11. Gas Exchange in + 12. Respiration Flashcards
Are gas exchange systems in all animals the same?
NO
The surfaces where gas exchange occurs in an organism are very different and different organisms have evolved different mechanisms for getting the gases to the gas exchange surface depending on size, where they live etc.
What do gas exchange features allow?
These features allow the maximum amount of gases to be exchanged across the surface in the smallest amount of time
What are the 4 main features of gas exchange surfaces?
Large surface area
Thin walls
Good ventilation with air
Good blood supply
How is a large surface area useful?
Gas Exchange Surfaces
to allow faster diffusion of gases across the surface
How are thin walls useful?
Gas Exchange Surfaces
to ensure diffusion distances remain short
How is a good ventilation with air useful?
Gas Exchange Surfaces
so that diffusion gradients can be maintained
How is a good blood supply useful?
Gas Exchange Surfaces
to maintain a high concentration gradient so diffusion occurs faster
Name the 8 structures of the respiratory system
ribs
intercostal muscle
diaphragm
trachea
larynx
bronchi
bronchioles
alveoli
Ribs definition
bone structure that protects internal organs such as the lungs
intercostal muscle definition
Muscles between the ribs which control their movement causing inhalation and exhalation
Diaphragm definition
Sheet of connective tissue and muscle at the bottom of the thorax that helps change the volume of the thorax to allow inhalation and exhalation
Trachea definition
Windpipe that connects the mouth and nose to the lungs
Larynx definition
Also known as the voice box, when air passes across here we are able to make sounds
Bronchi definition
Large tubes branching off the trachea with one bronchus for each lung
Bronchioles definition
Bronchi split to form smaller tubes called bronchioles in the lungs connected to alveoli
Alveoli definition
Tiny air sacs where gas exchange takes place
Why must there be two sets of intercostal muscles?
Muscles are only able to pull on bones, not push on them
This means that there must be two sets of intercostal muscles; one to pull the rib cage up and another set to pull it down
Where are the external intercostal muscles found?
One set of intercostal muscles is found on the outside of the ribcage (the external intercostal muscles)
Where are the internal intercostal muscles found?
The other set is found on the inside of the rib cage (the internal intercostal muscles)
What structure surrounds the trachea and bronchi?
Rings of cartilage surround the trachea (and bronchi)
Why are there rings of cartilage surrounding the trachea and bronchi?
The function of the cartilage is to support the airways and keep them open during breathing
What would happen if the rings of cartilage were not present around the trachea and bronchi?
If they were not present then the sides could collapse inwards when the air pressure inside the tubes drops
What are the passages down to the lungs lined with?
The passages down to the lungs are lined with ciliated epithelial cells
What do cilia do?
these cells have tiny hairs on the end of them that beat and push mucus up the passages towards the nose and throat where it can be removed
Where is mucus made?
The mucus is made by special mucus-producing cells called goblet cells
What is the role of the mucus?
The mucus traps particles, pathogens like bacteria or viruses, and dust and prevents them getting into the lungs and damaging the cells there
Describe the role of cilia and mucus
The mucus is produced by goblet cells and traps bacteria, dust, particles
The cilia beat
And push the mucus away from the lungs towards the throat
3 marks
WHat is the diaphragm responsible for?
it is ultimately responsible for controlling ventilation in the lungs
What happens during inhalation?
external intercostal muscles contract (pulls ribs)
ribcage moves up and out
diaphragm contracts and flattens
volume of thorax increases
air pressure inside thorax decreases relative to outside the body
air is drawn in
What happens during exhalation?
external intercostal muscles relax
ribcage moves down and in
diaphragm relaxes and becomes dome-shaped
volume of thorax decreases
air pressure inside thorax increases relative to outside the body
air is forced out
In what way do the the intercostal muscles work together?
The external and internal intercostal muscles work as antagonistic pairs (meaning they work in different directions to each other)
What happens when we need to increase the rate of gas exchange? What is this called
When we need to increase the rate of gas exchange (for example during strenuous activity) the internal intercostal muscles will also work to pull the ribs down and in to decrease the volume of the thorax more, forcing air out more forcefully and quickly – this is called forced exhalation
Why is forced exhalation needed?
There is a greater need to rid the body of increased levels of carbon dioxide produced during strenuous activity and to inhale more oxygen
This allows a greater volume of gases to be exchanged
Does inspired and expired air have a different amount of gases? Why?
YES
Air that is breathed in and air that is breathed out has different amounts of gases in it due to exchanges that take place in the alveoli
How much oxygen does atmospheric air have?
Atmospheric air contains around 20 – 21% oxygen
How much oxygen from atmospheric air do we absorb? How much do we exhale?
we only absorb around 4 – 5%, breathing out air containing around 16% oxygen
How much CO2 does atmospheric air have?
Normal carbon dioxide content of air is around 0.04%
How much CO2 is in expired air?
