This article all about explores how life works in terms of basics biological factors. I’m going to discuss here Cell, Cell division, DNA, Genes, Chromosomes, and proteins. We start from the smallest structural and functional unit of an organism called the cell. As an example, the human body contains trillion of the cell and in another word, it’s a structural, functional and biological unit of all organisms. The cell provides structure for the body, take in nutrients from food, convert those nutrients into energy, and carry out specialized functions. Physically cells always have a boundary membrane and a membrane-bound structure containing biomolecules, such as nucleic acids, proteins, and polysaccharides. According to the structure of the cell, biologists divide organisms into two group. Those groups are,
● Prokaryotes: prokaryotes cells surrounded by a membrane and a cell wall, with a circular strand of DNA contains their genes and it does not have a nucleus
● Eukaryotes: eukaryotic cells contained within the nuclear envelop and separated from the cytoplasm. Nevertheless, these cells boast their own personal “power plants”, called mitochondria. These tiny organelles in the cell not only produce chemical energy but also hold the key to understanding the evolution of the eukaryotic cell.
Cell division is the process of a parent cell divides into two or more daughter cells and it occurs as part of the large cell cycle.
There are two distinct types of cell division in eukaryotes,
● Vegetative division: daughter cells is generally identical to the parent cell(mitosis)
● Reductive cell division: number of chromosomes in the daughter cells is reduced by half, to produce haploid gametes(meiosis)
In terms of definition of the Meiosis is “A type of cellular reproduction in which the number of chromosomes is reduced by half through the separation of homologous chromosomes, producing two haploid cells.” and Mitosis is “A process of asexual reproduction in which the cell divides in two producing a replica, with an equal number of chromosomes in each resulting diploid cell.” Prokaryotes are much simpler in their organization than eukaryotes. There are great many more organelles in eukaryotes, also more chromosomes. The usual method of prokaryote cell division is termed binary fission. The prokaryotic chromosome is a single DNA molecule that first replicates, then attaches each copy to a different part of the cell membrane. When the cell begins to pull apart, the replicate and original chromosomes are separated. Following cell splitting (cytokinesis), there are then two cells of identical genetic composition (except for the rare chance of a spontaneous mutation).
DNA (Deoxyribonucleic acid)
DNA contains the biological instructions that make each species unique. DNA, along with the instructions it contains, is passed from adult organisms to their offspring during reproduction. In another word, it looks like a blueprint for building different parts of the cell. Most of DNA is found inside a special area of the cell called the nucleus. Apart from the DNA located in the nucleus, humans and other complex organisms also have a small amount of DNA in a different structure called mitochondria. A nucleotide is the chemical building blocks of the DNA and it contains three parts, a phosphate group, a sugar group and one of four types of nitrogen bases. The four types of nitrogen bases found in Nucleotides are adenine (A), thymine (T), guanine (G) and cytosine (C). The order or sequence, of these bases, determine what biological instructions are contained in a strand of DNA. For example, the sequence ATCGTT might instruct for blue eyes, while ATCGCT might instruct for brown. Nucleotides are arranged in two long strands that form a spiral called a double helix. The structure of the double helix is more likely a ladder. The important property of DNA is that it can replicate itself. Each strand of DNA in the double helix can serve as a pattern for duplicating the sequence of bases. This is critical when cells divide because each new cell needs to have an exact copy of the DNA present in the old cell.
Genes
In term of biology, “A gene is the basic physical and functional unit of heredity. Genes, which are made up of DNA, act as instructions to make molecules called proteins.” In humans, genes vary in size from a few hundred DNA bases to more than 2 million bases but when it comes to general, genes carry the information that determines traits, which are features that are passed from parents. Genes are found on tiny spaghettilike structures called chromosomes. The DNA also contains large sequences that do not code for any protein and their function is not known. The gene of the coding region encodes instructions that allow a cell to produce a specific protein or enzyme. There are nearly 50,000 and 100,000 genes with each being made up of hundreds of or thousands of chemical bases. Chromosomes
Chromosomes are the place where DNA is located since the cell is very small and organisms have many DNA molecules per cell, each DNA molecules must be tightly packaged and this package is a form of the DNA is called chromosome. Chromosomes come in matching sets of two (or pairs) and there are hundreds or thousands of genes in just one chromosome. Chromosomes in humans can be divided into two types those are, autosomes and sex chromosomes. Certain genetic traits are linked to a person's sex and are passed on through the sex chromosomes. The autosomes contain the rest of the genetic hereditary information. All act in the same way during cell division. Human cells have 23 pairs of chromosomes (22 pairs of autosomes and one pair of sex chromosomes), giving a total of 46 per cell. Half of these chromosomes come from one parent and half come from the other parent In addition to these, human cells have many hundreds of copies of the mitochondrial genome. Sequencing of the human genome has provided a great deal of information about each of the chromosomes.
Proteins
Proteins are a complex and large molecule that play critical roles in the body and proteins are made with hundreds or thousands of smaller units called amino acids, which are attached to one another in long chains. In order to make proteins, the gene from the DNA is copied by each of the chemical bases into messenger RNA (ribonucleic acid) or mRNA. The mRNA moves out of the nucleus and uses cell organelles in the cytoplasm called ribosomes to form the polypeptide or amino acid that finally folds and configures to form the protein.
All of the above factors are playing such a complex roles/ responsibilities to perform life with many more other things.
