2.2 Carbohydrates Flashcards
why do we need carbohydrates?
for energy
what are carbohydrates made up of?
hydrogen, oxygen and carbon
what type of compounds are carbohydrates?
organic compounds
what are the three types of carbohydrate?
monosaccharides, disaccharides and polysaccharides
what are the three types of monosaccharides?
glucose, fructose and galactose
what type of monosaccharide is glucose?
a hexose monosaccharide
what are monosaccharides?
the simplest single sugars
what happens when monosaccharides react with water?
they dissolve to form sweet tasting solutions
what are alpha glucose and beta glucose?
isomers
what type of monosaccharide is ribose?
a pentose monosaccharide
where is deoxyribose found?
DNA
where is ribose found?
RNA
what is formed when two monosaccharides join?
a disaccharide
what bond is formed when two monosaccharides join to form a disaccharide?
a glycosidic bond, for example when two glucose join to form maltose this is a 1-4 glycosidic bond as carbon 1 is bonded to carbon 4
What reaction occurs when a monosaccharide forms a disaccharide?
A condensation reaction, H2O is lost and as a result water is formed as a product
What happens to a disaccharide to go back to monosaccharides?
They hydrolyse (water is added)
What is a polysaccharide formed from?
Many monosaccharides
What are three types of polysaccharide?
Starch, glycogen and cellulose
What is starch used for?
It is the main storage polysaccharide in plants
What type of glucose is starch made of?
Alpha glucose
What are the two polymers of alpha glucose?
Amylose and amylopectin
What is the structure of amylose?
chain of glucose molecules, form a helix structure by hydrogen bonding
What is the function of the structure of amylose?
helix forms a compact shape good for packaging making it a good storage molecule
What is the structure of amylopectin?
Chains of glucose molecules, after every 25 glucose molecules adjacent chains are connected by alpha 1-6 glycosidic bonds, giving it a BRANCHED STRUCTURE
What is the function of the structure of amylopectin?
The branched ends can be hydrolysed rapidly allowing the rapid release of glucose for energy
What makes starch a good storage polysaccharide?
It is insoluble in water
What is glycogen used for?
It is the main storage polysaccharide of animal and fungi cells
What is the structure of glycogen?
Similar to amylopectin, but it has more branches which are shorter, making it more compact
What is the function of the structure of glycogen?
can be quickly broken down to release glucose for energy
structure allows faster hydrolysis important as animals may need emergency glucose faster than plants
What is cellulose used for?
It is the structural polysaccharide in plants
What is the structure of cellulose?
Long unbranched chains of glucose, linked to each other by hydrogen bonds, which are formed into strong microfibrils
What bonds are the glucose chains in cellulose linked by?
Beta 1-4 glycosidic bonds
What type of glucose is cellulose made of?
Beta glucose
What is the function of the structure of cellulose?
Hydrogen bonding prevents water entering the molecule making it resistant to enzyme hydrolysis, makes it a good structural polysaccharide.
Cellulose in plant cell walls provides protection
What are the three types of disaccharide?
Maltose, sucrose and lactose
What is maltose the product of?
Glucose + Glucose
What is sucrose the product of?
Fructose + Glucose
What is lactose the product of?
Galactose + Glucose
