Binary fission
Division of a cell into two daughter cells after DNA replication and nuclear division (mitosis). A form of asexual reproduction.
Budding
A form of asexual reproduction where a bud or outgrowth from the end or side of the parent cell emerges and develops into a new organism.
Cancer
A general term for more than 100 diseases that are characterised by uncontrolled, abnormal growth of cells. Cancer cells can spread locally or through the bloodstream and lymphatic system to other parts of the body.
Cell cycle
The cycle of cell growth, replication of the genetic material and nuclear and cytoplasmic division. The cell cycle is dived into a G1 (G for gap) phase in which the cell grows;an S (S for synthesis) phase where the DNA is replicated, a second gap phase called G2 and an M phase (for Mitosis) in which the replicated DNA (organized into chromosomes) is separated and the cell divides into 2 daughter cells. Mitosis is dived into Prophase, Prometaphase, Metaphase, Anaphase, Telophase and, Cytokinesis.
Chromosomes
The self-replicating genetic structures of cells containing the cellular DNA that bears in its proteins.
DNA
The molecule that encodes genetic information in the nucleus of cells. Deoxyribonucleic acid (DNA) is a nucleic acid — usually in the form of a double helix — that contains the genetic instructions monitoring the biological development of all cellular forms of life, and many viruses. It determines the structure, function and behaviour of the cell.
DNA is a double-stranded molecule held together by weak bonds between base pairs of nucleotides. The four nucleotides in DNA contain the bases: adenine (A), guanine (G), cytosine (C), and thymine (T).
Embryonic development
- In animals, those derivatives of the fertilized ovum that eventually become the offspring, during their period of most rapid development, i.e., after the long axis appears until all major structures are represented.
- In man, the developing organism is an embryo from about two weeks after fertilization to the end of seventh or eighth week.
Fertilization
The essential process in sexual reproduction, involving the union of two specialised haploid cells, the male and female gametes to give a diploid cell, the zygote, which then develops to form a new organism.
Fragmentation
The breaking of an entity into smaller parts.
Gametes
Specialised haploid cells produced by meiosis and involved in sexual reproduction.
(Haploid describes a nucleus, cell or organism possessing a single set of unpaired chromosomes. Gametes are haploid.)
Genes
Located in the nucleus of the cell, genes contain hereditary information that is transferred from cell to cell.
Meiosis
A two-stage type of cell division in sexually reproducing organisms. In meiosis, a diploid cell divides to produce four haploid cells, each with half the original chromosome content.
Mitosis
A process that takes place in the nucleus of a dividing cell, involves typically a series of steps consisting of prophase, metaphase, anaphase, and telophase, and results in the formation of two new nuclei each having the same number of chromosomes as the parent nucleus
Nucleolus
A spherical body of the nucleus of most eukaryotes that becomes enlarged during protein synthesis, is associated with a nucleolus organizer, and contains the DNA templates for ribosomal RNA
Sexual and asexual reproduction
Sexual: The process where two cells (gametes) fuse to form one hybrid, fertilized cell, resulting in a new genome that is different than that of either parent
Asexual: Reproduction in which an organism produces one or more clones of itself, such as by fission or budding.
Stem cells
Relatively undifferentiated cells of the same lineage (family type) that retain the ability to divide and cycle throughout postnatal life to provide cells that can become specialised and take the place of those that die or are lost.
Vegetative reproduction
A reproductive process that is asexual and so does not involve a recombination of genetic material. It involves unspecialized plant parts which may become reproductive structures (such as roots, stems, or leaves). Compared with sexual reproduction, it represents a savings of material and energy for the plant. It is especially common among grasses.
Zygote
A single diploid cell resulting from the fusion of male and female gametes at fertilization (sperm and ovum).
RESOURCES
Merriam-Webster Online
WordNet, Princeton
