Transcript
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Unit 8B
Respiration
Name: ……………………………..
Year 8: …………
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Unit 8 B: Respiration_______________________________________________________________________________________
Respiration:Respiration is a chemical reaction that happens in all living cells. It is the way that energy is released from
glucose, for our cells to use to keep us functioning.
Remember that respiration is not the same as breathing (which is properly called ventilation).
Aerobic respiration:
The glucose and oxygen react together in the cells to produce carbon dioxide and water. The reaction is called
aerobic respiration because oxygen from the air is needed for it to work.
Here is the word equation for aerobic respiration:
glucose + oxygen carbon dioxide + water (+ energy)
(Energy is released in the reaction. We show it in brackets in the equation because energy is not a substance.)
Now we will look at how glucose and oxygen get to the cells so that respiration can take place and how we get
rid of the carbon dioxide.
Glucose from food to cells:
Glucose is a type of carbohydrate, obtained through digestion of the food we eat. Digestion breaks food down
into small molecules. These can be absorbed across the wall of the small intestine into the bloodstream.
Glucose is carried round the body dissolved in blood plasma, the pale yellow liquid part of our blood. The
dissolved glucose can diffuse into the cells of the body from the capillaries. Once in the cell glucose can be
used in respiration.
Oxygen from the air to cells:
When we breathe in oxygen enters the small air sacs, called alveoli, in the lungs. Oxygen diffuses from there
into the bloodstream.
Oxygen is not carried in the plasma, but is carried by the red blood cells. These contain a red substance called
haemoglobin, which joins onto oxygen and carries it around the body in the blood, then lets it go whennecessary. Like glucose, oxygen can diffuse into cells from the capillaries.
Red blood cells carry oxygen around the body.
Carbon dioxide from cells to the air:
The carbon dioxide produced during respiration diffuses out of the cells and into the blood plasma. The blood
carries it to the lungs. It then diffuses across the walls of the alveoli and into the air, ready to be exhaled.
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The respiratory system and ventilation:
The respiratory system:
The human respiratory system contains the organs that allow us to get the oxygen we need and to remove the
waste carbon dioxide we don't need. It contains these parts:
• Lungs
• Tubes leading from the lungs to the mouth and nose
• Various structures in the chest that allow air to move in and out of the lungs.
Ventilation:
Movements of the ribs, rib muscles and diaphragm allow air into and out of the lungs. Take care - this is called
breathing or ventilation, not respiration. When we breathe in, we inhale. When we breathe out, we exhale.
Air passes between the lungs and the outside of the body through the windpipe, called the trachea. The trachea
divides into two bronchi, with one bronchus for each lung.
Each bronchus divides further in the lungs into smaller tubes called bronchioles. At the end of each bronchiole,
there is a group of tiny air sacs. These air sacs have bulges called alveoli to increase their surface area.
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• Some water vapour is also lost from the surface of the alveoli into the lungs - we can see this condensing when
we breathe out on cold days.
The circulatory system:
The circulatory system is the body’s transport system. Oxygen and nutrients including glucose travel around the
body in the blood.
Blood:
Blood is a mixture of different types of cells in a liquid.
• Red blood cells carry oxygen from the lungs to the cells and take carbon dioxide back to the lungs.
•
White blood cells help fight disease.• Plasma is a straw coloured liquid that carries nutrients, as well as hormones which control your body, and
antibodies which help fight disease.
• Platelets help blood to clot when you have a wound.
Circulation of blood:
Blood circulates around the body, pumped by the heart. It travels in a network of tubes called blood vessels.
There are three main types:
•
Arteries carry blood away from the heart.• Veins carry blood back to the heart.
• Capillaries are tiny vessels that join arteries to veins.
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Capillaries branch deep inside the body’s tissues. Here substances such as oxygen, glucose and carbon dioxide
can be exchanged between the blood and the cells.
Pumping faster and harder:
If you run a race, your muscle cells are respiring fast so they need lots of oxygen and glucose. They are
producing more carbon dioxide and water, as well as releasing lots of energy to win the race.
To supply the cells, your heart pumps faster and harder, circulating the blood faster and you breathe faster too.
What if you tried to sprint hard for an hour? Your lungs would not be able to pick up enough oxygen, and your
heart would not be able to circulate the blood fast enough. Your muscle cells would run short of oxygen. When
this happens you get cramp and feel exhausted. You have to stop! But if you jog slowly, your body can supply
enough oxygen and glucose for a long time.
1- The heart pumps blood to the lungs. Here,
it picks up oxygen, and carbon dioxide
leaves it.
2- Oxygenated blood goes back to the heart.
3- The heart pumps oxygenated blood
around the body to organs such as the gut,the muscles and the brain.
4- Deep in the tissues oxygen, glucose and
other nutrients pass from the blood to the
cells for respiration. Waste material such as
carbon dioxide passes from the cells to the
blood to be carried away.
