1.2, 1.3 & 1.4 Carbohydrates Flashcards
What is a polymer?
Long chains of monomers joined together
What is a monomer?
- small, basic molecular units
- eg monosaccharides, amino acids and nucleotides
What is an isomer?
- molecules with the same molecular formula as each other but the atoms are connected in different ways
- α-glucose and β-glucose are isomers
What is a monosaccharide?
- monomers from which larger carbohydrates are formed
- eg glucose, galactose, fructose
What is a hydrolysis reaction?
- breaks a chemical bond between two molecuels
- involved the use of a water molecule
What is a condensation reaction?
- joins two molecules together with the formation of a chemical bond
- involved the elimination of water molecule
What is a disaccharide?
Pairs of monosaccharides combined by a condensation reaction
What is a polysaccharide?
Monosaccharides combined in large numbers
How is maltose formed?
A disaccharide formed by the condensation of two glucose molecules
How is sucrose formed?
A disaccharide formed by condensation of a glucose and fructose molecule
How is lactose formed?
A disaccharide formed by condensation of a glucose and galactose molecule
What does the condensation of alpha glucose form?
- glycogen
- starch
What does the condensation of beta glucose form?
- cellulose
Describe the structure of a starch molecule
- made up of chains of alpha glucose monosaccharides linked by a glycosidic bond
- formed by a condensation reaction
- can be unbranched or branched chains
- unbranched chains wind into a tight coil that makes a molecule very compact
Describe the role of starch
- main storage of energy in plants
- store excess glucose as starch ~ when plants need more glucose for energy, it breaks down starch to release glucose
- mixture of two polysaccharides ~ amylose and amylopectin
- insoluble in water ~ doesn’t affect water potential so water cannot enter cells by osmosis