Question

Directions: Each of the questions or incomplete statements below is followed by five suggested answers or completions. Select the one that is best in each case. Answers can be found here. If the diploid number for an organism is \(24,\) the haploid number is (A) 6 (B) 12 (C) 18 (D) 24 (E) 48

Short answer

Therefore, the haploid number for the organism is 12 (Option B)

Step-by-step solution

Understand Diploid and Haploid numbers

Diploid cells contain two complete sets (2n) of chromosomes. Haploid cells have half the number of chromosomes (n) as diploid i.e. a single set of chromosomes.

Use the given diploid number

The problem mentions that the diploid number for the organism is 24. That is, \(2n = 24\).

Find the haploid number

The haploid number would be half of the diploid number because it's one set of chromosomes, not two. So, to find the haploid number (n), we divide the diploid number by 2. \(n = \frac{2n}{2}\). Substituting \(2n = 24\) into the equation, we get \(n = \frac{24}{2} = 12\).

Key concepts

Diploid Number

The diploid number refers to the total number of chromosomes present in a cell of an organism that has two complete sets. Most organisms that reproduce sexually have diploid cells. Each parent contributes one set of chromosomes, so the offspring have two sets in total. In genetic notation, this is described as \(2n\). For example, if an organism has a diploid number of 24, it means the organism's cells contain 24 chromosomes in total. These include pairs that account for two sets of chromosomes inherited from both parents.

Chromosomes

Chromosomes are the thread-like structures made of DNA and proteins. They carry genetic information essential for the inheritance of traits. Chromosomes reside in the nucleus of every cell and hold the instructions necessary for the development and function of living organisms.
Chromosomes can be seen as organized packages of DNA where specific genes are located. Each species has a characteristic number of chromosomes. For example:

• Humans have 46 chromosomes (23 pairs).
• Hamsters have 44 chromosomes.
• Fruit flies have 8 chromosomes.

During certain types of cell division, chromosomes ensure that DNA is accurately copied and distributed in the creation of new cells.

Cell Division

Cell division is a fundamental process by which a single cell divides into two or more daughter cells. It is crucial for growth, development, and repair in living organisms. There are two primary types of cell division: mitosis and meiosis.
- **Mitosis** results in two diploid daughter cells with identical genetic material to the parent cell. It is important for general growth and the maintenance of tissues.
- **Meiosis**, on the other hand, results in haploid cells, which contain half the usual number of chromosomes found in diploid cells. Meiosis is critical for sexual reproduction, reducing the chromosome number by half to form gametes (sperm and eggs). This ensures genetic diversity upon fertilization.

Genetics

Genetics is the study of genes, hereditary, and the variation of organisms. It deals with how traits and characteristics are passed from parents to offspring through genes, which are segments of DNA located on chromosomes. Genetics explains the principles of inheritance and how various traits manifest in individuals.
Gregor Mendel, known as the "father of genetics," discovered fundamental laws of inheritance through experiments with pea plants. Mendel's work established that genes come in pairs and are inherited from both parents. This involves dominant and recessive alleles, where dominant alleles are expressed over recessive ones. Understanding genetics helps decipher biological processes and can lead to advancements in areas such as medicine, agriculture, and biotechnology.