3.2.5

In a condensation reaction, two molecules work together and form one big molecule along with water, because water is released during this reaction. Two amino acids joining together and forming a dipeptide would be a condensation reaction. Same applies for monosaccharides becoming dissaccharides , simple sugars such as glucose joining together with another glucose and forming maltose.A triacylglycerol or triglyceride, is made up of a glycerol and 3 fatty acids. The fatty acids and the glycerol are bonded through a condensation reaction as shown below.
external image glycerol,%20fatty%20acids,%20triglyceride.gif
external image glycerol,%20fatty%20acids,%20triglyceride.gif

In a hydrolysis reaction, water molecules are used up to make a large molecule into a small molecule. "Hydro" means water and "lysis" means splitting. So, water is used up to split a disaccharide into a monosaccharide.

3.3.1
nucleotide.jpg
nucleotide.jpg

3.3.2
Adenine- a nucleobase that binds to thymine through two hydrogen bonds. It helps stabilize the nucleic structure.
Guanine – paired with cytosine, binds with cytosine through three hydrogen bonds.
Thymine- always paired with adenine, same function as adenine, helps stabilize nucleic structure.
Cytosine- pyrimidine base that pairs with guanine

3.3.3

DNA nucleotides are linked together though a covalent bond between the sugar of the nucleotide and the phosphate of the other.


3.3.4
A DNA double helix is formed when two opposite bases bond together using hydrogen bonds. There are four bases in DNA, which are adenine, cytosine, thymine, and guanine. The adenine bonds with the thymine using two hydrogen bonds, and the guanine bonds with the cytosine using three hydrogen bonds. An easy way to remember the pairs that go together is to say ATari GameCube. the A and the T in ATari stand for adenine and thymine which bond together, and the C and G in GameCube stand for the other two bases that bond together. Below is a picture of the four bases bonding with their complimentary base

Base_Pairing_DNA.gif

3.3.5

external image moz-screenshot-4.pngDNA_Molecule.GIF
7.5.1
There are four different levels of structure for proteins, each one having there own unique importance. the first level is the primary level, which which is the amino acid sequence of the protein. This tells the order that the amino acids are in. There are hundreds of different sequences for the amino acids to be in. The second level is the secondary structure which is the shape of the polypeptide chain. The secondary structure can be in the form of alpha helix coil or beta pleated sheets. Most proteins have a combination of the two forms, but each is in different amounts. The third level is the tertiary structure, which is when the protein begins to fold into itself, giving it its shape. the protein folds into itself due to the hydrophilic, hydrophobic, acidic molecules, and disulfide bridges. The hydrophobic molecules are on the inside of the protein, hydrophillic molecules are on the outside of the protein, the acidic molecules go together and the disulfide bridges go together. If the tertiary structure is changed, the protein becomes denatured and might not be able to function properly.The last level is the quaternary structure, which is the interaction between two or more proteins.
For more information follow the link and press play

Protein Structure Video

7.5.2
Outline the differences between fibrous and globular proteins, with reference to two examples of each protein type.

Globular Proteins are folded proteins to form a globe like shape, where as Fibrous are straight and not folded, they are linear. Globular and soluble in and Fibrous are insoluble. Globular Proteins are used in metabolic reactions, where Fibrous Proteins are structural. Two examples of Globular Proteins are Hemoglobin and Actin. Two examples of Fibrous Proteins are Collagen and Elastin.

external image moz-screenshot.jpg
FandG.JPG



7.5.4
State four functions of proteins, giving a named example of each.

Proteins can be Enzymes, and enzymes are used to catalyze reactions. Amalyse.
Proteins can be used to transport materials around the body. Hemoglobin.
Proteins can be Hormones, like Insulin, which regulates human blood sugar.
Proteins can be used to keep structure of the human body. Collagen.



7.6.1
Metabolic pathways consist of chains and cycles of enzyme catalysed reactions. Enzymes are catalysts that speed up biological reactions, which means less energy is being used, without being consumed in the process. The reactions which consist of the reactants and the substrates involve the enzyme attaching itself to the substrate and speeding up the process by either binding or breaking apart bonds.

7.6.2
The induced-fit model is an extension of the lock-and-key model. It accounts for the broad specificity of some enzymes. The induced fit model of enzymes states that the active site of an enzyme does not fit perfectly with the substrate, as would a lock and key. Instead, the fit is not quite perfect,when a substrate collides with an enzyme and enters the active site, the enzyme change their shape slightly, the substrate is stressed in a way that allows its bonds to break easier.

7.6.3
Enzymes lower the activiton energy of the chemical reactons that they catalyse. All reactions, either with or without enzymes, need collisions between molecules in order to occur. Many molecules have strong bonds holding them together, and require powerful collisions at high speed in order to break these bonds. However, increasing the rate of collision to a rate at which these reactions would occur would require prohibitive amounts of energy, usually in the form of heat. Enzymes, by stressing substrate bonds in such a way that a weaker collision is required to break them, reduce the amount of energy needed to cause these reactions to occur, or the activation energy.
7.6.4

Competitive Inhibition - binds to the active site of an enzyme.


Non- competitive- binds to the site other than the active site of an enzyme