Feedback is defined as the information gained about a reaction to a product, which will allow the modification of the product. Feedback loops are therefore the process whereby a change to the system results in an alarm which will trigger a certain result. This result will either increase the change to the system or reduce it to bring the system back to normal. A few questions remain: How do these systems work? What is a positive feedback? What is negative feedback? Where do we find these systems in nature?
The cell cycle encompasses the whole life of a cell from birth through to its death. It is the time from the formation of a cell from its parent cell until its division into its daughter cells. An important part of the cell cycle is cell division, the process whereby a cell is replicated to form either two daughter cells, through the process of mitosis, or asexual reproduction; or four daughter cells, through the process of meiosis, or sexual reproduction. However, this division forms only a small part of the cell cycle.
In this post, we will discuss what happens in the G1 and G2 Phases of the Cell Cycle. Cell division entails making more cells through duplication of the one cell’s contents and then splitting this cell into two equal and identical cells. These cells are identical to the parent cell. This is how we grow and replace injured cells.
Deoxyribonucleic acid, fondly known as DNA, is a molecule in the shape of a double helix, which is responsible for storing genetic information in the cells of all living organisms. Most people know or should know this. But what is DNA made of exactly?
Transcription generally refers to the written form of something. In biology, transcription is the process whereby DNA is usedas a template to form a complementary RNA strand – RNA is the “written” form of DNA. This is the first stage of protein production or the flow of information within a cell. DNA stores genetic information, which is then transferred to RNA in transcription, before directing the synthesis of proteins in translation. Three types of RNA can be formed: messenger RNA (mRNA), transfer RNA (tRNA) and ribosomal RNA (rRNA).
In 1887, the German anatomy biologist, Water Fleming, coined the term mitosis which comes from the Greek language which translates to “warp thread” from mitos and “act or process” from the osis part of mitosis. This term was based on the warped thread appearance of the chromatin of the cell nucleus in the first stages of mitosis.
Mitosis is the process whereby a cell reproduces asexually to produce two identical daughter cells. This occurs via nuclear division. Before mitosis, the number of chromosomes in the cell is doubled via chromosome replication, transforming the cell from a diploid (2n) cell to a tetraploid (4n) cell.
Meiosis is how eukaryotic cells (plants, animals, and fungi) reproduce sexually. It is a process of chromosomal reduction, which means that a diploid cell (this means a cell with two complete and identical chromosome sets) is reduced to form haploid cells (these are cells with only one chromosome set). The haploid cells produced by meiosis are germ cells, also known as gametes, sex cells or spores in plants and fungi.
Heredity is the passing on of characters from parents onto their progeny. In some organisms, like humans, a parent passes on one copy per gene to their offspring and as a result, the progeny gets two copies in total from its parents. These organisms are called diploids (2n).