1-A: Biological Molecules Flashcards
(18 cards)
What is the definition of a monomer?
A monomer is a smaller repeating unit from which polymers are made
Describe the biochemical test for non- reducing sugars. (4)
- Heat sample with dilute HCl
- Neutralise with Na hydrocarbonate
- Heat with Benedict’s reagent
- Traffic lights precipitate
Which two monomers make up the disaccharides Maltose, sucrose and lactose?
a-glucose + a-glucose
Fructose+ galactose
Galactose + glucose
What atom does a condensation reaction bond form around?
An oxygen atom: | |-O-| |
Not in proteins, C-N
How are a-glucose and B-glucose different? Which is which?
The positions of the hydrogen and hydroxyl groups on the carbon one atom are inverted.
B-glucose alternates
A- glucose has OH on the bottom
How is starch adapted for its function? (3x2)
- helical ( a-glucose spirals) compact =amylose (1,4)
- branched (a-glucose) fast release = amylopectin (1,4/1,6)
- insoluble doesn’t affect water potential
- large molecule cannot diffuse out of cell cell
Describe the structure of cellulose
- straight, unbranched (B-glucose) chain (1,4) alternate
- hydrogen bonds between chains
- strong fibrils, high tensile strength,
Describe the structure and function of glycogen.
- animal energy storage molecule (a-glucose)- (1,4/1,6)
- branched chain compact *efficient hydrolysis for respiration *
- large, insoluble
Define polymer
A larger molecule made up of monomers
Describe the iodine test for starch
- Add iodine dissolved in potassium dichromate solution
- orange to blue-black
Describe how to use colorimetric to give qualitative results for the concentrations of sugars in starch
- Make standard solutions and read absorbable
- plot calibration curve
- read absorbable of unknown
- use calibration curve to read off concentration
Describe the test for lipids
- shake substance with ethanol
- add water
- milky white emulsion
Contrast saturated and unsaturated fatty acids
Saturated:
Single bonds, unkinked, many contact points, higher mp, solid animal fats
Describe the structure and function of triglycerides
- high energy: mass ratio high caloric value
- insoluble: waterproofing
- slow conductor: *thermal insulation *
- less dense than water: buoyancy of aquatic animals
General amino acid structure
- NH2 amine group
- variable R group
- COOH group
Describe the bourses test for proteins
- sodium hydroxide sol
- copper(II) sulphate sol
- blue- purple
What are the bonds that affect protein structure and what are its structures?
- hydrogen (secondary and tertiary)
- ionic
- disulfide bridges
- a-helix= spiral, N-H on same side
- b-pleated sheet= N-H and C-O alternate
Describe the structure and function of globular proteins
- spherical/ compact
- hydrophilic R faces out
- hydrophobic R faces in
- metabolic processes, enzymes and haemoglobin
