3- Oxygen is Needed in Respiration

8/13/2019 3- Oxygen is Needed in Respiration

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OXYGEN IS NEEDED

IN RESPIRATION


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Air is one of the main resources onearth rich in oxygen.

All living cells required oxygen tocarry out its daily processes.

One of the process called respiration.

Respiration is the process wherebyour body obtains energy from food.

Respiration takes place in the cells ofour body.

Oxygen is needed for respiration tobreak down food in the form ofsugar (glucose) through oxidation.


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Oxidation is a chemical processwhich gives out energy and break

downs glucose into carbon dioxideand water vapour.

This energy comes from the chemical

energy stored in glucose.The energy given out is kept in the

cell and helps to maintain body

temperature at 37o

c.CO2 and water vapour are waste

products that need to be removed

from the body.


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Cell respiration is the oxidation of

food to obtain energy


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Respiration is represented by thefollowing equation :

Respiration is a living process which

takes place continuously in animalcells and plant cells.

Oxygen + glucose carbon dioxide +

water + energy


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Inhalation and exhalation

Living things obtain the O2needed forrespiration through breathing.

Breathing involves 2 physical process;inhalation and exhalation.

Air which is inhaled into the body calledinhaled air.

Air which is exhaled from the body is

called exhaled air. Inhaled air differs from exhaled air term of

its O2, CO2and water vapour content.


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Comparison of inhaled air

and exhaled air

The temperature of exhaled air ishigher than of inhaled air.

This is because heat energy isreleased during respiration and aportion of energy is used to carry outdaily processes of the organism.

Exhaled air also contains a highercontent of water vapour.


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Activity 1 : To compare the O2 contents in inhaled

air and exhaled airProcedure

- Exhaled air was collected

by blowing through arubber tube into a gas jarfilled with water as shownin figure 1

- 2 candles were lighted upand placed inside 2 gasjars as shown in figure 2

- 1 of the candles wasplaced inside a gas jar

containing inhaled air.- The other candle was

placed inside a gas jarcontaining exhaled air.

-

The flames of the 2candles were observed.


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Observation

The candle in the gas jar containingexhaled air goes out first.

The candle in the gas jar containinginhaled air continues to burn forsome time before it goes out


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INHALED AIR EXHALED AIR

N2 (78%) AND INERTSGAS (1%)

21 %

0.03 %

LESS

25OC (ROOM TEMP)37 % (BODY TEMP)

MORE

4 %

16 %OXYGEN

TEMPERATURE

WATER VAPOUR

CARBON DIOXIDE

Similarity

Differences


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Respiratory organs in humans

The lung is a respiratory organ in humansand other animals when breathing process.

Human lungs are located thoracic cavity,protect by-rib cage.

The lungs are connected to the nose through

the trachea. The trachea branches into 2 bronchi

(bronchus).

The bronchus branches into smaller tubes

called bronchioles. The bronchiole ends with alveolus.

The surface of the alveolus allows gasexchange to take place.


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RESPIRATORYORGANS IN

HUMAN


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Gas exchange in the lung

Gas exchange takes place in the alveolusthrough simple diffusion.

The wall of the alveolus acts as a respiratorysurface for the exchange of O2 and CO2.

O2 dissolves in the moist alveolus surface

and diffuses into the blood capillaries. This O2 will transported from lungs to other

cells in the body by the blood.

At the same time, CO2 also diffuses outfrom the blood capillaries into the alveolus.

CO2 is exhaled from lungs when we breathout.

3- Oxygen is Needed in Respiration

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