B2 - Organisation Flashcards
Large multicellular organisms are made up of what?
Organ systems
Talk about these types of tissues
a) Muscular tissue
b) Glandular tissue
c) Epithelial tissue
a) it contracts (shortens) to move whatever it’s attached to
b) it makes and secretes chemicals like enzymes and hormones
c) it covers some parts of the body, such as the inside of the gut
d) Tissues you cry into, ha
e) Tissue, by Imitiaz Dharkah
What is the definition of a tissue?
A group of similar cells that work together to carry out a particular function
What tissues is the stomach made of and why?
Muscular tissue - which moves the stomach and churns up the food
Glandular tissue - makes digestive juices to digest food
Epithelial tissue - which covers the outside and inside of the stomach
What is an organ?
A group of different tissues that work together to perform a certain function
What is an organ system?
A group of organs working together to perform a particular function
What organs is the digestive system made of?
Glands (pancreas & salivary glands for example) - produce digestive juices to digest food
The stomach & small intestine - digest food
Liver - produces bile
Small intestine - absorbs soluble food molecules
Large intestine - which absorbs water from undigested food, leaving faeces (ha, poo)
What are organisms?
Organ systems working together
What is the function of the digestive system?
To break down and absorb food
Chemical reactions are what make us work, but what makes them work?
Enzymes
What are enzymes?
Catalysts produced by living things - biological catalysts
A catalyst is a substance which increases the speed of a reaction by lowering the activation energy, without being changed or used up in the reaction
If increasing the temperature can increase the rate of reactions anywhere including in the body, why does our body use enzymes instead of focusing on being warm?
Because it would increase the rates of reactions of unwanted reactions too
Also, there’s a limit to how far you can raise the temperature inside a living creature before its cells start getting damaged
Using enzymes mean that they only can speed up the useful reactions that our bodies want
What are enzymes made of?
Large proteins, which are made from long chains of amino acids
These chains are folded into unique shapes, which enzymes need to do their jobs
Why do enzymes have special shapes?
So they can catalyse reactions - its substrate has a specific shape, so the enzyme needs to match it by having a specific shape too
What’s a substrate?
The substance an enzyme acts upon (protein, carbohydrates, lipids, etc)
Talk about the lock and key mechanism
Enzymes have an active site, which the only substrate it breaks down fits into
If the substrate doesn’t fit into the active site, the reaction won’t be catalysed
Once the correct substrate binds to the active site of the enzyme, it speeds up the reaction of the substrate into becoming its products
What is the induced fit model of enzyme action?
Because in reality the lock and key mechanism doesn’t completely work - the active site changes shape a little as the substrate binds it to get a tighter fit
What happens if enzymes don’t have the right temperature and pH?
Too low temp - the reaction is slower than it could be
Too high temp - the active site denatures (some bonds holding the enzyme together break), so the substrate can no longer fit into the active site, so the reaction can’t be catalysed
Too extreme pH - the active site denatures
What is the optimum pH and temperature of an enzyme?
pH optimum depends on the enzyme, but temperature is 37 degrees
Often the pH is 7, but for pepsin (breaks down proteins in the stomach), it works best at pH 2 because teh stomach is VERY acidic
The rate of reaction of the enzyme is affected by what?
