Biological Molecules Flashcards
What are monomers?
Smaller repeating units in which larger molecules are made of
Give three examples of monomers
Monosaccharides
Amino acids
Nucleotides
What are polymers?
Molecules made from a large number of monomers
Give three examples of polymers
Polysaccharides
DNA
Proteins
What is a monosaccharide?
Monomers from which larger carbohydrates are made
Give three examples of monosaccharides
Glucose
Galactose
Fructose
What is a condensation reaction?
Joining of two molecules that form a chemical bond by eliminating a water molecule
What is a hydrolysis reaction?
Breaking of a chemical bond between two molecules using a water molecule
What bond is formed in a condensation reaction in monosaccharides?
Glycosidic bond
Name three disaccharides and what they are formed from
Glucose + Glucose ~> Maltose
Glucose + Galactose ~> Lactose
Glucose + Fructose ~> Sucrose
What are the two isomers of glucose
Alpha glucose
Beta glucose
What are the differences between alpha and beta glucose?
(Use diagrams)
The OH group is inverted.
On alpha glucose it is located on the bottom right carbon whereas on beta glucose it is on the top right carbon
What are glycogen and starch made out of?
Alpha glucose
What is cellulose made out of?
Beta glucose
What is the function of of glycogen in relationship to its structure?
Function- Main storage for glucose in animals
Structure- many short branches with straight adjacent chains
Relationship- easily hydrolysed to release glucose and extremely compact
What is the function of starch in relationship to its structure?
Function- main storage in plants
Structure- Amylose: 1-4 glycosidic bonds
Amylopectin: branched, spiral, 1-4 and 1-6 glycosidic bonds
Relationship- shape allows tight packing, therefore it’s an excellent storage molecule
Insoluble and easily hydrolysed
What is the function of cellulose in relationship to its structure?
Function- main constituent of plant cell wall
Structure- branched chains, 1-4 glycosidic bonds and hydrogen bonds
Relationship- hydrogen bonds form microfibrils which provide structural support in plants, cellulose chains linked by hydrogen bonds
What is the biochemical test for reducing sugars?
Add 2cm^3 of sample
Add equal amount of Benedict’s reagent
Apply heat using water bath
Positive results = red/orange ppt
Negative results= remains blue sol
What is the biochemical test for non-reducing sugars?
Add 2cm^3 of sample
Add HCL to break glycosidic bonds
Add sodium hydrogen carbonate to neutralise solution
Add Benedict’s reagent
Apply heat using water bath
Positive results= red/orange ppt
Negative results= remains blue sol
What is the biochemical test for starch?
Add iodine or potassium iodide to sample
Positive results= blue/black sol
Negative results= remains orange/brown sol
Name two lipid groups
Phospholipids
Triglycerides
Describe the structure of a triglyceride
(Use diagram)
1 glycerol
3 fatty acid groups