5- The deoxygenated blood travels back to
the heart to be pumped back to the lungs
again.
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Q1:
1- Complete the sentences:
Food gives us the raw ______________ for making new cells.
We need new cells so that we can _____________________ and ________________ damage.Food also gives us the _____________________ that we need for growing, ________________________ and
keeping __________________.
2- Complete the table.
What we use when we respire What we release when we respire
3- a)Use the information in the table to complete the equation.
Glucose + ___________________ carbon dioxide + _______________+ ( __________________ )
b) Write the symbol equation for the reaction above.
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__________________________________________________________________________________________
c) Name the reactants and the products.
__________________________________________________________________________________________
__________________________________________________________________________________________
What else is produced? ____________________________
Q2:
Complete the following.
_________________ is the body’s transport system. It carries nutrients including _______________ and
oxygen around the body to the cells and tissues. Here they are used for __________________.
Q3:
Do an internet or library search on how people first found out about the human blood circulation. Try entering
these names: Galen, Vesalius, Harvey, Ibn -Al- Nafis.
Q4:
Label the following parts of the diagram:
Kidneys intestines heart cells in the body lungs
Then match each of the following descriptions to the correct part.
Blood collects digested food here: _________________
Blood drops off waste chemicals here: _________________________
Blood collects oxygen and drops off carbon dioxide here: _____________________
The heart keeps the blood moving round the body: ___________________
Blood takes carbon dioxide and waste chemicals away from here: _______________
Blood drops off oxygen and food here: __________________
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Q5:
Complete the following table:
Arteries Capillaries Veins
Carry blood ____________ from
the heart
Connect ________________ to
_________________
Carry blood ____________ the
heart
Carry __________________
blood
Carry both oxygenated and de-
oxygenated blood
Carry _____________________
blood
________ _________________ __________ _________________ Have valves to stop the back flow
of blood
Have a ______________ layer of
muscle
Walls are very _____________ Thin layer of muscle
_____________ space inside Tiny vessels in close contact to
cells
______________ space inside
Blood flows at ____________
Pressure due to the action of the
heart
Low blood pressure and slow speed
to allow exchange of materials
Blood flows at _______________
pressure
Q6:
1- Use the bold words around the diagram to complete the sentences.
Small blood vessels called _________________ take substances to the cells in your body.
Blood carries ________________ and ______________ to the cells.
These substances pass into the ____________________.
Waste _______________ _______________ and ______________ pass from the cells in to the
_________________.
2- The cells in your body need oxygen and glucose.
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a) Complete the flow diagram.
b) Why do the cells in your big toe need oxygen and glucose?
__________________________________________________________________________________________
Q7:
The diagram below shows the blood circulation.
Use arrows to show how blood circulates through
the blood vessels and heart.
(use red arrows to show oxygenated blood
and blue arrows to show de-oxygenated blood)
Q8:
Sometimes your cells don’t have enough oxygen to release all the energy that they need. But they can respire
for a short time without oxygen. Respiration without oxygen is called anaerobic repiration. It releases less
energy from glucose than aerobic respiration.
The waste products of aerobic and anaerobic respiration are also different.
Anaerobic respiration produces lactic acid, which is poisonous to cells.
It is what makes your muscles sore when you do more exercise than usual.
It can also give you cramp.
1- What does anaerobic respiration mean?
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__________________________________________________________________________________________
2- This is the word equation for aerobic respiration:
glucose + oxygen→ carbon dioxide + water + energy
This is the word equation for anaerobic respiration:
glucose→ lactic acid + carbon dioxide + some energy
Write down three differences between these equations.
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
3- Find out how you get rid of lactic acid.
__________________________________________________________________________________________
__________________________________________________________________________________________
4- Find out what “oxygen debt” is.
__________________________________________________________________________________________
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Q 9:
At sea level there is twice as much oxygen than at 6000m high on a mountain.
People who climb mountains therefore need to take a supply of oxygen.
The summit of Mount Everest is about 9000m above sea level.
People who live at high altitudes breathe more quickly and more deeply than people who live at sea level. Also,
their number of red blood cells is different.
Altitude (m) Number of red blood cells per
cm3 of blood
Sea level 5000
1000 6000
3000 7500
5000 8000
1- Look at the table. Use the information in the table to plot a bar chart.
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2- What do the results show us about the relationship between altitude and the number of red blood cells?
__________________________________________________________________________________________
3- Why do people who live at high altitudes breathe more quickly and more deeply?__________________________________________________________________________________________
__________________________________________________________________________________________
4- The 1968 the Olympic Games were held in Mexico City, which is 2000m above sea level. How do you think
this affected athletes from lowland countries?
__________________________________________________________________________________________
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5- Give a possible explanation why so many African runners are so successful in long distance and marathon
races.__________________________________________________________________________________________
__________________________________________________________________________________________
Q10:
Fire officer Allen has to use breathing apparatus to go into burning buildings. His breathing apparatus is
connected to an oxygen tank on his back.
