biology topic 2 aqa gcse

• What is a tissue?

  A group of cells with a similar structure and function.
• What is and organ?

  A group of tissues working together to perform a specific function.
• What are organ systems?


  A group of organs working together to form organisms.
• Large molecules such as carbohydrates, proteins, lipids (fats), are broken down into small molecules by _____ to be absorbed into the ______.

  Enzymes

  Bloodstream
• What does saliva in the mouth begin to digest?

  Starch into smaller sugar molecules.
• What do enzymes in the stomach begin to digest?

  Proteins
• What is in the stomach to help enzymes digest proteins?

  Hydrochloric acid
• Where is bile produced?

  In the liver
• What does bile do?

  Speeds up digestion of fats and neutralises the acid released from the stomach.

  
• What do enzymes do?

  Catalyse (speed up) chemical reactions
• What is the active site?


  The region on the enzyme where the substrate binds

  
• Where is protease produced?

  Stomach, pancreas, small intestine
• What does protease break down?

  Proteins into amino acids

  
• Where is amylase produced?

  Saliva and pancreas
• What does amylase break down?

  carbohydrates to simple sugars

  
• What does lipase break down?

  Lipids (fats) into glycerol and fatty acids
• Where is lipase produced?

  Pancreas and small intestine
• Where is bile made and stored?

  Made in liver

  Stored in gall bladder
• What happens when temperature is raised past an enzymes optimum?

  The enzyme changes shape due to immense vibration (due to high energy from heat), causing the active site to become denatured.
• What happens when enzymes are exposed to high or low pH?

  They become denatured
• What is a lipid molecule?

  Glycerol attached to fatty acids

  
• What colour does iodine change if starch is present?

  blue-black
• What solution do we use to find starch?

  Iodine solution (orange)
• What solution do use to find glucose?

  Benedict solution (blue)
• What colour does Benedicks solution to show us the glucose presents?

  Green = Small amount

  Yellow = medium amount

  Red = high amount
• What solution do we used to find proteins?

  Biuret solution (blue)
• What colour will biuret turn if proteins are present?

  Purple
• What solution do use to find lipids (fats)?

  Ethanol
• What colour will ethanol turn to if lipids are present?

  Cloudy white
• What do villi do?

  increase surface area absorption.
• Where are villi found?

  small intestine
• What do microvilli do?

  Increase the surface area even more.
• Label the heart

  
• What does the vena cava carry?

  Deoxygenated blood from the body

  
• What artery carries blood from the heart to the lungs?

  Pulmonary artery

  
• What vein carries oxygenated blood from the lungs to the heart?

  Pulmonary vein

  
• What artery carries blood to the rest of the body?

  Aorta

  
• Why does the left side of the heart have a thicker muscular wall?

  Because the left ventricle pumps blood around the entire body, so it needs a greater force.
• What is the purpose of the coronary artery?

  To provide oxygen to the muscle cells of the heart.
• What does an artificial pacemaker do?

  It is a small device that corrects irregularities in the heart rate.