Biochemistry Revision Notes

All notes on Biochemistry made from OCR unit 2 syllabus.

HideShow resource information
  • Created by: Zoe
  • Created on: 15-05-12 19:04
Preview of Biochemistry Revision Notes

First 100 words of the document:

BIOCHEMISTRY NOTES- 13/05/2012
PROTEINS
Proteins make up 50% of all organic matter. They are long chains of amino acids:
DIPEPTIDE is formed when two amino acids join
POLYPEPTIDES are formed when more than two amino acids join together
PROTEINS are made of more than two polypeptides.
Proteins are complex and diverse and have many functions:
STRUCTURE: collagen, keratin, actin
ENZYMES: amylase, pepsin, catalyse
RECEPTORS: rhodopsin
Proteins are POLYMERS, made by joining together a large number of smaller subunits- MONOMERS. In the case of
proteins the monomers are amino acids.

Other pages in this set

Page 2

Preview of page 2

Here's a taster:

BIOCHEMISTRY NOTES- 13/05/2012
ALPHA HELIX B-SHEET
In the alpha helix, the polypeptide chain is The polypeptide chain zigzags back
coiled tightly in the fashion of a spring. forward forming a sheet of ANTIPA
The "backbone" of the peptide forms the STRANDS held together by hydroge
inner part of the coil while the side chains bonds. One side is often hydrophob
extend outward from the coil.…read more

Page 3

Preview of page 3

Here's a taster:

BIOCHEMISTRY NOTES- 13/05/2012
GLOBULAR
Most proteins are globular- with compact ball shaped structures
Enzymes, receptors, membrane proteins, antibodies and plasma proteins are all globular proteins
(METABOLIC)
In globular proteins the hydrophobic R groups are turned inwards towards the centre of the structure
whilst the hydrophilic R groups are turned towards the outside. This gives them a water soluble layer
because water molecules can easily cluster around them.
An example of globular protein is HAEMOGLOBIN
FIBROUS
If they aren't globular they are fibrous.…read more

Page 4

Preview of page 4

Here's a taster:

BIOCHEMISTRY NOTES- 13/05/2012
CARBOHYDRATES
Carbohydrates make up about 10% of all organic matter of a cell. The functions of carbohydrates include
Energy source such as starch
Structural such as Cellulose
Substrate for respiration and immediate in respiration
Carbohydrates contain the elements C,H,O and some are part of larger molecules The simplest
carbohydrates are called MONOSACCHARIDES, these are made of monomers of carbohydrates. Larger
carbohydrates are made by joining monosaccharides together.…read more

Page 5

Preview of page 5

Here's a taster:

BIOCHEMISTRY NOTES- 13/05/2012
Joining two monosaccharides makes a disaccharide, joining many makes a polysaccharide such as starch,
glycogen and cellulose. The joining reaction is condensation forms a covalent bond known as a glycosidic
bond and water is removed. Hydrolysis reactions break down the bond and reinsert a water molecule.
Bonds can form between other carbon atoms leading the different shapes and branched chains.
Some common disaccharides include:
Maltose is formed when two glucose molecules join with a 1-4 glycosidic bond.…read more

Page 6

Preview of page 6

Here's a taster:

BIOCHEMISTRY NOTES- 13/05/2012
LIPIDS
Make up about 5% of organic matter. At room temperature they are
known as fats and as liquids they are oils. Lipids contain the elements C, H,
O and are insoluble in water. The functions of lipids include:
Insulation and protection
Some hormones are lipids- steroids
All biological membranes are made from lipids
Energy stores- lipids are stored in ADIPOSE cells
Energy- they can be respired to release energy.…read more

Page 7

Preview of page 7

Here's a taster:

BIOCHEMISTRY NOTES- 13/05/2012
SATURATED OR UNSATURATED
Unsaturated is used when talking about unhealthy
foods. Too much saturated fat is a feature of poor
diet. The term means if "all possible bonds are made
with hydrogen the fatty acid is saturated" It is
saturated with hydrogen.
1) Unsaturated fatty acids have a carbon to carbon
double bond. So less hydrogen molecules can bind
making it unsaturated. One double bond gives a
MONO-SATURATED FATTY ACID and two double
bonds (or more) creates a POLYUNSATURATED FATTY
ACID.…read more

Page 8

Preview of page 8

Here's a taster:

BIOCHEMISTRY NOTES- 13/05/2012
Cholesterol:
Cholesterol is a type of lipid which isn't formed from glycerol and fatty acid tails. It's a small molecule that
is a 4 carbon based ring. It's found in biological membranes- it's small, narrow, and hydrophobic and fits
between the hydrocarbon tails for membrane strength and stability. Steroid hormones, testosterone,
oestrogen and vitamin D are all made from cholesterol. The lipid nature of the steroid hormones allow
them to pass directly through the bilayer in order to reach target receptor.…read more

Page 9

Preview of page 9

Here's a taster:

BIOCHEMISTRY NOTES- 13/05/2012
CHEMICAL TESTS…read more

Page 10

Preview of page 10

Here's a taster:

BIOCHEMISTRY NOTES- 13/05/2012
Sometimes it is necessary to grind/ break up sample to carry out the chemical tests.…read more

Comments

AlgGeek

such an amazing set of notes. Thank you!!

Swallowtail

A detailed and beautifully presented set of notes on all the key biochemicals and the essential  biochemical tests. The useful glossary at the end could be used to generate a set of flashcards in order to learn the key definitions and chemical structural formulae.

Similar Biology resources:

See all Biology resources »See all resources »