1.1.1 During which phase of meiosis do homologous chromosome pairs separate?
A) Metaphase I
B) Anaphase I
C) Telophase I
D) Telophase II
1.1.2 A codon is a sequence of three nucleotides on a molecule of .. - NSC Life Sciences - Question 1 - 2017 - Paper 2
Question 1
1.1.1 During which phase of meiosis do homologous chromosome pairs separate?
A) Metaphase I
B) Anaphase I
C) Telophase I
D) Telophase II
1.1.2 A codon is a sequenc... show full transcript
Worked Solution & Example Answer:1.1.1 During which phase of meiosis do homologous chromosome pairs separate?
A) Metaphase I
B) Anaphase I
C) Telophase I
D) Telophase II
1.1.2 A codon is a sequence of three nucleotides on a molecule of .. - NSC Life Sciences - Question 1 - 2017 - Paper 2
Step 1
1.1.1 During which phase of meiosis do homologous chromosome pairs separate?
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Answer
Homologous chromosomes pair separate during Anaphase I of meiosis. At this stage, the spindle fibers pull the homologous chromosomes apart towards opposite poles.
Step 2
1.1.2 A codon is a sequence of three nucleotides on a molecule of ...
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Answer
A codon is a sequence of three nucleotides on a molecule of mRNA. It serves as a template for protein synthesis by specifying which amino acid will be added next during translation.
Step 3
1.1.3 Which of the following distinguishes prophase 1 of meiosis from prophase of mitosis?
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Answer
The key distinction in prophase 1 of meiosis is that homologous chromosomes pair up, allowing for crossing over and genetic recombination, which does not occur in prophase of mitosis.
Step 4
1.1.4 Scientists discovered the body of a woolly mammoth from the Arctic region. The DNA sequence of the woolly mammoth shows how closely related it is to the African elephant. What is evidence for this data?
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Answer
The evidence for this data is that the woolly mammoth and African elephant have a common ancestor. This relationship is supported by genetic analysis indicating shared genes.
Step 5
1.1.5 A pedigree was found to contain 14% (thymine). What percentage of the molecule is cytosine?
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Answer
Given that thymine pairs with adenine in DNA, and using Chargaff's rules, the percentage of cytosine can be calculated as follows:
If thymine is 14%, then adenine is also 14%.
Therefore, the total percentage of cytosine and guanine must be 100% - (14% + 14%) = 72%.
Since cytosine pairs with guanine, they must be equal, making cytosine 36%.
Step 6
1.1.6 Which ONE of the following statements is a correct description of a hypothesis and a theory?
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Answer
The correct statement is that an accepted hypothesis may become a theory. Hypotheses are tested and can evolve into theories based on substantial evidence and repeated validation.
Step 7
1.1.7 An extra finger in humans is rare, but is due to a dominant gene. When one parent is normal and the other parent has an extra finger but is homozygous for the trait, what is the chance that their children will be normal?
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Answer
If one parent is homozygous for the extra finger trait (AA) and the other is normal (aa), then all children will inherit the dominant trait, resulting in a 0% chance of normal children.
Step 8
1.1.8 Which ONE of the following correctly describes the ploidy and number of cells produced at the end of mitosis?
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Answer
Mitosis produces diploid cells, resulting in two cells that are genetically identical to the original cell. Therefore, the correct answer is diploid, two.
Step 9
1.1.9 Which two populations belong to the same species?
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The two populations that belong to the same species are P and Q based on the successful interbreeding indicated by the data provided.
Step 10
1.1.10 A gene in a bacterium codes for a protein that has 120 amino acids. How many mRNA nucleotides code for this protein?
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Answer
Since each amino acid is coded by a triplet of nucleotides (a codon), the number of mRNA nucleotides that code for a protein of 120 amino acids is calculated as:
