expressed and about half of the red blood cells will exhibit the sickle cell phenotype, half of the blood cells will be normal. The correct answer is (A).
Question No. 3 of 10 Instructions: (1) Read the problem statement and answer choices carefully, (2) Work the problems on paper as needed, (3) Pick the answer, and (4) Review the core concept tutorial as needed. 3. Prophase 1 of Meiosis. Question #03 (A) In Prophase I, the chromosomes condense, synapses occur, and a tetrad is formed. (B) In Prophase I, the chromosomes separate and segregate towards the centrosomes. (C) During Prophase I, the nuclear envelope but not the nucleoli break down. (D) During Prophase I, the nuclear remains intact and the nucleoli break down. (E) The chromosomes remain stationary at the periphery of the cell. A. Correct! In Prophase I, the chromosomes condense, synapses occur, and a tetrad is formed. In Prophase I, the chromosomes condense, synapses occur, and a tetrad is formed. During Prophase I, the nuclear envelope and nucleoli break down. During Prophase I, the nuclear envelope and nucleoli break down. The chromosomes begin their migration to the metaphase plate. In Prophase I, the chromosomes condense, synapses occur, and a tetrad is formed. Crossing over may occur at this point. Similar to mitosis, the centrosomes migrate away from one another and both the nuclear envelope and nucleoli break down. The chromosomes begin their migration to the metaphase plate. The correct answer is (A).
Question No. 4 of 10 Instructions: (1) Read the problem and answer choices carefully, (2) Work the problems on paper as needed, (3) Pick the answer, and (4) Review the core concept tutorial as needed. 4. Which of the following statements about Anaphase 1 of Meiosis is true? Question #04 (A) In Anaphase I, chromosomes move one of the poles via the microtubules and the kinetochore fibers. (B) In Anaphase I, chromosomes move to the opposite poles via random motion. (C) The homologous chromosomes move to opposite poles, and the sister chromatids separate. (D) The homologous chromosomes move to opposite poles, yet the sister chromatids remain together. (E) The homologous chromosomes move to opposite poles, yet the sister chromatids remain together. This is similar to anaphase in mitosis. A. Incorrect! In Anaphase I, chromosomes move to the opposite poles via the microtubules and the kinetochore fibers. In Anaphase I, chromosomes move to the opposite poles via the microtubules and the kinetochore fibers. The homologous chromosomes move to opposite poles, yet the sister chromatids remain together. D. Correct! The homologous chromosomes move to opposite poles, yet the sister chromatids remain together. The homologous chromosomes move to opposite poles, yet the sister chromatids remain together. This is different from anaphase in mitosis. In Anaphase I, chromosomes move to the opposite poles via the microtubules and the kinetochore fibers, similar to anaphase in mitosis. The homologous chromosomes move to opposite poles, yet the sister chromatids remain together. This is different from anaphase in mitosis. The correct answer is (D).
Question No. 5 of 10 Instructions: (1) Read the problem statement and answer choices carefully, (2) Work the problems on paper as needed, (3) Pick the answer, and (4) Review the core concept tutorial as needed. 5. Which of the following statements about a Telophase I of Meiosis is true? Question #05 (A) In Telophase I, the spindles continue to move the homologous chromosomes to the poles. (B) In Telophase I, the vesicles continue to move the homologous chromosomes to the poles. (C) After Telophase I, cytokinesis occurs. (D) Four daughter cells are produced, each with one half the numbers of chromosomes of the original parent cell. (E) Two daughter cells are produced, each with a complete set of chromosomes of the original parent cell. A. Correct! In Telophase I, the spindles continue to move the homologous chromosomes to the poles. In Telophase I, the spindles continue to move the homologous chromosomes to the poles. During Telophase I, cytokinesis occurs. Two daughter cells are produced, each with one half the numbers of chromosomes of the original parent cell (1N, 2C). Two daughter cells are produced, each with one half the numbers of chromosomes of the original parent cell (1N, 2C). In telophase I the spindles continue to move the homologous chromosomes to the poles. In telophase I cytokinesis occurs. Two daughter cells are produced, each with one half the numbers of chromosomes of the original parent cell (1N, 2C). The correct answer is (A).
