Biological molecules

• What are the three main groups of biological molecules?

  Carbohydrates, proteins, and lipids
• Why are biological molecules considered organic compounds?

  They contain the element carbon
• What elements are present in proteins?

  Carbon, hydrogen, oxygen, and nitrogen
• What are the basic units of carbohydrates?

  Simple sugars
• What are the types of carbohydrates and their definitions?

  • Monosaccharides: Simple sugars like glucose
  • Disaccharides: Formed from two monosaccharides, e.g., sucrose
  • Polysaccharides: Complex sugars, e.g., starch and glycogen
• What is the role of polysaccharides in plants?

  They provide slow release of energy
• What is the primary function of lipids?

  Energy storage
• What are the components of lipids?

  Glycerol and fatty acids
• What are proteins essential for?

  Growth and repair
• How many types of amino acids are there?

  Twenty different types
• What are essential amino acids?

  Amino acids that must be obtained from food
• What elements make up a carbohydrate molecule?

  Carbon, hydrogen, and oxygen
• What two substances are produced when fats are broken down by lipase?

  Fatty acids and glycerol
• What is the method for testing glucose using Benedict's test?

  1. Add food sample to test tube
  2. Add Benedict's solution
  3. Heat in water bath at 85°C for 5 minutes
  4. Observe color changes
• What is the method for testing starch using iodine test?

  1. Add food sample to test tube
  2. Add 2-3 drops of iodine
  3. Observe color changes
• What is the method for testing proteins using Biuret test?

  1. Add food sample to test tube
  2. Add Biuret solution
  3. Observe color changes
• What is the method for testing lipids using Emulsion test?

  1. Add food sample to test tube
  2. Add ethanol and shake
  3. Add water and observe for cloudy white substance
• How would you describe the presence of glucose in an unknown food sample?

  Use Benedict's solution and heat
• What safety precautions should be taken during glucose testing?

  Wear safety goggles and gloves
• What is the lock and key theory in relation to enzymes?

  • Enzymes have specific active sites
  • Substrates bind to these active sites
  • Enzymes catalyze reactions without changing
• How does temperature affect enzyme activity?

  Increased temperature increases reaction rate
• What happens to enzymes past their optimum temperature?

  They denature and lose function
• What is the effect of pH on enzyme activity?

  Deviations from optimum pH can denature enzymes
• What is the method to investigate enzyme activity affected by temperature?

  Set up water baths at varying temperatures
• What is the optimum temperature for enzyme activity?

  The temperature at which reaction is fastest
• What happens to the active site of an enzyme when it denatures?

  It changes shape and cannot bind substrates
• What is the role of enzymes in metabolic reactions?

  They act as biological catalysts
• How does the lock and key theory explain enzyme specificity?

  Each enzyme fits only one substrate
• What is the enzyme-substrate complex?

  It is formed when substrates bind to enzymes
• What is the primary function of enzymes?

  To speed up chemical reactions
• What happens to the enzyme after a reaction?

  It remains unchanged and can catalyze more reactions
• What is the effect of temperature on enzyme activity?

  Higher temperatures increase kinetic energy
• What is the effect of pH on enzyme activity?

  Extreme pH levels can denature enzymes
• What is the optimum pH for enzyme activity?

  The pH at which the reaction is fastest
• What happens to the enzyme's active site at optimum pH?

  It remains unchanged and functional
• What is the role of enzymes in digestion?

  They break down complex molecules into simpler ones
• How do enzymes affect the rate of metabolic reactions?

  They increase the rate of reactions
• What is the relationship between enzyme structure and function?

  The structure determines the enzyme's specificity
• How do enzymes lower activation energy?

  By providing an alternative reaction pathway
• What is the significance of enzyme specificity?

  It ensures that only specific reactions occur