A level Biology

• What do you call the small units larger molecules are made up from?

  Monomers
• What do you call the larger molecules made up from small repeating units?

  Polymers
• Give 3 examples of monomers

  Amino Acid, Monosaccharide, Nucleotide
• What reaction joins monomers together? Which molecule is eliminated?

  Condensation; water
• What reaction breaks chemical bonds between 2 molecules? Which molecule is needed?

  Hydrolysis; Water
• What is the monomer that makes up larger carbohydrates?

  Monosaccharides
• Name 3 common monosaccharides?

  Glucose, Ribose, Galactose, Fructose
• What is formed by the condensation of two glucose molecules?

  Maltose
• What is made by the condensation of glucose and fructose?

  Sucrose
• What is made by the condensation of glucose and galactose?

  Lactose
• Which 2 molecules are polymers of alpha-glucose?

  Starch, Glycogen
• Which molecule is a polymer of beta-glucose?

  Cellulose
• Why is a branched structure more rapidly hydrolysed than a linear molecule?

  More exposed ends
• Why is a polysaccharide better for storage than a monosaccharide/disaccharide?

  Does not affect water potential
• Describe the orientation of neighbouring monomers in a cellulose molecule?

  Flipped 180 degrees
• Why do multiple cellulose molecules form strong fibres?

  Hydrogen bonds between fibres
• What is the test for reducing sugars?

  Benedicts solution, warm, blue à orange
• What is the test for non-reducing sugars?

  Fails normal Benedict’s test,Boil with acid, neutralise acid,Benedicts solution, warm, blue à orange
• What is the test for starch?

  Iodine solution ,Orange à Black
• What is the structure of a triglyceride? (you could draw a labelled diagram)

  3 fatty acids and one glycerol
• What is the structure of a phospholipid? (you could draw a labelled diagram)

  3 fatty acids (tail), one phosphate (head), glycerol
• What bond forms between a glycerol and a fatty acid?

  Ester
• What type of reaction forms the bond between a glycerol and a fatty acid?

  Condensation
• What is the difference between a saturated fatty acid and an unsaturated fatty acid? (structure)?

  No double Carbon-Carbon bonds in a saturated fatty acid;Double Carbon-Carbon bond in unsaturated fatty acid
• Why will lipids made of unsaturated fatty acids be more fluid than lipids made of saturated fatty acids?

  Double bond causes a kink in the fatty acid so can’t be packed as closely.
• Describe the hydrophilic and hydrophobic regions of a triglyceride

  No hydrophilic area;Hydrophobic tails
• Describe the hydrophilic and hydrophobic regions of a phospholipid.

  Hydrophilic head;Hydrophobic tails
• Why won’t a triglyceride dissolve in water?

  It forms a globule with the hydrophobic heads arranged away from the water
• Why will a phospholipid form a bilayer in water?

  The hydrophillic heads will arrange themselves facing the water.The hydrophobic tails will arrange themselves facing away from the water
• What is the test for a lipid?

  Dissolve in ethanol.Add water.White emulsion forms.
• What is the monomer of a protein called?

  Amino Acid
• What is different about each amino acid?

  R group
• What is the bond that joins amino acids together called?

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

  Sequence of amino acids
• What two structures can be found in the secondary structure?

  Alpha helix, Beta pleated sheet
• Which bonds hold the secondary structure together?

  Hydrogen
• What is the tertiary structure in a protein?

  3D folding to give overall shape
• Which 4 bonds can determine the tertiary structure?

  Disulfide bonds; Ionic Bonds; Hydrogen Bonds; Hydrophobic interactions
• How does the primary sequence determine the tertiary structure?

  The sequence of R-groups determines the position of the tertiary bonds.
• What is an enzyme?

  A biological catalyst (protein)