Biologyical Molecules Flashcards
Monomer
Small units from which larger molecules are made
Polymer
Molecules made from large numbers of monomers joined together
Monosaccharides
Monomers from which larger carbohydrates are made. Glucose, galactose and fructose.
Condensation reaction
Two molecules join together creating a glycosidic bond. Water molecule is formed- eliminated out of molecules
Hydrolysis reaction
A molecule of water is added to break the chemical bond between the molecules
How are disaccharides formed?
By condensation of two monosaccharides.
Disaccharide maltose
Two glucose molecules
Disaccharide sucrose
Glucose and fructose molecule
Disaccharide lactose
Glucose and galactose molecule
Isomers of glucose
ALPHA- glucose and BETA- glucose
How are polysaccharides formed?
Condensation of many glucose units
Amylose in plant cells
Release glucose for respiration.
Breaks up starch into maltose.
Energy store.
Glycogen I’m animal cells
Broken down into glucose which is released into bloodstream to be used as fuel for cell.
Energy store.
Cellulose in plant cells
Holds cell together.
Provides strength.
Provides rigidity.
Properties of starch and glucose
Compact.
Easily hydrolysed.
No osmotic effect.
Insoluble.
Properties of cellulose
Insoluble.
High tensile strength.
Flexible.
Strong cell walls.
Reducing sugars test
Benedict’s:
Add 3cm^3 of sugar solution to 5cm^3 of Benedict’s in a test tube.
Heat(boiling water in hot water bath. 5 minutes.
Observe colour change: low- blue/green. Medium- orange. High- brick red.
Reducing sugar
Glucose
Galactose
Fructose
Maltose
Lactose
Test for non-reducing sugar
Boil acid (HCL) to hydroxide the covalent bond. Then neutralise (with sodium hydrogrencarbonate). Then boil with Benedict’s.
Non-reducing sugars
Sucrose
Triglycerides
Group of lipid
Important energy store in animals and plants.
One glycerol molecule and 3 fatty acids, joined by a condensation reaction
Phospholipid
One phosphate, one glycerol and 2 fatty acids.
Form a bilateral naturally: hydrophilic head, hydrophobic tails.
All biological membranes are made up of a phospholipid bilayer.
Functions of lipids
Waterproofing (insoluble, waxy cuticle)
Energy store (more energy per unit gram than any other food molecule type.)
Thermal insulation (adipose tissue- cushioning organs)
Membrane structure (made of phospholipid)
Electrical insulation (nerve fibres surrounded by fatty myelin sheath)
Steroid hormones (made from cholesterol)
How is the ester bond formed
Condensation reaction between glycerol and fatty acid
Fatty acids
Long hydrocarbon chains.
With a carboxylic acid group.
R-group maybe saturated or unsaturated.
Saturated fatty acid
NO carbon double bonds.
E.g. triglycerides (straight)
Unsaturated fatty acids
HAVE double carbon bonds
Monosaturated: one
Polusaturated: more than one
Double bonds = kinks
Emulsion test for fats
Dissolve sample in water.
Pour alcohol in water (ethanol) n
OUTCOMES:
P: cloudy
N- water stays clear
Alpha and beta glucose
CH2OH
ALPHA: OH is on bottom of Carbon 4 bond
BETA: OH is on top of carbon 4 bond
