Chapter 21: Biochemistry
21.5: Nucleic Acids
- Nucleic Acids
- Biomolecules that store and transmit genetic information, composed of nucleotide monomers.
- Nucleotide
- The basic unit of nucleic acids, consisting of a phosphate group, a sugar (ribose or deoxyribose), and a nitrogenous base.
- DNA (Deoxyribonucleic Acid)
- A nucleic acid that stores genetic information in the form of a double helix, using the bases adenine (A), thymine (T), cytosine (C), and guanine (G).
- RNA (Ribonucleic Acid)
- A nucleic acid involved in protein synthesis, single-stranded, and contains uracil (U) instead of thymine (T).
- Base Pairing
- The pairing of complementary nitrogenous bases in DNA (A-T, C-G) and RNA (A-U, C-G).
Structure of Nucleic Acids
- DNA: Double helix structure with complementary base pairs held together by hydrogen bonds.
- RNA: Single-stranded molecule involved in transcription and translation.
- Nucleotides: Consist of three parts:
- Phosphate group
- Five-carbon sugar (deoxyribose in DNA, ribose in RNA)
- Nitrogenous base (A, T, C, G, U)
Functions of Nucleic Acids
- Genetic Information: DNA stores the genetic blueprint for organisms.
- Protein Synthesis: RNA translates genetic information into proteins.
- Replication: DNA replicates itself during cell division to pass genetic information to the next generation.
Types of RNA
- mRNA (Messenger RNA): Carries genetic information from DNA to ribosomes.
- tRNA (Transfer RNA): Transfers amino acids to the ribosome during protein synthesis.
- rRNA (Ribosomal RNA): Combines with proteins to form ribosomes.
Questions for Students
- What are nucleotides, and what are their three components?
- Compare and contrast DNA and RNA in terms of structure and function.
- Explain the base pairing rules for DNA and RNA.
- Describe the three types of RNA and their roles in protein synthesis.
- Why are nucleic acids essential for the survival of living organisms?