Problem 13 - Biology Concepts and Applications

Question

Is this statement true or false? Inheriting three or more of each type of chromosome characteristic of the species results in a condition called polyploidy.

Step-by-Step Solution

Answer

True.

Step 1: Understanding chromosomal inheritance

In most species, chromosomes are inherited in pairs, one from each parent. This is the basis for the organism's diploid number. Typically, humans have 23 pairs of chromosomes, making for a total of 46.

Step 2: Decoding polyploidy

Polyploidy is a condition in which an organism has more than two complete sets of chromosomes. While humans are diploid, polyploid organisms might have three (triploid), four (tetraploid), or more sets of each chromosome type.

Step 3: Analyzing the given statement

The statement mentions inheriting three or more of each type of chromosome characteristic of the species. According to the definition of polyploidy, having more than two sets meets the criterion for polyploidy.

Step 4: Assessing the statement

Given that inheriting three or more of each type of chromosome fits the definition of polyploidy, the statement must be true.

Key Concepts

Chromosome Inheritance

In the realm of genetics, chromosome inheritance plays a pivotal role in determining the characteristics of an organism. Chromosomes are long strands of DNA that are found in the nucleus of cells, and they carry genes, which are the instructions for the development and functioning of all living things. In most animals and plants, this inheritance happens through a process where one complete set of chromosomes is inherited from each parent.
This results in what is called a diploid organism, meaning they have two sets of chromosomes. For example, in humans, there are 23 pairs of chromosomes, totaling 46.

• One chromosome in each pair is inherited from the mother.
• The other is inherited from the father.

Understanding this concept helps explain why offspring are a combination of both parents’ genetic material. Dominant and recessive genes also play a role here, determining which traits become visible. Overall, chromosome inheritance is fundamental to the diversity of life on earth.

Diploid Number

The diploid number refers to the total number of chromosomes present in the cells of an organism when there are two sets - one from each parent. This property is designated as "2n," where "n" represents the number of different chromosomes in a single set. In humans, "n" is 23, giving a diploid number of \(2n = 46\).
Every living organism has a characteristic diploid number of chromosomes, which varies greatly among different species.

• Mice, for instance, have a diploid number of 40.
• Frogs may have a diploid number of 24.

This count is crucial because it ensures the right number of chromosomes is passed down during reproduction. If the diploid number were to be different from the norm due to errors during cell division, it could lead to genetic disorders. Thus, maintaining the diploid number during reproduction is essential for healthy offspring and a balanced genetic makeup.

Triploid and Tetraploid

Polyploidy introduces more complexity to the genetic structure of an organism. In a typical diploid arrangement, an organism has two sets of chromosomes. However, polyploidy occurs when there are more than two sets.

• When an organism has three sets of chromosomes, it is termed "triploid" (3n).
• With four sets, it is referred to as "tetraploid" (4n).

This condition frequently appears in plants and can have significant evolutionary advantages, such as increased size and resistance to environmental stresses. Triploid plants might have triploid fruits, which are often seedless, a feature desirable in agriculture. Tetraploids, by having more genetic material, may exhibit greater variability and adaptability.
In humans and many other animals, however, polyploidy is less common and often not viable due to complex development processes. Understanding this concept in plants gives insight into how genetic variations can contribute to survival and reproduction, showing how nature uses different mechanisms to thrive.