As carbon dioxide diffuses into the alveoli from the blood, we breathe out air containing around 4% carbon dioxide
What other substance, apart from O2 and CO2, do we expire?
The air we breathe out contains more water vapour than when we breathe it in
What is also different about expired air, apart from its gas content?
the temperature of exhaled air is higher than inhaled air
Why is the oxygen content in expired and inspired air different?
oxygen is removed from blood by respiring cells so blood returning to lungs has a lower oxygen concentration than the air in the alveoli which means oxygen diffuses into the blood in the lungs
Why is the carbon dioxide content in expired and inspired air different?
carbon dioxide is produced by respiration and diffuses into blood from respiring cells: the blood transports the carbon dioxide to the lungs where it diffuses into the alveoli as it in a higher concentration in the blood than in the air in the alveoli
Why is the water vapour content in expired and inspired air different?
water evaporates from the moist lining of the alveoli into the expired air as a result of the warmth of the body
Why is the nitrogen content in expired and inspired air different?
THERE IS NO DIFFERENCE -78%
nitrogen gas is very stable and so cannot be used by the body, for this reason its concentration does not change in inspired or expired air
- What substance can be used to test for CO2?
Limewater
- Using a setup of two test tubes, containing limewater and connected by rubber tubing, how could you test the content of CO2 in expired air?
When we breathe in, the air is drawn through boiling tube A
When we breathe out, the air is blown into boiling tube B
- What change in the limewater would you see during this experiment?
(Using Limewater to Test for CO2 in Exhaled Air)
Lime water is clear but becomes cloudy (or milky) when carbon dioxide is bubbled through it
The lime water in boiling tube A will remain clear, but the limewater in boiling tube B will become cloudy
- What does this experiment show us?
Using Limewater to Test for CO2 in Exhaled Air
This shows us that the percentage of carbon dioxide in exhaled air is higher than in inhaled air
What is the effect of exercise on breathing?
Exercise increases the frequency and depth of breathing
- How can you Investigate the Effect of Exercise on Breathing?
This can be investigated by counting the breaths taken during one minute at rest and measuring average chest expansion over 5 breaths using a tape measure held around the chest
Exercise for a set time (at least 3 minutes)
Immediately after exercising, count the breaths taken in one minute and measure the average chest expansion over 5 breaths
- What will be the results of this experiment? (Investigating the Effect of Exercise on Breathing)
Following exercise, the number of breaths per minute will have increased and the chest expansion will also have increased
- Why does frequency and depth of breathing increase when exercising?
This is because muscles are working harder and aerobically respiring more and they need more oxygen to be delivered to them (and carbon dioxide removed) to keep up with the energy demand
- What happens if, during exercise, the muscles cannot receive enough nutrients?
If they cannot meet the energy demand they will also respire anaerobically, producing lactic acid
- Why does lactic acid need to be removed?
After exercise has finished, the lactic acid that has built up in muscles needs to be removed as it lowers the pH of cells and can denature enzymes catalysing cell reactions
- How can lactic acid be removed?
It can only be removed by combining it with oxygen – this is known as ‘repaying the oxygen debt’
- How can the time taken for a person to repay their oxygen debt be investigated?
This can be tested by seeing how long it takes after exercise for the breathing rate and depth to return to normal – the longer it takes, the more lactic acid produced during exercise and the greater the oxygen debt that needs to be repaid
- What increases in amount during exercise?
As respiration rates increase, more carbon dioxide is produced and enters the blood
- Why is carbon dioxide harmful?
As blood flows through the brain, the increase in carbon dioxide concentration stimulates receptor cells
- How are high carbon dioxide levels detected?
As blood flows through the brain, the increase in carbon dioxide concentration stimulates receptor cells
- What happens once the receptor cells have detected the high levels of CO2?
These send impulses to the muscles of the lungs, causing them to contract faster and more strongly
- What does the lungs contracting faster and stronger do to CO2 levels?
This causes the frequency and depth of breathing to increase until the carbon dioxide concentration of the blood has lowered sufficiently
Respiration definition
Respiration is a chemical process that involves the breakdown of nutrient molecules (specifically glucose) in order to release the energy stored within the bonds of these molecules
In what two ways can respiration take place and what does this mean?
Respiration can take place with oxygen (aerobically) or without oxygen (anaerobically
Why is aerobic respiration more effective than anaerobic respiration?
Much less energy is released for each glucose molecule broken down anaerobically compared to the energy released when it is broken down aerobically
Where does respiration take place?
Respiration occurs in all living cells. Most of the chemical reactions in aerobic respiration take place in the mitochondria
List 7 reasons why energy from respiration is needed
Contract muscle
Synthesise proteins
Cell division (to make new cells)
Grow
Enable active transport to take place
Allow nerve impulses to be generated
Maintain a constant internal body temperature
How is respiration controlled?
