Kaplan Nursing Entrance Practice Exam

What defines a diploid organism?

1. It has one copy of each chromosome

2. It has two copies of each chromosome

3. It has multiple copies of each chromosome

4. It has no chromosomes

The correct answer is: It has two copies of each chromosome

A diploid organism is defined by having two copies of each chromosome. This characteristic arises from the organism receiving one set of chromosomes from each parent during fertilization, effectively doubling the genetic material. Humans and most other animals and plants are diploid, with a typical number of chromosomes arranged in pairs. By having two copies, diploid organisms can benefit from genetic diversity, as variations can arise from the two different alleles present for each gene, leading to more robust trait expression and inheritance patterns. In contrast, a haploid organism would only have one copy of each chromosome, which is typical in gametes (sperm and egg cells). Multiple copies of each chromosome reflect polyploidy, often seen in certain plants, while the absence of chromosomes is not a viable state for any organism. Understanding these definitions is crucial for studying genetics and the mechanisms of inheritance.