Chapter 11, Problem 5STP

Summary Introduction

Introduction:

Most of the species have diploid cells but some also have polyploid cells. Such cells have one or more extra sets of chromosomes. Polyploidy is rare in animals except in earthworms and goldfish. It is lethal in humans but is very common in flowering plants. Some common polyploidy plants are sugarcane ( 8n ), oats ( 6n ), and wheat ( 6n ). Commercial plants like strawberries and coffee are also polyploids. These plants have increased vigor and size. Having multiple sets of chromosomes affect the looks of a plant.

Answer to Problem 5STP

Correct answer :

The correct answer is option D. 3n

Explanation of Solution

Explanation/justification for the correct answer:

Option D. 3n - There could be a triploid organism with 3n number of chromosomes. Such organisms are polyploid. Hence, this is the correct option.

Explanation for incorrect answer:

Option A. 1/ 2n - n represents number of chromosome pairs present in a cell/ organism.1/ 2n does not represent a polyploid organism. Hence, this is not the correct option.

Option B. 1 1/ 2n - 1 1/ 2n does not represent a polyploid organism. A polyploidy organism has an extra set of chromosome like 3n, 4n, 6n etc. Hence, this is not the correct option.

Option C. 2n - 2n refers to a diploid number of chromosomes. Such cells are not polyploid cells. Polyploid cells have an extra set of chromosomes. Hence, this is not the correct option.