Carbohydrates Flashcards
What type of hexose sugar is glucose?
It is a monosaccharide.
What sugar is in a DNA nucleotide?
Deoxyribose
What sugar is in a DNA nucleotide?
Deoxyribose
What sugar is in RNA?
Ribose.
What groups does a sugar have?
Hydroxyl, carbon and aldehyde.
Why is glucose small?
Glucose forms a compact helix due to intramolecular interactions. (Hydrogen bonds)
What are isomers?
A compound with the same molecular formula but a different arrangement. E.g a glucose and b glucose.
What disaccharide is formed by a glucose and b glucose undergoing a condensation reaction?
Starch (amylose)
Carbohydrate formulae:
Cx(H2O)x or (CH2O)n
Glucose + glucose =
Maltose
Glucose + galactose =
Lactose
Glucose + fructose =
Sucrose
What is the 1 non-reducing sugar?
Sucrose
What do all reducing sugars contain?
Have a free ketone or adelhyde group
Amylose properties,
- Made from alpha glucose
- coiled and unbranched
- 1-4 glycosidic bonds
- h bond within molecules
- Granular
Cellulose properties
-Fibrous -‘Fibrous chains’
-Not coiled
1-4 glycosidic bonds
-Beta glucose
-H bonds between adjacent molecules.
-Monomers alternatively at 180° to eachother
Is glycogen more compact than Amylopectin?
Yes
What bonds are between every 25 glucose molecules in amylopectin?
Alpha 1-6 glycosidic bonds.
Why does amylopectin hydrolyse rapidly?
Amylopectin is branched with many protruding ends.
Starch is made of…
Amylose + amylopectin
How can you identify what type of plant a starch polysaccharide comes from?
Microscopic analysis of the differing lengths of amylopectin and amylose.
Chitin:
A structural polysaccharide found in all exoskeletons of arthropods and in the hyphal walls of many fungi.
(Glucose + amino acid) glucosamine units linked by beta 1-4 glycosidic bonds.
What does the amino acid present in chitin affect?
Causes more hydrogen bonding, making it extremely resilient and a tough polysaccharide
Glycogen is similar to…
Amylopectin
Difference between Glycogen and amylopectin?
Glycogen is in animals and has more branches, which are shorter; and so glycogen has more free ends which can be hydrolysed and so glycogen hydrolyses faster. This because animals need a fast release of glucose which can be used for respiration to provide energy for motion.
Glycogen is less dense than starch and-so is less compact
Glycogen is more soluble than starch and-so is more easily transported.
Glycogen contains alpha glucose 1:6 glycosidic bonds
Glycogen and amylopectinforms granules.
Cellulose form a ….
Fibrous chain (microfibrils) and are used as structural support for the plant. It is non-granular
What form polysaccharides?
Many glucose units.
+ve test for starch.
Iodine - turns blue.
What carbohydrate molecule is used to store energy in plants?
Starch
What carbohydrate molecule is used to store energy in animals.
Glycogen
What bonds are in glycogen?
composed of alpha-1,4-glycosidic bonds with branched alpha-1,6 bonds present at about every tenth monomer
What are two similarities between Chitin and glycogen?
Both are polysaccharides and both are made up of hexose sugar units.
What are two differences between Chitin and glycogen?
Chitin contains nitrogen, whilst glycogen does not.
Glycogen is branched whilst Chitin is not.
Test for reducing sugar:
Add Benedicts reagent - mix - heat - colour change for positive result - amount of cchange shows concentration of sugar.
Test for non-reducing sugar:
Add dilute HCL - Boil - cool and neutralize with excess sodiumhydroxide - repeat test for reducing sugar.
What are the 6 functions of carbohydrates?
Immediate respiratory substrates Energy stores Structural components Metabolites Cell-to-cell attachment Transport
Why is cellulose a good structural polysaccharide?
Its hydrogen bonding prevents water from entering the molecule, making it resistant to enzyme hydrolysis
