1. Key Concepts: Enzymes Flashcards
What are Enzymes?
Catalysts produced by living things
Reactions inside living things need to be controlled carefully - to get right amount of substances
Raising temp - reaction happen more quickly - this speeds up useful reactions but also unwanted ones
Living things produce enzymes - biological catalysts
Enzymes reduce need for high temperatures - enzymes only needed to speed up useful chemical reactions in body
What do Enzymes have so can Catalyse Reactions?
Special shapes
Chemical reactions - either things being pulled apart or joined together
Substrate - molecule changed in reaction
Usually work with one substrate - high specificity for their substrate
For enzyme to work - substrate has to fit in the active site - if shape doesn’t match - reaction won’t be catalysed - “lock and key mechanism”
What are the things that affect the Rate of Reaction?
Temperature
PH
Substrate concentration
How does Temperature affect the Rate of Reaction?
Changing temperature changes rate of enzyme catalysed reaction
Temperature increased rate of reaction at first - once it gets too hot some of the bonds holding enzyme together break - changes shape of active site - substrate wont fit anymore - enzyme becomes denatured
All enzymes said to have an optimum temp
How does pH affect the Rate of Reaction?
If PH to high or low it interferes with bonds holding enzyme together - changes shape of active site - denatures
Optimum PH is usually PH 7
How does Substrate Concentration affect Rate of Reaction?
Higher substrate concentration - faster the reaction - because more likely enzyme will meet up and react with a substrate molecule
What is a Practical that can be used to Investigate effect of pH on Enzyme Activity?
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What is the rate of reaction?
Rate is a measure how much something changes over time
Rate of reaction = change / time
What do Enzymes do to Big Molecules?
Proteins, lipids and some carbohydrates are big molecules
Organism able to break them down into smaller components - used for growth and other life processes
What are examples of Big Molecules?
Proteins
Lipids
Carbohydrates
What type of Enzyme break down Carbohydrates?
Carbohydrases convert carbohydrates into simple sugars e.g. Amylase breaks down starch
What type of Enzymes break down Proteins?
Proteases covert proteins into amino acids
What type of Enzymes break down Lipids?
Lipases convert lipids into glycerol and fatty acids
When lipids are broken down - fatty acids will lower the PH of the solution they are in
How do some Enzymes Join Molecules Together?
Organisms - have to be able to synthesise carbohydrates, proteins and lipids from their smaller compounds
Carbohydrates - synthesised by joining together simple sugars
Proteins are made by joining amino acids together - enzymes catalyse the reactions needed to do this
Lots of enzymes involved in synthesis of lipids from fatty acids and glycerol
