4.1 Enzyme action Flashcards
Anabolic reactions
reactions that build up molecules
catabolic reactions
reactions that break down molecules
Metabolism
a chemical reaction involved in maintaining the living state of the cells in an organism
-> combination of anabolic and catabolic reactions
Catalyst
a substance that speeds up reactions without changing the produced substance
Metabolic pathway
sequence of enzyme controlled reactions
Specificity
can only catalyse particular reactions
Substrate:
a substance that binds to the enzyme
Product
molecules formed by enzymes
What are enzymes (5 points)
Enzymes are biological catalyst that help speed up metabolic reactions
They remain unchanged at the end of reactions and can be used again
Can catalyse large numbers of substrates into products
Increase a rate of reaction by lowering its activation energy
Can be intracellular or extra cellular
Can be prevented from working by molecules called enzyme inhibitors
V max
maximum initial velocity or rate of enzyme-catalysed reaction
–> affected by temp, pressure, pH
What is necessary for a reaction to occur?
Molecules move and collide randomly but molecules must collide in the RIGHT ORIENTATION
–> High temp & pressure increases the speed of molecules (more kinetic energy)
–>
Lock and key hypothesis
The enzyme is a lock that only a specific key aka substrate can bind to
–> due to specificity of active site
This forms an enzyme substrate complex.
–> If product/s are formed then it is the enzyme-product complex
Substrate is held due to the R groups within the active site of the enzyme being able to form interactions with the substrate, forming temporary bonds
Lock and key hypothesis
The enzyme is a lock that only a specific key aka substrate can bind to
–> due to specificity of active site
This forms an enzyme substrate complex.
–> If product/s are formed then it is the enzyme-product complex
Substrate is held due to the R groups within the active site of the enzyme being able to form interactions with the substrate, forming temporary bonds
Intracellular (inside cells) enzymes
essential role in cells and organisms
–> synthesis of polymers from monomers e.g. polysaccharides from glucose
Hydrogen peroxide is broken down by catalase to oxygen and water, prventing accumulation
What do all reactions need and what form does that substance take?
All reactions need substrates (raw materials which are constantly supplied to cell in demand
–> Nutrients are made in the form of polymers e.g. proteins or polysaccharides
–> large molecules cannot enter cells directly so they must be broken down first
Extracellular (outside cells) enzymes
Enzymes are released from cells to break down large nutrient molecules into smaller molecules during digestion
–> both single celled and multicellular organisms rely on these enzymes to make use of polymers for nutrition
How do single celled organisms like bacteria and yeast use extra cellular enzymes
they release enzymes into their immediate environment
==> breaks down larger molecules like proteins and smaller molecules are produced like amino acids and glucose (which are then absorbed by cells)
How do multicellular organisms use extra cellular enzymes? e.g. humans
Even though food is eaten to gain nutrients, larger molecules still need to be further digested to fit into blood stream
–> in humans, enzymes like amylase and trypsin are extracellular
What is amylase and trypsin?
Amylase produced in pancreas and saliva-producing gland
–> breaks down complex carbs into simpler ones, which are ultimately broken down into glucose
Trypsin is produced by the pancreas and helps break down dietary proteins in digestive tract
Digestion of starch
Starts in mouth and continues to small intestine
1. Starch polymers are partially broken into maltose, disaccharide (done by amylase)
2. Maltose is then broken down into glucose (maltase, produced in small intestine)
