Nucleic Acids and Protein Synthesis Notes

DNA and RNA Bases

• DNA Bases: Adenine (A), Guanine (G), Cytosine (C), Thymine (T)
• RNA Bases: Adenine (A), Guanine (G), Cytosine (C), Uracil (U)

Pentose Sugars

• RNA Sugar: Ribose
• DNA Sugar: Deoxyribose
  • Note: Deoxyribose lacks one oxygen atom at the 2' carbon
• Numbering: The carbon atoms in the sugar are numbered with primes (e.g., 2') to differentiate them from bases.

Nucleosides

• Definition: A nucleoside is formed by the combination of a sugar and a base.
• Example: Adenine + Ribose = Adenosine

Nucleotides

• Definition: A nucleotide consists of a nucleoside plus a phosphate group.
• Comparison of RNA and DNA Nucleotides:
  • RNA: Contains ribose and uridine
  • DNA: Contains deoxyribose and deoxythymidine, substituting uridine

Components in DNA and RNA

Nucleic Acid Sequence

• Reading Direction: Nucleic acid sequences are read from the 5' end (sugar with free phosphate) to the 3' end (sugar with free hydroxyl group).
• Example Sequence: 5'- ACGU -3'

DNA Double Helix

• Structure: The double helix consists of two strands held together by hydrogen bonds.
• Base Pairing:
  • Adenine (A) pairs with Thymine (T)
  • Guanine (G) pairs with Cytosine (C)

DNA Replication

• Process: During DNA replication, the original strands of DNA serve as templates for new strands synthesis.
• Outcome: This results in the formation of two identical copies of DNA.

Protein Synthesis

• Role of DNA: The genetic information in DNA is duplicated during cell division.
• mRNA Production: This information is transcribed into mRNA which encodes for the amino acids necessary for protein synthesis.

Codons in mRNA: The Genetic Code for Amino Acids

• Codons: Three-base sequences in mRNA that specify particular amino acids.
• Importance: Understanding which codons correspond to which amino acids is crucial for interpreting the genetic information during protein synthesis.