orginisation

• 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 into a form that can be absorbed 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 the large intestine?


  Absorbs water from undigested food to produce faeces
• 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 where the substrate binds
• What is the Lock and Key Hypothesis?

  The shape of the substrate is complementary to the shape of the active site, forming an enzyme-substrate complex
• What is the optimum temperature range for most enzymes?

  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?

  Its shape changes so the substrate can no longer fit in
• What is the optimum pH for most enzymes?

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


  The forces holding the amino acid chains are affected, changing the shape of the active site
• 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 all cells
• What is the purpose of the tests for carbohydrates, proteins, and lipids?

  To determine whether a solution is made up of these substances
• What does Benedict’s test indicate?


  Presence of sugars
• What color does Benedict’s test turn if sugars are present?

  Brick red
• What does the iodine test indicate?


  Presence of starch
• What color does the iodine test turn if starch is present?

  Blue-black
• What does the Biuret test indicate?


  Presence of protein
• What color does the Biuret test turn if protein is present?

  Purple
• What does the emulsion test indicate?

  Presence of lipids
• How is the emulsion test performed?

  Add ethanol which results in a cloudy layer if a lipid is present