BIOLOGY: RDI: THE REPORT!!!

OUR REPORT:

We have decided to use the food products, sweet potato and milk to achieve the RDI.

Proteins:

Milk contains proteins, and so does sweet potato.

Primary structure of a protein refers to the linear sequence and number of amino acid residues which make up a polypeptide chain. The primary structure of a protein is unique, which means each polypeptide chain has its specific number, sequence and variety of amino acids. The precise primary structure of each protein is determined by information stored in a specific gene in an individual's genome. Only peptide bonds are involved in primary structure of a protein. Slight changes in primary structure can cause changes to subsequent levels of protein structure (secondary and tertiary), and may ultimately result in change of a protein's conformation and ability to function.

Secondary structure refers to the repetitive folding or coiling of the polypeptide chains and contribute to the protein's overall conformation and are the result of hydrogen bonds formed at regular intervals between the C=O and N-H groups of neighbouring amino acid residues on the backbone of the polypeptide chains. Since secondary structure arises from the functional groups found in the peptide bonds and not from the R groups, they are expected to occur in all protein sequences, regardless of the primary sequence of the protein. There are two types of secondary structures, the alpha helix and the beta pleated sheet. Alpha helix is in the form of an extended spiral spring, the alpha helical structure in stabilized by intramolecular hydrogen bonds, which occur between the O atom of the carbonyl group and the H atom of the amino group four amino acids away, within the polypeptide chain. The helix makes a complete turn for every 3.6 amino acids. As the intramolecular hydron bonds in the alpha helix are arranged linearly, they are maximally stable. Beta pleated sheet is form when a single polypeptide chain folds back and forth, or when two regions of the polypeptide chain like parallel to each other to form sheets and this structure is stabilized by large numbers of H bonds formed between C=O and N-H groups of one part of the backbone and an adjacent part in the parallel regions that hold the structure together. The polypeptide chaings may either be parallel to each other or anti-parallel to each other. This structure is stable as all the N-H and C=O groups on the back bone are involved in hydrogen bonding.

Tertiary structure refers to the precise and compact 3D shape of a protein, formed from extensive bending and folding of the polypeptide chain. This structure is maintained by four types of interactions that occur between the variable side chains (R groups) of the amino acid residues, which are often far apart in the primary structure of the polypeptide chain. Ionic bonds, hydrophobic interactions and hydrogen bonds are the weak interactions and the disulphide bonds and the strong covalent linkages. The folding of a polypeptide to form its tertiary structure is not random, and for polypeptides to form functional proteins, they need to fold into specific conformations. Tertiary structure gives rise to precise clefts and grooves on the surface of the protein, which may be involved in the binding of the protein to other substances, these are important in the function of enzymes and grooves in the structure function as active sites which have specific conformation. Only substrate molecules with correct complementary shape can fit into the active site.
Quaternary structure refers to the interaction between two or more polypeptide chains to form and intact and complex functional protein, each polypeptide chain is a subunit, and held together by hydrophobic interactions, hydrogen, ionic and disulphide bonds. The subunits of a multi subunit protein may be identical or different.

ENZYME

The enzyme amylase is found in sweet potato. Enzymes are globular proteins which are specific with specific 3D conformations. It is the enzyme specific to starch. The enzyme achieves its quaternary structure by the interactions between its polypeptide chains, hydrophobic interactions, hydrogen, ionic and disulphide bonds. The enzyme is flexible physically and closes up and enfolds substrates when they bind to the active sites. Starch binds to the active site of the amylase and breaks down into maltose.

CARBOHYDATE

Your body uses carbohydrates (carbs) to make glucose which is the fuel that gives you energy and helps keep everything going.

Your body can use glucose immediately or store it in your liver and muscles for when it is needed.

Carbohydrates contain carbon, hydrogen and oxygen.

General formula: Cx(H2O)y

Either aldehydes or ketones.

Best known monosaccharide- C6H12O6 (Glucose)

Alpha Glucose has hydroxyl group on carbon 1 projecting below the ring.

Beta Glucose has the hydroxyl group of carbon 1 projecting above the ring.

Disaccharides

A disaccharide is formed by a condensation reaction between two monosaccharide units, combining together with the elimination of a molecule of water.

General formula: C12H22O11

The covalent bond formed between two monosaccharaides is called a glycosidic bond.

Milk contains lactose and is an important energy source for young mammals.

Sweet potato contains sucrose and it is very soluble and can therefore be transported efficiently in high concentrations.

Polymer

Alpha glucose: Starch glycogen-storage polysaccharides

Beta glucose: Cellulose-structural polysaccharides

Starch

-food reserve in plants

Structure

Monomers are joined by alpha (1->4) glycosidic bonds.

(i) Amylose :

1)has an unbranched, straight chain structure consisting of several thousand glucose residues joined by alpha (1->4) glycosidic bonds.

2) the chains coil into a helix with 6 glucose units in every turn, forming a more compact shape.

(ii) Amylopectin

1) Highly branched.

2) Glucose residues are joined together by alpha(1->4) & alpha (1->6) glycosidic bonds.

3) Branch point occur at every 25-30 glucose residues.

Glycogen

1) Alpha glucose residues are linked by alpha (1->4) and alpha (1->6) glycosidic bonds.

Extensively branched

Cellulose

1) Linear, unbranched polymer of beta glucose molecules joined by beta (1->4) glycosidic bonds.

2) Straight and unbranched.

3) Rigid cross- linking

Functions of cellulose

1) Highly rigid-> tremendous mechanical or tensile strength.

2) Maintain the shape of plant cells

3) Important food source

Fats

Fatty acids present in milk: Conjugated Linoleic Acid (CLA)

CLA is an 18 carbon fatty acid with 2 double bonds that are conjugated (double bonds are on adjacent carbon atoms in the fatty acid chain and are not separated by one or more carbons). Since there is carbon-carbon double bond present in the fatty acid, CLA is unsaturated. CLA are all polyunsaturated fatty acids, even though some may be trans fatty acid. The most common isomers of CLA are c9t11 (cis-9, trans-11) and the other t10c12 (trans-10, cis-12).

General components of lipids : 1 Glycerol + 3 Fatty acids

Glycerol: It has 3 carbon atoms, in which each carbon atom has a hydroxyl (-OH) group attached to it.

Fatty acid: It has 2 essential features. First, it has a long linear hydrocarbon chain. The chain length ranges from 4 to 30 but 12 to 24 is most common since the chain usually contains an even number of carbons. Second, the fatty acid also has a carboxylic acid group.