Nucleic Acids

Nucleic acids (nu-kle'ik as'idz) constitute genes, the instructions that control a cell's activities, and play important roles in protein synthesis. These molecules are very large and complex. They contain atoms of carbon, hydrogen, oxygen, nitrogen, and phosphorus, which form building blocks called nucleotides. Each nucleotide consists of a 5-carbon sugar (ribose or deoxyribose), a phosphate group, and one of several organic bases (fig. 2.19). Such nucleotides, linked in a chain, form a polynucleotide (fig. 2.20).

There are two major types of nucleic acids. One type is composed of molecules whose nucleotides contain ribose sugar; it is called RNA (ribonucleic acid), and

A nucleotide consists of a 5-carbon sugar (S), a phosphate group (P), and an organic base (B).

Blood Vessels Figures

Figure 2.20

A schematic representation of a polynucleotide chain. A nucleic acid molecule consists of (a) one (RNA) or (b) two (DNA) polynucleotide chains.

Essentials of Human Physiology

Essentials of Human Physiology

This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.

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