Topic 2 - Organisation Flashcards
(86 cards)
What is an tissue?
A group of similar cells working together to carry out a specific function.
What is an organ and give an example?
A group of different tissues that work together to perform a particular function.
The stomach.
What is an organ system and give an example.
A group of organs that work together to perform a particular function.
The digestive system.
What is an enzyme?
An enzyme is a biological catalyst.
They are basically large proteins made of large chains of amino acids.
What is an active site of an enzyme?
It is complementary to the substrate.
What happens if the substrate does not fit in the active site?
The reaction will not be catalysed.
Explain the lock and key model.
Scientists originally thought substrates fit perfectly into the active site like a key.
Explain the induced to fit model.
Scientists now know the enzyme changes shape slightly as it binds to the substrate.
The active site is complementary to the substrate.
What is the optimum temperature for enzymes to work?
37 degrees around body temperature.
How does temperature increase affect the functioning of enzymes?
At the start the temperature increases and so does the rate of reaction as all of the particles have more kinetic energy increasing collisions. However after about 37 degrees the rate of reaction decreases rapidly as the high temperature breaks the bonds holding the enzymes together. Then the active site starts to change shape. If it changes shape enough the enzyme will not be able to bind to the substrate this is called ‘denatured’.
What is the optimum pH for enzymes?
Mostly pH 7 but depends where they work such if they work in the stomach it would be like 2.
Write a method to describe the effect of pH on the rate of reaction of amylase and give the variables and how do you calculate the rate.
Independent variable - pH of the buffer solution.
Dependent variable - Rate of starch breakdown.
Control variables - Temperature of the reaction, concentration of amylase, concentration of starch, volume of solutions.
Set the water bath to 35 degrees and wait for the water to warm and place a test tube inside.
Then use a syringe to add 1 cm cubed of amylase solution and 1cm cubed of buffer solution into the test tube and wait 5 minutes.
Next use a different syringe to add 5cm cubes of starch solution to the boiling tube and immediately mix and start a stop watch.
Every 30 seconds take a little bit of your solution out with a pipette and drop it into the spotting tile with iodine. Repeat this until the iodine changes colour from blue - black to brown/orange and stop the stopwatch.
Repeat experiment with different buffer solutions with different pH.
Rate = 1000/time
Why do we need digestion for carbohydrates, proteins, and lipids?
As they are big molecules so have to be broken down into smaller pieces this is where enzymes are involved to be absorbed into our bloodstream.
How is starch absorbed into our blood stream?
Amylase breaks down starch into maltose.
Maltase breaks down maltose to glucose which is small enough to absorb.
How are proteins absorbed into our bloodstream?
Proteins are broken down by protease enzymes into amino acids.
How are lipids absorbed into our blood stream?
They are broken down by lipase enzymes into glycerol + fatty acids
Define digestion.
The process by which we break down large food molecules into smaller molecules. Such as starch into glucose.
Define absorption.
The process of which we absorb small molecules into the bloodstream.
What is the role of the teeth?
To physically break down the food by chewing which increases the surface area of the food therefore it is easier for enzymes to break it down.
What is the role of the salivary gland?
Releases saliva which contains the enzyme amylase which digests starch into maltose.
Where does the food go through after you swallow it?
The Oesophagus.
What is the role of the stomach?
Contracts muscular walls to churn food.
Produces pepsin which is a protease enzyme.
Produces hydrochloric acid - kills bacteria and provides correct pH of pepsin enzyme.
What enzymes are produced in the pancreas and what happens to them?
All of them
Amylase
Protease
Lipase
They are then released into the small intestine.
Where is bile produced and where is it stored and what is the role of it?
Bile is produced in the liver and stored in the Gallbladder.
The role of bile is neutralise stomach acid (bile is alkaline)
It also emulsifies lipids. (breaks large bits of fat and oil into tiny droplets) This gives the lipids a larger surface area for digestive enzymes to work on.