pH
Temperature
Probably more but who cares
How can you investigate the effect of pH on Enzyme activity? - rearrange these instructions of the practical
1) Next, use a different syringe to add 5 cm cubed of a starch solution to the boiling tube
2) Repeat the whole experiment with buffer solutions of different pH values to see how pH affects the time taken for the starch to be broken down
3) Use a syringe to add 1 cm cubed of amylase solution and 1 cm cubed of buffer solution with a pH of 5 to a boiling tube. Using the test tube holders, put the tube into the beaker of water and wait for 5 minutes
4) Put a drop of iodine solution into every well of a spotting tile, then leave to use later
5) Remember to control any variables each time (e.g. concentration and volume of amylase solution to make it a fair test
6) Use continuous sampling to record how long it takes for the amylase to break down all of the starch. To do this, use a dropping pipette to take a fresh sample from the boiling tube every 30 seconds, and put a drop into a new well. When the iodine solution remains browny-orange, starch is no longer present, and the reaction is complete
7) Immediately mix the contents of the boiling tube and start a stop watch
8) Place a Bunsen burner on a heat-proof mat, and a tripod and gauze over the Bunsen burner. Put a beaker of water on top of the tripod and heat the water until it is 35 Celsius (use a thermometer to measure the temperature) Try to keep the temperature of the water constant through the experiment, as it is a control variable
4) Put a drop of iodine solution into every well of a spotting tile, then leave to use later
8) Place a Bunsen burner on a heat-proof mat, and a tripod and gauze over the Bunsen burner. Put a beaker of water on top of the tripod and heat the water until it is 35 Celsius (use a thermometer to measure the temperature) Try to keep the temperature of the water constant through the experiment, as it is a control variable
3) Use a syringe to add 1 cm cubed of amylase solution and 1 cm cubed of buffer solution with a pH of 5 to a boiling tube. Using the test tube holders, put the tube into the beaker of water and wait for 5 minutes
1) Next, use a different syringe to add 5 cm cubed of a starch solution to the boiling tube
7) Immediately mix the contents of the boiling tube and start a stop watch
6) Use continuous sampling to record how long it takes for the amylase to break down all of the starch. To do this, use a dropping pipette to take a fresh sample from the boiling tube every 30 seconds, and put a drop into a new well. When the iodine solution remains browny-orange, starch is no longer present, and the reaction is complete
2) Repeat the whole experiment with buffer solutions of different pH values to see how pH affects the time taken for the starch to be broken down
5) Remember to control any variables each time (e.g. concentration and volume of amylase solution to make it a fair test
What solution is used to alter the pH of a solution?
A buffer solution
You can then use a pH meter to accurately measure the pH of the solutions
How do you calculate the rate of reaction when:
a) doing the experiment on investigating the effect of pH on enzyme activity
b) Normally, by measuring how much something changes over time
a) 1000 ÷ time - units = s to the power of -1
b) Change in product ÷ time
At pH 6, the time taken for amylase to break down all of the starch in a solution was 90 seconds. So what is the rate of reaction?
1000 ÷ 90 = 11 s^-1 (to 2 significant figures)
The enzyme catalase catalyses the breakdown of hydrogen peroxide into water and oxygen. During an investigation into the activity of catalase, 24 cm cubed of oxygen was released in 50 seconds. Calculate the rate of reaction, write your answer in cm^3 s^-1
Amount of product formed = change = 24 cm cubed
Rate of reaction = change ÷ time
24 ÷ 50 = 0.48 cm cubed s^-1
Enzymes used in digestion are produced by cells and then…
Released into the gut to mix with food
What do digestive enzymes break down?
Big molecules - starch, proteins and fats
Why do digestive enzymes have to break down big molecules?
Because they are too big to to pass through the walls of the digestive system. Then, the small, soluble molecules can pass easily through the walls of the digestive system, allowing them to be absorbed into the bloodstream then taken somewhere they’re needed
What does each enzyme break down, and into what?
a) Carbohydrases (like amylase)
b) Proteases (like pepsin in the stomach)
c) Lipases
a) Converts carbohydrates (starch is a carbohydrate) into simple sugars (e.g. glucose, maltose, dextrins)
b) Converts proteins into amino acids
c) Converts lipids (fats and oils) into glycerol and fatty acids
Where do each of the enzymes work?
Carbohydrase works in 3 places - the salivary glands (mouth), the pancreas, the small intestine
Protease works in 3 places - the stomach (pepsin there), the pancreas, the small intestine
Lipase works in 2 places - the pancreas, the small intestine
What does the body do with the products of digestion - simple sugars, amino acids, glycerol, fatty acids, etc
It makes good use of them - they can be used to make new carbohydrates, proteins and lipids. Some of the glucose (a sugar) that’s made is used in respiration
What does bile do?
It neutralises the stomach acid and emulsifies fats (so it breaks the fat into tiny droplets, giving a bigger surface area of fat for the lipase to work on - speeds up digestion).
The hydrochloric acid in the stomach makes the pH too acidic for enzymes in the small intestine. As bile is alkaline, it neutralises the acid and makes conditions alkaline, so the enzymes there can work as they work best in these alkaline conditions
Bile is created in the gall bladder and stored in the liver before it’s released into the small intestine. True or false?
