B2 - 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 tissues 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?

  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 does the stomach produce to aid digestion?

  Hydrochloric acid
• What is the role of hydrochloric acid in the stomach?

  To kill bacteria and provide optimum pH for protease
• 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 absorb?

  Water from undigested food
• What is the role of enzymes in the digestive system?

  To break down large molecules and join small ones
• What are enzymes classified as?

  Biological catalysts
• Why is the shape of an enzyme important?

  Because it determines the function of the enzyme
• What is the active site of an enzyme?

  The uniquely shaped area where the substrate binds
• What happens when a substrate binds to an 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 decreases and the enzyme may denature
• What does it mean when an enzyme is denatured?

  Its active site changes shape and can no longer bind to the substrate
• What is the optimum pH for most enzymes?

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

  The enzyme may denature and its active site changes shape
• 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
• Where are proteases produced?

  In the stomach, pancreas, and small intestine
• 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 glucose in the body?

  To be used in respiration and to build new carbohydrates
• What is Benedict's test used for?

  To test for sugars
• What color does Benedict's test turn if sugars are present?

  Brick red
• What is the iodine test used for?

  To test for starch
• What color does the iodine test turn if starch is present?

  Blue-black