Types of Proteins: Proteins are made of long chains of amino acids. Each protein has its own number and sequence and number of amino acids, which results in differently shaped molecules, which have different functions. The function of proteins includes: Structural – used to build cells and tissues (limited to collagen) Hormones – carry messages to control a reaction (limited to insulin) Carrier Molecules – self explanatory (limited to haemoglobin which carries oxygen) Enzymes Enzymes: Describe enzymes as: Biological catalysts (speed up reactions in the body) Catalysing chemical reactions occurring in living cells: respiration, photosynthesis, protein synthesis Having a high specificity for their substrate. The substrate molecule fits into the active site like a key into a lock: This is why enzymes are described as working in a ‘lock and key mechanism’ It also explains why each enzyme can only work with a certain substrate. This is called specificity and happens because the substrate must be the right shape to fit into the active site Enzymes work best at a particular temperature and pH. This is called optimum and any change away from either optimum will slow the reaction down. When explaining how enzyme activity is affected by pH and temperature, include: lower collision rates at low temperatures denaturing at extremes of pH and high temperatures denaturing as an irreversible change inhibiting enzyme function denaturing changing the shape of the active site It’s possible to work out how temperature affects the rate of reaction by calculating the temperature coefficient, called Q10. This is done for a 10oC change in temperature using:
Types of Proteins: Proteins are made of long chains of amino acids. Each protein has its own number and sequence and number of amino acids, which results in differently shaped molecules, which have different functions. The function of proteins includes: Structural – used to build cells and tissues (limited to collagen) Hormones – carry messages to control a reaction (limited to insulin) Carrier Molecules – self explanatory (limited to haemoglobin which carries oxygen) Enzymes Enzymes: Describe enzymes as: Biological catalysts (speed up reactions in the body) Catalysing chemical reactions occurring in living cells: respiration, photosynthesis, protein synthesis Having a high specificity for their substrate. The substrate molecule fits into the active site like a key into a lock: This is why enzymes are described as working in a ‘lock and key mechanism’ It also explains why each enzyme can only work with a certain substrate. This is called specificity and happens because the substrate must be the right shape to fit into the active site Enzymes work best at a particular temperature and pH. This is called optimum and any change away from either optimum will slow the reaction down. When explaining how enzyme activity is affected by pH and temperature, include: lower collision rates at low temperatures denaturing at extremes of pH and high temperatures denaturing as an irreversible change inhibiting enzyme function denaturing changing the shape of the active site It’s possible to work out how temperature affects the rate of reaction by calculating the temperature coefficient, called Q10. This is done for a 10oC change in temperature using:
Proteins-and-Mutations.docx