Cellular Functions and Genetics: Core Concepts

Cellular Functions

Cellular functions are basic units of life and conduct nutrition, relationships, and reproduction. Unicellular cells perform all these functions within a single cell, while multicellular organisms have specialized cells.

• Nutrition: Molecular intake from the external environment provides energy to renew cellular structures. This process inside the cell is known as metabolism.
• Relationships: Cells communicate with the outside environment, adapting to changes and maintaining stability.
• Reproduction: New cells are formed from existing ones. In unicellular organisms, this leads to a new being. In multicellular organisms, it replaces dying cells and increases cell numbers during growth. Cells pass their genetic material to their daughter cells, ensuring they are identical.

The Cell Core

The core, where genetic material is located, can be considered the cellular control center. When not dividing, its state is interphase. Key components include:

• Karyoplast: The medium.
• Chromatin: Formed by genetic material.
• Nucleolus: A spherical structure involved in creating genetic messages.

Chromosomes

Chromosomes are a condensed form of genetic material, useful for transport. They consist of two strands of chromatin called chromatids, joined by a centromere.

Mitosis

Mitosis, except for sex cells, ensures that daughter cells are identical to each other. It is vital that the same genetic information is transmitted to each of them. The most important process is the division of the nucleus (mitosis) to distribute the genetic material. Before mitosis, the genetic information is duplicated. Mitosis can be subdivided into four basic stages: prophase, metaphase, anaphase, and telophase.

Meiosis, on the other hand, does not create a cell like the parent cell but cells with half the genetic information. This is necessary when forming gametes or sex cells. Gametes unite to form a zygote, which develops into a whole body through multiple cell divisions. It is essential that gametes originate from a special division process to have half the genetic information. This process, where a cell with 2n chromosomes originates cells with n chromosomes, is called meiosis. Meiosis consists of two consecutive divisions.

Fundamental Concepts of Genetics

A gene is the unit of genetic transmission. It may have different variations, each called an allele.

• If both alleles are identical, the individual is homozygous. If different, the individual is heterozygous.
• The first allele is called dominant, and the second, which only appears when homozygous, is recessive.
• When two alleles are equally capable of expression, they are called codominant, leading to intermediate inheritance.