respiration and gas exchange Flashcards
what is respiration
is the process of transferring energy from glucose, which happens constantly in every living cell
where is some of the energy transferred by in respiration
by heat
how does respiration work
Breathing in (Inhalation): You take in oxygen from the air through your nose or mouth, and it travels to your lungs.
Oxygen to Cells: Oxygen moves from your lungs into your blood, which carries it to your cells.
Energy Production:
Inside the cells, oxygen combines with glucose (from food) in tiny structures called mitochondria.
This process releases energy in the form of a molecule called ATP (adenosine triphosphate), which cells use for work.
Carbon dioxide and water are made as waste products.
Breathing out (Exhalation): Your body gets rid of carbon dioxide by breathing it out.
state –> the energy transferred by respiration cannot be used directly by cells - so it is used to make a substance called ATP, ATP stores the energy needed for many cell processes
when a cell needs energy, ATP molecules are broken down and energy is released.
what are the two types of respiration
aerobic
anaerobic
temp change in beans experiment
- soak some dried beans in water for a day or two. they will start to germinate. germinating beans will respire.
- boil a similar - sized, second bunch of dried beans. this will kill the beans and make sure they cannot respire. the dead beans will act as your control
- add each set of beans to a vacuum flask, making sure there is some air left in the flaks (so the beans can respire anaerobically )
- place a thermometer into each flask and seal the top with cotton wool
- record the temp of each flask daily for a week.
- repeats should be carried out using the same mass of beans each time
- the beans are well insulated in the flasks, so when the germinating beans respire, the test flask’s temp will increase compared to the control flask.
when does aerobic happen
when there is plenty of oxygen available
what does aerobic respiration mean
it means ‘with oxygen’ and it is the most efficient way to transfer energy from glucose. it produces lots of ATP - 32 molecules per molecule of glucose
what type of respiration are you using most of the time
aerobic
anaerobic respiration uses
NO OXYGEN AT ALL
what does anerobically oxygen mean
without oxygen, it is not the best way to convert glucose into energy - it releases much less energy per glucose molecule than aerobic respiration (just two molecules of ATP are produced
state –> in anaerobic respiration, the glucose is only partially broken down, and lactic acid is also produced
- the lactic acid builds up in the muscles and it gets painful and leads to cramps
word equation for anaerobic respiration
glucose –> lactic acid (+ energy)
anaerobic respiration in plants
- plants can respire without oxygen too, but they produce ethanol (alcohol) and CO2 instead of lactic acid
word equation for anaerobic respiration in plants
glucose –> ethanol + carbon dioxide (+ energy)
what can be used to show that living organisms produce CO2 as they respire
hydrogen carbonate indicator
what colour does the liquid change in the presence of carbon dioxide
the hydrogen carbonate indicator is orange but it changes to a yellow in the presence of carbon dioxide
investigating respiration
- prepare one set of germinating beans and one set of boiled beans
- put the same amount of hydrogen carbonate indicator into two test tubes.
- place a platform made of gauze into each test tube and place the beans on this.
- seal the test tubes with a rubber bung
- leave the apparatus for a set period of time (eg an hour)
during that time the CO2 produced by the germinating beans should have had an effect on the hydrogen carbonate indicator - it would have turned yellow
the control tube will have stayed the same
what do plants exchange
carbon dioxide and oxygen
what is the word equation for respiration
glucose + oxygen –> carbon dioxide + water (+ energy)
state –> when plants photosynthesise they use up CO2 from the atmosphere and produce O2 as a waste product
state –> when plants respire they use up O2 and produce CO2 as a waste product
how are these waste products lost
through little holes in the undersides of leaves called stomata
how do plants exchange gases
by diffusion, there are lots of gases moving to and from in plants, and this movement happens by diffusion
what is an example of plants exchanging gases by diffusion
- when a plant photosynthesises it uses up lots of CO2 so there is hardly any inside the leaf. this makes more CO2 move into the leaf by diffusion
- at the same time lots of oxygen is being made as a waste product of photosynthesis, some is used in respiration, and the rest diffuses out through the stomata
what does the net exchange of gases depend on
light intensity
the net exchange of gases depends on light intensity :
photosynthesis only happens during the day, but plants must respire all the time, day and night, to get the energy they need to live
during the day (when light intensity is high) plants make more oxygen by photosynthesis than they use in respiration. so in daylight , they release oxygen. they also use up more carbon dioxide. than they produce, so they take in carbon dioxide
at night ( when light intensity is low) plants only respire - there is not enough light for photosynthesis. This means they take in oxygen and release carbon dioxide - just like humans.
why are leaves broad
so theres a large surface area for diffusion
why are leaves thin
so gases only have to travel a short distance to reach the cells where they are needed.
what is the function of the air spaces inside the leaf
it lets gases like carbon dioxide and oxygen move easily between cells. it also increases the surface area for gas exchange.