Question No. 6 of 10 Instructions: (1) Read the problem and answer choices carefully, (2) Work the problems on paper as needed, (3) Pick the answer, and (4) Review the core concept tutorial as needed. 6. Meiosis II. Question #06 (A) In Telophase II, a single nuclei form at one pole and cytokinesis occurs. (B) In Telophase II, distinct nuclei form at the opposite poles and cytokinesis occurs. (C) Two haploid cells form from the original parental diploid cell. (D) Six haploid cells form from the original parental diploid cell. (E) In Anaphase II, the sister chromatids remain together and move toward the cell pole. A. Incorrect! In Telophase II, distinct nuclei form at the opposite poles and cytokinesis occurs. B. Correct! In Telophase II, distinct nuclei form at the opposite poles and cytokinesis occurs. Four haploid cells form from the original parental diploid cell. Four haploid cells form from the original parental diploid cell. In Anaphase II, the sister chromatids separate and move toward the opposite cell poles. In Metaphase II, the chromosomes line up at the metaphase plate. In Anaphase II, the sister chromatids separate and move toward the opposite cell poles. In Telophase II, distinct nuclei form at the opposite poles and cytokinesis occurs. Four haploid cells form from the original parental diploid cell. The correct answer is (B).
Question No. 7 of 10 Instructions: (1) Read the problem and answer choices carefully, (2) Work the problems on paper as needed, (3) Pick the answer, and (4) Review the core concept tutorial as needed. 7. Which of the following statements about The Hardy-Weinberg Law is true? Question #07 (A) The genotype frequencies of a large, randomly mating population remain constant in all cases. (B) The genotype frequencies of a large, inbred population remain constant if immigration, mutation, and selection do not take place. (C) Evolution is a change in the genetic composition of a population from generation to generation. (D) Evolution is a change in the genetic composition of a population in a single generation. (E) The study of constancy in gene frequency over time is population genetics and is described using the Hardy-Weinberg equation. A. Incorrect! The genotype frequencies of a large, randomly mating population remains constant if immigration, mutation, and selection do not take place. The genotype frequencies of a large, randomly mating population remains constant if immigration, mutation, and selection do not take place. C. Correct! Evolution is a change in the genetic composition of a population from generation to generation. Evolution is a change in the genetic composition of a population from generation to generation. The study of changes in gene frequency over time is population genetics and is described using the Hardy-Weinberg equation. The Hardy-Weinberg Law: The genotype frequencies of a large, randomly mating population remains constant if immigration, mutation, and selection do not take place. It explains how Mendelian segregation influences allelic and genotypic frequencies in a population. Evolution is a change in the genetic composition of a population from generation to generation. Evolution happens in populations, not individuals. The correct answer is (C).
Question No. 8 of 10 Instructions: (1) Read the problem and answer choices carefully, (2) Work the problems on paper as needed, (3) Pick the answer, and (4) Review the core concept tutorial as needed. 8. Cytogenetics. Question #08 (A) Early studies used specific stains, such as Giemsa, to perform visualization of the allele properties of chromosomes. (B) Early studies used specific stains, such as Giemsa, to perform visualization of the G-banding properties of alleles. (C) Using fluorescence microscopy, FISH studies allow more detailed studies of smaller RNA sequences on chromosomes. (D) Using fluorescence microscopy, FISH studies allow more detailed studies of smaller DNA sequences on chromosomes. (E) Newer techniques, such as fast in situ hybridization (FISH), have become available for cytogenetic studies. A. Incorrect! Early studies used specific stains, such as Giemsa, to perform visualization of the G- banding properties of chromosomes. Early studies used specific stains, such as Giemsa, to perform visualization of the G- banding properties of chromosomes. Using fluorescence microscopy, FISH studies allow more detailed studies of smaller DNA sequences on chromosomes. D. Correct! Using fluorescence microscopy, FISH studies allow more detailed studies of smaller DNA sequences on chromosomes. Newer techniques, such as fluorescent in situ hybridization (FISH), have become available for cytogenetic studies. The study of genetics, specifically whole chromosomes, is known as Cytogenetics. Early studies used specific stains, such as Giemsa, to perform visualization of the G- banding properties of chromosomes. This allowed translocations and deletions of whole or part chromosomes to be studied. In addition to these techniques, newer ones, such as fluorescent in situ hybridization (FISH), have become available. Using fluorescence microscopy, FISH studies allow more detailed studies of smaller DNA sequences on chromosomes. The correct answer is (D).
