Digestion system

• what small soluble food molecule does protein turn into?

  Amino acid
• what small soluble food molecule does carbohydrates turn into?

  Glucose
• what type of small soluble food molecule does lipids turn into?

  3 Fatty acids and 1 glycerol
• describe oxygen in gas exchange

  1. The oxygen moves from the alveoli to the bloodstream.
  2. oxygen moves from a high concentration to low concentration
  3. Oxygen moves down a concentration gradient
  4. Oxygen is transported to the body cells for respiration
• describe carbon dioxide in gas exchange

  1. Carbon dioxide moves from the bloodstream to the alveoli.
  2. Carbon dioxide moves from a high concentration to low concentration
  3. Moves down a concentration gradient
• what are the adaptations of the alveoli that increases the rate of diffusion?

  -thin walls That are one Cell thick: short diffusion pathway

  -covered in capillaries

  -They are moist

  -They have a large combined surface area

  -Good blood supply that maintains a steep concentration gradient
• what is digestion?

  It’s the breaking down of large insoluble food molecules into simpler smaller soluble food molecules
• What is physical digestion?

  Breaking the food down into smaller pieces in increases the surface area of the food to help chemical digestion by enzymes
• what are the two ways physical digestion occurs?

  Chewing action: by the mouth with help of the teeth

  Peristalsis: the walls of the oesophagus stomach and intestine

  no chemical change occurs
• what is chemical digestion?

  The breaking down of large in soluble molecules into smaller soluble molecules by breaking bonds. Enzymes are required so food is chemically changed.
• what is amylase

  an enzyme that breaks down starch into sugar
• What does the mouth and salivary glands do in digestion

  -Where mechanical digestion takes places

  -where saliva lubricates food

  Amylase enzymes break down starch into maltose
• What does the oesophagus do?

  It contracts to push the food down this is called peristalsis
• what does the stomach do?

  -It mechanically digest by turning

  -protease enzymes start to chemically digest proteins

  -hydrochloric acid is present to kill bacteria in food and provide optimum pH for enzymes
• What do small intestines do?

  -The first section is called the duodenum: food comes out stomach finishes being digested by enzymes produced from the pancreas

  -pH is slightly alkaline around eight or nine

  -2nd section is called ileum absorption of food molecules takes place
• what does large intestines do?

  Water is absorbed and faeces is stored in the rectum
• what does the pancreas do?

  Produces all three types of digestive enzymes: amylase, protease and lipase

  Secrete enzymes in an alkaline fluid into the duodenum to raise pH of fluid coming out the stomach
• what does the liver do?

  -Produces bio to emulsify fats this is an example of mechanical digestion

  -Amino acids are broken down here which produces urea
• what does the gallbladder do?

  -Stores bile
• what is a carbohydrate?

  A long chain of glucose molecules
• what is a protein?

  Long chain of amino acids
• what is an enzyme?

  are biological catalyst that speed up the rate of reaction and don’t get used up in the process
• what are enzymes made out of

  proteins, long chains of amino acids
• describe the structure of an enzyme

  They have an active site which has a unique shape so it can bind with a specific substrate.

  The active site is complementary to the substrate
• what is a substrate?

  It’s the thing that the enzyme is trying to break down
• what happens when a substrate fits into an active site?

  The reaction has been catalysed and is breaking down the substrate into smaller molecules. This is called a enzyme-substrate complex.
• what is a anabolic enzyme?

  an enzyme that builds bigger molecules from smaller ones
• what is a catabolic enzyme?

  Breaking bigger molecules down into smaller ones
• what is the lock and key mechanism?

  The substrate must fit into the active site of an enzyme for the reaction to be catalysed if the substrate does not fit the reaction will not be catalysed
• what does denature mean?

  changing shape
• what is the food test for protein?

  Test: biurets solution

  Start colour: blue

  Detected colour: purple
• what is the food test for carbs?

  Test: iodine

  Start colour: orange

  Detected colour: blue black
• what is the food test for sugar/glucose?

  Test: Benedict solution

  Start colour: blue

  Detected colour: low level= green, moderate sugar= yellow/orange, high sugar levels= red
• what is the test for fats?

  Test: equal parts, water, ethanol and fat

  When shaken up mixture will turn cloudy if fat is present
• enzymes can be reused with a new substrate
• describe the enzyme process

  1. Substrate molecule moves towards active site
  2. Forms enzyme substrate complex complementary to each other
  3. Substrate molecule fits in active site
  4. Reaction occurs and products made enzyme speeds this up
  5. Product molecules do not fit in the active site anymore so are released
  6. The enzyme can then be used again with a new substrate
• what is optimum conditions?

  The conditions that enzymes work the fastest
• what are the two things proteins are affected by

  Temperature and pH
• what happens if the specific optimum temperature and pH isn’t right for that specific enzyme?

  It will denature
• how does a lower temperature affect the rate of a reaction?

  The rate is slower because the number of successful collisions between the enzyme and the substrate is reduced because the movement decreases this is because there is much less heat so lower energy