topic 2- organisation

• What makes up all living things?

  Cells
• What is a tissue?

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

  Yes
• What is muscular tissue an example of?

  A tissue
• What are organs formed from?

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

  An organ
• What do organ systems do?

  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 type of juices do glands produce in the digestive system?

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

  Produces hydrochloric acid to kill bacteria and provide optimum pH for enzymes
• 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 help with the digestion of lipids
• What does the large intestine do?

  Absorbs water from undigested food to produce faeces
• What are enzymes?

  Biological catalysts
• What is the role of enzymes in reactions?

  To increase the rate of reaction without being used up
• Why is the shape of an enzyme important?

  Because each enzyme has a uniquely shaped active site
• What is the Lock and Key Hypothesis?

  The substrate shape is complementary to the active site shape
• What happens when the substrate binds to the enzyme?

  An enzyme-substrate complex is formed
• What is the optimum temperature for most enzymes?

  A range around 37 degrees Celsius
• What happens to enzymes at temperatures above their optimum?

  The reaction rate rapidly decreases and eventually stops
• What does it mean when an enzyme is denatured?

  The shape of the active site changes, preventing substrate binding
• What is the optimum pH for most enzymes?

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

  The shape of the active site changes, preventing substrate binding
• What are carbohydrases?

  Enzymes that 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 do?

  Convert proteins into amino acids
• What is an example of a protease?

  Pepsin
• What do lipases convert?

  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 the tests for carbohydrates, proteins, and lipids?

  To determine the composition of a solution
• What does Benedict’s test indicate?

  Presence of sugars
• What color does iodine turn in the presence of starch?

  Blue-black
• What does the Biuret test indicate?

  Presence of proteins
• What is the emulsion test used for?

  To test for lipids
• What are the two roles of bile?

  Neutralise hydrochloric acid and emulsify fats
• Why is bile alkaline?

  To neutralise hydrochloric acid from the stomach