Chapter 1 - Biological molecules Flashcards
What is a monomer
smaller units from which larger molecules are made
e.g. monosaccharides, amino acids and nucleotides
What is a polymer
molecules made of a large number of molecules joined together
What is a condensation reaction
reaction that joins two molecules together with the formation of a chemical bond, and involves the elimination of a molecule of water
What is hydrolysis
Hydrolysis – reaction that breaks a chemical bond between two molecules and involves the use of a water molecule
what is the bond called when two monosaccharides are joined by a condensation reaction (with diagram)
glycosidic
what is a monosaccharide and its features
a single sugar unit
mono - one saccharide - sugar
sweet tasting
soluble
reducing sugars
(CH2O)n from 3-6
suffix ose
examples: glucose, galactose and fructose
structure of alpha glucose
structure of beta glucose
carbon positions labelled on an alpha glucose
what is the difference between alpha glucose and beta glucose
a– glucose carbon 1 – the hydroxyl (OH) group is below the hydrogen, whereas on
b – glucose carbon 1 – the hydroxyl (OH) group is above the hydrogen
what is the test for reducing sugars
a reducing sugar will act as a reducing agent
what is a disaccharide and its properties
*Two monosaccharides joined together
*Soluble
*Some are reducing sugars. Some are non-reducing sugars
*Disaccharides are formed by a condensation reaction between two monosaccharides, forming a glycosidic bond.
table showing disaccharides
What is a non-reducing sugar
a sugar that does not donate electrons, or change colour with benedict’s reagent
what is the method of testing for a non-reducing sugar
what is a polysaccharide and its features
*Many monosaccharides joined together
*Formed by condensation reactions
*Joined by glycosidic bonds
*Insoluble
*Storage/structural molecules
*Examples: starch, cellulose, glycogen
what is the test for starch
*Add two drops of sample to a spotting tile
*Add two drops of iodine solution
*If starch is present, the sample will turn blue-black
what are the three main polysaccharides and what monosaccharides are they made out of
What are the features of starch
Energy storage in plants
Polymer of a – glucose
1- 4 glycosidic bonds linking glucose molecules in chains
1- 6 glycosidic bonds linking branches to chains
What are the features of Glycogen and how is it different from starch
Energy storage in animals
Polymer of a – glucose
1-4 and 1-6 glycosidic bonds so coiled and branched
More 1-6 glycosidic bonds than starch so more glucose available for energy as animals have higher metabolic rates than plants
What is the function of starch and glycogen related to their function
What is the function of cellulose
Function = Provide strength for plant cell walls
What is the structure of cellulose
Polymer of b – glucose molecules linked by 1 – 4 glycosidic bonds
To form bonds, alternate b – glucose molecules invert
Cellulose is therefore long, straight chained and unbranched
Straight cellulose chains run parallel
Parallel cellulose chains linked by hydrogen bonds between adjacent H and OH groups
Cellulose chains make up microfibrils
How is cellulose used in the structure of the cell wall
Hydrogen bonds link parallel cellulose chains
These form a cellulose microfibril
Microfibrils form cellulose fibres
Fibres are laid down, anti – parallel and are embedded in a matrix
Compare the structures of starch glycogen and cellulose
