Hsc Biology, Maintaining a Balance & Blueprint of Life, Theory Dotpoint Notes
Maintaining a Balance
Enzymes
1.1 Identify the role of enzymes in metabolism, describe their chemical composition and use a simple model to describe their specificity on substrates
Enzymes are biological catalysts, meaning they are organic and speed up a chemical reaction without taking part in it. This means it has a vital role in metabolism where it ensures that the chemical reactions that make up metabolism can function fast enough to sustain life by lowering activation energy. Metabolism consists of two types of reactions: Anabolic (Build up of smaller molecules into larger ones) and Catabolic (Break down of larger molecules into smaller ones)
Enzymes are proteins. They are a polypeptide chain of amino acids which are heavily folded to form a three dimensional shape. Within this structure is an active site, typically composed of 3-4 amino acids which are areas that substrates will bind to and catalyse chemical reactions.
There are two theories to describe enzyme action and specificity. The original theory, the lock and key theory explains enzyme action by likening it to a lock and key where only a specific substrate will unlock a specific active site. The current theory – the induced fit theory assumes that the substrate plays a role in determining the final shape of the enzyme substrate complex and the active site is more flexible. The substrate enters and binds to the enzyme to shape the active site to properly align the complex for a reaction to take place.
1.2 Identify pH as a way of describing the acidity of a substrate
pH is a measure of the acidity of a substance. It is measured on a scale from 0-14. * pH of 7 is neutral * pH under 7 is acidic * pH over 7 is alkaline/basic
Enzymes usually function best at a specific temperature and pH range. If these are too extreme the enzyme will denature.
Homeostasis
1.3 Explain why the maintenance of a constant internal environment is important for optimal metabolic efficiency
Enzymes
1.1 Identify the role of enzymes in metabolism, describe their chemical composition and use a simple model to describe their specificity on substrates
Enzymes are biological catalysts, meaning they are organic and speed up a chemical reaction without taking part in it. This means it has a vital role in metabolism where it ensures that the chemical reactions that make up metabolism can function fast enough to sustain life by lowering activation energy. Metabolism consists of two types of reactions: Anabolic (Build up of smaller molecules into larger ones) and Catabolic (Break down of larger molecules into smaller ones)
Enzymes are proteins. They are a polypeptide chain of amino acids which are heavily folded to form a three dimensional shape. Within this structure is an active site, typically composed of 3-4 amino acids which are areas that substrates will bind to and catalyse chemical reactions.
There are two theories to describe enzyme action and specificity. The original theory, the lock and key theory explains enzyme action by likening it to a lock and key where only a specific substrate will unlock a specific active site. The current theory – the induced fit theory assumes that the substrate plays a role in determining the final shape of the enzyme substrate complex and the active site is more flexible. The substrate enters and binds to the enzyme to shape the active site to properly align the complex for a reaction to take place.
1.2 Identify pH as a way of describing the acidity of a substrate
pH is a measure of the acidity of a substance. It is measured on a scale from 0-14. * pH of 7 is neutral * pH under 7 is acidic * pH over 7 is alkaline/basic
Enzymes usually function best at a specific temperature and pH range. If these are too extreme the enzyme will denature.
Homeostasis
1.3 Explain why the maintenance of a constant internal environment is important for optimal metabolic efficiency