Aminoácidos y Proteínas

Amino Acids

• Amino acids are organic compounds containing both an amino group (-NH2) and a carboxyl group (-COOH).
• They are the building blocks of proteins.
• There are 20 standard amino acids, each with a unique side chain (R group).
• The R group determines the specific properties of each amino acid (e.g., polarity, charge).
• Amino acids are linked together by peptide bonds to form polypeptide chains.
• Peptide bonds are formed through a dehydration reaction.
• The sequence of amino acids in a polypeptide chain determines its structure and function.
• Essential amino acids cannot be synthesized by the body and must be obtained from the diet.
• Nonessential amino acids can be synthesized by the body.
• Amino acids are involved in many cellular processes beyond protein synthesis, like energy metabolism.

Proteins

• Proteins are complex molecules composed of one or more polypeptide chains.
• Proteins have diverse functions in living organisms, including:
  • Structural support (e.g., collagen).
  • Catalysis (e.g., enzymes).
  • Transport (e.g., hemoglobin).
  • Regulation (e.g., hormones).
  • Defense (e.g., antibodies).
• Protein structure is hierarchical:
  • Primary structure: linear sequence of amino acids.
  • Secondary structure: local folding patterns (e.g., alpha-helices, beta-sheets).
  • Tertiary structure: overall 3D shape of the polypeptide chain.
  • Quaternary structure: arrangement of multiple polypeptide chains in a complex protein.
• Protein structure is crucial for its function.
• Protein shape can be altered by environmental factors (e.g., temperature, pH).
• Denaturation occurs when a protein loses its 3D structure, and often its function.
• Proteins are crucial for maintaining and regulating most of the cellular processes.

Nucleic Acids

• Nucleic acids are the informational molecules of cells.
• They store and transmit genetic information.
• Two main types of nucleic acids:
  • DNA (deoxyribonucleic acid)
  • RNA (ribonucleic acid)
• DNA:
  • Double-stranded helix.
  • Composed of nucleotides:
    • Deoxyribose sugar
    • Phosphate group
    • Nitrogenous base (adenine, thymine, guanine, cytosine).
  • Stores genetic information.
  • Typically found in the nucleus of eukaryotic cells.
• RNA:
  • Single-stranded.
  • Composed of nucleotides:
    • Ribose sugar
    • Phosphate group
    • Nitrogenous base (adenine, uracil, guanine, cytosine).
  • Several types of RNA have crucial roles in protein synthesis:
    • mRNA (messenger RNA)
    • tRNA (transfer RNA)
    • rRNA (ribosomal RNA)
  • Involved in protein synthesis and gene regulation.
• The sequence of nucleotides in DNA determines the sequence of amino acids in proteins.
• DNA replication is the process of copying DNA to produce identical copies.
• Gene expression is the process by which genetic information is used to synthesize proteins.
• Nucleic acids are crucial for all life processes, underpinning heredity and cellular function.