Bio Molecules Flashcards
Globular proteins
1) spherical/ball shaped eg Hb, myoglobin
2) curl up = NON POLAR hydrophillic R groups point to center of mol AWAY from aqueous environment
3) POLAR hydrophilic R groups outside = mixing + dissociating in water easier
4) usually soluble
5) precise shape - have roles in metabolic activities, specific in nature
Secondary structure
- Primary structure coiled + FOLDING itself in specific way
- Fibrous
- Hydrophobic R groups point OUTWARDS
- Water insoluable
- H+ bonds between NH of 1 AA + CO of another AA
- Alpha helix and Beta pleated sheets
Polar molecules
1) have groups with dipoles
2) attracted to H2O molecules as they also have dipoles = are hydrophilic
3) soluble in water
Eg- amino acids, glucose, NaC
How molecular structure of GLYCOGEN makes it suitable for storage (4)
- 1,4 and 1,6-α glycosidic bond
- ALPHA glucose = used for aerobic rep + releases energy
- lots of branches for enzyme attachment
2) can be hydrolyzed easily + quickly
3) compact + insoluble= no effect on water potential
Polysaccharides
A polymer whose subunits = monosaccharides joined via glycosidic bonds
• Eg- starch, glycogen, cellulose
• NOT sugars
• if glucose itself accumulated in cells it would dissolve + contents of the cell too concentrated = effects osmotic properties
• storage polysaccharides- convenient, compact, inert & insoluble
Define monomer and polymer
- many small molecules that combine to form a polymer (larger molecules).
- large molecules made from many similar repeating subunits e.g proteins/nucleic acids.
Define macromolecule and monosaccharides
- large molecules formed due to polymerization of monomers e.g proteins/polysaccharides.
- molecule consisting of a single sugar unit with general formula of C(H2O)n
Define isomer
- molecule w/ same chem formula + different structural arrangement
Breaking a glycosidic bond: disaccharide and polysaccharides e.g sucrose test
- hydrolysis - water is added into the ring
- disaccharide + polysaccharides broken down into hydrolysis reaction
-Sucrose heated w HCL used to break disaccharide = 2 monosaccharides when testing for non-reducing sugar (sucrose). = positive Benedict’s test
Molecule structure of starch (plant)
- made of 2 POLYMERS; Amylose and Amylopectin
- polymer of ALPHA glucose
- via condensation reactions between α-glucose linked by a 1-4 glycosidic links/bonds.
- MAIN storage polysaccharides PLANTS ONLY - inert,compact + insoluable (tightly coiled)
Structure of amylose(plant)
- made via condensation joined by 1,4 linked alpha glucose molecules (glycosidic bonds)
- long unbranching/NOT BRANCHED chain
-forms helix with 6 glucose molecules per turn and 300 per helix = COMPACT
Structure of amylopectin(plant)
- polymer of ALPHA glucose joined by 1,4 glycosidic bonds BUT branches of 1,6 glycosidic link bonds
-branched every 20 monomers = easier hydrolyzed for faster release of glucose monomers
Structure of cellulose
- MAIN structural of plant cell wall
- STRAIGHT UNBRANCHED PARELLEL chains
- subunit of BETA glucose
- insoluble + High mechanical strength (maintains turgidity/support)
- staggered ends
- many H+ within cellulose mol = forms microfibrils
- microfibrils held tgt by H+ = fibres
Why must polysaccharides be insoluable
- cannot dissolve in water as it affects water potential
- decreases water potential in OSMOSIS
- hydrolysis occurs
- cells burst if water enters (mammals)
Reducing sugars test- monosaccharides (simple sugars)
- add equal vol of Benedict’s reagent +food sample IN LIQUID FORM to test tube
- heat gently in boiling tube in WB AT 80ºC for 5 mins
- If RS present = blue,green, yellow, orange/brick red (HIGHEST)
- ^^^ conc of reducing sugars INCREASING
