Chapter 1: Biological Molecules Flashcards
What is a covalent bonding?
Atoms share a pair of electrons in their outer shells. As a result, the outer shell of both atoms is filled and a molecule is formed.
What is an ionic bonding?
The electrostatic attraction between ions with opposite charges which attract one another.
What is hydrogen bonding?
The electrons within a molecule are not evenly distributed. One region is more negatively charged than the rest of the molecule - a polar molecule
Monomers?
Single small sub-units
Polymers?
Many monomers linked together to form long chains
What is a condensation reaction?
A reaction that joins molecules together and release water. e.g. glucose into starch
What is a hydrolysis reaction?
A reaction that breaks molecules with the addition of water e.g. lipids into glycerol and fatty acids
What is metabolism?
All the chemical processes that happen in living organisms
What is the mole?
It is a SI unit for measuring the amount of a substance and is abbreviated to mol
6/02x10^23
Molar solution?
A solution that contains one mol of solute in each litre of solution
Monosaccharides
A single monomer
Polysaccharides
Combined monosaccharides joined together
Test for reducing sugars?
Benedict’s reagent added to food sample solution.
Heat gently in boiling water.
If a reducing sugar is present, the solution will change from blue to red.
Maltose
Glucose + Glucose
Sucrose
Glucose + Fructose
Lactose
Galactose + Glucose
A glycosidic bond?
The bond formed between two monosaccharides when they join together.
Test for non-reducing sugars?
Conducts Benedict’s test
Then add a bit more food sample and add HCl, put the tube in gently boiling water for 5 mins
Slowly add some sodium hydrogen-carbonate solution to the test tube - test with pH paper to check the solution is alkaline
Retest the solution with Benedict’s reagent
If the solution turns orange-brown then a non reducing sugar was present (it was hydrolysed)
Test for starch?
Add iodine to the liquid form of the food sample
If the sample turns from yellow to blue-black then iodine is present
Starch?
Found it parts of plants Made up of alpha glucose monosaccharides linked by glycosidic bonds May be branched or unbranched Large and insoluble Compact
Glycogen?
Found in animals and bacteria
Made up of alpha monosaccharides but has a shorter chain
It is more highly branched
Insoluble and Compact
Cellulose?
Found in plants
Made from Beta glucose
Unbranched straight chains which run parallel to each other with hydrogen bonds
Molecules are grouped to form microfibrils- these form fibres for more strength