what is the lower surface full of
little holes called stomata. they are known to let gases like CO2 and O2 diffuse in and out. They also allow water to escape
stomata can be
opened and closed
when do stomata begin to close
as it gets dark. photosynthesis cannot happen in the dark, so they dont need to be open to let CO2 in. when the stomata are closed, water cant escape. this stops the plant from drying out
when can stomata also close
when supplies of water from the roots start to dry up. this stops the plant from photosynthesising ( bad) but if they did not close , the plant might dry out and die (worse)
what is the opening and closing of stomata controlled by
by the cells that surround them (called guard cells) Guard cells do this by changing their shape and volume. Guard cells increase in volume to open stomata and decrease in volume to close stomata
what happens when CO2 concentration increases
more CO2 will dissolve in it and it becomes more yellow
what happens when CO2 concentration decreases
CO2 will come out of the solution and it becomes purple
the experiment using hydrogen carbonate indicator to show how light affects gas exchange
- add the same volume of hydrogen carbonate indicator to 4 boiling tubes
- put similar sized healthy looking leaves into 3 of the tubes and seal with rubber bung. Trap the leaf stem with the bung to stop it from falling down into the solution. keep the fourth tube empty as a control.
- completely wrap one tube in aluminium foil and a second tube in gauze
- place all the tubes in bright light. this will let plenty of light onto the uncovered leaf and a little light onto the leaf covered in gauze. the leaf covered in foil will get no light.
- leave the tubes for an hour then check the colour of the indicator.
RESULTS
- There shouldnt be any change in the colour of the control tube
- you would expect the indicator in the darkened tube to go yellow. respiration will still take place but there will be no photosynthesis, so the CO2 concentration in the tube will increased
- you will expect the indicator in the shaded tube to stay a similar colour. with a little photosynthesis and some respiration taking place, roughly equal amounts of CO2 will be taken up and produced by the leaf, so the CO2 concentration in the tube will not change very much
- you will expect the indicator in the well lit tube to go purple. there will be some respiration but lots of photosynthesis, leading to net uptake of CO2. This will lower the CO2 concentration in the tube.
where are lungs
in the thorax
where is the thorax
in the top part of your body. it is seperated from the lower part of the body by a muscle called the diaphram
what are the lungs protected by
the ribcage
what are the lungs surrounded by
pleural membranes
where do the intercostal muscles run between
the ribs
where does the air you breathe out go through
the trachea, this splits into two tubes called bronchi (each one is a bronchus) one going to each lung
where do the bronchioles end
at small bags called alveoli where the gas exchange takes place
what does the bronchi split into to
smaller tubes called bronchioles
what happens you breath in
intercostal muscles and diaphram contract
thorax volume increases
this decreases the pressure drawing air in
what happens when you breathe out
intercostal muscles and diaphram relax
thorax volume decreases
air is forced out
investigating breathing
sit still for 5 mins
for one min count the number of breaths you take
now do 4 mins of exercise . and as soon as u stop count your breaths for a minute
repeat the steps above and work out your mean results for resting and after exercise
investigating the release of carbon dioxide in your breath
set up 2 boiling tubes. put the same amount of limewater in each
put your mouth around the mouth piece and breath in and out several times
as u breathe in air from the room is draw in in through boiling tube A.
this air contains very little carbon dioxide so the limewater in this boiling tube remains colourless.
when you breathe out the air you exhale bubbles through the limewater in boiling tube B. This air contains CO2 produced during respiration, so the limewater in this boiling tube turns cloudy.
what do the lungs contain?
the lungs contain millions and millions of little air sacs called alveoli where gas exchange happens
the process of alveoli carrying out gas exchange in the body
-the blood passing next to the alveoli has just returned to the lungs from the rest of the body, so it contains lots of carbon dioxide and very little oxygen.
- oxygen diffuses out of the alveolous (high concentration) into the blood (low concentration)
- carbon dioxide diffuses out of the blood (high concentration) into the alveolus (low concentration) to be breathed out
- when the blood reaches body cells, oxygen is released from the red blood cells (where theres high concentration) and diffuses into the body cells (where concentration is low)
- at the same time, carbon dioxide diffuses out of body cells (where theres a high concentration) into the blood (where theres a low concentration). its carried back to the lungs
what does the huge number of microscopic alveoli give the lungs
gives the lungs an enormous surface area
theres a ____ for gasses to dissolve in
moist lining
state- the alveoli have very thin walls- only one cell thick, so gasses dont have far to diffuse
what do they have to maintain a high concentration gradient
great blood supply
state- the walls are permeable so gasses can diffuse across easily
what does smoking damage?
smoking damages the walls inside the alveoli, reducing the surface area for gas exchange and leading to diseases like emphysema
what does tar in cigarettes damage
damages the cilia (little hairs) in your lungs and trachea. there hairs along with mucus, catch a load of dust and bacteria before they reach the lungs
what does the cilia also help with
keep the trachea clear by sweeping mucus back towards the mouth, when the cilia are damaged, chest infections are more likely to happen.
what does the tar also do
irritates the bronchi and bronchioles, encouraging mucus to be produced which cant be cleared very well by damaged cilia- this causes smokers cough and chronic bronchitis
coronary heart disease
- the carbon monoxide in cigarette smoke reduces the amount of oxygen the blood can carry. to make up for this, heart rate increases- which leads to an increase in blood pressure
what does high blood pressure damage
damages the artery walls, making the formation of blood clots more likely, increasing the risk of coronary heart disease
state- tobacco smoke also contains carcinogens- chemicals that lead to cancer
