Biology Unit 4: Nucleic Acids Review

General Characteristics of Nucleic Acids

• Nucleic acids are macromolecules essential for life.
• Composed of long chains of nucleotides, each consisting of a sugar, phosphate group, and nitrogenous base.

Functions of Nucleic Acids

• Store and transmit genetic information.
• Direct the synthesis of proteins through processes like transcription and translation.

Composition of Nucleic Acids

• DNA is made of deoxyribonucleotides, featuring deoxyribose sugar.
• RNA is composed of ribonucleotides, containing ribose sugar.

Kinds of Nucleic Acids

• Primary types include DNA (deoxyribonucleic acid) and RNA (ribonucleic acid).
• DNA is primarily found in the nucleus, while RNA is found throughout the cell.

Properties of Nucleic Acids

• Exhibit specific base pairing (A-T and C-G in DNA, A-U and C-G in RNA).
• Can form double-stranded structures (DNA) or single-stranded structures (RNA).

Derivatives of Nucleic Acids

• Include various forms such as cyclic AMP (cAMP) and nucleotide coenzymes like NAD+.
• Derivatives play roles in cellular signaling and metabolism.

Levels of Structure of Nucleic Acids

• Primary structure: sequence of nucleotides.
• Secondary structure: double helix in DNA; various structures in RNA including hairpins and loops.
• Tertiary and quaternary structures often refer to complex folding and interactions with proteins.

Bases of DNA

• Four nitrogenous bases: adenine (A), thymine (T), cytosine (C), guanine (G).
• A-T pairs form two hydrogen bonds, while C-G pairs form three hydrogen bonds.

Structure of DNA

• The double helix model was proposed by Watson and Crick.
• Antiparallel strands create a stable structure with the sugar-phosphate backbone on the outside and bases on the inside.

RNA Structure

• Generally single-stranded but can fold into complex three-dimensional shapes.
• Types of RNA include messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA), each serving distinct functions in protein synthesis.

Nucleoproteins

• Complexes of nucleic acids and proteins crucial for DNA packaging and regulation.
• Chromatin is a nucleoprotein that helps condense DNA in eukaryotic cells.

Nucleotides and Nucleosides

• Nucleotides consist of a nitrogenous base, a sugar, and one or more phosphate groups.
• Nucleosides are similar but do not contain phosphate groups; they consist only of a sugar and a nitrogenous base.