Topic 2 - Organisation Flashcards
What does the circulatory system do?
Carries food and oxygen to every cell in the body. It also carries waste products to where they can be removed from the body
What is the circulatory system made up of?
The heart, blood vessels, and blood
What kind of circulatory system do humans have?
Humans have a double circulatory system. Which is 2 circuits joined together
What does the right ventricle do?
It pumps deoxygenated blood to the lungs. Oxygenated blood returns the the heart
What does the left ventricle do?
Pumps oxygenated blood around all the other organs of the body. All the body cells are given oxygen then deoxygenated blood returns to the heart to be pumped out to the lungs again.
What is the heart?
It’s a pumping organ that keeps the blood flowing around the body.
What is the heart made of?
The walls of the heart are mostly made of muscle tissue
Why does the heart have valves?
To make sure that blood flows in the right direction. They prevent it flowing backwards
What are the 4 chambers of the heart?
Right atrium, right ventricle, left atrium, left ventricle
How does the heart use it’s 4 chambers?
Blood flows into the atria via the vena cava and pulmonary vein
They contract pushing blood into ventricles
Ventricles contract forcing blood into pulmonary artery and aorta and out
What happens after the 4 chambers in the circulatory system?
The blood flows to the organs through arteries and returns through veins.
Atria fill again cycle restarts
How does the heart receive it’s own supply of oxygen?
Arteries called coronary arteries branch of the aorta and surround the heart, making sure it gets all the oxygenated blood it needs
cells are…
the basic building blocks that make up all living organisms
what is differentiation?
the process by which cells become specialised for a particular job. it occurs during the development of a multi cellular organism
what do specialised cells form?
cells form tissues, which form organs, which form organ systems
why do large multi cellular organisms have different systems inside them?
for exchanging and transporting materials
what is tissue?
a group of similar cells that work together to carry out a particular function. it can include more than one type of cell
examples of tissues in mammals:
muscular tissue
glandular tissue
epithelial tissue
what does muscular tissue do?
it contracts to move whatever its attached to
what does glandular tissue do?
it makes and secretes chemicals like enzymes and hormones
what does epithelial tissue do?
it covers some parts of the body e.g. the inside of the gut
what is an organ?
a group of different tissues that work together to perform a certain function
what tissues is the stomach made of?
muscular tissue
glandular tissue
epithelial tissue
what does muscular tissue do in the stomach?
it moves the stomach wall to churn up food
what does glandular tissue do in the stomach?
it makes digestive juices to digest food
what does epithelial tissue do in the stomach?
it covers the outside and the inside of the stomach
what is an organ system?
a group of organs working together to perform a particular function. e.g. the digestive system that breaks down and absorbs food. organ systems work together to make entire organisms
what organs make up the digestive system?
glands (pancreas and salivary glands) stomach small intestine liver large intestine
what happens inside of living things constantly?
living things have thousands of chemical reactions going on inside them all the time. these reactions need to be carefully controlled to get the right amount of substances
how can you usually make a reaction happen more quickly?
by raising the temperature
whats the problem with raising the temperature during a reaction?
it speeds up the useful reactions but also the unwanted ones. there’s also a limit to far you can raise the temperature before a living creatures cells are damaged
what can be used to speed up a reaction instead of increasing temperature?
enzymes, which living things produce
what do enzymes do?
they act as biological catalysts. they reduce the need for high temperature, they only speed up useful chemical reactions.
what is a catalyst?
a substance which increases the speed of a reaction, without being changed or used up in the reaction.
what are enzymes?
they are large proteins, which are made up of chains of amino acids. the chain are folded into unique shapes, which enzymes need to do their jobs
what do chemical reactions usually involve?
things being split apart or joined together
what does every enzyme have?
an active site with a unique shape that fits onto the substance involved in a reaction
how are enzymes specific?
they usually only catalyse one specific reaction
why are enzymes specific?
for the enzyme to work the substrate has to fit into its active site. if it doesn’t match the active site, then the reaction wont be catalysed
how is the lock and key theory simpler than how an enzyme actually works?
the active site actually changes shape a little as the substrate binds for a tighter fit. this is called the induced fit model of enzyme reaction
what can change the rate of an enzyme-catalysed reaction?
changing the temperature
how does temperature change the rate of an enzyme catalysed reaction?
higher temperature increases the rate at first but if it gets too high the rate of the reaction will decrease
why will too high a temperature reduce rate of reaction?
if it gets too hot some of the bonds holding the enzyme together break. this changes the shape of the active site so the substrate wont fit. this means the enzyme is denatured
whats the temperature called when the enzyme works best?
the optimum temperature
what also effects rate of reaction other then temperature?
pH
what happens if pH it too high or too low?
it interferes with the bonds holding the enzyme together, which changes the shape of the active site and the enzyme becomes denatured
what is often the optimum pH of an enzyme?
neutral pH 7, but not always. e.g. pepsin breaks down proteins in the stomach with an optimum pH of 2, well suited for acidic conditions
what does amylase do?
it catalyses the breakdown of starch to maltose
what can be used to detect starch?
