Unit 2 - Biological Molecules Flashcards
Three Monosaccharides
Glucose
Fructose
Galactose
Three Disaccharides
Sucrose
Maltose
Lactose
Three Polysaccharides
Starch
Cellulose
Glycogen
What’s the difference between alpha and beta glucose?
Alpha glucose has the hydroxide is on the bottom and the hydrogen on the top. Opposite for beta
define disaccharide [3]
Made of two monosaccharides
joined together by a glycosidic bond
formed by a condensation reaction
What monomer is starch made from?
alpha glucose
What monomer is cellulose made from?
beta glucose
What monomer is glycogen made from?
alpha glucose
Which polysaccharides have 1-4 and 1-6 glycosidic bonds?
Amylopectin (starch) and Glycogen
Which polysaccharide have 1-4 glycosidic bonds?
Cellulose
What is a feature of all polysaccharides?
They are large and insoluble - they won’t affect water potential
What’s an advantage of the 1-6 glycosidic bond?
It has many branches and therefore and large surface area for rapid hydrolysis back to glucose
The two types of lipids
Triglycerides and Phospholipids
What is the structure of a triglyceride?
one glycerol and three fatty acids
what is the structure of a phospholipid?
a glycerol backbone
attached to 2 hydrophobic fatty acid tails
and one hydrophilic polar phosphate head
How are triglycerides formed?
Via condensation between one molecule of glycerol and three molecules of fatty acid
What is the bond in tryglycerides called?
ester bond
What’s the difference between saturated and unsaturated fatty acids
saturated fatty acids only have single bonds between carbons while unsaturated fatty acids have double bonds between carbons
how are polymers made?
by joining smaller molecules with covalent bonds
what type of sugar is sucrose
non reducing
what type of sugars are glucose, fructose and maltose
reducing
How do you test for a non reducing sugar? [3]
Boil test sample with HCI
Neutralise with nAHCO
Add Benedict’s solution to sample, then heat over water bath
Define macromolecule
A large molecule formed by condensation reactions between smaller molecules.
define monomer
a single used to build larger polymers
how are glycosidic bonds broken?
water is used to break the bond in hydrolysis
function of phospholipids
forms phospholipid bilayer in water - the hydrophobic tails allow for control of movement of water soluble molecules in and out of the cell
describe common structure of an amino acid [4]
- Amine group (-NH2)
- Variable side chain (R)
- Carboxyl Group (-COOH)
- H atom
how are peptide bonds formed?
OH is lost from the carboxyl group and a H from the amine group
structure of a primary protein
a sequence of amino acids in a polypeptide held by peptide bonds
secondary structure
the regular folding of a polypeptide into alpha helixes and beta pleated sheets held together by hydrogen bonds
tertiary structure
further coiling of a protein into its functional 3d shape. Held by hydrogen, ionic and disulphide binds and hydrophobic interactions
quaternary structure
the folding of 2 or more polypeptides into a 3d shape, which may include prosthetic (non protein) groups. held together by hydrogen, ionic and disulphide bonds and hydrophobic interactions
describe globular proteins
generally soluble
have physiological roles
describe fibrous proteins
- insoluble
- structural role