2.1.2 - Carbohydrates Flashcards
Glucose
- C6H12O6
- Hexose sugar
- 6 carbons
Functions of glucose
- Source of energy in respiration
- Building block for larger carbohydrates
Properties of glucose
- Small : Easily transported in and out of cells through carrier proteins
- Soluble : Easily transported around an organism through the blood
- Less reactive than other monosaccharides : Breakdown must be catalysed
Isomers
Molecules which have the same chemical formula but a different arrangement of atoms in space
Alpha glucose
OH on Carbon-1 below the plane of the ring
Beta glucose
OH on Carbon-1 above the plane of the ring
Monosaccharide
Monosaccharides are the simplest carbohydrates, consisting of only one sugar molecule
Disaccharide
Disaccharides are sugars that are composed of two monosaccharides joined together in a condensation reaction
Polysaccharide
Polysaccharides are polymers made up of many sugar monomers
Ribose
- Pentose monosaccharide
- C5H10O5
- Found in RNA and ATP
Maltose
Alpha glucose and alpha glucose
Sucrose
Alpha glucose and fructose
Lactose
Beta glucose and galactose
Synthesis of disaccharides
- Joined together in a condensation reaction
- Produces water and a disaccharide
- Glycosidic bond formed in the disaccharide
Condensation reaction
A chemical process in which two molecules combine to form a more complex molecule with the removal of water
Glycosidic bond
Covalent bond formed between two monosaccharides through a condensation reaction
Hydrolysis reaction
The breakdown of a molecule into two smaller molecules requiring the addition of a water molecule.
Breakdown of disaccharides
- Broken down by hydrolysis reaction
- Forms a monosaccharide
- Water has to be added
Starch (Structure)
- Consists of two different types of polysaccharides: amylose, amylopectin
Amylose
- Source : Plant cells
- Subunit : Alpha glucose
- Bonds : 1-4 glycosidic bonds
- No branches
Amylopectin
- Source : Plant
- Subunit : Alpha glucose
- Bonds : 1-4 and 1-6 glycosidic bonds
- Branches : Yes
Starch (Function)
- The function of starch is to store energy in plants.
- It is helix shaped so it is compact and more energy can be stored in a small space
- It is branched, so starch can be readily hydrolysed back into glucose
Glycogen (Structure)
- Source : Animal cells
- Subunits : Alpha glucose
- Bonds : 1-4 and 1-6 glycosidic bonds
- Branched : Yes
Glycogen (Function)
- It is insoluble, branched and compact
- The function of glycogen is to store energy in animals and fungi
- It is more coiled than amylopectin. The coiling and branching makes it compact, so more energy can be stored.
- Branching means that there are many free ends where glucose molecules can be added or removed. Animals require quick release of energy, that is why glycogen is more branched than amylopectin
Cellulose (Structure)
- Source : Plant cells
- Subunit : Beta glucose
- Bonds : 1-4 glycosidic bonds
- Branches : No
- Alternate beta glucose molecules are turned upside down
- Straight and unbranched
Cellulose (Function)
- Cellulose is used to make cell walls
- Cellulose -> Microfibrils -> Macrofibrils -> Fibres
- Cellulose has a high tensile strength preventing plant cells from bursting