it is easy to detect starch with iodine solution- if iodine is present it will turn from orange/brown
to blue/black
how to set up an investigation for how pH affects amylase activity:
put a drop of iodine solution in every dimple of a spotting tile
put a Bunsen burner on a heat proof mat and a tripod and gauze over the Bunsen
put a beaker of water on the tripod and heat the water to 35*C
what is needed for an investigation for how pH affects amylase activity:
1cm³ of amylase solution
1cm³ of buffer solution
5cm³ of starch solution
method for an investigation for how pH affects amylase activity:
add amylase and buffer solution to a test tube
put it in beaker of water and leave for 5 mins
add starch solution, mix and start a stop clock
every 30 seconds, add a drop of the solution to spotting tile and continue until iodine stays orange/brown
repeat experiment with buffer solution of different pH values
what precautions must be used when investigating how pH affects amylase activity?
use syringe when adding amylase, buffer and starch
use thermometer to record temperature
use test tube holders when putting test tubes in water
what control variables are there in an investigation for how pH affects amylase activity?
concentration and volume of amylase solution
keep temperature of water in beaker constant
what is it useful to calculate after an experiment for investigating how pH affects amylase activity?
to calculate rate of reaction. rate is measure of how much something changes over time
formula for rate of reaction:
’’’’’’’’’’’’‘<u>1000</u>
Rate = time
what are the units for rate of reaction?
s^-1
how to calculate rate of reaction of something that changes over time:
<u>amount that has changed</u>
time taken
how do digestive enzymes help us to absorb food?
starch proteins and fats are too big to pass through the walls of the digestive system. so digestive enzymes break them down into small molecules like sugars, amino acids, glycerol and fatty acids. small soluble molecules can easily ass through allowing them to be absorbed into the bloodstream
examples of sugars:
glucose and maltose
what do carbohydrases do?
they converts carbohydrates into simple sugars
e.g. amylase breaks down starch into maltose or other sugars like dextrins
where is amylase made?
the salivary glands
the pancreas
the small intestine
what do proteases do?
they converts proteins into amino acids
where is protease made?
the stomach (pepsin) the pancreas the small intestine
what do lipases do?
they convert lipids into glycerol and fatty acids
lipids are fats and oils
where is lipase made?
the pancreas
the small intestine
what does the body do with products of digestion?
they can be used to make new carbohydrates, proteins and lipids. some of the glucose (carbohydrate) thats made is used in respiration
what journey does bile take through the digestive system?
its produced in the liver, stored in the gall bladder, then released into the small intestine
how is bile used in the s,all intestine?
the HCL acid in the stomach is too acidic for enzymes in the small intestine. bile is alkaline and neutralises the stomach acid ad makes conditions alkaline which the enzymes work best in
how does bile speed up digestion?
it emulsifies fat. which means it breaks up fat into tiny droplets, which gives it a larger surface area for lipase to work on
where are digestive enzymes produced?
they’re produced by specialised cells in glands and in the gut lining. different enzymes catalyse the breakdown of different food molecules
organs in the digestive system in order:
salivary glands gullet (oesophagus) stomach liver gall bladder pancreas small intestine large intestine rectum
what do the salivary glands do?
produce amylase enzyme in the saliva
what does the stomach do?
it pummels food with muscular walls
it produces protease enzyme in pepsin
it produces HCL to kill bacteria and to give right pH for protease
what does the liver do?
produces bile, which neutralises stomach acid and emulsifies fat
what does the gall bladder do?
it stores bile before its released into the small intestine
what does the pancreas do?
it produces protease, amylase and lipase enzymes and releases them into the small intestine
what does the small intestine do?
it produces protease, lipase and amylase to complete digestion.
its where the digested food is absorbed out of the digestive system into the blood
what does the large intestine do?
it absorbs excess water from the food
what does the rectum do?
it stores faeces (made of mainly indigestible food) before they leave through the anus
how do you prepare a food sample for identifying what food molecule it has?
break up the food with a pestle and mortar
put it in a beaker with distilled water
stir the mixture with a glass rod to dissolve some of it
filter the solution to get rid of the solid food
what foods can sugars be found in?
biscuits, cereal and bread
what are the 2 types of sugars?
non-reducing and reducing
what does the Benedict’s test test for?
reducing sugars
how to carry out Benedict’s test:
put about 10 drops of Benedict’s solution in 5cm³ of food sample in test tube
put test tube in 75*C water bath for 5 mins
if there’s sugar the solution will turn from blue to green, yellow or brick red
what foods contain lots of starch?
pasta, rice and potatoes
how can you test for starch?
put 5cm³ of prepared food in beaker
add a few drops of iodine solution then gently shake.
if it has starch it will turn from orange/brown to black/blue
which foods contain protein?
meat and cheese
how can you test for protein?
the Biuret test
how to carry out biuret test:
add 2cm³ of prepared food and 2cm³ of biuret solution to a test tube and mix
if it contains protein it will go from blue to purple
what foods are lipids found in?
olive oil, margarine and milk
how to test for lipids:
with Sudan III stain solution
how to carry out Sudan III test:
put 5cm³ of unfiltered prepared food sample in a test tube
add 3 drops of Sudan III stain solution and gently shake
it stains lipids. if there are lipids the mixture will separate into 2 layers and the top will be bright red
what’s the top part of your body called?
the thorax, its separated from the lower part of your body by the diaphragm