biology chapter 9 (understanding aerobic respiration (three ways you use…
biology chapter 9
understanding aerobic respiration
three ways you use energy are running, swimming and rugby. you use energy in many ways with to contract your muscles so that you can move, to keep your body temperature at a suitable level and constant and to grow
you need to obtain this energy from your food . respiration is the chemical that release energy from food that you have eaten
your muscles need energy to contract and move bones.food contains energy, cells need to carry out a reaction to release energy. this reaction take place inside all your cells the time without you even thinking about it
some of your food is digested in the intestines to convert to glucose. the glucose travels in the bloodstream to all the cells of your body. respiration takes place in the cells to release energy from the glucose.
respiration is a series of reactions that takes place in the cells of animals and plants. overall the reaction can be shown by the equation : glucose + oxygen ---> carbon dioxide + water (+energy) 'energy' is in brackets because it is not a subtances
This type of respiration, where oxygen is used, is known as aerobic respiration. Oxygen (from breathing) is carried from the lungs to all the cells of the body in the blood
The waste products of respiration are carbon dioxide and water. These are taken away from the cells by the blood and breathed out from the lungs.
plants cells have a cell wall made from cellulose. Plants make cellulose by joining glucose molecules together the energy comes from respiration
building molecules requires energy from respiration. In order to grow bigger and repair tissues, you need protein. Protein is made of lots of smaller molecules, amino acids, joined together. When you eat protein , it is broken down into amino acids during digestion. inside your body you rebuild by joining amino acids back together . This process needs energy and energy comes from respiration
understanding anaerobic respiration
plants and microbes like animals sometimes need to respire anaerobically . as in animals this process uses glucose to release energy. but the products of anaerobic respiration in plants and microbes differ from the products in animals
just like animals plants respire anaerobically when oxygen is in short supply. however the products of anaerobic respiration are different
in plants ethanol and carbon dioxide are produced
in animals lactic acid is produced
the type of anaerobic respiration that produces ethanol and carbon dioxide is called fermentation. it can occur in the roots when a plant is growing is boggy or waterlooged
microbes are tiny organisms that we cannot see with the naked eye - they include bacteria viruses and fungi. microbes often respire by fermentation
some microbes are capable of both aerobic and anaerobic respiration and fermentation and use fermentation only when oxygen levels fall. examples of microbes that do this are the bacterium Escherichia coli and the fungus all round us. some microbes are adapted to survive only in anaerobic conditions for example bacteria that live far below the oceans surface
you can show that a gas is given off by fermentation.mix some dried yeast with warm water in a conical flask to activate it then give the yeast some sugar as source of food. if the conical flak is then covered with a balloon any gas given of gas will collect in the ballon
yeast is a simple organism that reproduces and ferments sugar rapidly. these features make it ideal to use in studies of fermentation. fermentation by yeast has many applications for example in baking and brewing
fermentation is used in brewing and the production of alcoholic drinks as one of the products of fermentation is ethanol ( a type of alcohol). the type of alcoholic drink produced depends on the source of the sugar used in the process. for example wine uses grapes whereas beer is made using hops and barley
fermentation is also important in baking . yeast and sugar are included in bread recipes because the carbon dioxide produced during the fermentation is in the production of 'gasohol' - a fuel containing mixture of gasoline and alcohol. mixing alcohol with a fossil fuel makes the non- renewable fossil fuels last longer
we can describe a correlation using a sentence a structure such as 'as the independent variable increases the dependent variable decrease/increases
exploring respiration in sport
when athletes need to sprint they cannot get enough oxygen to respire is the usual way.
they need to work without oxygen for a short time, but also must release the energy that allows them to run.
the boddy has mechanisms to manage without oxygen but there are consequences
so when jogging or swimming over a long distance, you respire in the normal way
when you exercise steadily, you gain enough oxygen to carry out aerobic respiration
however, when you exercise in short , energetic bursts the energy the energy needed outweighs the oxygen that you can take in and you have to respire without oxygen
this type of respiration, without oxygen, is called anaerobic respirition
as sports have become more competitive and lucrative, sport science has emerged to help sportspeople to understand how their bodies work.
anaerobic respiration is important in sprinting and weightlifting. other sports which involve steady exercise as well as short bursts of high energy exercise, rely on both aerobic and anaerobic respiration
the lactic acid produced during anaerobic respiration builds up in muscles. this can be felt as an aching in muscles during or after exercise. after the short burst of vigorous exercise is over, you need to get rid lactic acid using using the oxygen that you breathe in. this oxygen is a 'payback' so that the body can rid itself of lactic acid - it is known as the oxygen debt. you may find yourself breathing deeply after excerise to repay this oxygen debt.
animals bodies have developed ways of storing glucose. this means that they can slowly release energy as and when they need it.
although anaerobic respiration does release some energy, it does not release as much as aerobic respiration does
animals store energy sevearal
as glycogen in the liver
as glycogen in the muscles
in fat reserves
anaerobic respiration can be shown an equation: glucose ---> lactic acid (+energy)
you can damage your body if you exercise too much without taking in sufficient energy as food. once all other energy stores such as glycogen and fat have been used up, protein in the body can be used as a last resortt