4 Big Molecules

• Macromolecule


  A very large molecule, such as a polymer or protein, consisting of many smaller structural units linked together by a process called dehydration synthesis
• Biological macromolecules


  • Proteins
  • Lipids
  • Carbohydrates
  • Nucleic acids
• Polymer


  A large molecule composed of repeating structural units connected by chemical bonds
• Monomer


  A small molecule that can be bonded to other identical molecules to form a polymer
• Biological macromolecules are made up of a small number of elements: Carbon, Hydrogen, Oxygen, (Nitrogen, Phosphorus)
• Three out of the 4 types of biochemical macromolecules can be found on food nutrition labels
• Enzymes


  • Organic catalysts that can either initiate or speed up chemical reactions
  • The substances that are transformed with the help of enzymes are called substrate
• Lock and key model

  Demonstrates the specificity of enzymes, where the enzyme changes shape slightly as the substrate binds to the active site
• As temperature increases


  • Enzymes work well in temperature ranging from 30°C to 40°C
  • Below this, enzymes are inactivated
• pH of the substrate

  Affects the relative acidity of the medium where the substrate is located
• The 3 biochemical molecules found on a nutrition label are carbohydrates, proteins, and lipids
• Carbohydrates


  • They are the main source for the body to gain energy
  • They make up the cell wall in plants which allow them to grow tall
• Where carbohydrates are found

  • In plant foods (fruits, vegetables, peas, beans, sugar, flour)
  • In animal products (milk)
• Simple carbohydrates


  Carbohydrates made up of 1 or 2 monomers, and they taste sweet
• Complex carbohydrates


  Carbohydrates that are polymers made up of many monomers, and they often taste starchy
• The most common monomer of carbohydrates is glucose
• Chemical digestion of carbohydrates

  1. Begins in the mouth with salivary amylase ptyalin

  2. Continues in the stomach, where the bolus is changed into chyme

  3. In the small intestine, the enzyme amylopsin in the pancreatic juice repeats the work of ptyalin

  4. The intestinal glands release the final enzymes for the digestion of carbohydrates
• Proteins


  • They are the major structural molecules in living things for growth and repair
  • They make up antibodies in the immune system
  • They make up enzymes for helping chemical reactions
  • They make up non-steroidal hormones
• Where proteins are found

  • In plant foods (cell membranes)
  • In animal products (cell membranes, muscles, living things like cows, chicken, fish)
• Proteins


  They are made up of long chains (polymers) of the monomer amino acid
• Proteins are made up of carbon, hydrogen, oxygen, nitrogen, and sometimes sulfur
• Chemical digestion of proteins

  1. Begins in the stomach with pepsin

  2. Continues in the small intestine with trypsin

  3. The intestinal glands release the final enzymes (aminopeptidases and eripsin) to break down polypeptides into amino acids
• Lipids


  • They are a great source of stored energy
  • They insulate the body and cushion internal organs
  • They produce hormones called steroids
  • They waterproof surfaces of animals, plants, and fruits
• Where lipids are found

  • In plants
  • In animals (adipose tissue, connective tissue, cell membranes)
• Chemical digestion of lipids


  Begins and ends in the small intestine, where pancreatic steapsin breaks down fats into fatty acids and glycerol
• Nucleic acids


  Large, complex organic compounds that store information in cells, using a system of four compounds to store hereditary information, arranged in a certain order as a code for genetic instructions of the cell
• Types of nucleic acids

  • DNA (Deoxyribonucleic Acid)
  • RNA (Ribonucleic Acid)
• Nucleotide


  The monomer of nucleic acids, consisting of a phosphate group, a 5-carbon sugar, and a nitrogenous base
• Almost all of the molecules that make up the body are polymers, chains of subunits
• The structure of each type of macromolecule is what determines how the molecules function in our bodies
• Elimination of waste products

  1. Wastes exit the body in several forms: solid, liquid, and gas

  2. As food groups are broken down, water is released and the large intestine eliminates solid waste as feces