Globular and fibrous proteins

• What is the shape of fibrous proteins?

  Long, thin, and linear
• What contributes to the strength of fibrous proteins?

  Parallel polypeptide chains or sheets, often cross-linked
• Why are fibrous proteins insoluble in water?

  Due to the presence of many hydrophobic amino acids
• What contributes to the durability of fibrous proteins?

  Repetitive sequences of amino acids
• What is the primary function of fibrous proteins?

  Provide structural support
• What is an example of a fibrous protein?

  Collagen
• Where is collagen found?

  In connective tissues like tendons and ligaments
• What is the structure of collagen?

  A triple-helix structure providing tensile strength
• What is another example of a fibrous protein besides collagen?

  Keratin
• What role does keratin play in the body?

  Provides mechanical protection and prevents water loss
• What is elastin found in?

  Elastic tissues like skin and blood vessels
• What is the primary function of elastin?

  Allows tissues to stretch and recoil
• What is the shape of globular proteins?

  Compact and spherical
• How are the side chains of globular proteins arranged?

  Hydrophilic side chains face outward
• Why are globular proteins water-soluble?

  Hydrophilic side chains face outward
• Why are globular proteins less stable than fibrous proteins?

  They are not designed for structural roles
• What is the primary function of globular proteins?

  Perform metabolic and regulatory functions
• What is an example of a globular protein?

  Enzymes
• What role do enzymes play in the body?

  Catalyze biochemical reactions
• What is a function of hormones like insulin?

  Regulates blood glucose levels
• What do antibodies do?

  Involved in immune defense
• What is the function of transport proteins like hemoglobin?

  Carries oxygen in the blood
• What are the key differences between fibrous and globular proteins?

  • Fibrous: Long and linear, structural roles, insoluble
  • Globular: Compact and spherical, metabolic/regulatory roles, soluble
• What are the examples of fibrous and globular proteins emphasized in the WJEC specification?

  • Fibrous: Collagen for tensile strength
  • Globular: Enzymes and transport proteins like hemoglobin