Respiration is a series of reactions that are controlled by enzymes
Aerobic respiration definition
Aerobic respiration requires oxygen and is defined as the chemical reactions in cells that use oxygen to break down nutrient molecules to release energy
Does aerobic respiration break down glucose molecules completley?
YES
It is the complete breakdown of glucose to release a relatively large amount of energy for use in cell processes
What does aerobic respiration produce?
It produces carbon dioxide and water as well as releasing useful cellular energy
Write the chemical equation for respiration
C6H12O6 + 6O2 –> 6CO2 + 6H2O
- How can we investigate oxygen uptake by respiring organisms?
We can investigate aerobic respiration in living organisms by measuring the amount of oxygen that they take from the air
This is done by measuring the change in volume in an enclosed tube containing the organisms
- What is one problem with this experiment? How can it be solved?
Investigating Uptake of Oxygen by Respiring Organisms
However, as they respire the organisms release carbon dioxide, which increases the gas volume
The carbon dioxide must therefore be removed from the tube using a chemical
- What chemicals can be used to remove carbon dioxide?
Investigating Uptake of Oxygen by Respiring Organisms
soda lime or sodium hydroxide
- What organisms can be used in this experiment?
Investigating Uptake of Oxygen by Respiring Organisms
Any small organisms can be used in the apparatus, including seeds or arthropods
- What is the apparatus used in this experiment known as?
Investigating Uptake of Oxygen by Respiring Organisms
The apparatus is known as a respirometer
- What does a respirometer consist of?
Investigating Uptake of Oxygen by Respiring Organisms
The apparatus consists of two tubes, one containing the living organisms and the other with glass beads to act as a control
- What is monitored during the experiment?
Investigating Uptake of Oxygen by Respiring Organisms
Once the apparatus has been set up, the movement of the coloured liquid towards the insect will give a measure of the volume of oxygen taken up by the insect for respiration
- What causes the liquid in the tube to move?
Investigating Uptake of Oxygen by Respiring Organisms
The reduction of volume in the tube increases pressure causing the coloured liquid to move
- What will the distance moved by the liquid provide?
Investigating Uptake of Oxygen by Respiring Organisms
The distance moved by the liquid in a given time is measured will provide the volume of oxygen taken in by the insect per minute
- What is a control?
Investigating Uptake of Oxygen by Respiring Organisms
A control is a duplicate experiment set up with the condition being investigated having been removed or neutralised in some way.
- How is a control used in this experiment?
Investigating Uptake of Oxygen by Respiring Organisms
As they are not alive, they will definitely not be respiring. If the volume of oxygen decreases in the tube with the glass beads during the course of the experiment, then we know that the condition being investigated (respiration in living organisms) is not the cause of it.
- What is the overall use of a control?
Investigating Uptake of Oxygen by Respiring Organisms
A control helps to make your experiment valid.
- How can this experiment be modified to investigate the effect of temperature on the rate of respiration?
Investigating the Effect of Temperature on the Rate of Respiration
To investigate the effect of temperature on the rate of respiration of germinating seeds the respirometer can be set up and the tubes submerged in a series of water baths set at different temperatures, eg 10℃, 15℃, 20℃, 25℃, 30°C
- What must be done to the seeds before the experiment starts?
Investigating the Effect of Temperature on the Rate of Respiration
The seeds should be kept in the water bath for 15 minutes before the start of the experiment to ensure they have acclimated to the temperature
- Why is a temperature not higher than 40 degrees used?
Investigating the Effect of Temperature on the Rate of Respiration
As respiration is an enzyme controlled reaction, it is unlikely to work faster beyond around 40℃ as the enzymes will denature
Anaerobic respiration definition
Anaerobic respiration does not require oxygen and is defined as the chemical reactions in cells that break down nutrient molecules to release energy without using oxygen
Does anaerobic respiration break down glucose completely?
NO
It is the incomplete breakdown of glucose and releases a relatively small amount of energy for use in cell processes
What type of products does anaerobic produce?
It produces different breakdown products depending on the type of organism it is taking place in
When does anaerobic respiration mainly take place?
Anaerobic respiration mainly takes place in muscle cells during vigorous exercise
Why does anaerobic respiration mainly take place when we exercise?
When we exercise vigorously, our muscles have a higher demand for energy than when we are resting or exercising normally. Our bodies can only deliver so much oxygen to our muscle cells for aerobic respiration
What is a product of anaerobic respiration in animals and why?
as much glucose as possible is broken down with oxygen, and some glucose is broken down without it, producing lactic acid instead
Why is less energy released during anaerobic respiration?
There is still energy stored within the bonds of lactic acid molecules that the cell could use; for this reason, less energy is released when glucose is broken down anaerobically
What is the word equation for anaerobic respiration in animals?
glucose —> lactic acid
What does lactic acid do in muscle cells?
