Organic molecules

Organic molecules

• Proteins:-
• When two amino acid join together they form dipeptide bond
• when more than two amino acid join together they are called polypeptide bond
• Protein is made up of one or more polypeptides

Slide 2

• https://www.youtube.com/watch?v=H8WJ2KENlK0 (Embed)

Slide 3

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• Caption: General structure of amino acid
• all amino acids have same general structure,
• carboxyl group (-COOH),
• amino group (-NH2) attached to a carbon atom.
• R- is the variable group

Slide 4

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• Amino acids are joined together by peptide bonds, by condensation reaction which releases a water molecule during the reaction.
• the reverse of this reaction is called hydrolysis, which adds the water molecule in order to break the peptide bond.

Structural levels

• Primary structure:-
• Sequence of amino acid in polypeptide chain.
• Bonds: Peptide bond
• Secondary structure:-
• when Hydrogen bonds form between the amino acids, they begin to coil into alpha helix or beta pleated sheet
• Bonds: Hydrogen bonds
• Tertiary structure:-
• Coiled amino acid can be coiled even further, as more bonds form between different parts poly peptide chains. For single polypeptide this is their final 3D structure.
• Bonds:- Ionic interaction, Hydrophobic & Hydrophilic, Di sulfide bond, Hydrogen bond
• Quaternary structure:-
• More than one polypeptide joined together to form final 3D structure (e.g. Haemoglobin)
• Bonds:- same as the tertiary bonds

Slide 6

• A protein's primary structure determines its 3D structure
• The amino acid sequence will determine what bonds will form and how it will fold up.
• A protein's 3D structure allows it to carry out its function
• Protein's shape is closely related it its function, (E.g. Insulin's function is to make cells take up glucose from the blood, so its a compact protein, which makes it easier to transport around the blood.)

Globular

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• round, compact proteins. Made of several polypeptide chains.
• Chains are coiled up so that Hydrophlic parts are facing outwards and Hydrophobic parts are facing inwards.
• They are soluble, easily transported in fluids.

Fibrous

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• long, insoluble polypeptide chains. tightly coiled around each other to form a rope shape
• held together by lots of bonds, thus they are strong.
• Because they are strong, they are found in connective tissue.

Functions of Proteins

• Enzyme:
• roughly spherical in shape, due to tight folding of peptide chain
• They are soluble and often have roles in metabolism
• Break down or synthesize
• Antibodies:
• Involved in immune response
• Made up of 2 light polypeptides & 2 heavy polypeptides joined together.
• The amino sequence may vary, due to the variable regions.
• Transport proteins:
• present in cell membranes
• Contain Hydrophillic and Hydrophobic amino acids, which cause the protein to fold up and create a channel.
• Transports molecules and Ions across cell membrane.
• structural Protein:
• They are Physically strong
• They are made up of long polypeptide chains lying parallel to each other with cross links between them
• Structural protein found in Keratin and Collagen.

Carbohydrates

• monosaccharides are units of sugar molecules.
• Carbohydrates is made out of long chains of monosaccharides .
• Glucose is a Hexose sugar (meaning it contains 6 carbons in each molecule)
• There are two forms of GLUCOSE
• Alpha
• Beta
• Glucose's structure is related to its function: as it is the main energy in animals and plants, needs to be slouble and easily transported.

Glycosidic bond

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• Monosaccharides are joined together by Glycosidic bond by condensation reaction
• One Hydrogen bonds with a Hydroxyl from the other group to release an H20 molecule.
• To break the bond a water molecule is addded back to break the bond between the monosaccharides.
• when 2 monosaccharides join together they are called disaccharide
• When more than two Monosaccharides join together they are called polysaccharide.

BOnds

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• Glycosidic bonds can form in different places to form different molecules. Carbons are 1 to 6.
• Glucose is 1-4 glycosidic bond
• Lactose 1-4 glycosidic bond
• Sucrose 1-2 gycosidic bond
• Amylose 1-4 gycosidic bond
• Amylopectin 1-6 gycosidic bond (branched)
• Glycogen 1-4 and a few 1-6 which causes branching

Slide 13

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• Starch is the main storage in plants