Carbohydrates Flashcards
What are carbohydrates made from?
Monsaccharides
What is the general formula of a monosaccharide?
[CH2O]n (n = 3-7)
What kind of sugar is glucose?
6 carbon (hexose)
What are some isomers of glucose
- Fructose
- Galactose
What are examples of pentose sugars?
- ribose
- deoxyribose
- ribulose
What are examples of triose sugars?
- glycerate phsphate
- glyceraldehyde
What is a disaccharide?
Two monosaccharides joined with a glycosidic bond [C-O-C]
What does a glycosidic bond involve?
- Condensation reaction
- Formation of a molecule of water
Which chemical reaction is used to digest carbohydrates?
Hydrolysis (adding a water molecule)
What are 3 examples of diasaccharides?
- Maltose
- Sucrose
- Lactose
Describe maltose
- Glucose + Glucose
- Formed from the digestion of starch
- Via amylase enzyme
How is starch broken down?
By amylase enzyme
- Starch (100s of glucose molecules)
- Dextrins (10s)
- Maltose (2)
- Glucose (1)
Describe Sucrose
- Glucose + Fructose
- Main transport sugar in phloem vessels (leaves -> roots)
Describe Lactose
- Glucose + Galactose
- Found in mammalian milk
What is a polysaccharide?
Long chains of glucose monomers (often 1000s) joined by glycosidic bonds
What are the two types of glucose?
Alpha and Beta
What are 3 examples of polysaccharides?
- Starch
- Glycogen
- Cellulose
Describe starch
- Storage in plants (in roots)
- Insoluble so does not change water potential of cells - doesn’t influence osmosis
- Mixture of amylose and amylopectin
What is amylose?
- A poly [1-4] alpha glucose chain
- Coils into a helix held together by hydrogen bonds for stabilisation
What is amylopectin?
- A poly [1-4] alpha glucose chain with [1-6]
- Has multiple ends so can be hydrolysed quickly by almylase enzymes (int maltose)
Describe Glycogen
- Storage in muscle and liver (animal) cells
- Poly [1-4] alpha-glucose chain with [1-6] branches
- Multiple ends so can be hydrolysed quickly by enzymes (glycogen phosphorylase) to mobilise glucose for energy
- More branched than amylopectin because it is needed much more in the muscles and liver
Describe Cellulose
- Main component of plant cell wells
- Poly [1-4] beta glucose chain
- Hydroxyl group on carbon 1 in a different position to alpha-glucose
- ALternate glucose molecules inverted to form a straight chain
- Hundreds of alternating chains are joined with hydrogen bonds
- Forms microfibrils which are very strong
- Beta-glycosidic bond is hydrolysed by enzyme cellulase - only bacteria have cellulase so herbivorous animals have mutualistic relationships with bacteria in order to break down their food