Lactic acid builds up in muscle cells and lowers the pH of the cells (making them more acidic)
Why is lactic acid harmful when it builds up?
This could denature the enzymes in cells so it needs to be removed
Where do cells excrete lactic acid into?
Cells excrete lactic acid into the blood
Once in the blood, where does lactic acid go and what happens to it?
When blood passes through the liver, lactic acid is taken up into liver cells where it is oxidised, producing carbon dioxide and water
What process is occuring when lactic acid is being oxidised in the liver?
Lactic acid reacts with oxygen – this is actually aerobic respiration with lactic acid as the nutrient molecule instead of glucose
What are the waste products of lactic acid oxidation?
So the waste products of lactic acid oxidation are carbon dioxide and water
Why do we keep breathing heavily after exercise?
This is the reason we continue to breath heavily and our heart rate remains high even after finishing exercise – we need to transport the lactic acid from our muscles to the liver, and continue getting larger amounts of oxygen into the blood to oxidise the lactic acid
This is known as ‘repaying the oxygen debt’
Why is anaerobic respiration in yeast useful and how do we take advantage of it?
We take advantage of the products of anaerobic respiration in yeast by using it in bread making (where the carbon dioxide produced helps dough to rise) and in brewing (where the ethanol produced makes beer)
What is the word equation for anaerobic respiration in yeast?
glucose —> alcohol + carbon dioxide
What is the chemical equation for anaerobic respiration in yeast?
C6H12O6 —> 2C2H5OH + 2CO2
What are the 4 features of gas exchange surfaces in humans?
Large surface area to allow faster diffusion of gases across the surface.
Thin walls to ensure diffusion distances remain short.
Good ventilation with air so that diffusion gradients can be maintained.
Good blood supply to maintain a high concentration gradient so diffusion occurs faster.
What percentage composition of nitrogen, oxygen, carbon dioxide, and water vapor in inspired and expired air?
Nitrogen
78 - 78.
Oxygen
21 - 17
Carbon dioxide
0.04 - 4.
Water vapor
Variable - Saturated
What is the function of the rings of cartilage that surround the trachea (and bronchi)?
The function of the cartilage is to support the airways and keep them open during breathing.
If they were not present then the sides could collapse inwards.
What happens during breathing in (inspiration)?
External intercostal muscles contract and internal intercostal muscles relax, causing the ribs to move upwards and outwards.
Diaphragm contracts and flattens.
Volume of the thorax increases, and pressure inside the thorax decreases.
Air is drawn in.
What happens during breathing out (expiration)?
External intercostal muscles relax, internal intercostal muscles contract causing the ribs to move downwards and inwards.
Diaphragm relaxes and becomes dome-shaped.
Volume of the thorax decreases, and the pressure inside the thorax increases.
Air is forced out.
Describe the difference in composition between inspired and expired air.
It contains less oxygen.
It contains more carbon dioxide.
It contains more water vapor.
It is warmer.
Why is there less oxygen and more carbon dioxide in expired air than in inspired air?
Oxygen is used in cells for respiration and carbon dioxide is produced as a waste product of respiration. The carbon dioxide is released from the blood at the alveoli and diffuses into the lungs before being exhaled. Thus there is more carbon dioxide in exhaled air.
Why is there more water vapor in expired air than in inspired air?
Water evaporates from the moist lining of the alveoli into the expired air as a result of the warmth of the body.
Describe the effects of physical activity on the rate and depth of breathing.
When exercise is carried out, muscles increase the rate of respiration to produce energy for muscle contraction. Aerobic respiration requires oxygen; thus a greater amount of oxygen is demanded and a greater amount of carbon dioxide is produced as a waste substance that diffuses into the blood.
Why would an increased rate and greater depth of breathing occur?
An increased carbon dioxide concentration in the blood is detected by the brain, leading to an increased rate and greater depth of breathing allowing gas exchange to happen more rapidly, expelling the carbon dioxide whilst taking in more oxygen.
The function of cilia and mucus is often a 3-mark question on the extended paper. The examiners are looking for you to state the following:
The mucus is produced by goblet cells and traps bacteria, dust, and particles and prevents them from getting into the lungs and damaging the fells there.
The cilia beat.
And push the mucus away from the lungs towards the nose and throat where it can be removed.
What is breathing?
The action of drawing air into the body (inspiration) and pushing air and waste gases out of the body (expiration).
How do we show that we breathe out carbon dioxide?
Air is blown through a straw into limewater, the limewater turns from colorless to milky.
Define gaseous exchange.
Gaseous exchange is the movement of oxygen in inhaled air into the blood and the movement of carbon dioxide from the blood into the airways of the lungs.
What do cells need energy for?
Contracting muscels
Making protein molecules
Cell division
Active transport
Transmitting nerve impulses
Produce heat
Uses of energy in the body of humans.
maintenance of a constant body temp
cell division + growth
active transport
Passage of nerve impulses
Muscle contraction
Protein synthesis
What is the main nutrient used to provide energy?