False - it is created in the liver, stored in the gall bladder before it’s released into the small intestine
What are enzymes?
Biological catalysts (that speed up the rate of reaction, but aren’t used or depleted during the reactions)
Where are enzymes produced?
In the glands and in the gut lining
Talk through these different features of the digestive system, in the right order
1) Rectum
2) Salivary glands
3) Stomach
4) Gullet
5) Large intestine
6) Gall bladder
7) Pancreas
8) Liver
9) Small intestine
(number) means food doesn’t actually go there, but it’s still relevant
2) Salivary glands - produce amylase in the saliva
4) Gullet, or oesophagus - a pipe that channels the food into the…
3) Stomach - 1, pummels food with it’s muscular walls. 2, produces the protease enzyme pepsin. 3, it produces hydrochloric acid to kill bacteria & for the optimum pH of protease
(8) Liver - where bile is produced, which neutralises stomach acid and emulsifies fats
(6) Gall bladder - where bile is stored before released into small intestine
(7) Pancreas - produces protease, amylase and lipase enzymes, which are released into the small intestine
9) Small intestine - 1, produces protease, amylase and lipase to complete digestion. 2, where digested food is absorbed out of digestive system into blood
5) Large intestine - where excess water is absorbed from the food
1) Rectum - where the faeces (mainly made up of indigestible food) are stored before “they bid you a fond farewell through the anus”
Give 2 reasons as to why the stomach produces hydrochloric acid
To kill bacteria
To give the optimum pH for the protease enzyme pepsin (pH 2) in the stomach
What is the difference between the small intestine and the large intestine?
The small intestine produces protease, amylase and lipase to complete digestion. AND where digested food is absorbed out of digestive system into blood
The large intestine is where excess water is absorbed from the food
What is faeces?
Poo, ha. No, it’s mainly made up of indigestible food
How do you prepare a food sample so that you can conduct a food test on it later?
1) Get a piece of food then break it up with a mortar and pestle
2) Transfer the ground up food to a beaker and add some distilled water
3) Give the mixture a stir with a glass rod to dissolve some of the food
4) Filter the solution using a funnel lined with filter paper to get rid of the solid bit of food
What must you do before testing a piece of food for sugars or starch or whatnot?
Create a food sample:
1) Get a piece of food then break it up with a mortar and pestle
2) Transfer the ground up food to a beaker and add some distilled water
3) Give the mixture a stir with a glass rod to dissolve some of the food
4) Filter the solution using a funnel lined with filter paper to get rid of the solid bit of food
What are these testing for and the colours for:
a) Benedict’s solution
b) Sudan III stain solution
c) Iodine solution
d) Biuret solution
a) Sugars - goes from blue – green, yellow or brick red (depending on how much sugar is present)
b) Lipids - goes from white – a separate red layer on top
c) Starch - goes from browny-orange – black or blue black
d) Proteins - goes from blue – pink or purple
Which solution is used to test for and the colours:
a) Sugars
b) Lipids
c) Starch
d) Proteins
a) Benedict’s solution - goes from blue – green, yellow or brick red (depending on how much sugar is present)
b) Sudan III stain solution - goes from white – a separate red layer on top
c) Iodine solution - goes from browny-orange – black or blue black
d) Biuret solution - goes from blue – pink or purple
What is the test for sugars?
To test for reducing sugars (doesn’t detect non-reducing sugars, whatever that means)
1) Prepare a food sample and transfer 5cm^3 to a test tube
2) Prepare a water bath set to 75C
3) Add some BENEDICT’S solution to the test tube (about 10 drops) using a pipette
4) Place the test tube in the water bath using a test tube holder and leave it there for 5 minutes. Make sure the tube is pointing away from you
5) If the food sample contains a reducing sugar, the solution in the test tube will change from its natural blue colour to green, yellow or rick red, depending on how much sugar is in the food
What is the test for starch?
1) Make a food sample and transfer 5cm^3 of your sample to a test tube
2) Then add a few drops of IODINE solution and gently shake the test tube to mix the contents.
3) If the sample contains starch, the solution in the test tube will change from its natural browny-orange to black or blue-black
What is the test for proteins?
