Biology · MU Sofia

2. Proteins. Protein domains. Protein families.

Covers the main functions of proteins, such as support, movement, catalysis and membrane transport, with examples and a mnemonic. It then explains protein composition from amino acids and peptide bonds, and walks through the four levels of structure, from primary sequence to quaternary assemblies. It also lists the side-chain interactions that stabilise folding, with a mnemonic, and closes with protein families, motifs and domains.

Inside: 8 sections · 5 labelled pictures · 20 flashcards · 2 min

Topic 3 of 105 in the MU Sofia syllabus for Biology (Medicine, Year 1). The free AceMed note covers it in 8 sections, about 268 words (2 min of reading), with 20 flashcards.

In this note

  1. Proteins, Protein Domains, and Protein Families
  2. Functions of Proteins
  3. Protein Composition
  4. Four Levels of Protein Structure
  5. Spatial Structure
  6. Protein Assembly Line
  7. Key Interactions
  8. Protein Domains and Families

Proteins, Protein Domains, and Protein Families

This summary organizes information about proteins, their structure, functions, domains, and families in a clear and study-friendly format, including mnemonics.

Functions of Proteins

  • Support: Structural support (e.g., collagen in bones).
  • Movement: Muscle contraction and cell movement (e.g., actin, myosin).
  • Catalysis: Enzymes (e.g., sucrase).
  • Membrane Transport: Molecule transport (e.g., ion channels).
  • Recognition and Binding: Interaction with molecules (e.g., antibodies).
  • Homeostasis: Internal balance (e.g., hemoglobin, albumin).
  • Gene Expression: Involved in replication, transcription, translation.

Mnemonic: Some Men Can Make Really Healthy Genes

Protein Composition

Proteins are polymers made from 20 amino acids linked by peptide bonds. Each amino acid has a unique side chain determining protein structure and function.

Four Levels of Protein Structure

  1. 1. Primary: Sequence of amino acids, encoded by genes.
  2. 2. Secondary: Folding patterns (alpha helices, beta sheets).
  • Antiparallel and parallel beta sheets.
  1. 3. Tertiary: 3D folding via side chain interactions (H-bonds, ionic, disulfide, hydrophobic).
  • Disulfide bonds form between cysteine residues.
  • Example: Myoglobin
  1. 4. Quaternary: Multiple polypeptide chains form a complex (e.g., hemoglobin - 2 alpha & 2 beta subunits).

Mnemonic: Primary Sequence Starts The Quest

Continue reading free

The whole note, all 8 sections, is free with an AceMed account, with its 20 flashcards. Premium adds flashcard recall, highlights and Ask AI.

Start freeAlready a member? Open the note