Biology Hsc Notes

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* A reactant in an enzyme-catalyzed reaction is called a substrate. The area of the enzyme that binds to the substrate is called the active site - where the action takes place.

* Cofactors and coenzymes are small molecules or ions that help enzymes to act.

HSC Biology Notes – Hugh Phillips
Maintaining a Balance
1.Most organisms are active in a limited temperature range:
Identify the role of enzymes in metabolism, describe their chemical composition and use a simple model to describe their specificity on substrates: Enzymes: Break the molecule bonds, but need energy to do so – ACTIVATION ENERGY (required to start chemical reaction). In a reaction with an enzyme, the molecules require lower activation energy. * The role of enzymes in metabolism

* Metabolism refers to all the chemical reactions occurring in organisms. * Enzymes are biological catalysts for all processes going on inside cells. * They can be used over and over again.

* They increase the rate of chemical reactions at lower temps and decrease the activation energy needed for metabolic reactions to occur. * Chemical composition of enzymes
* Enzymes are made up of proteins.
* I.e. long chains of Amino Acids.
* When enzymes denature the cross linkage bonds are broken, protein loses its normal shape and becomes inactive. * The substrate is the molecules, which the enzyme acts upon. * Enzyme specificity on substrates

* The Chemical on which an enzyme acts is called a substrate * The active site (enzyme that binds to the substrate) of the enzyme fits the substrate like a lock and key * They are highly specific in their actions; this means that each enzyme acts on one substrate only The Lock and Key Model: states that the substrate fits exactly into the active site of the enzyme like a key fits a lock. Assumes the enzyme has a rigid and unchanging shape.

The Induced Fit Model: states that the binding of the substrate to the enzyme ‘induces’ a temporary change in the shape of the enzyme. The new shape of the enzyme better accommodates the shape of the substrate and a reaction occurs. Identify the pH as a way of describing the acidity of a substance: * The substance that makes a solution acidic is hydrogen ions * pH is a measure of the alkalinity or the acidity of a substance * pH is a measure of the concentration of hydrogen ions per liter of solution * The pH scale→

* 0-14
* pH of 7 is neutral (pure distilled water)
* above 7 is alkaline (Basic)
* below 7 is acidic

* A reactant in an enzyme-catalyzed reaction is called a substrate. The area of the enzyme that binds to the substrate is called the active site - where the action takes place.

* Cofactors and coenzymes are small molecules or ions that help enzymes to act.

HSC Biology Notes – Hugh Phillips
Maintaining a Balance
1.Most organisms are active in a limited temperature range:
Identify the role of enzymes in metabolism, describe their chemical composition and use a simple model to describe their specificity on substrates: Enzymes: Break the molecule bonds, but need energy to do so – ACTIVATION ENERGY (required to start chemical reaction). In a reaction with an enzyme, the molecules require lower activation energy. * The role of enzymes in metabolism

* Metabolism refers to all the chemical reactions occurring in organisms. * Enzymes are biological catalysts for all processes going on inside cells. * They can be used over and over again.

* They increase the rate of chemical reactions at lower temps and decrease the activation energy needed for metabolic reactions to occur. * Chemical composition of enzymes
* Enzymes are made up of proteins.
* I.e. long chains of Amino Acids.
* When enzymes denature the cross linkage bonds are broken, protein loses its normal shape and becomes inactive. * The substrate is the...
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