Specification Revision Notes- Biological Molecules

So I had a look through the specification and went through each requirement in the first section (Biological Molecules) and made a few notes mainly from my text book and revision guide. I haven't had time to do any other units yet but if I find it has been useful I'll do the other topics as well. Please tell me what you think, and good luck for the exam!

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  • Created by: Jade
  • Created on: 31-05-13 15:14

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Specification- 2.1.1- Biological Molecules
(a) describe how hydrogen bonding occurs between water molecules, and relate this, and other
properties of water, to the roles of water in living organisms

A molecule of water is one atom of oxygen joined to two atoms of hydrogen shared
by electrons. Because the shared…

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Two or more amino acids can join together to form a polypeptide in a condensation reaction. This
occurs Between the OH on the carboxyl group on one amino acid and the H on an amino group on
another amino acid. These molecules take part in the condensation reaction and are…

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(g) explain, with the aid of diagrams, the term quaternary structure with reference to the
structure of haemoglobin.

A quaternary structure involved several different polypeptide chains held together by bonds and
describes the way in which they're assembled. Eg. Haemoglobin has four polypeptide chains
bonded together.

(h) describe, with the…

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(k) State the structural difference between alpha and beta glucose

Both alpha and beta have a similar molecular formula, however at C1 in alpha helix the OH molecule is
below and in beta helix the OH molecule is above the carbon atom.

(l) Describe, with the aid of diagrams, the…

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(o) Explain how the structures of glucose, starch, glycogen and cellulose relate to their functions
in living organisms

Glucose- It's the main energy source in animals and plants so the structure makes it soluble so it can
be easily transported. The chemical bonds also contain lots of energy.

Starch- Starch…

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(r) describe how to carry out chemical tests to identify the presence of the following molecules:
protein (biuret test), reducing and non-reducing sugars (Benedict's test), starch (iodine solution)
and lipids (emulsion test). ffdsuffdsfds

Protein (Biuret Test) Add a few drops of sodium hydroxide solution Blue Purple layer
to make it…

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measure the concentration of blue Benedict's solution that's left after the test so the higher the
glucose concentration, the lower the absorbance of solution.


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