Factors Affecting Rate Of Enzyme Reaction - pH, Temperature, Substrate Concentration, Enzyme Concentration

Factors affecting rate of enzyme reaction are pH, temperature, substrate concentration and enzyme concentration.

Effect of pH on enzyme reaction

Enzymes are active within narrow range of pH. At optimum pH, the rate of enzyme reaction reaches its maximum. Pepsin works best in acidic environment, amylase works best in neutral environment and trypsin works best in alkaline environment.

Effect of temperature on enzyme reaction

At low temperature, the rate of enzyme reaction is low because enzymes are inactive. As temperature increases, the rate of enzyme reaction increases. At optimum temperature of 370C, the rate of enzyme reaction reaches its maximum. At high temperature, the rate of enzyme reaction decreases. At temperature above 600C, enzymes are denatured.

Effect of substrate concentration on enzyme reaction

As substrate concentration increases, the rate of enzyme reaction increases to a certain level, whereby the enzyme concentration becomes the limiting factor.

Effect of enzyme concentration on enzyme reaction

As enzyme concentration increases, the rate of enzyme reaction increases to a certain level, whereby the substrate concentration becomes the limiting factor.

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Effects Of Osmosis On Animal And Plant Cells - Hypotonic Solution, Isotonic Solution, Hypertonic Solution

Hypotonic solution is a solution which has higher water potential than another solution.

Isotonic solution is a solution which has equal water potential as another solution.

Hypertonic solution is a solution which has lower water potential than another solution.

Effects of osmosis on animal cells

In hypotonic solution, more water molecules entering the cells than leaving the cells. The cells swell and burst (lysed).

In isotonic solution, water molecules entering and leaving the cells at equal amount. The size and shape of cells remain the same.

In hypertonic solution, more water molecules leaving the cells than entering the cells. The cells shrink (crenated).

Effects of osmosis on plant cells

In hypotonic solution, more water molecules entering the cells than leaving the cells. The cells swell and become turgid as the cell walls prevent the cells from bursting.

In isotonic solution, water molecules entering and leaving the cells at equal amount. The size and shape of cells remain the same.

In hypertonic solution, more water molecules leaving the cells than entering the cells. The cytoplasm shrinks away from cell walls (plasmolysed) and the cells become flaccid.

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Four Structural Levels Of Proteins - Primary, Secondary, Tertiary, Quaternary Structures

The four structural levels of proteins are primary structure, secondary structure, tertiary structure and quaternary structure.

Primary structure

Primary structure is the number and sequence of amino acids or peptides. An example of primary structure is a polypeptide.

Secondary structure

Secondary structure involves coiling of a polypeptide chain in a helical or parallel structure which is stabilised by hydrogen bonds. An example of secondary structure is a fibrous protein.

Tertiary structure

Tertiary structure involves folding of polypeptide into a more compact, globular structure which is stabilised by disulphide, ionic and hydrogen bonds. An example of tertiary structure is a globular protein.

Quaternary structure

Quaternary structure involves combining two or more polypeptide chains to form a larger, more complex molecule which is stabilised by disulphide, ionic and hydrogen bonds. Non protein molecules are usually integrated onto this complex, forming a conjugated protein. An example of quaternary structure is haemoglobin.

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