Maintaining a Balance

Essay by itsme_noelHigh School, 12th grade January 2008

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Maintaining a Balance1. Most organisms are active in a limited temperature range1.1. identify the role of enzymes in metabolism, describe their chemical compositions and use a simple model to describe their specificity on substratesRole of Enzymes: enzymes are organic catalysts which cause chemical reactions to proceed which could not normally occur under normal conditions found in cells. For example:Sucrosesucrase glucose + fructose(substrate) (enzyme)The enzyme sucrase is very specific and will break down only sucrose molecules.

Maltose maltaseglucose + glucose(substrate)(enzyme)Cattle, kangaroos, sheep, etc., consume lots of cellulose.

cellulosecellulose glucosefats (lipids) lipase fatty acids + glycerolprotein protease amino acidsTheir role in metabolism: metabolism is the sum of all reactions taking place inside a cell. Enzymes role in metabolism is to maintain the rate of chemical activity. The catalyst can be reused many times.

The chemical composition: Enzymes are proteins. There are 20 different types of amino acids. The type of amino acid, the number and the arrangement of these amino acids in a 3-D shape structure gives the protein a particular shape which makes it specific to only one type of reaction.

Lock and key method: The active site of the enzymes is shaped in such a way that the substrate molecules can be bound together causing a reaction to occur. The substrate is the key and the active site of the enzyme is referred to as the lock.

Induced fit model: In this model, if the substrate molecules do not fit into the active site, then the enzymes can slightly modify its active site to allow the substrate to fit into it. Once the molecules are joined together, the enzyme will return to its original shape.

1.2. identify the pH as a way of describing the acidity of a substanceIf you are given the pH of a substance, this indicates...