Biology - Organisation pt 2

• What is a tissue?

  group of cells with similar structure and function
• What is an organ?


  A group of different tissues that work together to perform a certain function. Eg the stomach
• When breathing in what is the path of air?

  -in through mouth or nose

  -down the trachea

  - into the 2 bronchi

  - through the bronchioles

  - into the alveoli

  - oxygen then diffuses into the blood
• What do foods contain?

  Carbohydrates (eg starch), protein and lipids
• What are large molecules broken down by?

  Enzymes into small molecules that can be absorbed into the blood.
• How does the mouth aid in digestion?

  Food is chewed, increasing surface area and mix with saliva where there are enzymes that start to digest starch into smaller sugars molecules.
• How does the oesophagus aid in digestion?

  Carries food from throat into stomach

  Uses peristalsis contractions to push food down
• How does the stomach break down food?

  Enzymes begin the digestion of proteins, churns food to increase surface area for enzymes, mixes food with hydraulic acid.
• How does the pancreas aid in digestion?

  releases enzymes that help break down starches and proteins and fats to be used by the body. Also start the digestion of starch
• How does the liver aid in digestion?

  Releases bile which speeds up the digestion of lipids and neutralises stomach acid.
• What does the small intestine do in digestion?

  The small food molecules are absorbed into the blood stream
• Where does it go after the small intestine?

  The large intestine- where water is absorbed into the blood stream and then faeces is released from the body
• What do enzymes do?

  Catalyse reactions
• What is an active site?

  A groove in their surface where a substrate fits into it to break it down
• What is the lock and key theory?

  That the enzyme must fit perfectly with the substrate to break it down
• What breaks down proteins?

  Proteases
• What breaks down carbohydrates?

  Carbohydrase
• What breaks down starch?

  amylase
• What is starch an example of?

  carbohydrate
• What breaks down lipids?

  Lipase
• How are proteins brocken down?

  By the enzyme protease

  Protease enzymes convert the long chain of amino acids into individual amino acids and then these can be absorbed by body cells.
• What are proteins composed of?

  A long chain of amino acids
• What are carbohydrates (starch) consist of?

  A chain of glucose molecules.
• Where is amylase found?

  Pancreatic fluid and small intestine
• Where are proteases found?

  stomach and small intestine
• How are carbohydrates broken down?

  Amylase breaks down starch to produce simple sugars
• What do lipids consist of?

  A molecule of glycerol attached to 3 molecules of fatty acids
• How are lipids broken down?

  Digested by lipase, it breaks the lipids down into glycerol and separated fatty acids
• Where is lipase produced?

  Pancreas and small intestine
• Where is bile made?

  Liver
• Where is bile stored?

  Gall bladder
• What does bile do?

  emulsifies fat (lipids)
• What does emulsifies mean?

  Bile does this, it means it breaks down fats into smaller droplets increasing the surface area
• What is it called when the temperature or ph is increased past the optimum so the active site of an enzyme changes shape?

  Denatures
• What does the graph for activity of enzymes and pH look like?

  A single spike up the top is the optimum pH
• where do the arterys carry blood?

  away from the heart
• Do the artery's carry blood under a high or low pressure?

  High pressure
• What is the structure of artery's?

  Thick muscular and elastic walls, walls can stretch and withstand a high pressure, small lumen
• Where do veins carry the blood?

  towards the heart
• Do the vines carry blood under a high or low pressure?

  Low pressure