Enzymes Flashcards
What is differentiation
The process of which cells become specialised for a specific job
What do large multicellular organisms contain
Different organ systems inside of them for exchanging and transporting material
What is a tissue
A group of cells that work together to carry out a particular function
Examples of tissues and what they do
- muscular tissue - contracts to move whatever it’s attached to
- glandular tissue - makes and secretes chemicals like enzymes and hormones
- epithelial tissue - covers some parts of it he body
What is an organ
A group of different tissues that work together to perform a certain function
What tissues is a stomach made up of
- muscular tissue - which moves the stomach wall to churn up the food
- glandular tissue - which makes digestive juices to digest food
- epithelial tissue - which covers the outside and inside if the stomach
What is an organ system
A group of organs working together to perform a particular function
What organs is the digestive system made out of
- glands - which produces digestive juices
- stomach and small intestine- which digest food
- liver- which produces bile
- small intestine- which absorbs soluble food molecules
- large intestine- which absorbs water from undigested food, leaving faeces
Cons of speeding up a reaction by raising the temperature
- would speed up unwanted reactions
- there a limit on how much you can raise the temperature without damaging cells
Advantages of enzymes
- reduces the need for high temperatures
- they only speed up useful chemical reactions in the body
What is a catalyst
A substance which increases the speed of a reaction without being changed or used up in a reaction
What are enzymes
They are proteins that act as a biological catalyst
lock and key model explanation
1) substrate collides with the active site of enzyme and becomes attached
2) the active site has a complementary shape to the substrate and once the substrate binds to the enzyme it forms an enzyme substrate complex
3) the enzyme catalyses the reaction and breaks down the substrate
4) the reaction takes place rapidly and products are released from the surface of the enzyme
5) the enzyme molecule is unchanged an can be used again
What happens if the substrate does not match the enzymes active site
The reaction won’t be catalysed
What is the induced fit model of enzyme action
It’s a more accurate model of the enzyme action as the active site of the enzyme changes shape a little as the substrate binds to it to get a tighter fit
What do chemical reactions involve
Things either being split apart or joined together
How do enzymes speed up reactions
- breaking down larger molecules into smaller ones
- building larger molecules into smaller ones
- changing one molecule to another
What factors effect enzyme action
- temperature
- pH
How does temperature effect enzyme action
- changing temperature changes the rate of an enzyme catalysed reaction
- a high temperature increases the rate at first but after around 40 degrees the binds holding the enzyme together break, this changes the shape of the enzymes active site so the substrate won’t fit anymore so other enzyme is denatured and can no longer act as a catalyst
- all enzymes have an optimum temperature they work best at
How does pH effect enzyme action
- if the pH is too high or low it can affect the binds that hold the enzymes together, this changes the shape of the active site and denatures the enzyme
How to calculate the rate of the reaction
1000/ time OR the amount a substance has changed/ time
Effect in pH on enzyme activity REQUIRED PRACTICAL
1) place one drop of iodine solution into each well of a spotting tile
2) take 3 test tubes in test tube 1 add 2cm3 of starch solution in test tube 2 add 2cm3 of amylase solution in test tube 3 add 2cm3 of a pH 5 buffer solution (this controls the pH)
3) place all the test tubes in a water bath at 30 degrees no leave them for 10min to allow the solutions to reach the correct temperature
4) combine the three solutions into one test tube and mix with a stirring rod and return to the test then test tube to the water bath and start a stopwatch
5) after 30s use the stirring rod to transfer 1 drop of solution to quell in the spotting tile which contains iodine
6) the iodine should turn blue black to show that starch is present
7) we take a sample every 30 seconds and continue until the iodine remains orange, when the iodine remains orange tells us that starch is no longer present and the reaction has completed, and we record the time for this in our results
8) repeat the experiment several times using different pH buffers
Anomalies of REQUIRED PRACTICAL of the effect on pH
- we are only taking samples every 30 seconds, this means that we only have an approximate time for the reaction to complete, we can improve this by taking samples every 10 seconds
- we are looking for the time when iodine does not go blue black and this is not always obvious, as the colour change tends to be gradual as some wells can have a small amount of blue black mixed with orange, you can improve this by getting several people to loot at the toe and decide whether the reaction is completes
Examples of large molecules
- starch
- proteins
- fats
What do digestive enzymes do to big molecules
- they break them down into smaller ones e.g sugars, amino acids, glycerol and fatty acts these smaller, soluble molecules can pass through the walls of the digestive system allowing them to be absorbed into the blood stream
What chemicals are carbohydrates made form
Carbon, hydrogen and oxygen
