题目
题目

Bio 93 Section CDE 2025 Final Exam Practice Part 2

多重下拉选择题

A man who is a dwarf with achondroplasia and normal vision marries a color-blind woman of normal height. The man's father was average height, and both the woman's parents were of average height. A) Dwarfism caused by achondroplasia is autosomal dominant, which means the gene is carried on a non-sex chromosome . B) Red-green color blindness is X-linked recessive, which means that in female offspring, [ Select ] the gene is carried on the Y chromosome the gene must have both recessive alleles to be expressed in the phenotype the gene is carried on a non-sex chromosome the recessive allele is actually dominant . C) What proportion of their sons would be color blind and of normal height? [ Select ] none all half one out of four . D) What proportion of their daughters would be color blind and of normal height? none .

选项
A.the gene is carried on a non-sex chromosome
B.the gene must have both recessive alleles to be expressed in the phenotype
C.half
D.none
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思路分析
We start by restating the scenario and the four dropdown prompts to be analyzed. Question context: A dwarf man with achondroplasia (normal vision) marries a color-blind woman of normal height. The man’s father was average height, and both of the woman’s parents were average height. There are four dropdown questions (A–D) with the following selected options in the provided answer field: A) the gene is carried on a non-sex chromosome B) the gene must have both recessive alleles to be expressed in the phenotype C) half D) none Now, we evaluate each option in turn, considering basic genetics and what each statement implies. Option A (for the statement about achondroplasia): 'the gene is carried on a non-sex chromosome.' - Key biology: Achondroplasia is caused by a mutation in FGFR3 and is inherited in an autosomal dominant pattern. This means the responsible gene is located on an autosome (a non-sex chromosome). The trait is not sex-linked, so transmission does not depend on the sex of the parent or child. Therefore, saying the gene is carried on a non-sex chromosome correctly reflects the autosomal nature of the condition. This aligns with standard genetic understanding of achondroplasia and explains why the statement is true in this context. - Why this is a reasonable interpretation: recognizing autosomal dominant inheritance correctly identifies the chromosomal category (autosome vs. sex chromosome) and matches the conventional explanation of achondroplasia genetics. - Why this could be seen as potentially incomplete: the statement omits mentioning the dominance of the allele (homozygous vs. heterozygous......Login to view full explanation

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