Glucose
What is respiration?
Cells that have to break down glucose molecules to release energy through a series of metabolic reactions which also involves the actions of of enzymes.
What is aerobic repiration?
Cells releasing energy from glucose by combining it with oxygen
Where does aerobic respiration happen?
Mitochondria
What is the equation for respiration?
C6H1206 + 602 => 6CO2 + 6H2O + ATP
How can we investigate aerobic respiration?
By measuring the amount of oxygen that they take from the air using a respirometer.
How do we remove the carbon dioxide?
Potassium hydroxide and sodium hydroxide
What does a respirometer consist of?
Two tubes one containing living organisms and the other containing glass beads to act as a control.
What happens once the apparatus is set up?
Movement of the coloured liquid towards the living organism giving a measure of the volume of oxygen taken up for respiration.
What is anaerobic respiration?
Energy released from sugar without using oxygen
What is the equation for anaerobic respiration in yeast cells?
Glucose = (yeast above the equal) ethanol + carbon dioxide
C6H12O6 = (yeast above the equal) 2C2H5OH + 2CO2
Where does anaerobic respiration take place in humans?
In muscle cells
What is the equation for anaerobic respiration in muscle cells?
Glucose= lactic acid+ energy
What does lactic acid do?
Lowers the pH level of the cells and could denature enzymes.
What happens to the lactic acid once exercise is done?
Blood with lactic acid is passes through thte liver where it is taken to the liver celss where it is oxidised produced carbon dioxide and water
Why do we continue to breathe heavily after exercise?
We need to transport lactic acid to the liver and continue getting large amounts of oxygen into the blood to oxidise the lactic acid.
What surrounds the trachea?
Rings of cartillage
What is the function of the rings of catillage?
To support the airways and keep them open during breathing.
What are the passages down to the lungs lined with?
Ciliated epithelial cells
What do ciliated epithelial cells have?
Tiny hairs that beat and push mucus up the passages towards the nose and throat.
Where is mucus made?
Goblet cells
What does mucus do?
Traps particles, pathogens and dust and prevents them from getting into the lungs.
What are the ribs?
Bone structure that protects internal organs such as lungs
What are intercostal muscles?
Muscels between ribs which control the movements causing inhalation and exhalation
What is the diaphragm?
Sheet of connective tissue and muscle at the bottom of the thorax that helps change the volume of th ethorax to allow inhalation and exhalation.
What is the trachea?
Windpipe that connects the mouth and nose to the lungs
What is the larynx?
When the air passes across here we are able to make sounds
What is the bronchi?
Large tubes branching of the trachea with one bronchus for each lung.
What are bronchioles?
Bronchi split to form smaller tubes called bronchioles in the lungs connected to alveoli
What are alveoli?
Tiny air sacs where gas exchange takes place
What increases the gas exchange?
Larger surface area
Thin walls
Good ventillation with air
Good blood supply
What do intercostal muscles do during inhalation?
Pull the ribs up and out
They relax
What do exhalation muscles do during exhalation?
Pull the ribs down and in
They relax
What do the diaphragm muscels do during inhalation?
Contracts and moves downwards
What happens to the lung volume during inhalation?
Increases and pressure fall
What happens to the lung volume during inhalation?
Increases and pressure fall
What do the diaphragm muscels do during exhalation?
Relax and returns to its dome shape
What do the diaphragm muscels do during exhalation?
Relax and returns to its dome shape
What happens to the lung volume during exhalation?
lung volume decreases and pressure increases
Describe gas exchange
Blood returned from the body have a lack of oxygen
and alveoli have fresh oxygen so a perfect concentration gradient is created as the oxygen diffuses down the gradient into the red blood cells and the CO2 diffuses from the plasma into the alveoli.
How much is oxygen in inspired air?
21%
How much is carbon dioxide in inspired air?
0.04%
How much is water vapour in inspired air?
Lower
How much is oxygen in expired air?
16%
How much is carbon dioxide in expired air?
4%
How much is nitrogen in expired air?
78%
How much is water vapour in expired air?
higher
What can we use to test for CO2?
Limewater- turns cloudy
How can we investigate the effect of exercise on breathing?
By counting the breaths taken during one minute
What do we expect would happen to the frequency and depth of breathing?
The number of breaths will increase and chest expansion increase
Why does frequency and depth of breathing increase during exercise?
Bc of muscles are working harder and aerobically respiring more and need more oxygen to be delivered to them to keep up the energy demand.
What happens as respiration increases?
More CO2 is produced and enters the blood
What does the increase the CO2 concentration do to the brain?
