Biomolecules Test - 4

• Silicon is a trace element present in negligible amounts.
• Magnesium is present in the chlorophyll in plants. In humans it is involved in many cellular biochemical reactions.
• Iron is present in haemoglobin which is used to carry oxygen.
• Sodium is largely involved in the nerve impulse generation.

• Lactose, commonly known as milk sugar, is a disaccharide. It is made up of one molecule of glucose and one molecule of galactose. It is a type of reducing sugar.
• Glucose + Glucose = maltose.
• Fructose + Glucose = sucrose.

The reduction in activity of succinate dehydrogenase by malonate, oxaloacetate and other anions is one of the classical examples of competitive inhibition. In this type of inhibition, an inhibitor (competitive inhibitor) which has the resemblance with substrate molecule, competes with the substrate for the active site of an enzyme. The inhibitor binds to the active site and prevents attaching of the substrate to the enzyme.

• Allosteric feedback inhibition is a inhibition in which the final product of enzymatic reactions accumulates in plenty. Due to excess amount of this product, the final product binds to an allosteric site on the first enzyme in the series of reactions to inhibit its activity.
• Hexokinase catalyzes the phosphorylation of hexose and is found in the cells that metabolize glucose. The enzyme has low Km (high affinity, strong bonding) with glucose in such a way that it is active at low glucose concentration and shows allosteric feedback inhibition by glucose-6-phosphate.
• The competitive inhibion is which where the inhibiting agent competes with the actual substrate for binding at an active site. 
• While in non-competitive inhibition is one where the inhibitor interacts with the enzyme but does not binds at an active site, it only changes the shape of the enzyme so that the actual substrate will not be able to interact with the enzyme.  

All enzymes are proteins. Simple enzymes are made up of protein only, while holoenzymes are made up of apoenzymes (protein part) and prosthetic group (non-protein part).

• The transfer of lipid molecules from one side of the bilayer to the other is the flip flop movement.
• Lipids can flip flop at times but proteins never have this type of movement.
• The enzymes are concerned with the enzymatic activity of the membrane.