Nucleic Acid

Nucleic Acids Overview

Nucleic acids are essential biomolecules that play a critical role in the storage and expression of genetic information.

Alternative Learning Tools

Resources Available:

  • CK-Interactive Textbook

  • Textbook lesson posted under the content in the textbook

  • Videos included in the slideshow

  • Worksheets with answer keys available on Brightspace

  • Simulation links for DNA structure and building molecules

Learning Objectives

  • Understand the roles of nucleic acids in the body.

  • Identify the functional groups that comprise nucleic acids.

  • Analyze the monomer units that make up DNA.

  • Describe the bonding that maintains the structure of DNA strands.

Functions of Nucleic Acids

Informational Macromolecules:Nucleic acids serve as the basis for genetic information storage and transmission.They facilitate the transfer of hereditary information through processes such as replication, transcription, and translation, enabling organisms to grow, develop, and reproduce.

Types of Nucleic Acid Polymers:

  • ATP (Adenosine Triphosphate): Acts as the primary energy currency of the cell, used to drive various cellular processes.

  • DNA (Deoxyribonucleic Acid): Stores the genetic blueprint for all living organisms, ensuring the continuation of life through heredity.

  • RNA (Ribonucleic Acid): Plays a central role in synthesizing proteins, acting as a messenger and facilitator in transcribing and translating genetic information.

Structure of Nucleic Acids

Nitrogenous Base Pairing:

  • DNA includes bases: Cytosine (C), Guanine (G), Adenine (A), Thymine (T).

  • RNA has Uracil (U) in place of Thymine (T).

Components:

  • Backbone: Comprised of sugar and phosphate groups.

  • Base Pairing: A pairs with T (in DNA), and G pairs with C; in RNA, A pairs with U.

DNA Functionality

Hereditary Information:DNA serves as the repository of hereditary information, crucial for the structure and function of organisms. The double helical structure allowing base pairing is fundamental for DNA replication, ensuring that genetic information is accurately copied and transmitted during cell division.

Protein Synthesis via RNA:

  • mRNA (messenger RNA): Translates genetic information from DNA into sequences of amino acids to form proteins.

  • tRNA (transfer RNA): Transfers specific amino acids to the ribosome during protein synthesis. Each tRNA molecule carries an amino acid and has an anticodon that matches the codon on mRNA.

  • rRNA (ribosomal RNA): A structural component of ribosomes, playing a key role in translating mRNA into proteins. It helps facilitate the bonding of amino acids together to form a polypeptide chain.

Energy Currency - ATP

ATP is the primary energy carrier in cells.

  • Structure: Composed of adenine, ribose, and three phosphate groups.

  • High energy bonds are present between the phosphate groups; breaking these bonds releases energy, which powers countless cellular processes, including muscle contraction, nerve impulse propagation, and biochemical reactions involved in metabolism.

Nucleotide Structure

Nucleotide Components:

  • Phosphate group

  • Five-carbon sugar (deoxyribose in DNA, ribose in RNA)

  • Nitrogenous Base (with pyrimidines and purines)

Types of Nitrogenous Bases:

  • Pyrimidines: Uracil (U), Thymine (T), Cytosine (C)

  • Purines: Adenine (A), Guanine (G)

Bonding in DNA

Base Pairing Rules:

  • Adenine (A) forms two hydrogen bonds with Thymine (T).

  • Cytosine (C) forms three hydrogen bonds with Guanine (G).

Strand Structure:DNA is arranged as a double helix, with a sugar-phosphate backbone and base pairs within the helix.

  • Bond Types:

    • Hydrogen bonds between bases

    • Phosphodiester bonds between nucleotides in a single strand

Antiparallel Orientation of DNA Strands:Strands run in opposite directions for proper base pairing and stability.

Comparison of DNA and RNA

  • DNA: Double-stranded, uses deoxyribose, contains thymine (T).

  • RNA: Single-stranded, uses ribose, contains uracil (U) instead of thymine.Both nucleic acids are linked through phosphodiester bonds.

Summary

Nucleotides form the basic building blocks of nucleic acids, with distinct functionalities in heredity, protein synthesis, and energy transfer.