Carbohydrates Flashcards
What are organic molecules?
Molecules containing carbon, carbon-carbon or carbon-hydrogen bonds.
Monomers definition
Monomers are small repeating units from which larger molecules called polymers are made
Polymer definitions
Polymers are molecules from large numbers, 3 or more, joined together
Carbohydrate monomers
Monosaccharides e.g. glucose, fructose and galactose
Carbohydrate dimers
Disaccharides e.g. maltose, lactose and sucrose
Carbohydrate polymers
Polysaccharides e.g. starch, cellulose and glycogen
Protein monomers
Amino acids e.g. glycine and tyrosine
Protein polymers
Polypeptides + proteins e.g. haemoglobin and enzymes
Nucleic acid monomers
Nucleotides e.g. thymine and adenine
Nucleic acid polymers
Polynucleotides e.g. DNA and RNA
In carbohydrates what are the bonds called?
Glycosidic bonds
In proteins what are the bonds called?
Peptide bonds
In DNA what are the bonds called?
Phosphodiester bonds
What are condensation reactions?
Joining of two molecules with a chemical bond, involving the elimination of a water molecule.
What is the purpose of a condensation reaction?
Required to join monomers, to form dimers and polymers. For every new bond formed, a water molecule is formed.
What are hydrolysis reactions?
To break chemical bonds between two monomers involves using a water molecule
What is the purpose of hydrolysis reactions?
To break apart polymers and dimers, because only monomers are small enough to cross the cell membrane
What is an isomer?
Molecules that have the same molecular formula but different atom arrangements
Isomers of glucose
Alpha and Beta
Alpha glucose bonding type
1-4 and 1-6 glycosidic bonding
Beta glucose bonding type
1-4 glycosidic bonding
Glucose + glucose = ?
Maltose -> Germinating seeds
Glucose + galactose = ?
Lactose -> milk sugar
Glucose + fructose = ?
Sucrose -> cane sugar, transported in the phloem of plants
Monosaccharide molecular formula
C6 H12 O6
Disaccharide molecular formula
C12 H22 O11
Trisaccharide molecular formula
C18 H32 O16
Structure and functions of starch: (Plants)
-Alpha glucose -> 1-6 bonding, making it highly branched to provide more ends for enzyme action and faster and easier hydrolysis
-Alpha glucose -> Break down into glucose for respiration
-Insoluble -> Allow plants to maintain a water potential, so doesn’t affect the amount of water osmosis
-Helical structure -> Makes it compact, so many molecules can fit into a small space
-Large molecule -> Cannot pass across the cell membrane
Purpose of starch
Ready and consistent source of energy over a longer period of time
Structure and function of glycogen: (animals)
-Helical structure -> Makes it compact so many molecules can fit into small spaces
-Insoluble -> Doesn’t affect water osmosis as water potential doesn’t change
-Large molecules ->Doesn’t pass across the cell membrane
-Alpha glucose -> 1-6 bonding, so it’s highly branched providing more ends for faster hydrolysis used for respiratory substances
Purpose of glycogen
Stored in the liver and muscle. Animals have higher metabolic demands, so adapted to have; shorter chains, highly branched 1-6 bonds and large surface area
Structure and functions of cellulose: (plants)
Long straight chains of beta glucose, each molecule flips 180 degrees to create several chains of cellulose joined together by weak hydrogen bonds ( formed between the OH group), this forms microfibrils wound to form cellulose fibres. This provides strength and support to the cell wall, which can resist somatic pressure and prevent osmotic lysis.
Similarities between cellulose and starch:
-Both are polysaccharides.
-Both have glycosidic bonds.
-Both contain carbon, hydrogen and oxygen.
Differences between cellulose and starch:
-Starch is alpha glucose but cellulose is beta glucose.
-Starch is helical whereas cellulose is straight chains.
-Starch is branched whereas cellulose isn’t/ it’s straight
-Cellulose forms microfibrils whereas starch doesn’t.
-Starch does 1-4 and 1-6 glycosidic bonding whereas cellulose has 1-4 only as well as hydrogen bonds
Starch is made from what?
2 polysaccharides, it has one unbranched component
Glycogen and cellulose is made from what?
1 polysaccharide, (glycogen has the most bonds)
What is starch found?
In the stomata of chloroplasts of plants
Where is glycogen found?
In liver and muscle cells of animals
Where is cellulose found?
In the cell walls of plants
Where is cellulose found?
In the cell walls of plants
What are the common monosaccharides; glucose, galactose and fructose used for?
Commonly found in fruits giving them a sweet flavour. They are soluble
Alpha glucose monomers
Maltose, sucrose, lactose, starch and glycogen
