Embryology Overview and Gamete Formation

The full number of chromosomes (46 in humans), present after fertilization.

Half the diploid number; 23 chromosomes in humans in sperm or ovum.

Restoration of the diploid number of chromosomes in a zygote.

The common cell division process in tissues.

Embryo from fertilization to 2 months, fetus from the 3rd month to birth.

The human body has 46 chromosomes in its somatic cells.

Chromosomes have different characteristics; including length, arm size, and other qualities.

Chromosomes contain genes, which carry instructions for the body's development and functioning.

Genes are composed of deoxyribonucleic acid (DNA).

Genes control the production of proteins.

Chromosomes contain chromatids; the short and long arms, with centromeres.

Individual chromosomes can be distinguished by analyzing their total length, the relative lengths of their arms, and additional features.

The process of cells dividing to create new cells, essential for growth and replacing dead cells.

Chromosomes within the nucleus carry genetic information that governs the development and functioning of cells, tissues, and the whole organism.

During cell division, the entire genetic information carried by chromosomes must be passed on to both daughter cells, ensuring they have identical genetic content.

As telophase progresses, the tightly coiled chromatin of the chromosomes relaxes and unravels, becoming less visible.

Although chromosomes become indistinguishable during telophase, they are believed to retain their identity throughout the resting interphase period.

During a specific phase of interphase, called S phase, the DNA content of the chromosome is duplicated, creating an identical chromatid.

As mitosis begins in prophase, the chromatin of the chromosome starts to coil and condense, becoming visible as a thread-like structure.

During prophase, the condensed chromosome gradually adopts a rod-like shape, becoming more and more recognizable.

The intricate process of chromosome coiling, uncoiling, and duplication ensures that each daughter cell receives a complete and identical set of genetic information during cell division.

Points where non-sister chromatids of homologous chromosomes cross over and exchange genetic material during meiosis.

The exchange of genetic material between homologous chromosomes during meiosis, resulting in new combinations of alleles.

A group of four chromatids formed by two homologous chromosomes, each consisting of two sister chromatids, during meiosis.

A pair of homologous chromosomes that synapse during meiosis.

The stage in meiosis I where homologous chromosome pairs align at the equator of the cell, attached to the spindle fibers by their centromeres.

The stage in meiosis I where homologous chromosome pairs separate and move to opposite poles of the cell, each pole receiving one chromosome from each pair.

In meiosis I, homologous chromosomes separate; in mitosis, sister chromatids separate. Centromeres do not divide in meiosis I.

Each of the four chromatids in a tetrad has a unique combination of genetic material due to the exchange of segments during crossing over.

Crossing over increases genetic variation by shuffling alleles between homologous chromosomes, creating new combinations of genes.