1.1 - Monomers, polymers and carbohydrates Flashcards
What are monomers?
small units from which larger molecules are made
What are polymers?
molecules made from a large number of monomers (repeating units) joined together
Give three examples of monomers
- monosaccharides e.g glucose
- amino acids
- nucleotides
Define condensation reaction
2 molecules join together forming chemical bond, and the elimination of a water molecule
Define hydrolysis reaction
chemical bond broken between 2 molecules with the use of a water molecule
What is a monosaccharide?
monomer from which larger carbohydrates are made
Give 3 examples of monosaccharides
- glucose
- galactose
- fructose
Type of bond formed by the condensation of two monosaccharides
glycosidic bond
How are disaccharides formed?
condensation of 2 monosaccharides
Give 3 examples of disaccharides
- maltose
- sucrose
- lactose
What is maltose made up of?
2 glucose molecules
What is sucrose made up of?
glucose molecule and fructose molecule
What is lactose made up of?
glucose molecule and galactose molecule
Name the 2 isomers of glucose
- alpha glucose
- beta glucose
Draw the structures of alpha and beta glucose
How are polysaccharides formed?
condensation of many glucose units
Which type of glucose are glycogen and starch made up of? (polymers of…)
alpha glucose
Which type of glucose is cellulose made up of? (polymer of…)
beta glucose
Give the structure and function of glycogen
- main energy storage molecule in animals
- 1,4,6 glycosidic bonds
- lots of branches = quick release of energy via enzyme action
- large but compact = maximises energy it can store
- insoluble = doesn’t affect cell WP and can’t diffuse out of cells
Give the structure and function of starch
- insoluble = doesn’t affect water potential
- branched/helical = makes molecule compact
- polymer of glucose = provides glucose for respiration
- branched = fast breakdown/enzyme action
- large = can’t cross cell membrane/leave cell
Name the 2 polysaccharides starch is made up of and describe them
amylose
- unbranched chain
- 1,4 glycosidic bonds
- coiled and compact = stores a lot of energy
amylopectin
- branched chain
- 1,4,6 glycosidic bonds
- side branches = fast enzyme action to release energy
Give the structure and function of cellulose
- long, straight chains
- strong microfibrils joined by H bonds = strong cross linkages which provide strength to cell wall
- exerts inward pressure stopping influx of water, preventing lysis and maximising SA of plants for photosynthesis
Describe the biochemical test for a reducing sugar
- heat with Benedict’s solution
- positive: blue -> brick red
Describe the biochemical test for a non-reducing sugar
(after a negative test for reducing sugar)
- heat with acid (HCl) and neutralise with sodium hydrogen carbonate
- heat with Benedict’s solution
- positive: blue -> brick red
Describe the biochemical test for starch
- add iodine
- positive: orange/brown -> blue/black
What are reducing sugars?
all monosaccharides and some disaccharides e.g maltose, lactose
