1. Biological molecules

• define the term monomer

  is a repeating single subunit that joins to make long chain polymers.
• define the term polymer

  a chain on monomers
• what is a monosaccharides state some examples

  is a single unit monomer

  -glucose

  -galactose

  -fructose
• what is happens during a condensation reaction

  joining of molecules to form a chemical bond, excluding water
• what happens during a hydrolysis reaction

  bonds are broken and water is added
• give example of monomers

  glucose

  amino acids

  nucleoids
• name the bond that forms between 2 monosaccharides through a condensation reaction

  glyosidic
• define the term disaccharides

  two monosaccharides joined together through a condensation reaction
• name the three disaccharides and how they are formed

  maltose (maltase) - alpha glucose + alpha glucose

  sucrose(sucrase)- alpha glucose + fructose

  lactose (lactase)- alpha glucose + galactose
• Describe how lactose is formed and where in the cell it would be attached to a polypeptide to form a glycoprotein

  1. Glucose and galactose;

  2. Joined by condensation (reaction);

  3. Joined by glycosidic bond;

  4. Added to polypeptide in Golgi (apparatus);
• name the two isomers of glucose

  alpha glucose

  beta glucose
• draw beta glucose

  remember to write H20

  
• Draw alpha glucose

  
• what is a polysaccharide

  are complex carbohydrates

  when more than 2 monosaccharides join together by a condensation reaction

  
  

  the production involves formation of glyosidic bonds and water.
• name the three polysaccharides

  starch

  glycogen

  cellulose
• describe the structure of starch, cellulose, glycogen

  STARCH

  -storage molecule of glucose in plants

  -polymer of alpha glucose

  -helical/ spiral structure

  -insoluble

  -large

  -1-4 glyosidic bonds in amylose

  -1-4 and 1-6 in amylopectin

  GLYCOGEN

  -polysaccharide of alpha glucose

  -joined through a condensation reaction

  Branched structure

  -found in muscles and liver cells

  -1-4 and 1-6 glyosidic bonds

  -it isn't coiled and rest of the functions are same as starch

  CELLULOSE

  -a structural carbohydrate in plants

  -structure strength for cell wall

  1-4 glyosidic bonds

  -polymer non-branched of beta glucose units - alternative molecules are inverted (the hydroxyl and hydrogen groups on carbon 1 are inverted).

  -long straight chains linked by

  -many hydrogen bongs this forms fibres called fibrils

  -high energy hydrogen bongs

  -this provides strength so cellulose can support the cell wall.
• Test for starch

  Iodine solution into sample

  -Positive: Blue black precipitate

  -Negative: Orange yellow
• benedict's test for reducing

  All monosaccharides (glucose), some disaccharides (maltose and lactose)

  
  

  Add blue Benedict's reagent to the sample

  Heat the solution using a water bath

  
  

  A coloured precipitate will form if the test is positive

  
  

  The higher the concentration of sugar, the further the colour change will be

  blue-green-yellow-orange-brick red

  
  

  Alternatively, the solution can be filtered and the precipitate weighed (this is more accurate)
• Testing for non-reducing sugars

  Add dilute hydrochloric acid

  
  

  boil the solution in a water bath (to break any bonds)

  
  

  Neutralise the solution with sodium hydrogen carbonate

  
  

  Repeat the Benedict's test as for non-reducing sugars

  
  

  The solution staying blue means not even a non-reducing sugar is present

  
  

  A colour change along the scale means a non-reducing sugar is present:

  
  

  Blue- brick red
• Describe the test for analyse

  Add biuret (reagent) and becomes purple

  
  

  Add starch (leave for a time) test for reducing sugar/ absence of starch
• link starch's structure to its function

  -helical/spiral so compact

  
  

  - insoluble so osmotically inactive

  
  

  -branched so glucose is easily hydrolysed/ released for respiration

  
  

  -large molecule so cannot leave cell
• link cellulose's structure to its function

  -made form B glucose flipping over of alternative molecules

  
  

  -joined through a condensation reaction to form a glycosidic bond

  
  

  -long straight/ unbranched molecule of beta glucose

  
  

  -bonded together by hydrogen bonds

  
  

  -forming microfibrils

  
  

  -provides high strength

  
  

  -can resist osmotic pressure
• link glycogen's structure to its function

  -long strai
• compare starch with glycogen
• compare starch with cellulose

  Alpha vs beta

  
  

  Helical * branched vs linear structure

  
  

  1,6 bonds vs only 1,4

  
  

  No hydrogen bonding between molecules in starch

  
  

  No fibres in starch
• compare glycogen with cellulose

  Alpha vs beta

  Branched vs straight chain

  
  

  Carole's vs straight chain

  
  

  1,4 and 1,6 glycosidic bonds vs only 1,4 glycosidic bonds
• function of a lipid

  -insulations

  -energy store

  -protection
• How are triglycerides formed?

  condensation of one molecule of glycerol and 3 fatty acids
• name the bond that forms in lipids through a condensation reaction

  ester bonds + 3H2O

  (hydrogen and hydroxyl gorup)
• facts about the R group in amino acids

  20 R group
• What is a phospholipid?

  one fatty acid replaced by a phosphate- containing group.
• triglycerides properties related to its function

  ➤ source of energy - high ratio of energy storing Carbon to hydrogen bonds compared to Carbon atoms

  ➤ storage - low mass to energy ratio; much energy can be stored in a small volume without increasing he mass and preventing movement

  ➤ insoluble in water - large, non polar hydrophobic molecules don't affect water potential

  ➤ metabolic water source - high ratio of Hydrogen to Oxygen atoms, release water when oxidised e.g. desert animals
• phospholipids properties related to its function

  -made of C,H,O

  -a phosphate group in place of one fatty acid.

  -polar hydrophilic (negatively charged phosphate group which is attracted to water) and non- polar hydrophobic regions (fatty acid chains are repelled by water)

  -mono layer on surface and bilayer in water

  -forms phospholipid bilayer membrane structure which makes plasma around cells.
• whta is a satuarated acid

  the hydrocarbon chains has only single bonds between carbons in fatty acid chains
• un/saturated fats

  the hydrocarbon chain consists of at least one double bond between carbons in fatty acids
• suggests why fat substile cannot be digested in the gut by lipase

  -the bond between glycerol/ fatty acid and propylene glycol is different to the one between glycerol and fatty acid

  
  

  -no ester bond

  
  

  -unable to bind to active side of lipase
• emulsion test for lipids (method)

  -add ethanol/ alcohol to sample

  -shake

  -add water

  -positive result from colourless to a white emulsion
• diagram of saturated and unsaturated fatty acids

  
• Compare and contrast the structure and properties of triglycerides and phospholipids

  Similarities

  
  

  -both contain and ester bond

  -both contain a glycerol

  -fatty acids on both many be mono saturated/ saturated

  -both contain C, H, O

  
  

  Differences

  
  

  -phospholipids contains phosphate group

  -triglycerides have 3 fatty acids, whereas phospholipids have 2 fatty acids+ phosphate group

  -try are hydrophobic/non-polar whereas phospholipids have hydrophilic and hydrophobic regions

  -phospholipids form bilayer in water/ Mono layer on surface.
• Other than ethical reasons, suggest two reasons why they chose to use cats as model organisms

  1. (Are mammals so) likely to have same physiology / reactions as humans;

  2. Small enough to keep in laboratory / produce enough milk to extract;

  3. (Can use a) large number