Topic 2 - Organisation Flashcards
What is a tissue
A group of similar cells that work together to carry out a particular function
What are muscular tissues functions in mammals
They contract to move whatever it’s attached to
What are glandular tissues functions in mammals
They secrete chemicals like enzymes and hormones
What are epithelial cells in mammals
They cover some parts of the body, like inside and outside of the stomahc
What do muscular tissues do in the stomach
Move the stomach wall to churn up the food
What do glandular tissues do in the stomach
Make digestive juices to digest food
What organs is the digestive system made up from
Mouth, Oesophagus, stomach, small intestine, large intestine, liver and glands
What does the stomach do in the digestive system
-Pummels food with muscular walls
-Produces the protease enzyme pepsin
-Produces hydrochloric to give the right pH for the protease to work and it kills bacteria
What does the liver do in the digestive system
Produces bile which emulsifies fat and neutralises stomach acid
What does the small intestine do in the digestive system
-Absorbs soluble food molecules into the blood
-Produces lipase, protease and amylase
What does the large intestine do in the digestive system
Absorbs water from undigested food leaving faeces
What are enzymes
Large proteins that are made up of chains of amino acids that act as biological catalysts speeding up the useful chemical reactions in our body
What is the lock and key hypothesis
Each enzyme has an active site of a specific shape meaning usually only one type of substrate can fit into the active site, so enzymes are highly specific. When the substrate fits into the active site the enzymes catalyses the reaction and the products are then released. The active remains unchanged so it can be used again.
How does temperature affect the rate of an enzyme catalysed reaction
A higher temperature increases the rate at first, but if it gets too hot some of the bonds holding the enzyme together break changing the shape of the active site so the substrate won’t fit anymore. This is where an enzyme is denatured.
What is optimum temperature for enzymes
The temperature at which enzymes work best at
How does pH affect enzymes
If the pH is too high or too low it inferred with the bonds holding the enzymes together so the active site shape changes and the enzyme is denatured
What is optimum pH and what is it generally
The optimum pH of an enzyme reaction is the pH level an enzyme works best at and it’s usually pH 7
Give an example of an enzyme that doesn’t have an optimum pH of 7
Pepsin is an enzyme used to break down proteins in the stomach but it works best at a pH of 2, in acidic conditions.
Outline how to investigate the effect of pH on enzyme activity
- Put a drop of iodine into each well of a spotting tile
- Put a beaker of water on a bunsen burner and tripod and heat until it is 35° using a thermometer and try keep the temperature constant
- Use a syringe to add 1cm of amylase solution and 1cm of buffer solution with a pH of 5 to a boiling tube, then using test tube holders put the tube into the beaker of water and wait five minutes
- Using a different syringe put 5cm of starch solution to the boiling tube
- Mix the contents of the boiling tube and start a stop watch
- Use continuous sampling to record how long it takes for the amylase to break down all of the starch by dropping the solution into a well using a pipette every 30 seconds and when the iodine remains brown/orange the starch is broken down
- Repeat with buffer solutions of different pHs to see how quickly the starch is broken down
- Remember to control any variables each time (e.g. concentration and volume of amylase to make it a fair test.
What is the formula for rate of reaction
Rate = 1000/time
How to calculate the rate of reaction of an experiment which measures how much something changes over time
you calculate it by diving the amount it has changed by the time taken
What product do digested proteins make, what enzyme breaks them down and where
They make amino acids when broken down by protease in either the stomach, small intestine and pancreas
What product do digested carbohydrates/starch make, what enzyme breaks them down and where
They make sugar/glucose when they are broken down by carbohydrase (e.g amylase) in either mouth, pancreas, small intestine.
What product do digested lipids make, what enzyme breaks them down and where
They make glycerol and fatty acids when lipase breaks them down in the pancreas and small intestine
What is biles job in the digestion system
-As it is an alkaline it neutralises acid and makes the conditions in the small intestine alkaline so the enzymes can work properly
-Emulsifies fat so it is broken down into small drops so the surface area is larger and it is easier for lipase to work on so digestion is faster.
What is the job of salivary glands in the digestive system
These produce amylase enzyme in the saliva
What is the job of the gall bladder
It stores bile before it’s released into the small intestine
What is the job of the pancreas in the digestive system
Produces protease, amylase and lipase and releases them into the small intestine
How do you start each food test before adding the solutions (digestive system)
-Get a piece of food and break it up using a pestle and mortar
-Transfer it into a beaker and add some distilled water
-Give the mixture a good stir with a glass rod to dissolve some of the food
-Filter it using a funnel lined with filter paper to get rid of the solid bits of food
How to test for sugars
-Put a 5cm of a food sample into a test tube
-Prepare a water bath so that’s so that it’s set to 75°C
-Add some Benedict’s solution the test tube using a pipette
-Place the test tube in the water bath using a test tube holder and leave it in there for 5 minutes and make sure the tube is pointing away for you.
-If it contains sugar it will turn from blue to yellow/red depending how much sugar there is
How to test for starch
-Transfer 5cm of your food sample to a test tube
-Then add a few drops of iodine solution and gently shake the test tube to mix the contents
-If it contains starch it will change from browny-orange to blue/black
How to test for proteins
-Transfer 2cm of your food sample to a test tube
-Add 2cm of biuret solution to the sample and max by gently shaking it
-If the sample contains protein, the solution will change from blue to purple
How to test for lipids
-Prepare a sample of the food you’re testing and transfer 5cm
-Use pipette to add 3 drops of Sudan III stain solution to the test tube and gently shake the tube
-Sudan III stain solution stains lipids so if the sample contains lipids the mixture will separate out into two layers and the top will be bright red. If no lipids no separate will form.
What happens to air when you breathe (outline)
It goes in through the trachea this splits two tubes called bronchi one going to each lung
The bronchi split progressively smaller tubes tubes called bronchioles
The bronchioles finally end at small bags called alveoli where the gas exchange takes place
How do the alveoli carry out gas exchange in the body
-They are surrounded by a network of blood capillaries and the blood passing through has just returned to the lungs from the rest of the body so it contains lots of CO2 and very little oxygen.
-The oxygen diffuses out of the alveoli into the blood and the CO2 diffuses from the blood into the alveoli to be breathed out
What happens to oxygen and carbon after gas exchange
When the blood reaches body cells the oxygen diffuses out from the red blood cells into the body cells
At the same time carbon dioxide diffuses out of the body cells into the blood where it’s the n carried back to the lungs
Outline the double circulatory system system
-The right ventricle pumps deoxygenated blood to the lungs to take in oxygen the blood the returns to the heart
-The left ventricle pumps oxygenated blood around all the other organs of the body. The blood gives up it’s oxygen at the body cells and the deoxygenated blood returns to heart to be pumped out to the lungs again.
What do valves do in the heart
They make sure blood flows in the right direction - they prevent it flowing backwards.
How does the heart use its four chambers to pump blood around
-Blood flows into the two atria from the vena cava and pulmonary veins
-Then they go down into the ventricles which contract forcing the blood into pulmonary artery aorta , and out of the heart
-They flow to organs through the arteries and return through veins
-The atria fill again and the whole cycle
How does the heart receive its own supply of oxygenated blood
Coronary arteries branch off the aorta and surround the heart, making sure that it gets all the oxygenated blood it needs