Stimulates receptor cells that send impulses to the muscles of the lungs causing them to contract and move more strongly
What are the alveoli
They alveoli are small cavities inside the lung tissue. They look like a bunch of grapes in that they have a bumpy surface, this increases the surface area to allow for gas exchange to happen quickly in the form of diffusion
What do we breathe in
Oxygen
What do we breathe out
Carbon dioxide and water vapour
What is gas exchange
Gas exchange is the process by which the gases oxygen and carbon dioxide move between the air and blood circulating in the lung tissue
What is the pigment that carries oxygen in red blood cells
Haemoglobin
What is the difference between a bronchi and a bronchiole?
The bronchi are the 2 tubes that the trachea divides into
The bronchioles are the branches that come off of these
What effects can smoking have on the lungs
Cilia are destroyed (mucus accumulates in the respiratory tubes)
Lung cancer
Emphysema is when the walls of the alveoli are destroyed (less surface area for gas exchange and breathing becomes hard)
Carbon monoxide replaces oxygen in the haemoglobin
Possible effects of smoking in the heart
CO reduces oxygen in the blood, heart needs to pump more, raised blood pressure damages heart
Less energy (no oxygen) , cells in heart could die, cardiac arrest
Platelets become too sticky, clots can block coronary arteries
Where can you find ciliates cells
Ciliated cells line the trachea, bronchi, and bronchioles
They waft out stuff
What are the two moist membranes called that separate the lungs from the rib cage
Pleural membranes. The form a continuous layer around the lungs with form an air tight seal. Between the two layers there is pleural fluid which acts as a lubricating agent so that the surfaces of the lungs don’t stick to the inside of the chest cavity/rib age when we breath
When you breath in what happens
The rib cage expands outwards and upwards (external intercostal muscles contract and internal intercostal muscles relax) the diaphragm contracts and pulls downwards. The volume of the thorax or chest cavity increases. And the pressure inside the thorax decreases and air is sucked in from outside
What happens when you breath out
External Intercostal muscles relax and the internal intercostal muscles contract task the ribcage moves downwards and inwards. The diaphragm relaxes and returns to domed shape. The volume in the thorax decreases and the pressure increases and therefore forces air out
What does antagonistic mean?
Working in opposition to each other
What is cellular respiration
Substances such as glucose are broken down to release energy. Can be aerobic or anaerobic
1 molecule of glucose = how much ATP
1 molecule glucose = 40 molecules ATP (approx.)
Word equation for aerobic respiration
Glucose + Oxygen –> carbon dioxide + water + energy as ATP
Chemical equation for aerobic respiration
C6H12O6 + 6O2 –> 6CO2 + 6H2O (+energy as ATP)
Word equation for anaerobic respiration (mammals)
Glucose –> lactic acid + energy as ATP
Word equation for anaerobic respiration (plants and microorganisms)
Glucose –> ethanol + carbon dioxide + energy as ATP
How much energy is produced in aerobic and anaerobic respiration in the same amount of time.
Aerobic respiration produces twice as much ATP as anaerobic respiration
(Aerobic respiration produces very little energy very quickly)
When would muscle cells use anaerobic respiration
Muscle cells can respire anaerobically when they are short of oxygen
Anaerobic respiration :
Does not use oxygen
Lactic acid or alcohol made
CO2 not made in animal cells
Very little energy made approx 2 ATP
Aerobic respiration
Uses oxygen
No alcohol or lactic acid made
CO2 always made
Large amounts of energy made approx 40
What happens to your breathing if you do exercise
The average number of breaths per minute goes up
Why do alveoli have big surface areas?
To allow gas exchange to occur quickly by diffusion
Which pigment inside red blood cells is responsible for transporting oxygen
Haemoglobin
What are the features that alveoli and capillaries have that makes them suitable for gas exchange
They lie close together
Large surface area in contact for both
Both made from a single layer of cells (thin) = rapid diffusion
Summary about volume to surface area
As organisms become larger (multi cellular) their surface area to volume ratio decreases. This makes it more difficult for materials to pass into or out of cells without the extra help from the circulatory system
Bronchioles split to form many alveoli that function
Large surface area for gas exchange
The alveolar surface is a moist function
Allows gases to dissolve in water for diffusion
The wall of alveoli and capillaries are one cell thick function
Allows for efficient diffusion of gases
Network of blood capillaries function
O 2 inhaled quickly, CO 2 exhaled quickly
The function of cartilage in the trachea:
In the trachea, there is tracheal cartilage. Cartilage is a strong but flexible tissue. The tracheal cartilages
help support the trachea while still allowing it to move and flex during breathing.
