Monomers, Polymers and Carbohydrates Flashcards
What are monomers?
small units that are the components of larger molecules, e.g monosaccharides such as glucose, amino acids and nucleotides
Give examples of monomers?
monosaccharides such as glucose, amino acids and nucleotides
What are polymers?
molecules made from many monomers joined together.
What are monomers joined by?
A chemical bond in a condensation reaction where by a water molecule is eliminated.
What is a condensation reaction?
A reaction that joins two molecules together with the formation of a chemical bond and the elimination of a molecule of water.
What is a hydrolysis reaction?
A reaction that breaks a chemical bond between two molecules and involves the use of a water molecule.
What are monosaccarides?
A single monomer
What is a disaccharide?
Two monomers joined together
Name three monosaccarides?
Glucose, Galactose and fructose
What is glucose?
A monosaccharide containing 6 carbon atoms in each molecule, and is the main substrate for respiration and therefore of great importance. It has two isomers – alpha and beta glucose with structures
What is Maltose?
A disaccharide formed by the condensation of two glucose molecules.
What is sucrose?
A disaccharide formed by condensation of glucose & fructose.
What is lactose?
A disaccharide formed by condensation of glucose & galactose.
What is a polysaccharide
Long chains of monosaccharides linked by glycosidic bonds.
What do polysaccharides include?
- Glycogen and starch are both formed by the condensation of alpha glucose.
- Cellulose formed by the condensation of beta glucose
What is Glycogen?
The main energy storage molecule in animals and is formed from many molecules of
alpha glucose joined together by 1, 4 and 1, 6 glycosidic bonds.
Describe the components of glycogen?
- large number of side branches meaning that energy can be released quickly as enzymes can act simultaneously on these branches.
- relatively large but compact molecule thus maximising the amount of energy it can store.
- Insoluble means it will not affect the water the potential of cells and cannot diffuse out of cells.
What is Starch?
A polysaccharide that stores energy in plants and is a mixture of two polysaccharides called amylose and
amylopectin
What is Amylose?
Amylose is an unbranched chain of glucose molecules joined by 1, 4 glycosidic bonds, and as a result amylose is coiled and thus a very compact molecule storing a lot of energy.
What is Amylopectin?
Amylopectin is branched and is made up of glucose molecules joined by 1, 4 and 1, 6 glycosidic bonds. Due to the presence of many side branches, these can be acted upon simultaneously by many enzymes and thus broken down to release their energy.
What are the properties of starch?
- insoluble: so will not affect cell water potential,
- Compact: so a lot of energy can be stored in a small space
- When it is hydrolysed the released alpha glucose can be transported easily
What is Cellulose?
A component of cell walls in plants and is composed of long, unbranched chains of beta glucose which is joined by glycosidic bonds.
What are Microfibrils?
Strong threads are made of long cellulose chains running parallel to one another that are joined together by hydrogen bonds forming strong cross-linkages
Why is Cellulose important?
Cellulose is important in stopping the cell wall from bursting under osmotic pressure:
- it exerts inward pressure that stops the
the influx of water. - Meaning: that cells stay turgid and rigid, helping to maximise the surface area of plants for photosynthesis.