Oxygen is Needed for Respiration

8/6/2019 Oxygen is Needed for Respiration

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OXYGEN IS NEEDED

FOR RESPIRATION





� The chemical process in which energy released frombreaking down of food.

� Respiration begins with every breath you take.

� Respiration requires oxygen (breath in).� Oxygen oxidises the glucose in the body cells to release

energy.

� Carbon dioxide, water vapour and energy are thewaste products in respiration (breath out).



Glucose OxygenCarbon

dioxide

Water

vapourEnergy+ + +

Breath in

(tarik nafas)

Breath out

(hembus nafas)





� The air that we breath in (udara yang

disedut masuk ke dalam badan).

� The air that surround you.

� The air that we breath out (udara yang

dihembus keluar dari dalam badan).

� Contain less oxygen compared to inhaled

air.





Nitrogen 78%

In rt s s 0.97%

Simil riti s

Diff r nc s

0.03 % Carbon dioxide 4%

21% Oxy n 16%

V ri s W t r v pour S tur t d

Inh l d ir

cont nt

Exh l d ir

cont nt



� During cell respiration, food substances combine with

oxygen to release the energy stored in food.

This energy is used by body cell for various types of

activities.

� Oxygen is very important during respiration.



Procedure:� The apparatus is set up as shown below

Test tube P Test tube Q

Test tube R

Wire gauzeCotton soaked with sodium hydroxide solution

Glass tube

Indicator droplet

Leaves

Cockroach



� The position is marked of the indicator droplet with a marker

pen

� Keep the apparatus in a cupboard for three hours

� Observe the position of the indicator droplet of each test tube.

Observation:

� At the end of experiment, the indicator in apparatus Q and

move towards the boiling tube.

� The indicator of apparatus A does not move at all.

Explanation:

� The cockroach and leaves use the oxygen in boiling tubes

during respiration. They breath out carbon dioxide which is

absorbed by the sodium hydroxide solution.

� The volume of air in boiling tube decreases cause the indicator



Procedure:

� Set up the apparatus as shown below

�

All three apparatus are kept in dark cupboard for a few hours.

Lime water

Cockroach Leaves

Test tube A Test tube B Test tube C



Observation:

� The limewater solution in the test tube A and B become chalky.

� The limewater solution in test tube C does not change.

Explanation:

� The carbon dioxide released during respiration by the

cockroach and leaves cause the limewater solution become

chalky.

Test tube A

T

est tube B Test tube C



1. Fill a gas jar with exhaled air as shown in figure below

2. Prepare another gas jar to collect air from the atmosphere

(inhaled air)

Gas jar

Blow

Basin

Water

ubber tube



Inhaled air Exhaled air

Candle

Gas jar Gas jar

3. Observe the candles in the inhaled and exhaled air in the gas

gars as shown below:

Which of the candles goes out first?

Exhaled air

Do both candles burn for the same length of time?

No

Does the inhaled air or the exhaled air contain more oxygen?

Inhaled air

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Oxygen is Needed for Respiration