An African violet grower observes that genetically identical African violet plants growing near the walls of the greenhouse have white flowers, that plants growing farther away from the walls have pale blue flowers, and that plants growing nearest the center of the greenhouse have dark blue flowers.

Which of the following best explains the differences in flower color of the African violets in the greenhouse?

Question

An African violet grower observes that genetically identical African violet plants growing near the walls of the greenhouse have white flowers, that plants growing farther away from the walls have pale blue flowers, and that plants growing nearest the center of the greenhouse have dark blue flowers.

Which of the following best explains the differences in flower color of the African violets in the greenhouse?

BlackTom AI · Accepted Answer

The question presents a scenario where genetically identical African violet plants show a gradient of flower colors depending on their position in the greenhouse, suggesting an environmental influence rather than genetic differences alone.
Option 1: 'More light is available along the walls of the greenhouse, so the flowers need less pigment to absorb sunlight for photosynthesis.' While light can influence pigment production in some cases, pigment for flower color in violets is typically governed by enzymes in pigment biosynthesis, not a simple need to absorb more light. This explanation doesn’t align well with a temperature-related gradient described in the scenario.
Option 2: 'Warmer temperatures result in genotypic alterations, which result in flower color differences.' Temperature does not cause permanent genotypic changes in plants that would alter flower color. Genotype remains the same; phenotypic changes can occur due to environmental effects on gene expression or enzyme activity, but not a heritable genotypic alteration. This makes the statement inaccurate as described.
Option 3: 'The plants along the walls of the greenhouse are homozygous recessive and therefore have white flowers.' Since the plants are genetically identical and the color gradient correlates with distance from walls and center, a static genetic difference like homozygosity for white flowers cannot explain the continuous color change observed across the greenhouse. This option contradicts the premise of identical genotypes and fails to account for environmental influence on enzyme function.
Option 4: 'An enzyme responsible for flower color does not fold correctly in cooler temperatures, and the greenhouse is warmest in the center.' This option links environmental temperature to enzyme folding and activity, which can affect pigment synthesis. Cooler areas can reduce enzyme efficiency or folding quality, leading to lighter colors (white) near the cooler walls, while warmer central areas permit proper enzyme function, yielding deeper blue hues. This aligns with the pattern described and with known principles of temperature-sensitive enzyme activity influencing pigment production.
In sum, the first three options either misattribute the cause (genetics vs. environment), misunderstand how temperature interacts with phenotype, or rely on incorrect assumptions about inheritance. The last option coherently explains a gradient in pigment production through temperature-dependent enzyme folding and activity, matching the observed spatial pattern of color variation in the greenhouse.

APBIO141-031 with labs S14 - CollegeBoard* AP Exam Prep: Multiple Choice

查看解析

登录即可查看完整答案

类似问题

Which of these is a type of adaptation an individual might undergo in order to survive a change in the environment?

The range (norm) of reaction refers to

Individuals respond to environmental change through _____, and species respond to environment change through .

In a consumer society, many adults channel creativity into buying things

Economic stress and unpredictable times have resulted in a booming industry for self-help products

People born without creativity never can develop it

A product has a selling price of $20, a contribution margin ratio of 40% and fixed cost of $120,000. To make a profit of $30,000. The number of units that must be sold is: Type the number without $ and a comma. Eg: 20000

更多留学生实用工具

考试浏览器助手

风格化写作助手

论文查重助手

文献引用助手

课堂转译助手

课堂笔记助手

Quiz搜索助手

学校历年真题

智能刷题助手

智能匹配练习

希望你的学习变得更简单