🏥 Chapter 3- Biological Molecules

• What are carbohydrates?


  Organic molecules made of carbon, hydrogen and oxygen

  
• What are suagrs?


  Sweet and soluble in H2O, and provides us with energy

  
• What are Single Sugars? (Monosaccharide)


  Basic unit of carbohydrates. can pass through cell membranes and be absorbed in cells.

  
  

  e.g. Glucose & Fructose

  
• What are double sugars? (Disaccharides)

  when two single sugars are joined together.

  
  

  
  

  e.g.

  
  

  glucose + glucose --> maltose

  glucose + fructose --> sucrose

  
• What are complex carbohydrates? (polysaccharides)

  chains of glucoses linked together to form a large molecule. bonds between starch, glycogen and cellulose are different. they are insoluble in water, large and will not be lost in the cell, and can easily be broken down to glucose.

  
  

  
  

  starch --(with amylase)--> maltose

  maltose --(with maltase)--> glucose

  
• What are the functions of carbohydrates?

  -immediate energy source

  -formation of DNA (nucleic acids)

  - can be converted to amino acids and fats

  
• How to test for reducing sugar (maltose and glucose)

  place equal amt of benedict solution & and food sample in a test tube and shake in a boiling water bath

  
  

  Brick-red precipitate - large amount of RS

  yellow/orange precipitate - moderate amount of RS

  green precipitate - trace amounts of RS

  blue precipitate- no RS present

  
• How to test for starch?

  add a few drops of iodine to food sample

  
  

  
  

  if brown --> blue-black = starch present

  if brown = starch absent
• What are fats?


  Organic molecules made of carbon, hydrogen and oxygen, in a different ratio then carbohydrates.

  
  

  they can break down to glycerol and three fatty acid molecules by lipase.

  
• What are the functions of fats?

  - long-term storage of energy

  - insulating material to reduce heat loss

  - oily to prevent water loss from skin

  
• How to test for fats?

  add equal amount of ethanol and food sample and shake. then add same amount of water and shake. white emulsion present indications presence of fat

  
• What are proteins?


  Organic molecules made of carbon, hydrogen and oxygen and nitrogen (and sulfur)

  
  

  amino acids --> polypeptides --> protein

  
• What are the functions of proteins?

  - synthesis of new cytoplasm for growth and repair of worn out cells

  -synthesis of enzymes and hormones

  -formation of antibodies to fight diseases

  
• How to test for proteins?

  place biuret solution to food sample and shake and leave for 5 minutes.

  
  

  blue --> violet = proteins present

  blue --> blue = proteins absent

  
• yt video on chapter


  https://www.youtube.com/watch?v=dN7c2JniR8U