Unit 1: Chapter 5

5.1

Macromolecules are polymers built from monomers

enzymes: catalysts which speed up reactions

Dehydration reaction: two monomers join together by releasing water, one gives an OH and the other gives a H. Together, which can create a polymer.

Hydrolysis: Polymers being disassembled

  • the bond between monomers is broken in addition to water
  • one monomer gets the OH group and the other gets a H
  • this is used in our digestive tract when we break down food

5.2

Carbohydrates: Sugars and polymers of sugars

  • monosaccharides, disaccarides, polysaccarides
  • Glucose is the most common monosaccharide
  • can be aldoses or ketoses

what binds two monomers together is a glycosidic linkage

Polysaccharides

  • storage material
      * plants use starch to store energy
      * many animals also use starch for this same reason and access to glucose
  • provide sugar for cells
  • protection of the cell
      * cellulose is a major component of the cell wall in plants

5.3

Lipids: smallest macromolecule, fats, phospholipids, and steroids

  • mix poorly with water

Fats: (triglycerol) glycerol + 3 fatty acids

  • the nonpolar C--H bonds make fats hydrophobic
  • made from dehydration reaction
  • bonded together by an Esther linkage
  • saturated: C--C
      * can pack together closely and therefore are solid at room temp ex. butter
  • unsaturated: C=C
      * cannot pack closely and are liquids at room temp ex. olive oil

Phospholipids: similar to a fat molecule but instead of 3 fatty acids, only 2 are attached and the third attached to the OH group from the glycerol is a phosphate group. Additionally, a small charged or polar molecule is attached to the phosphate group

  • Major constituents of cell membranes
  • Has a hydrophilic head (glycerol, phosphate group, polar molecule) but a hydrophobic tail (fatty acids)
  • Phospholipids create a bilayer which shields their hydrophobic tails from water
  • The bilayer also forms a boundary between the cell and its environment

Steroids: consist of a carbon skeleton of four fused rings

ex. cholesterol

  • a common component in animal cell membranes
  • sex hormones

  cholesterol:

   

5.4

Protein: made up of many polypeptides (amino acids) (possibly thousands)

  • help speed up chemical reactions - enzymes
  • storage
  • transport - hemoglobin transports oxygen
  • structural support - keratin, found in hair that makes it stronger
  • defence - antibodies help inactivate and destroy viruses
  • Made of many amino acids linked by peptide bonds which are referred to as polypeptide chains

Amino Acids:

Hydrophobic amino acids:

  1. Glycine - H
  2. Alanine - CH3

Hydrophilic amino acids:

  1. Serine - OH -- CH2
  2. Cysteine - SH -- CH2

Polypeptides: amino acid polymers

  • amino acids are joined together by a peptide bond
  • amino end (Nitrogen and 2 hydrogens) is called N-terminus
  • carboxyl end (carboxyl group) is called C-terminus
  • the polypeptide backbone is the main chain

connecting smaller branches are called side chains 1

Four levels of protein structure:

  • Primary Structure - its sequence of amino acids which is specific to each protein
  • Secondary Structure - Segments of their polypeptide chains are either coiled or folded
      * are a result of the hydrogen bonds between the polypeptide chain
      * ^^A helix coil^^ is found on every ^^four^^ hydrogen bonds. Some proteins will only have one while others have multiple A helix coils
      * ^^B helix is a pleated sheet^^, two or more pleated sheets side by side are connected by ^^hydrogen bonds^^. The hydrogen bonds make the bonds stronger

     

Tertiary structure - overall shape of the polypeptide according to the interactions of its side chains (R)

  • an example of tertiary structure is hydrophobic interactions
      * as a polypeptide folds into its shape, hydrophobic amino acids will cluster in the core of the protein
  • another example can be disulphide bridges
      * two cysteines (SH) groups can interact with each other when close
      * from that, the sulphur will bond together (S--S) creating a bridge

Quaternary structure - two polypeptides aggregated together to form one macromolecule

  • some proteins only

denaturation - a process where a protein loses its shape due to weak chemical bonds and interactions

5.5

2 types of nucleic acids:

DNA - deoxyribonucleic acid

  • applies directions for its own replication

RNA - ribonucleic acid

  • synthesis

the flow of genetic information: DNA → RNA → Proteins

Nucleic acids as polymers are called: polynucleotides

a monomer of nucleic acid: nucleotide

What is in a nucleotide: adenine, guanine, and cytosine are found in DNA and RNA while thymine is only found in DNA and uracil is only found in RNA