4.1 : Enzyne Action Flashcards
What are enzymes?
Biological catalysts. Globular proteins that interact with substrate molecules causing them to react at much faster rates without the need for harsh environment conditions.
What is metabolism ?
The sum of all the difference reactions and reaction pathways happening in a cell or an organism.
Define anabolic and catabolic reactions?
Anabolic : building up
Catabolic : breaking down
What is specificity?
The fact that each enzyme catalyses one biochemical reaction
What is activation energy?
The energy needed for a reaction to start
Describe the lock and key hypothesis
In the same way that only the right key will fit into a lock, only a specific substrate will ‘fit’ the active site of an enzyme.
When the substrate is bound to the active site an enzyme substrate complex is formed. The substrate or substrates then react and the product or products are formed in an enzyme product complex.
The products are then released, leaving the enzyme unchanged and able to take part in further reactions.
Th substrate is held in such a way by the enzyme that the right atom - groups are close enough to react. The R - groups within the active site of the enzyme will also interact with the substrate, forming temporary bonds. These put strain on the bonds within the substrate, which also helps the reaction along.
What is the induced fit hypothesis?
It suggests the active site of the enzyme changes shape slightly as the substrate enters.
The initial interaction between enzyme and substrate is quite weak, but these weak interactions rapidly induce changes in the enzymes tertiary structure that strengthen binding, putting strain on the substrate molecule.
This can weaken a particular bond or bonds in the substrate, therefore lowering the activation energy for the reaction.
What are intracellular enzymes?
Enzymes that act within cells e.g. Catalase
What is the role of catalase?
Hydrogen peroxide is a toxic product of many metabolic reactions.
Catalase ensures it is broken down to oxygen and water quickly, preventing its accumulation.
It is found in both plant and animal tissues.
What are extracellular enzymes ?
Enzymes that work outside the cells that made them eg ámalase, trypsin
What do extracellular enzymes do?
Break down large nutrient molecules into smaller nutrient molecules in the process of digestion so that they can enter cells through the cell surface membrane.
Describe enzymes in single called organisms
Single celled organisms like bacteria and yeast release enzymes unto this immediate environment.
The enzymes break down larger molecules, such as proteins, and the smaller molecules produced such as amino acids and glucose are then absorbed by the cells.
Describe the digestion of starch
Starch polymers are broken down into maltose ( disaccharide ) by amylase. Amylase is produced by the salivary glands ( into the mouth) and the pancreas ( into small intestine ).
Maltose is broken down into glucose ( monosaccharide ) by maltase ( small intestine)
How are proteins digested?
Trypsin is a protease - catalyses the digestion of proteins into smaller peptides, which can then be broken down further into amino acids by other protease.
Produced in the pancreas and repressed with the pancreatic juice into the small intestine.
Amino acids produced absorbed by cells lining digestive system and then absorbed into the bloodstream.
