It is important to understand that the biological meaning of ‘Respiration’ refers to a chemical process taking place in all living cells. The function of this chemical process is to make energy available for all the cell’s activities which keep it alive. ‘ Breathing’, in some cases, plays a part but ‘respiration’ to a biologist does not mean the same as ‘breathing’.
Some of the energy released in living organisms always appears in the form of heat
Coal and wood are the carbon sources. The carbon dioxide goes up the chimney.
The word ‘respiration’ is used in everyday language to mean breathing; as in,for example, ‘respiration rate’ (breathing rate) or ‘artificial respiration’. In biology, it is best to avoid confusion by using the term ‘respiration’ for the chemical reaction in cells. ‘Artificial respiration’, is better described as ‘resuscitation’.
Organisms living in water absorb oxygen from it. But it is not the O of H 2 O that they use. The oxygen which they can use is dissolved in the water and comes, originally, from the air.
The carbon-containing substance in this case, is glucose (C 6 H 12 O 6 ) but all food contains some carbon. Although the reaction is shown as if it takes place in one step, there are many more intermediate changes and the energy is released in stages, The progress of each step in controlled by chemicals called enzymes which are the subject of a separate presentation
These are only a few examples. Every living process in living organisms needs energy from respiration
The drawing represents the human arm bones with two of the muscles which produce movement (biceps and triceps)
The water produced as a waste product of respiration is picked up by the blood stream and may be lost in sweat, water vapour from the lungs or in urine
Respiration will be occurring in all parts of the human body that consists of living cells. Fingernails, toenails and hair do not contain living cells and so will not be respiring
Any wet or damp non-living material (e.g. a line full of washing) will be releasing water vapour.
Air is a mixture of nitrogen, oxygen, carbon dioxide and a small proportion of other gases. We cannot selectively breathe in only oxygen and breathe out only carbon dioxide. The lungs absorb oxygen from the air we breathe in and give out carbon dioxide. So the air we breathe out contains less oxygen and more carbon dioxide than the air we breathe in.
Anaerobic respiration is involved at some stage in the preparation of these foodstuffs
The vast majority of bacteria are harmless. Some are beneficial, such as those which bring about decay of dead remains. A very small proportion are harmful and cause disease in animals and plants.
Some bacteria can use both aerobic or anaerobic respiration according to the availability of oxygen, There are some anaerobic bacteria which cannot survive in the presence of oxygen.
Yeasts can be seen as a thin, greyish ‘bloom’ on the surface of grapes, but they are present on the surface of most fruits. When these fruits are crushed and mixed with water, the anaerobic respiration of the yeasts causes fermentation with the production of carbon dioxide and alcohol.
The carbon dioxide bubbles plus some of the beer constituents produce a dense froth on top of the beer. The fermentation vessel is an old-fashioned open type.
Powerpoint respiration copy
2THE CONCEPT OF ‘RESPIRATION’ ISCENTRAL TO ALL LIVING PROCESSESIt is worth while studying this presentationthoroughly because it is essential for anunderstanding of all the activities of living cellsand organisms
3All living cells are made up of chemical substancesThe processes of living involve reactions between the substancesA reaction is an event which produces a change in a substanceFor example, a reaction between carbon and oxygen (such as burning coal in air) changes the carbon in the coal, and oxygen in the air into carbon dioxideThis reaction can be represented by the equation C + O2 CO2 carbon oxygen carbon dioxide
4an atom of carbon plus a molecule of oxygen O2 c C o o combine to form a molecule of carbon dioxide CO2
5The reaction between carbon andoxygen also releases energy in theform of heat and light (flames)Living organisms get their energy fromreactions like this (but not reactionswhich are violent enough to produceflames)
6 CO2 energy releasesource of carbon source of carbon oxygen
7One of the energy-producing reactions is calledrespiration(Respiration is not the same thing as breathing)The chemical reactions of respiration take placein all living cellsThe reaction takes place between oxygen and asubstance which contains carbon. The reactionproduces carbon dioxide and water, and releasesenergy
8The carbon-containing substances come from FOODThe oxygen comes from the AIR (or water)The energy is used to drive other chemical reactions taking place in cellsOne example of this is the release of energy in muscle cells to make them contract and produce movement
9One example of an energy-producing reaction in cells isthe breakdown of sugar when it combines with oxygen This can be represented by the equationC6H12O6 + 6O2 6CO2 + 6H2O + energy sugar oxygen carbon water(glucose) dioxide This means that one molecule of sugar reacts with six molecules of oxygen to produce six molecules of carbon dioxide and six molecules of water. Energy is released during this process
10Some examples of the use muscleof energy in organisms contraction Respiration supplies the energy for germination ls cel in es ng c ha l ica cell division em
Energy use in muscle contraction 11 shoulder blade The blood stream brings food and oxygen to the muscle cells. Respiration occurs in the cells and releases energy which…… upper arm bone lower arm bones
12…….makes the muscle contractand pull the lower arm up
15 One example of respiration in ourselves2. The lungs absorb oxygenfrom the air 1. Air taken in 1.Food taken in2.The stomach andintestine digest food.One of the products 3.The blood streamis glucose carries glucose and oxygen to the muscles4 RESPIRATION 5 Carbon dioxideGlucose and is carried to the lungsoxygen react to by the bloodproduce energy formuscle contraction
16 Question 1What is the most important point about respiration?(a) it uses oxygen(b) It releases energy(c) It produces carbon dioxide(d) It needs food and air
17 Question 2In which part of the human body is respiration most likely to be occurring?(a) The lungs(b) The heart(c) The muscles(d) All of these
18 Question 3Which of these are waste products of respiration?(a) Carbon dioxide(b) Water(c) Oxygen(d) Nitrogen
19 Question 4Which of the following would be reliable indicators of respiration in a living organism?(a) Output of water vapour (H2O)(b) Output of carbon dioxide (CO2)(c) Uptake of oxygen (O2)(d) Production of energy
20 Question 5Which of the following statements are correct?(a) We breathe in air(b) We breathe in oxygen(c) We breathe out air(d) We breathe out carbon dioxide
24The process of respiration described so far has been defined as the release of energy when foodstuffs such as glucose react with oxygen to produce carbon dioxide and water.This form of respiration, which needs oxygen, is called aerobic respiration.There is another form of respiration which does not need oxygen and is called anaerobic respiration.In anaerobic respiration, glucose is still broken down to carbon dioxide with the release of energy, but without the involvement of oxygenThe glucose is not completely broken down to CO2 and H2O but to CO2 and alcohol (ethanol).
