Biolgoical molecules

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  • Created on: 24-06-13 08:11
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Module 2.1: Biological Molecules
State the functions of biological molecules in organisms
Carbohydrates ­ energy storage and supply, structure (in some organisms)
Proteins ­ Structure, transport, enzymes, antibodies, most hormones
Lipids ­ Membranes, energy supply, thermal insulation, protective layers/padding, electrical insulation in
neurones, some hormones
Vitamins and minerals ­ From parts of some larger molecules and take part in some metabolic
reactions, some act as coenzymes or active enzyme activators
Nucleic acids ­ information molecules, carry instructions for life
Water ­ Takes part in many reactions, support in plants, solvent/medium for most metabolic reactions,
Define metabolism
Metabolism is the sum total of all the biochemical reactions taking place in the cells of an organism.
Name the monomers and polymers of carbohydrates, proteins and nucleic acids.
Monomer Polymer
Carbohydrates Monosaccharides (simple Polysaccharides
Proteins Amino acids Polypeptides and proteins
Nucleic Acids Nucleotides DNA and RNA
Describe the general features of condensation and hydrolysis reactions.
Condensation reactions link monomers together. The same
reaction is repeated many times to make a polymer and is used
to link subunits in lipid molecules.
In condensation reactions a water molecule is released, a
covalent bond is formed and a larger molecule is formed by the
bonding together of smaller molecules.
When a larger molecule splits this is called a hydrolysis reaction.
In hydrolysis reactions a water molecule is used, a covalent
bond is broken, smaller molecules are formed from splitting
larger ones.
State the structural difference between and glucose.
The two ring structures are virtually identical but the OH and H
groups are either above or below the plane of carbon 1. In
glucose the OH at carbon 1 is below the plane of the ring. In
glucose he OH at carbon 1 is above the plane of the ring.

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Describe the formation and breakage of glycosidic bonds in the synthesis and hydrolysis of a
A condensation reaction joins to monosaccharides together to form a disaccharide molecule. A
covalent bonds called a glycosidic bond is formed. Water breaks the glycosidic bond in a hydrolysis
reaction. A H and OH from each molecule is used to form water. When you break down large molecules
in digestion which breaks the glycosidic bonds.
Describe the molecular structure of alph-glucose as an example of a monosaccharide carbohydrate.…read more

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They are both energy storage molecules. They don't dissolve so the molecules don't affect water
potential of the cell. They hold glucose in their chains which can be broken off and used to provide
glucose for respiration.
Explain how the structure of cellulose relates to its function in living organisms.
Cell walls in plant cells give strength to cells supporting the plant. The macro fibril arrangement allows
water to move in and out of the cells easily.…read more

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Further folding of the secondary structure and 3D shape is formed. Hormones rely on 3D shape for
receptor molecules. Can be structural. Disulfide bonds have a very strong covalent bond. Ionic bonds
are strong when oppositely charged amino acids are next to each other. Hydrogen bonds are found
whenever charged groups are found close to hydrogen. Hydrophobic tend to be on the inside and
hydrophilic tend to be on the outside of proteins.…read more

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Fatty acids consist of a hydrocarbon chain and an acid group. They can be
unsaturated or saturated. Many saturated fats are solid (animal lipids ­ lard) and many unsaturated fats
are liquid like oils. Triglycerides are a glycerol molecules bonded to 3 fatty acid molecules. They are
formed through condensation reactions and broken with hydrolysis reaction. The bond formed is an
ester bond and they are insoluble in water (hydrophobic).
Compare the structure of triglycerides and phospholipids.…read more

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Property Importance Examples
Solvent Metabolic processes depend on 70-95% of cytoplasm is water.
chemicals being able to react in Dissolved chemicals take part in
a solution processes like reparation and
photosynthesis in living
Liquid Movement of materials around Blood in aminals and vascular
organisms, in calls and in tissues in plants use water for
multi-cellular organisms. transport medium.…read more

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Benedict's test.
Protein Add biuret reagent Blue to lilac
Lipid Add ethanol to extract (dissolve) White emulsion forms near top
lipid and pour alcohol into water of water.
in another test tube
Describe how the concentration of glucose in a solution may be estimated by using colour
Glucose is reducing sugars so we carry out the Benedict's test which forms and orange-red precipitate.…read more

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This is
semi-conservative replication.
State that a gene is a sequence of DNA nucleotides that codes for a polypeptide
DNA is a sequence of nucleotides which contain the instructions to code for the amino acids in a
protein. A gene is a length of DNA that codes for one or more polypeptides.
Outline the roles of DNA and RNA in the cells of living organisms.
DNA codes for the amino acid sequence in a protein.…read more

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Describe how enzymes lower the activation energy of a reaction.
They lower the activation energy needed because the active site induces a fit to the substrate molecule
which strains the substrate. This then requires less energy to break the bonds in this molecule than
Describe and explain the affect of temperature changes on enzyme activity.
Temperature increase increases the kinetic energy of both the substrate and enzyme molecules. This
will increase the number of collisions which will also increase the rate of reaction.…read more

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Cofactores are substances which ensure that enzyme-controlled reactions take place at an appropriate
rate. A type of cofactor is an enzyme.
Conenzymes are organic, non-protein molecules which are not permanent and bond to the active site.
They can bind before or at the same time as the substrate molecule. They can take part in the reaction
and be changed like the substrate. They can be recycled to take part in the reaction again.…read more


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