Nucleic acid double helixIn molecular biology, the double helix is the structure formed by double-stranded molecules of nucleic acids such as DNA. The double-helical structure of a nucleic acid complex arises as a consequence of its secondary structure, and is a fundamental component in determining its tertiary structure. The DNA double-helix biopolymer of nucleic acids is held together by nucleotides which base pair together.
ProteinBiomolecule consisting of chains of amino acid residuesA representation of the 3D structure of the protein myoglobin showing turquoise α-helices. This protein was the first to have its structure solved by X-ray crystallography. Toward the right-center among the coils, a prosthetic group called a heme group (shown in gray) with a bound oxygen molecule (red).Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acidresidues.
RNAFamily of large biological moleculesA hairpin loop from a pre-mRNA. Highlighted are the nucleobases (green) and the ribose-phosphate backbone (blue). This is a single strand of RNA that folds back upon itself. Ribonucleic acid (RNA) is a polymeric molecule that is essential for most biological functions, either by performing the function itself (non-coding RNA) or by forming a template for the production of proteins (messenger RNA).
Nucleic acidNucleic acids are large biomolecules that are crucial in all cells and viruses. They are composed of nucleotides, which are the monomer components: a 5-carbon sugar, a phosphate group and a nitrogenous base. The two main classes of nucleic acids are deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). If the sugar is ribose, the polymer is RNA; if the sugar is deoxyribose, a variant of ribose, the polymer is DNA.
VirusA virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea. Viruses are found in almost every ecosystem on Earth and are the most numerous type of biological entity. Since the first discovery of a virus, the tobacco mosaic virus, in the 1890s, more than 16,000 of the millions of virus species have been described in detail.
GeneticsScience of genes, heredity and variationGenetics is the study of genes, genetic variation, and in organisms. It is an important branch in biology because heredity is vital to organisms' evolution. Gregor Mendel, a MoravianAugustinian friar working in the 19th century in Brno, was the first to study genetics scientifically. Mendel studied "trait inheritance", patterns in the way traits are handed down from parents to offspring over time.
ReproductionReproduction (or procreation or breeding) is the biological process by which new individual organisms – offspring – are produced from their parent or parents. There are two forms of reproduction: asexual and sexual. In asexual reproduction, an organism can reproduce without the involvement of another organism. Asexual reproduction is not limited to single-celled organisms. The cloning of an organism is a form of asexual reproduction.
PolynucleotideIn molecular biology, a polynucleotide (from Ancient Greek πολυς (polys) 'many') is a biopolymer composed of nucleotide monomers that are covalently bonded in a chain. DNA (deoxyribonucleic acid) and RNA (ribonucleic acid) are examples of polynucleotides with distinct biological functions. DNA consists of two chains of polynucleotides, with each chain in the form of a helix (like a spiral staircase).
PolysaccharidePolysaccharides (; from Ancient Greek πολύς (polús) 'many, much' and σάκχαρ (sákkhar) 'sugar') are "compounds consisting of a large number of monosaccharides linked glycosidically". They are the most abundant carbohydrates in food. Their structures range from linear to highly branched polymers. Examples include storage polysaccharides such as starch, glycogen, and galactogen and structural polysaccharides such as hemicellulose and chitin.
PolymerIUPAC definitionA polymer is a substance composed of macromolecules. A macromolecule is a molecule of high relative molecular mass, the structure of which essentially comprises the multiple repetition of units derived, actually or conceptually, from molecules of low relative molecular mass.OrganismAn organism is any living thing that functions as an individual. Such a definition raises more problems than it solves, not least because the concept of an individual is also difficult. Several criteria, few of which are widely accepted, have been proposed to define what constitutes an organism. Among the most common is that an organism has autonomous reproduction, growth, and metabolism. This would exclude viruses, even though they evolve like organisms.
LipidLipids are a broad group of organic compounds that include fats, waxes, sterols, fat-soluble vitamins (such as vitamins A, D, E and K), monoglycerides, diglycerides, phospholipids, and others. The functions of lipids include storing energy, signaling, and acting as structural components of cell membranes. Lipids have applications in the cosmetic and food industries, and in nanotechnology.*As an Amazon Associate I earn from qualifying purchases.