Inspiration
External intercostal muscles contract and internal intercostal muscles relax
This raises the ribs upwards and outwards
At the same time, the diaphragm contracts and flattens
Both these movements increase the volume in the thorax, decreasing the pressure
Since atmospheric pressure is greater, air moves into the lungs and they inflate
Expiration
The internal intercostal muscles contract and the external intercostal muscles relax
This lowers the ribs downwards and inwards
At the same time, the diaphragm relaxes and bulges upwards
These actions decrease the volume in the thorax, increase pressure in the thorax
Since atmospheric pressure is lower, air moves out of the lungs
The two types of intercostal muscles
contract and expand accordingly
to allow inspiration and expiration
composition of oxygen in inhaled air
21%
composition of oxygen in exhaled air
16%
composition of CO2 in exhaled air
4%
composition of CO2 in inhaled air
0.04%
composition of nitrogen in inhaled air
78%
composition of nitrogen in exhaled air
78%
composition of water vapor in inhaled air
variable
composition of water vapor in exhaled air
variable but more saturated than inspired air
Experiment to test for the differences in the volume of CO2 between inspired and expired air
The test tubes are both filled with lime water which turns
cloudy when CO2 is present.
-The test tube on the right will turn cloudy because the air we
breathe in contains about 0.04% carbon dioxide while the air
we breathe out contains about 4% carbon dioxide.
-Hence the air we exhale contains about 100 times the
concentration of CO2 compared to the air we inhale.
vital capacity.
The maximum amount of air that can be inhaled
Rate and depth of breathing
Increases with exercise. On working, muscles require more oxygen for respiration. They also need to
expel more carbon dioxide.
When you respire more, the increase in the production of CO2 and lactic acid from anaerobic respiration
reduces the pH in the tissues and the
blood.
The brain detects this drop in pH and sends nerve impulses to the
The brain
detects this drop in pH and sends nerve impulses to the diaphragm and intercostal muscles to contract
faster and increase the rate and depth of breathing. By breathing deeper and more rapidly, more O 2 is supplied to cells for respiration, and more CO2 is removed from the body, reducing the pH. This is an
example of homeostasis
The brain detects this drop in pH and sends nerve impulses to the
The brain
detects this drop in pH and sends nerve impulses to the diaphragm and intercostal muscles to contract
faster and increase the rate and depth of breathing. By breathing deeper and more rapidly, more O 2 is supplied to cells for respiration, and more CO2 is removed from the body, reducing the pH. This is an
example of homeostasis
Goblet cells in the trachea release mucus that
traps any dirt, dust, or pathogens. This is then swept by
ciliated epithelial cells into the gullet to be swallowed.
uses of energy in human body
● Muscle contraction
● Protein synthesis
● Cell division
● Active transport during absorption in the villi
● Growth
● Sending impulses along nerves
● Maintaining the body temperature
Respiration involves the action of
enzymes in cells
Aerobic respiration
chemical reaction in cell that use oxygen to break down nutrient molecules to release energy
Glucose + oxygen
→ Carbon dioxide + water
C6H12O6 + 6O2 →
6CO2 + 6H2O
Anaerobic respiration
the chemical reaction in cells that break down nutrient molecules to release energy without using oxygen
anaerobic respiration in muscles
glucose → lactic acid + energy
C6H12O6 → 2C3H6O3 + energy
anaerobic respiration in yeast
glucose → ethanol + carbon dioxide + energy
C6H12O6 → 2C2H5OH +2CO2 + energy
Anaerobic respiration releases much less
energy per glucose molecule than aerobic respiration
Energy released (kJ/g -1 glucose) for aerobic respiration
16.1
Energy released (kJ/g -1 glucose) for fermentation by yeast
1.2
Energy released (kJ/g -1 glucose) for anaerobic respiration in muscles
0.8
Lactic acid and oxygen debt
During vigorous exercise, the muscles of the body perform anaerobic respiration releasing lactic acid.Lactic acid can slowly poison muscles and cause cramps, so it must be removed from the body. The buildup of lactic acid in the body causes oxygen debt . This is the amount of oxygen required after exercise to facilitate the breakdown of lactic acid in the body. After vigorous exercise, lactic acid is rapidly transported to the liver to be broken down. The heart continues to pump blood faster after exercise to quickly transport lactic acid to the liver. We carry on breathing faster and deeper to supply more oxygen for aerobic respiration to break down the lactic acid in the liver even after completing the exercise.
In what part of the cell does respiration occur and ATP made
Small structures called mitochondria
What is germination
When seeds start to grow and develop roots and shoots. They have to use up stored chemical energy in the seeds to do this.
When would muscle cells use anaerobic respiration
Muscle cells can respire anaerobically when they are short of oxygen
How do yeast cells reproduce
Asexually. They do this by creating a bud, this bud eventually breaks off from the parent cell forming a new cell
What is energy released as ?
ATP (Adenosine Triphosphate), an energy rich compound
What can the energy produced from respiration be used for
Muscle cells, liver cells, kidney cells
How does yeast reproduce?
Asexually. They do this by creating a bud, this new cell developed until it eventually breaks away from the parent cell
How is beer made?
