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Chemistry of Life
Focus on Proteins
GMO- Factor IX
3.2.5 -- Outline the role of condensation and hydrolysis in the relationships between monosaccharides, disaccharides and polysaccharides; between fatty acids, glycerol and triglycerides; and between amino acids and polypeptides.
In hydrolysis, one molecule, in my example, a disaccharide, reacts with water to form two monosaccharides. Condensation is the opposite, when two molecues, in my example, monosaccharides, react together to form water and a disaccharide. This works the same with polysaccharides, except with more saccharides. This will also work in peptides instead of saccharides. For example, through condensation, amino acids can form a polypeptide. It also applies to the formation of glycerol from fatty acids.
3.3.1 -- Outline DNA nucleotide structure in terms of sugar (deoxyribose), base and phosphate.
DNA is composed of sugar, a phosphate group and a nitrogen base. The phosphate group is covalently bonded to the carbon of the sugar and then nitrogenous base is attached to the sugar with hydrogen bonds.
3.3.2 -- State the names of the four bases in DNA.
Adenine, Cytosine, Thymine, and Guanine
3.3.3---Outline how DNA nucleotides are linked together by covalent bonds into a single strand.
DNA nucleotides and like together through covalent bonds. This bond occurs between the sugar of one nucleotide and the phosphate of another nucleotide.
3.3.4---Explain how a DNA double helix is formed using complementary base pairing and hydrogen bonds.
DNA contains two strands of nucleotides. These two strands of nucleotides wind together to in order to form a double helix (a spiraled ladder) The strands of nucleotides consists of complementary bases that bond together. Adenine only bonds with Thymine, and Cytosine only bonds with Guanine. They all bond through hydrogen bonds.
3.3.5---Draw and label a simple diagram of the molecular structure of DNA.
7.5.1 -- Explain the four levels of protein structure, indicating the significance of each level.
Primary Structure: The primary structure of a protein is its unique amino acid sequence. In other words, the primary structure is the pattern that the amino acids create when bonding together to form a protein. The primary structure is very important because there are thousands of different ways to arrange amino acids in a polypeptide chains. This arrangment designates the specific function and use of the protein. Lastly, the precise primary structure is determined by inhereted genetic information.
Secondary Structure: This structure refers to the coils and folds that contribute to the proteins overall conformation. These coils and folds are the result of hydrogen bonds between the polypeptide backbone. The positively charged hydrogen atom attached to the nitrogen atom has a weak attraction towards the oxygen atom of a nearby peptide bond. One type of secondary structure is the alpha helix. The alpha helix is a coil held together by hydrogen bonds between every fourth amino acid. The other type is the beta pleated sheet. This type of secondary structure includes two polypeptide chains that lay parallel to one another in terms of their backbones. Hydrogen bonding connects parts of these two parallel backbones.
Tertiary Structure: In the third structure of proteins, the secondary structures are manipulated to get the overall shape of the polypeptide chains. This occurs because of interactions between the "R" groups of the various amino acids. For example, one of these interactions is called a hydrophobic interaction where the hydrophobic side chains cluster in the center of the protein. Another one of these interactions are called disulphide bridges. Disulphide bridges are covalent bonds between the sulpher atoms of two cysteine monomers. All of these interactions when completed fold and bend the protein to form its tertiary structure.
Quaternary Structure: The overall protein structure resulting from the aggregation of many polypeptide subunits. This is the final shape of the protein macromolecule. The two main types of quaternary structure are globular and fibrous.
7.5.2 -- Outline the difference between fibrous and globular proteins, with reference to two examples of each type of protein.
Fibrous Proteins: Polypeptide chains that run parallel to each other in the quaternary structure. These weaving chains are linked by disulphide chains and cross bridges which give the protein its strength. Fibrous proteins usually have structural functions. Two examples are collagen which is a type of connective tissue and keratin which is the protein in hair.
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Globular Proteins: Become globular in the tertiary or quaternary structure. They are usually soluble because the hydrophobic side chains usually reside in the center of the sphereical shape. Their solubility means that they have a large role in metabolic reactions. An example is hemoglobin which has four polypeptide chain subunits would together in a globular shape. Another example is the transthyretin protein which also folds in a globular manner.
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7.5.4 – State four functions of proteins, giving a named example of each.
1) Framework for connective tissue- Collagen.
2) Transport of other substance- Hemoglobin.
3) Support- Silk and Keratin.
4) Storage of amino acids- Ovalbumin and Casein.
7.6.1- metabolic pathways consist of chains and cycles of enzyme catalyst reactions. Enzymes are catalysts that speed up biological reactions, which means less energy is being used, without being consumed in the process. The reactions are connected by their reactants/substrates the enzyme attaches itself to the substrate and speeds up the process by either binding or breaking apart bonds.
external image Metabolism_790px_partly_labeled.png
7.6.2 - The induced fit model is when the enzyme changes its shape to bind to the substrate. This is good because it allows reactions to occur with limited specificity. The bad side is that a virus or bacteria may disguise itself as a substrate and bind to the enzyme(s) and eventually attack the immune system.
File:Induced fit diagram.svg
File:Induced fit diagram.svg
Click on the following link to see how enzymes work:
7.6.3 - Enzymes lower the activation energy of the chemical reactions the catalyse. The activation energy is the amount of energy a reaction must overome in order to work. Enzymes are catalyst, which means that they speed up a procees which means less energy is needed( they assist/ help out the reactors). So on regular reaction with no enzyme the activation energy is higher but reactions that use enzymes require less energy so the activation energy is lower but the outcome is still the same.
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7.6.4 - Enzyme inhibitors, selectively ihnibits activity of certain enzymes. It can have a permanent effect on the enzyme and the way they work. The inhibition may be reversed. There are two types inhibitors; competitive and non- competitive.
They take the place of a substrate at the active site of enzymes and substrates. Hence they block the actual substrate from binding with the enzyme. This form of inhibition is able to be reversed by taking an enzyme supplement/ increasing the concentration of substrates.
external image Competitive_inhibition.png
Impete enzymatic reactions by binding on a part of the enzyme. This causes the enzyme to change its shape. It is also like a leech which allows the reaction to go on bt in a much slower pace that is if the enzyme was not dentatured in the process. This process is irreversible.
external image 400px-Comp_inhib3.png
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