1) Prepare a food sample and transfer 2cm^3 of your sample to a test tube
2) Add 2cm^3 of BIURET solution to the sample and mix the contents of the tube by gently shaking it
3) If the food sample contains protein, the solution will change from blue to pink or purple
What is the test for lipids?
1) Prepare a food sample (but you don’t need to filter it). Then transfer about 5cm^3 into a test tube
2) Use a pipette to add 3 drops of SUDAN III stain solution to the test tube and gently shake it
3) Sudan III stain solution stains lipids. So:
4) If the sample contains lipids, teh mixture will separate out into 2 layers, teh top layer being bright red. If no lipids are present, no separate layer will form
What type of food are these? a) Biscuits b) Pasta c) Potatoes d) Cheese e) Meat f) Bread g) Cereal h) Milk i) Olive oil j) Rice k) Margarine (Starch, lipids, proteins or sugars)
a) Sugars
b) Starch
c) Starch
d) Proteins
e) Proteins
f) Sugars
g) Sugars
h) Lipids
i) Lipids
j) Starch
k) Lipids
Which of the food tests:
a) Need to be shook?
b) Create 2 layers if it’s present?
c) Needs to have the test tube pointed away from you, when left for around 5 minutes?
d) Need a food sample produced beforehand?
e) Need a food sample, but it doesn’t need to be filtered?
f) Start blue?
g) Need a water bath?
a) Iodine test for starch, Biuret test for proteins, Sudan III test for lipids
b) Sudan III test for lipids
c) Benedict’s test for sugars
d) All of them
e) Sudan III test for lipids
f) Benedict’s test for sugars, Biuret test for proteins
g) Benedict’s test for sugars
How do you spell the fancy test for proteins?
B I U R E T
Why do you need to get oxygen into your bloodstream?
To supply the cells for respiration
You also need to get rid of carbon dioxide form your blood, which happens in the lungs when you breathe in and out
Where are the lungs? How is is separated from the other part of the body?
In the thorax - (the top part of the body)
It is separated from the lower part of the body with the diapragm
Give a function of the ribcage
To protect the lungs
Where and what are pleural membranes?
They are thin layers which reduce friction between the chest walls and the lungs when breathing.
The 2 layers also have pleural fluid between them, which further reduces the friction
What helps reduce the friction between the lungs and the chest walls/ ribcage?
Pleural membranes (2 layers with pleural fluid between)
Talk through the lungs and pipes and gas exchange stuff
1) Trachea (wind pipe)
2) Splits into 2 tubes called Bronchi (to the 2 halves of the lungs)
3) Each broncus splits into Bronchioles
4) Finally end at small bags called alveoli, where gas exchange takes place
Where does gas exchange take place?
In the alveoli (in the lungs)
The trachea is where food gets taken into the stomach. True or false?
False - the trachea is where air gets taken to the lungs.
The oesophagus is where food gets taken to the stomach
The alveoli has a good supply of what?
Blood - they are surrounded by a network of capillaries
How does gas exchange occur in the alveoli? Fill the blanks:
The blood passing in the ____________ next to the ______ has just returned to the lungs from the rest of the body, so it contains lots of ______ _______* and little ______. The latter diffuses out of the alveolus (____ concentration) into the _____ (___ concentration).
The other gas* diffuses out of the blood (____ concentration) into the alveolus (___ concentration) to be breathed ___
Capillaries Alveoli Carbon dioxide Oxygen High Blood Low High Low Out
What happens when oxygenated blood reaches the body cells?
Oxygen is released, as the blood has a high concentration of oxygen but as the cells have a low concentration, so the oxygen diffuses into them
When on about breathing, what can you calculate?
The breathing rate per minute (number of breaths/ minutes)
What is the function of the circulatory system?
To carry food and oxygen to every cell in the body.
As well as delivering, it also collects waste products and takes them to where they can be removed from the body
Why is the heart described as a double circulatory system?
Because it is 2 circuits joined together by the heart - one going to the lungs, one going to the rest of the body.
Because it passes through the heart twice before it does a complete cycle
What controls your resting heart rate?
A group of cells in the right atrium wall that act as a pacemaker.
These cells produce an electrical impulse which spreads to the surrounding muscle cells, causing them to contract
