If the haploid number for a plant species is 4, how many chromosomes are found in a member of the species that has one of the following characteristics? Explain your reasoning in each case.

trisomy

Verified step by step guidance

1. Understand the concept of haploid and diploid numbers: The haploid number (n) is the number of chromosomes in a gamete (sperm or egg), which is 4 in this case. The diploid number (2n) is the total number of chromosomes in a somatic cell, which is 2 times the haploid number, so 2n = 8.
2. Define trisomy: Trisomy is a condition where an organism has one extra chromosome in addition to the normal diploid set. This means there is one chromosome present in triplicate instead of the usual pair.
3. Calculate the number of chromosomes in a trisomic individual: Start with the diploid number, which is 8 for this species, and add one extra chromosome to account for the trisomy.
4. Express the calculation: The total number of chromosomes in a trisomic individual is 8 (diploid number) + 1 (extra chromosome) = 9.
5. Summarize the reasoning: A member of this plant species with trisomy will have 9 chromosomes because it has one additional chromosome beyond the normal diploid set.

Key Concepts

Haploid and Diploid Numbers

The haploid number (n) refers to the number of chromosomes in a gamete, which is half the total number of chromosomes in a diploid organism. In this case, if the haploid number for the plant species is 4, the diploid number (2n) would be 8, representing the total chromosomes in somatic cells.

Trisomy

Trisomy is a genetic condition where an organism has three copies of a particular chromosome instead of the usual two. For a plant with a haploid number of 4, a trisomic individual would have one extra chromosome, resulting in a total of 9 chromosomes (4 + 1 = 9) in its somatic cells.

Chromosome Structure and Function

Chromosomes are structures within cells that contain DNA and proteins, playing a crucial role in heredity and gene expression. Understanding chromosome structure is essential for grasping how variations like trisomy can affect an organism's development and traits, as the presence of an extra chromosome can lead to abnormal phenotypes.