By fermentation which uses yeast to convert sugars to ethanol
What are the uses of energy in living organisms?
Muscle contraction.
Protein synthesis.
Cell division.
Active transport.
Growth.
The passage of nerve impulses.
The maintenance of a constant body temperature.
Investigate and describe the effect of temperature on respiration in yeast.
When temperature increases, the rate of respiration increases as well because the heat speeds up the reactions which means kinetic energy is higher.
The higher the temperature, the more carbon dioxide will be released by yeast, forming greater bubbles. Once the temperature gets above a certain point, the respiration rate will decrease.
What is aerobic respiration?
Aerobic respiration as the chemical reactions in cells that use oxygen to break down nutrient molecules to release energy.
What is the word equation for aerobic respiration?
Glucose + oxygen → carbon dioxide + water.
What is the balanced chemical equation for aerobic respiration
C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O.
What is anaerobic respiration?
Anaerobic respiration as the chemical reactions in cells that break down nutrient molecules to release energy without using oxygen.
What is the energy comparison of anaerobic respiration to aerobic respiration?
Anaerobic respiration releases much less energy per glucose molecules than aerobic respiration.
What is the word equation for anaerobic respiration in yeast?
Glucose → alcohol + carbon dioxide.
What is the word equation for anaerobic respiration in muscles during vigorous exercise?
Glucose → lactic acid.
What is the chemical equation for anaerobic respiration in yeast?
C₆H₁₂O₆ → 2C₂H₅OH + 2CO₂
What builds up in muscles and blood during vigorous exercise?
Lactic acid builds up in muscles and blood during vigorous exercise causing an oxygen debt.
How is oxygen debt is removed after exercise?
Continuation of fast heart rate to transport lactic acid in the blood from the muscles to the liver.
Continuation of deeper and faster breathing to supply oxygen for aerobic respiration of lactic acid.
Aerobic respiration of lactic acid in the liver.
Features of gas exchange surface area in humans:
large surface area
thin surface
good blood supply
good ventilation with air
Oxygen percentage in inspired air
21%
oxygen percentage in expired hair
16%
CO2 percentage inspired air
0.04%
CO2 percentage in expired air
4%
Expired air contains less oxygen because
oxygen is used up by the cells in the body
Expired air contains more
carbon dioxide because it is a waste product of respiration. It contains more water vapour
because the water from the lining of the windpipe evaporate and is expired.
Function of cartilage is
keep the airway/ trachea open
prevent collapse
protects (named) airways ;
allows (free flow of) air into (the lungs) ;
allows flexibility / can breathe even when, bent / swallowing / AW ;
reduces resistance to movement of air ;
sound production in larynx ;
forms incomplete rings around, trachea / bronchi ;
During inspiration
rib cage moves upwards and outwards, diaphragm contract,
external intercostal muscles contract, internal intercostal muscles relax, volume of
thorax increase, pressure in thorax decrease, air move into the lungs to equalize the
pressure.
During expiration
rib cage moves downwards and inwards, diaphragm relax,
external intercostal muscles relax, internal intercostal muscles contract, volume of
thorax decrease, pressure in thorax increase, air move out the lungs to equalize the
pressure.
As physical activity increase breathing rate increase because
muscles contract
more. Muscles require more energy. More aerobic respiration takes place. More
carbon dioxide is produced, pH of blood decrease because carbon dioxide is acidic.
This is detected by the brain, brain send impulses to breathing muscles like heart
and diaphragm to contract more frequently and more hardly. This leads to an
increased rate and greater depth of breathing.
Goblet cells produce
mucus
Mucus
sticky substance which traps pathogens
and dust particles and prevent them from entering the lungs. Ciliated cells beat and
move the mucus up towards the throat where it can be sneezed out of the body.
Uses of energy in living organism:
muscle contraction
protein synthesis
cell division
active transport
growth
the passage of nerve impulses
the maintenance of a constant body temperature
Aerobic respiration
the chemical reactions in cells that use oxygen to break down
nutrient molecules to release energy. glucose + oxygen → carbon dioxide + water
aerobic respiration reaction
C6H12O6 + 6O2 -> 6CO2 +6H20
Anaerobic respiration
chemical reactions in cells that break down nutrient
molecules to release energy without using oxygen
Word equation for anaerobic respiration in yeast
glucose → alcohol(ethanol) +
carbon dioxide
Q
the chemical equation for anaerobic respiration
C6H12O6 -> 2C2H5OH + 2CO2
Word equation for anaerobic respiration in muscles during vigorous exercise as
glucose → lactic acid
Lactic acid builds up in muscles and blood during vigorous exercise causing
oxygen debt
To remove oxygen debt after exercise:
fast heart rate continues to transport lactic acid in the blood from the muscles to
the liver.
deeper and faster breathing continues to supply oxygen for the aerobic
respiration of lactic acid.
aerobic respiration of lactic acid in the liver.
