BT2

• What do cells make up in living organisms?

  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 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 primary function of the digestive system?

  To break down food into a form that can be absorbed by cells
• What do glands in the digestive system produce?

  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
• How do enzymes function in reactions?

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

  Its function
• What is an active site?


  The uniquely shaped area where the substrate binds on an enzyme
• 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 active site?

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

  Because they are proteins and their structure can be affected
• What is the optimum temperature range for most enzymes?

  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 an enzyme?

  The enzyme becomes 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 an enzyme?

  The enzyme becomes denatured and can no longer work
• What types of molecules do enzymes break down in the digestive system?

  Carbohydrates, proteins, and lipids
• 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 role of glucose in the body after digestion?


  It is 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