ORGANISATION

• What do cells make up?

  All living things
• What is a tissue?

  A group of specialised cells with a similar structure and function
• Can a tissue be made of more than one type of cell?

  Yes
• Give an example of a type of tissue.

  Muscular tissue
• What are organs formed from?

  A number of different tissues working together
• What is an example of an organ?

  The stomach
• What do organ systems do?

  They work together to perform a certain function
• What organ system is the stomach part of?

  The digestive system
• What is the function of the digestive system?

  To break down food for absorption by cells
• What do glands in the digestive system produce?

  Digestive juices containing enzymes
• What is the role of hydrochloric acid in the stomach?

  To kill bacteria and provide optimum pH for protease enzyme
• Where are soluble molecules absorbed in the digestive system?

  The small intestine
• What does the liver produce that aids in digestion?

  Bile
• What is the function of bile?

  To emulsify fats and neutralise stomach acid
• What does the large intestine do?

  Absorbs water from undigested food
• What are enzymes?

  Biological catalysts that increase the rate of reaction
• How do enzymes function in reactions?

  They can break up large molecules and join small ones
• What is the importance of the shape of an enzyme?

  It is vital to its function
• What is the active site of an enzyme?

  The uniquely shaped area where the substrate binds
• What does the Lock and Key Hypothesis explain?

  How enzymes work by forming an enzyme-substrate complex
• What happens when the substrate binds to the enzyme?

  An enzyme-substrate complex is formed
• Why do enzymes require an optimum pH and temperature?

  Because they are proteins
• What is the optimum temperature for most enzymes?

  A range around 37 degrees Celsius
• What happens to the rate of reaction as temperature increases up to the optimum?

  The rate of reaction increases
• What occurs when the temperature exceeds the optimum for enzymes?

  The enzyme is denatured and can no longer work
• What is the optimum pH for most enzymes?

  7
• What happens if the pH is too high or too low for enzymes?

  The enzyme is denatured and can no longer work
• What do carbohydrases convert carbohydrates into?

  Simple sugars
• What is an example of a carbohydrase?

  Amylase
• Where is amylase produced?

  In the salivary glands, pancreas, and small intestine
• What do proteases convert proteins into?

  Amino acids
• What is an example of a protease?

  Pepsin
• What do lipases convert lipids into?

  Fatty acids and glycerol
• Where are lipases produced?

  In the pancreas and small intestine
• What happens to soluble glucose, amino acids, fatty acids, and glycerol after digestion?

  They pass into the bloodstream to be carried to cells
• What is the purpose of tests like Benedict's test?

  To determine whether a solution contains carbohydrates, proteins, or lipids
• What color does Benedict's test turn if sugars are present?

  Brick red
• What color does the iodine test turn if starch is present?

  Blue-black
• What does the emulsion test for lipids involve?

  Adding ethanol to produce a cloudy layer if a lipid is present
• What color does the Biuret test turn if proteins are present?

  Purple