1- Complete the flow diagram with the followings:
Alveoli blood fine tubes in lungs mouth
Our lungs can be damaged by things that we breathe in. Dust, smoke from fires and cigarette smoke can all
harm our lungs.
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How well our lungs can take oxygen into our blood is called our lung function. The graph shows how cigarette
smoke affects lung function.
2- How does the lung function of a smoker compare with that of a non- smoker?
__________________________________________________________________________________________
3- What is the difference in lung function between a 65-year-old smoker and a 65-year-old who quit smoking at
the age of 45?
__________________________________________________________________________________________
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Q11:
Look at the diagram to answer the following questions.
1- Complete these sentences:
The gas ___________________ moves from X to Y.
The gas ____________________ moves from V to W.
2- The wall around the alveolus is very thin.
Why is it useful for the alveolus to have a very thin wall?
_______________________________________________
_______________________________________________
Q12:
Sometimes, patients in hospitals have to be fed by injecting liquid food directly into the blood vessels known as
veins. This is called intravenous feeding. It happens when there is a problem with a person’s digestive system.
1- Find out some other examples of when a person might need to be fed in this way.
__________________________________________________________________________________________
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2- Intravenous feeding has to provide a balance of nutrients.
a) What do you think intravenous food contains?
__________________________________________________________________________________________
b) Why does the intravenous fluid contain only soluble foods?
__________________________________________________________________________________________
c) What parts of the intravenous food provide a patient with energy?
__________________________________________________________________________________________
3- Doctors can use the intravenous feeding method to get other things into the patient’s body.
Write down one example.
__________________________________________________________________________________________
Q13:
List the parts of the blood. Underline the part that carries oxygen, and in another colour the part that carries
glucose.
_________________________________________________________________________________________
Q14:
Mrs Daniel, the science teacher, set up three gas jars and timed how long it took for each candle to go out. The
diagram shows us what she did.
1- For each gas jar, write down the percentage of oxygen in the air.
2- Predict the order that the candle go out. Explain your prediction.
__________________________________________________________________________________________
__________________________________________________________________________________________
3- What should Mrs Daniel do to make this experiment a fair test?
__________________________________________________________________________________________
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4- Mrs Daniel did a similar experiment again using inhaled air. This time, she grew a small pot of cress plants in
the jar under a lamp for one week, before putting the burning candle in the jar (carefully, so as not to let the
gases in the jar escape).
The candle burnt for longer. Find out why this happened.
__________________________________________________________________________________________
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Activity: Using a respirometer
This is a diagram of apparatus that you can use to measure the rate of respiration. It is used to measure the
amount of oxygen removed or carbon dioxide added to the air in the test tube.
The maggots take in oxygen and give out carbon dioxide. Any carbon
dioxide in the test tube is absorbed by the soda lime.
So as oxygen is taken out of the air in the test tube and carbon dioxide
is added, the coloured liquid moves towards the maggots. You can
use the scale to measure how much the liquid moves.
Planning your investigationYour task is to plan an investigation to find out the effect of temperature on the volume of oxygen and carbon
dioxide exchanged by the maggots.
For your plan, you must do the following:
1- Decide on a heading for your investigation.
The heading might start like this:
The effect of temperature on the ....
2- Make a prediction.
We normally make a prediction about what will happen and we say why we think it will happen.
Fanoulla;
As it gets hotter, the air will expand and the coloured liquid will move away from the test tube.
Christopher:
As it gets hotter, the maggots become more active and they take up more oxygen. This causes the coloured
liquid to move towards the test tube.
Maliwan:
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As it gets hotter, the maggots produce more carbon dioxide. This pushes the coloured liquid away from the test
tube.
a) Discuss Fanoulla’s, Christopher’s and Maliwan’s ideas with other pupils.
b) Write down your prediction.
3- Decide the temperatures that you will use.
Ideally you need a range of at least five temperatures (ranging from 0°C to 40°C).
4- Decide how you will measure the temperature.
(Whether you will use a temperature sensor or a thermometer).
5- How you will keep each experiment at a constant temperature.
You could use:
• Ice
• Hot water from a kettle
• A Bunsen burner to heat water
• An electronic water bath
6- The number of times that you will repeat each experiment, and why.
7- What things (factors) you will keep the same and how you will make this a fair test.
You could consider:
• The number of maggots
• The kind of maggots (species, size, age)
• The glassware
• The time it is left before taking a reading
8- What safety precautions you will take.
When we handle living material, we always wash our hands and wipe the bench with disinfectant.
Remember, you will be handling glassware, hot water and living things.
9- What results you will take from the experiment.
You will need to produce a table for your results.
In this experiment, you will be measuring:
• Different temperatures
• The volume of oxygen taken up by maggots, or
• The volume of carbon dioxide released by the maggots
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