25Anaerobic respiration can be represented by theequation energyC6H12O6 2C2H5OH + 2CO2 glucose alcoholThe energy released by anaerobic respiration is considerablyless than the energy from aerobic respiration.Anaerobic respiration takes place at some stage in the cellsof most living organisms.For example, our own muscles resort to anaerobicrespiration when oxygen is not delivered to them fastenough.
26Anaerobic respiration is widely used by many micro-organismssuch as bacteria and yeasts.Bacteria and yeasts are microscopic single-celled organisms.Bacteria are to be found everywhere, in or on organisms,in water, air and soilYeasts are usually found in close association withvegetable matter such as fruit
27 Bacteria cell wall there are many nucleus species of bacteria and they have different shapes and sizescytoplasm 0.002mm a single bacterium
28Aerobic and anaerobic bacteriaBacteria which need oxygen in order to respire are calledaerobic bacteria.Aerobic bacteria are likely to be found in the air, waterand soil where oxygen is availableBacteria which can respire without needing oxygen arecalled anaerobic bacteriaAnaerobic bacteria are to be found in situations whereoxygen is lacking, such as in stagnant water, waterloggedsoils or the intestines of animals
30FermentationOne form of anaerobic respiration in bacteria and yeastsis called fermentation.During fermentation, sugar is broken down to alcohol andcarbon dioxideThe reaction described in slide 25 is an exampleof fermentation Fermentation is involved in brewing and wine-making
33BrewingIn brewing beer, a sugary product (malt) is dissolved outof germinating barleyYeast is added to this solution and fermentation begins,producing alcohol and carbon dioxideSome of the carbon dioxide escapes but the restdissolves in the beer when it is bottled or put into casksWhen the bottles or casks are opened, the dissolvedCO2 escapes as bubbles
35BakingIn baking, yeast is added to a mixture of flour and water, made into the form of a doughThe yeast first changes the flour starch into sugar and thenferments the sugar into alcohol and CO2The CO2 forms bubbles in the dough which cause it toexpand (‘rise’)When the dough is baked, the heat evaporates thealcohol but makes the trapped bubbles expand giving the bread a ‘light’ texture
Dough rising 36The yeast is mixedwith the doughAfter 1 hour in a warmplace the dough hasrisen as a result of thecarbon dioxideproduced by the yeast
37The ‘holes’ in thebread are made bythe carbon dioxidebubbles.This gives thebread a ‘light’texture
38 Question 1Which statements are correct ?Anaerobic respiration is different from aerobicrespiration becausea it produces CO2b it does not need glucosec it does not need oxygend it produces less energy
39 Question 2In what circumstances do our muscle use anaerobicrespiration ?a When insufficient glucose reaches the musclesb When the carbon dioxide level increasesc When insufficient oxygen reaches themusclesd When we are asleep
40 Question 3Anaerobic bacteria are most likely to be founda in the middle of a compost heapb in the airc in fast-flowing streamsd on the surface of the skin
41 Question 4In which of the following is the production of CO 2more important than the production of alcohol ?a Brewing beerb Fermenting grape juicec Making breadd Bottling wine
THE EFFECT OF LACTIC ACID IN MUSCLES DURING EXERCISE• Muscles respire aerobically, but when they are working hard a lot of energy is needed.• We breathe deeper and faster to get more O₂ into our blood.• Our heart beats faster to get the O₂ to the leg muscles as quickly as possible.• A limit is reached, but we still need more energy.
EXTRA ENERGY CAN BE PRODUCED BY ANAEROBIC RESPIRATION• Glucose → lactic acid + energy• C₆H₁₂O₆ → 2C₃H₆O₃ + energy• The lactic acid must be broken down by combining it with O₂ in the liver.• Even though we don´t need the O₂ any more, we are still taking in extra O₂ to break down the lactic acid.• While we were running we built up an oxygen debt.
Summary• AEROBIC RESPIRATION (38 ATP) - Glucose + oxygen → carbon dioxide+ water + E - C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + E
ANAEROBIC RESPIRATION (2ATP)• Yeast (important in brewing and baking) : - Glucose → alcohol + carbon dioxide + E- C₆H₁₂O₆ → 2C₂H₅OH + 2CO₂ + E• Animals (in muscle cells during exercise): - Glucose → lactic acid + E - C₆H₁₂O₆ → 2 C₃H₆O₃ + E
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