1 markShort AnswerSection A

A Mendelian experiment consisted of breeding pea plants bearing violet flowers with pea plants bearing white flowers. What will be the result in F₁ progeny?

Heredity

Rules for the Inheritance of Traits – Mendel's Contributions

Official Answer

In the $F_1$ progeny, all the plants will bear violet flowers. This is because violet flower color is the dominant trait, which completely masks the expression of the recessive white flower color trait in the heterozygous state.

violet flowersdominant traitrecessiveF1 progenyheterozygous

Marking Scheme

1Stating that all $F_1$ progeny will bear violet flowers. (0.5 marks)
2Reasoning that violet is the dominant trait and white is the recessive trait. (0.5 marks)

Hint

Think about which flower color trait is dominant in garden pea plants according to Mendel's observations.

Quick Oral Answer

All the $F_1$ progeny will have violet flowers because violet is the dominant trait, which suppresses the expression of the recessive white trait.

Analysis & Explanation

In Mendel's experiments, crossing parents with contrasting characters (homozygous dominant violet flowers, represented as $VV$ , and homozygous recessive white flowers, represented as $vv$ ) results in $F_1$ progeny that are all heterozygous ( $Vv$ ). Since there are no 'halfway' or intermediate characteristics in the $F_1$ generation, only the dominant trait (violet color) is expressed, while the recessive trait (white color) remains unexpressed.

Common Mistakes

1Expecting a blend or intermediate color (like pink or light violet), which does not occur in Mendelian single-gene inheritance.
2Incorrectly identifying white as the dominant trait.

Interesting Facts

Mendel's choice of garden peas (Pisum sativum) was brilliant because they have clear, contrasting, and easily observable traits with no intermediate forms in the $F_1$ generation.

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Frequently Asked Questions

How many marks does this question carry in CBSE Class 10 Science 2018?

This question carries 1 mark in the CBSE Class 10 Science 2018 examination.

Which chapter does this question come from in Science?

This question is from the chapter "Heredity" in the CBSE Class 10 Science syllabus.

What topic does this question cover in Science?

This question covers the topic "Rules for the Inheritance of Traits – Mendel's Contributions" from CBSE Class 10 Science.

What type of question is this in the CBSE Class 10 Science 2018 paper?

This is a Short Answer question from Section A in the CBSE Class 10 Science 2018 paper.