Question No. 9 of 10 Instructions: (1) Read the problem and answer choices carefully, (2) Work the problems on paper as needed, (3) Pick the answer, and (4) Review the core concept tutorial as needed. 9. Which of the following statements about PCR amplification is true? Question #09 (A) Polymerase chain reaction (PCR) is a technique used to amplify a single or small number of copies of a sequence of DNA to allow molecular studies to take place. (B) Polymerase chain reaction (PCR) is a technique used to amplify a chromosome to allow molecular studies to take place. (C) The procedure is made up of a 60 hot (90-96 C) cycle, allowing certain invitro reactions to take place. (D) The procedure involves a series of hot (20-30 C) and cold (less than 0 C) temperature cycles, allowing certain in-vitro reactions to take place. (E) With only the DNA sequence of interest and a special DNA poylmerase enzyme, the changes in temperature optimize the separation, polymerization and re-annealing of copies of DNA. A. Correct! Polymerase chain reaction (PCR) is a technique used to amplify a single or small number of copies of a sequence of DNA to allow molecular studies to take place. Polymerase chain reaction (PCR) is a technique used to amplify a single or small number of copies of a sequence of DNA to allow molecular studies to take place. The procedure involves a series of hot (90-96 C) and somewhat cooler (60-65 C) temperature cycles, allowing certain in-vitro reactions to take place. The procedure involves a series of hot (90-96 C) and somewhat cooler (60-65 C) temperature cycles, allowing certain in-vitro reactions to take place. By exposing the DNA sequence of interest along with primers, a special DNA poylmerase enzyme, and the building block for DNA (nucleotides), the changes in temperature optimize the separation, polymerization and re-annealing of copies of DNA. Polymerase chain reaction (PCR) is a technique used to amplify a single or small number of copies of a sequence of DNA to allow molecular studies to take place. Nucleic acid samples are transferred into PCR tubes to be used in the Thermocycler shown here. The procedure involves a series of hot (90-96 C) and somewhat cooler (60-65 C) temperature cycles, allowing certain in-vitro reactions to take place. By exposing the DNA sequence of interest along with primers, a special DNA poylmerase enzyme, and the building block for DNA (nucleotides), the changes in temperature optimize the separation, polymerization and re-annealing of copies of DNA. The correct answer is (A).
Question No. 10 of 10 Instructions: (1) Read the problem statement and answer choices carefully, (2) Work the problems on paper as needed, (3) Pick the answer, and (4) Review the core concept tutorial as needed. 10. Which of the following statements about gene splicing and genetic engineering is true? Question #10 (A) Genetic Fingerprinting, or DNA profiling, allows an investigator or police authority the opportunity to identify an individual based on expression of their DNA in tissue culture cells. (B) Genetic Fingerprinting, or DNA profiling, allows an investigator or police authority the opportunity to identify an individual based on the comparison of their DNA and a reference sample. (C) Gene Splicing (genetic engineering) is the process of modifying a target gene s or organism s DNA by breeding specific pairs of animals. (D) Engineering new DNA sequences through gene splicing is dependent on cutting out the DNA of interest using strong acids and bases. (E) Inserting the DNA into a target sequence is done using DNA polymerase. A. Incorrect! Genetic Fingerprinting, or DNA profiling, allows an investigator or police authority the opportunity to identify an individual based on the comparison of their DNA and a reference sample. B. Correct! Genetic Fingerprinting, or DNA profiling, allows an investigator or police authority the opportunity to identify an individual based on the comparison of their DNA and a reference sample. Gene Splicing (genetic engineering) is the process of modifying a target gene s or organism s DNA by direct manipulation. Engineering new DNA sequences through gene splicing is dependent on cutting out the DNA of interest using enzymes. Inserting the DNA into a target sequence is also done using enzymes restriction endonucleases. Genetic Fingerprinting, or DNA profiling, allows an investigator or police authority the opportunity to identify an individual based on the comparison of their DNA and a reference sample. The process involves collecting an individual DNA sample and then fragmenting it using restriction enzymes. Then, by using PCR, large samples can be created for separation using electrophoresis and, finally, it is compared to a database or, in the case of police work, a sample of DNA found at a crime scene. Gene Splicing (genetic engineering) is the process of modifying a target gene s or organism s DNA by direct manipulation. Engineering new DNA sequences through gene splicing is dependent on cutting out the DNA of interest using enzymes. Inserting the DNA into a target sequence is also done using enzymes restriction endonucleases. The correct answer is (B).