The carbon atoms of the sugar molecule are numbered as 1′, 2′, 3′, 4′, and 5′ (1′ is read as “one prime”). The difference between the sugars is the presence of the hydroxyl group on the second carbon of the ribose and hydrogen on the second carbon of the deoxyribose. The pentose sugar in DNA is deoxyribose, and in RNA, the sugar is ribose (Figure 1). DNA contains A, T, G, and C whereas RNA contains A, U, G, and C. In molecular biology shorthand, the nitrogenous bases are simply known by their symbols A, T, G, C, and U. Each of these basic carbon-nitrogen rings has different functional groups attached to it. Cytosine, thymine, and uracil are classified as pyrimidines which have a single carbon-nitrogen ring as their primary structure (Figure 1). The primary structure of a purine is two carbon-nitrogen rings. Each nucleotide in DNA contains one of four possible nitrogenous bases: adenine (A), guanine (G) cytosine (C), and thymine (T). RNA nucleotides also contain one of four possible bases: adenine, guanine, cytosine, and uracil (U) rather than thymine.Īdenine and guanine are classified as purines. They are bases because they contain an amino group that has the potential of binding an extra hydrogen, and thus, decreases the hydrogen ion concentration in its environment, making it more basic. The nitrogenous bases, important components of nucleotides, are organic molecules and are so named because they contain carbon and nitrogen. Each nitrogenous base in a nucleotide is attached to a sugar molecule, which is attached to one or more phosphate groups. Each nucleotide is made up of three components: a nitrogenous base, a pentose (five-carbon) sugar, and a phosphate group (Figure 1). The nucleotides combine with each other to form a polynucleotide, DNA or RNA. Other types of RNA-like rRNA, tRNA, and microRNA-are involved in protein synthesis and its regulation.ĭNA and RNA are made up of monomers known as nucleotides. This intermediary is the messenger RNA (mRNA). The DNA molecules never leave the nucleus but instead use an intermediary to communicate with the rest of the cell. The other type of nucleic acid, RNA, is mostly involved in protein synthesis. DNA controls all of the cellular activities by turning the genes “on” or “off.”
Protein backbone ends code#
Many genes contain the information to make protein products other genes code for RNA products. A chromosome may contain tens of thousands of genes. In eukaryotic cells but not in prokaryotes, DNA forms a complex with histone proteins to form chromatin, the substance of eukaryotic chromosomes. The entire genetic content of a cell is known as its genome, and the study of genomes is genomics. In prokaryotes, the DNA is not enclosed in a membranous envelope. It is found in the nucleus of eukaryotes and in the organelles, chloroplasts, and mitochondria. DNA is the genetic material found in all living organisms, ranging from single-celled bacteria to multicellular mammals. The two main types of nucleic acids are deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). They carry the genetic blueprint of a cell and carry instructions for the functioning of the cell. Nucleic acids are the most important macromolecules for the continuity of life. Describe the basic structure of nucleic acids.
0 kommentar(er)
