• List out the elements that make up proteins.

  C, H, O, N, S
• Explain the polar nature of water.

  - O is more electronegative than H / unequal share of e- / e- spend more time orbiting around O than H

  - give regions of slight positive and negative"
• What allows water molecules to have cohesive and adhesive properties?

  Hydrogen bond
• Describe the structure of amylose, including the bonds involved and the shape.

  All 1,4-glycosidic bonds, straight helix
• Describe the structure of amylopectin, including the bonds involved and the shape.

  1,4 and 1,6 glycosidic bonds, branched
• State the two structures that make up starch.

  Amylose + Amylopectin
• State the reaction that breaks down maltose.

  Hydrolysis
• What is the reaction to join monosaccharides together?

  Condensation
• What are the 3 types of polysaccharides that α-glucose can form?

  amylose, amylopectin, glycogen
• What are the two monosaccharides that join up to make sucrose?

  glucose + fructose
• 1,6 glycosidic bonds are found on ........

  amylopectin and glycogen
• β-glucose can only be found in ........

  Cellulose
• How are the monosaccharides in cellulose arranged?

  Alternative β-glucose molecules are turned upside down
• Based on the arrangement of cellulose molecules, explain why cell walls provide strength and support to plant cells.


  - cellulose molecules form hydrogen bonds with each other to make microfibrils

  - microfibrils join to make microfibrils

  - macrofibrils join to make fibres

  - fibres are insoluble and tough
• What does the Benedict's test test for?

  Reducing sugar
• Explain how a positive result is formed in Benedict's test.


  Reducing sugar reacts with blue Cu2+ --> to make brick-red Cu+
• How can we test for starch?

  Iodine solution
• How can we use a colorimeter to do a quantitative Benedict's test?

  - Colorimeter measure the absorbance or transmission of light by a coloured solution

  - More concentrated solution = more light absorbed / less light transmitted

  - Compare to data table or calibration curve (known concentrations vs. abs/trans value)
• What are the two parts that make up a carboxylic acid?

  Carboxyl group + Hydrocarbon chain
• How many water molecule(s) is/are needed when breaking down a triglyceride?

  3
• What is another term for the condensation reaction that makes lipids?

  Esterification
• What is the difference in structure between saturated and unsaturated lipids?

  - Saturated: all single C-C bonds in fatty acid chain

  - Unsaturated: 1 or more double C=C bonds in fatty acid chain
• Why do oils contain unsaturated triglycerides rather than saturated?

  - Unsaturated fatty acids cause the molecule to kink/bend

  - Cannot pack closely closely together (i.e. cannot form more H bonds)
• What is the difference in structure between triglyceride and phospholipid?

  - Phospholipid: 2 fatty acid chains + 1 phosphate group

  - Triglyceride: 3 fatty acid chains
• Describe the phospholipid bilayer arrangement.

  - Hydrophilic heads point outwards into water

  - Hydrophobic tails point inwards (shielded from aqueous environment)
• Describe 2 similarities and 1 difference between phospholipids and sterols.

  - Similarities: both have dual hydrophilic/hydrophobic characteristics / both make up the plasma membrane

  - Difference: sterols are complex alcohol molecules; phospholipids are lipids
• Describe the steps in identifying lipids and state the positive result.

  - mix sample with ethanol

  - mix solution with water and shake

  - white emulsion layer formed = lipid present
• State the monomer of a protein.

  amino acids
• What are the components that make up an amino acid?

  Central carbon + H atom + Amine group + Carboxyl group
• Name the bond formed between two amino acids.

  Peptide bond
• What is the primary structure of a protein?

  Amino acid sequence
• What is the secondary structure of a protein?

  alpha-helix + beta-pleated sheets
• What is the tertiary structure of a protein?

  Folding into a 3D shape
• What is the quaternary structure of a protein?

  Binding with other subunits
• State the bond involved in the primary structure of a protein.

  peptide bond (between hydrogen of amine group and OH from carboxyl group)
• State the bond involved in the secondary structure of a protein

  hydrogen bond (between amine group and carboxyl group)
• State the bonds involved in the tertiary structure of a protein.

  - ionic (between oppositely charged R groups)

  - covalent

  - hydrogen

  - hydrophobic interactions

  - disulphide bridges (between cysteine - type of amino acid)
• State the bond involved in the quaternary structure of a protein.

  ionic, covalent, hydrogen, hydrophobic interactions, disulphide bridges
• What is the importance of primary structure of proteins?

  Particular amino acids in the sequence influences how the polypeptide folds to give proteins final shape - determining function
• What is the importance of secondary structure of proteins?

  Can be used to predict tertiary structure since predicting only with the amino acid sequence may not be sufficient