Monomers, Polymers and Carbohydrates Flashcards
What is amylose?
- Formed from alpha glucose monomers
- Chain forms a coiled shape
What is amylopectin?
- Formed from alpha glucose monomers
- Branched shape
Why is amylopectin branched?
- It has its branched shape due to the extra alpha 1,6 glycosidic bonding
- More branched means it is more easily hydrolysed into glucose or maltose to provide energy when needed.
What is the test for starch?
- Add two drops of iodine in potassium iodide to a test solution
- Shake or stir
- If starch is present, the solution will change from yellow/orange to blue-black.
What is glycogen?
- Formed from chains of monosaccharide alpha glucose
- More alpha 1,6 bonds and less alpha 1,4 bonds which results in extensive branching
- Its main role is energy storage
- It is also stored in small granules, like starch, found mainly in muscle and the liver.
What is cellulose?
- A major component of plant cell walls
- Formed from chains of the monosaccharide beta glucose
What is the structural role of cellulose in plants?
- Provide rigidity for plant cells
- Prevents plant cells from bursting when water enters by osmosis
- Maintains turgidity and rigidity in plant cells (and therefore the whole plant) which maximises surface area for photosynthesis
What are polysaccharides?
- Very large molecules which are insoluble in water
- Formed from many monosaccharide monomers joined together by glycosidic bonds (many condensation reactions)
- When they are hydrolysed they break down into monosaccharides or disaccharides
What are the two main functions of polysaccharides?
- Energy storage
- Structural role
What is starch?
- The energy storage polysaccharide found in plants
- Especially large granules found in storage organs and seeds of plants
- Major energy source in our diet
- Made up of the polysaccharides amylose (20%) and amylopectin (80%)
What makes starch and glycogen suitable for storage?
- Coiled and branched so they are compact for granule storage
- Large insoluble molecules so they are osmotically inactive
- Branched so glucose is easily hydrolysed for use in respiration
- Large molecules so it doesn’t cross the cell membrane and leave the cell.
What makes cellulose suited for its structural role?
- Long, straight, unbranched chains of beta glucose so long microfibrils and formed
- Hydrogen bonding between these chains so provides rigidity and strength
What is a condensation reaction?
- Small molecules are assembled into large ones. Chemical bonds are formed and water is produced.
What is the purpose of condensation reactions?
- Synthesizing complex molecules from simpler ones.
What is an example of a condensation reaction?
- Protein synthesis
What is hydrolysis?
- Large molecules are broken down into smaller ones. Chemical bonds are broken and water is consumed.
What is the purpose of hydrolysis?
Breaking down complex molecules into simpler ones
What is an example of a hydrolysis reaction?
- Starch hydrolysis
What are monomers?
The smaller units from which larger molecules are made.
What are polymers?
Molecules made from a large number of monomers joined together.
What are some examples of monomers?
- Monosaccharides
- Amino acids
- Nucleotides
What are monosaccharides?
The monomers from which larger carbohydrates are made.
What are some examples of monosaccharides?
- Glucose
- Galactose
- Fructose
What is maltose?
A disaccharide formed by the condensations of two glucose molecules.
