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 do glands in the digestive system produce?

  Digestive juices containing enzymes
• What is the function of the digestive system?

  To break down food for absorption by cells
• 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 the large intestine?

  Absorbs water from undigested food
• What are enzymes?

  Biological catalysts that 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 does the Lock and Key Hypothesis explain?

  How enzymes work by forming an enzyme-substrate complex
• What is the optimum temperature for most enzymes?

  Around 37 degrees Celsius
• What happens to enzymes at temperatures above their optimum?

  Their activity decreases and they can become denatured
• What is denaturation in enzymes?

  When the shape of the active site changes and the enzyme can no longer function
• What is the optimum pH for most enzymes?

  7
• What do carbohydrases convert?

  Carbohydrates into simple sugars
• What happens if the pH is too high or too low for an enzyme?

  The enzyme can become denatured and lose its function
• What is an example of a carbohydrase?

  Amylase
• What do proteases convert?

  Proteins into amino acids
• Where is pepsin produced?

  In the stomach
• 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 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
• What is the Biuret test used for?

  To test for proteins
• What color does the Biuret test turn if proteins are present?

  Purple
• What is the emulsion test used for?

  To test for lipids
• What happens in the emulsion test if a lipid is present?

  A cloudy layer forms
• What is the role of bile in digestion?

  To neutralise hydrochloric acid and emulsify fats
• Where is bile produced?

  In the liver
• What is the purpose of emulsifying fats?

  To increase the surface area for lipase to break down lipids faster