B1. Biological Molecules (DONE) Flashcards
What is covalent bonding?
Electrons in valence shell are shared
What is ionic bonding?
Ions with opposite charges attract each other, weaker than covalent bonds
What is hydrogen bonding?
Attractive force between partially positive charged hydrogen attached to electronegative atom of one molecule and an electronegative atom of a different molecule
What is polymerisation?
Monomers joining together to make a long molecule, polymer
What is a condensation reaction?
Joins monomers by chemical bond and involves the elimination of a water molecule
What is a hydrolysis reaction?
Break chemical bond between molecules with the use of water
What is the definition of metabolism?
Sum of all chemical processes in an organism
What are organic molecules?
Carbon containing molecules
What are the monomers of a carbohydrate?
Saccharide (sugar); Monosaccharide (single unit); Disaccharide (2 units); Polysaccharide (more than 2 units)
What is the test for reducing sugars?
Add benedict’s solution (Copper(II) Sulfate and Sodium hydroxide), heat in water bath; Reducing sugar donates electron to benedict’s solution; Precipitate of Copper(I) Oxide formed; Blue to brick red
What is the test for non-reducing sugars?
Boil sugar w/ dilute HCl in water bath; Neutralise solution with Sodium Hydrogen Carbonate; Red litmus paper to test pH, solution needs to be slightly alkaline; Carry out Benedict’s test
What are the equations for the formation of major disaccharides?
Glucose + Glucose => Maltose
Glucose + Fructose => Sucrose
Glucose + Galactose => Lactose
How do monosaccharides bond and break bonds?
Condensation reaction, forming glycosidic bond; Bonds broken by hydrolysis reactions
What is the test for starch?
Add drops of Potassium Iodide; Starch changes Iodine in solution from yellow to blue black
What makes Glycogen and Starch good storage molecules?
Compact; Insoluble, no osmotic effect that would change a cells water potential
What is Glycogen and what are its properties?
Animal and fungi storage polysaccharide; Highly branched not coiled, easily hydrolysed to glucose; High concentration in live and muscle cells;
What are the polysaccharides that make up starch?
Amylose 10% - 30%; Amylopectin 70% - 90%
What are the properties of amylose?
Unbranched helix chain shape; 1,4 glycosidic bonds; Helical shape allows it to be more compact, more resistant to digestion
What are the properties of amylopectin?
1,4 glycosidic bonds; 1,6 glycosidic bonds between glucose molecules creating branched molecule; Branched chains, easy hydrolysis for cellular respiration
What is starch?
Storage polysaccharide for plants; stored as granules in plastids; Longer to digest than glucose due to many monomers
What is cellulose and what are its properties?
Consists of beta glucose; Structural carbohydrate; Neighbour molecules, 180 degree rotated due to H, OH group on beta glucose; Straight unbranched chains; Cross linkages between adjacent chains; Keeps cell turgid by exerting inward force; Microfibrils; Fibres
What are the roles of lipids?
Energy source, 2x more than carbohydrates; Waterproofing, hydrophobic; Insulating, Slow conductors; Protection, stored around delicate organs; Non polar
What do fats and oils consist of?
Fats, saturated fatty acids; Oils, unsaturated fatty acids
What is the structure of glycerol?
C3H8O3; carbon molecule w/ 3 alcohol groups (OH)
What is the structure of fatty acids?
Long molecule; Non polar hydrocarbon chain (R group); R-COOH polar carboxyl group
How are triglycerides formed?
1 glycerol molecule forms 3 ester bonds with 3 fatty acids in a condensation reaction (3H2O); Fatty acid carboxyl group w/ glycerol alcohol group
What is the difference between a saturated and unsaturated fatty acid?
Saturated fatty acid, no double bonds; Unsaturated, double bonds; Monounsaturated fatty acid, 1 =; Polyunsaturated fatty acid, more than 1 =
What is the structure of a phospholipid?
Hydrophilic head, attracted to H2O; Hydrophobic tail, oirients away from H2O but mixes w/ fat
How do you test for lipids?
Emulsion test; Add ethanol; Shake thoroughly, dissolve lipids; Add water, shake gently; Cloudy white emulsion
What are the monomers of a phospholipid?
2 fatty acid molecules and 1 phosphate molecule bonded to a glycerol molecule
What is the structure of an amino acid?
Amino group left (NH2); Carbon; Carboxylic group right (COOH); H above; R group side chain bellow (20 unique types)
How do amino acids bond?
Peptide bonds between C, N; 2 amino acids, dipeptide; 2+, polypeptide; Condensation reaction between carboxyl group and H;
What is the primary structure of proteins?
Sequence of amino acids bonded by covalent peptide bonds; DNA, responsible for primary structure, instructs order of amino acids
What is the secondary structure of proteins?
Hydrogen bonds between (amino group) N - O (carboxyl group) causes: α-helix, H bond between every 4th peptide bond; β-pleated sheet, folds so 2 parts of polypeptide chain are parallel, H bonding between parallel peptide bonds; High temperature and pH changes can break H bonds
What level of structure do most fibrous proteins have?
Secondary structure eg. collagen, keratin
What is the tertiary structure of proteins?
Helices folded to form unique 3D structure; Conformational changes of secondary structure lead to additional bonds forming between R groups; Hydrogen, Disulphide, Ionic; Common in globular proteins
What is the quaternary structure of proteins?
Proteins that have more than 1 polypeptide chain working together as functional macromolecule; Each polypeptide chain is referred to as a subunit
What are enzymes?
Globular proteins that act as a biological catalyst; Speed up rate of reaction without being used up for altering itself
What is the test for proteins?
Treat liquid solution w/ sodium hydroxide, make alkali; Add few drops of copper(II) sulfate; (biuret solution, alkali + copper(II) sulfate) ; Blue to lilac
Describe the structure of enzymes.
Globular protein, specific 3D shape; Substrate binds to active site forming enzyme substrate complex; Active site has specific shape; Extreme heat or pH change can denature active site; Shape of active site is determined by tertiary structure
How does the lock and key model function?
Substrate fits exactly into active site, enzyme substrate complex; Reaction takes place, enzyme product complex formed; Product released
How does the induced fit model function?
Substrate does not fit perfectly into active site; Active site undergoes conformational change; Enzyme substrate complex formed; Reaction takes place, enzyme product complex; Products released
How can you measure an enzyme catalysed reaction
Formation of products to disappearance of substrates; Plot graph, find gradient y/x
What are the effects of increasing temperature and changing pH on enzyme reaction?
Increased kinetic energy, more collisions, bonds in enzymes break; 60c enzyme denatures; pH change alters amino acid charges, denaturing active site; pH change breaks bonds in tertiary structure, denaturing active site
What is standard deviation used to measure?
Measures spread of all data in relation to the mean
What are enzyme inhibitors?
Substances that directly or indirectly interfere with the active site, reducing activity
What are competitive inhibitors?
Enzyme inhibitor; Similar molecular shape to substrate; Compete with substrate for active site; Non permanent; Lowers rate of complex
What are non competitive inhibitors?
Enzyme inhibitor; Binds to enzyme’s allosteric site; Alters shape of active site; Prevents enzyme substrate complex; Permanent; Lowers rate of complex
