Practical 1: Is it alive?

   1.    List all the characterisitics of living things

i)       Respond to changes

Grow

ii)      ReproduceAbility to reproduceànot all living things reproduce but they have the ability to reproduce.

iii)     Can die

iv)     Can grow

v)      Made of cells

vi)     Hereditary information (DNA)

vii)     Respiration

viii)    Excrete waste✓ Egestion of waste (Exception of bacteria)

Respond to changes

Excretion: Process, act or functio of discharging or ejecting waste product of metabolism, especially from the systam of our organism. Examples could be sweat, uria, faeces, etc. àOnly liquid waste are considerd as excretion.
Egestion: The act or process of voiding or discharging undigested food as faeces.

Reproduce

DNA

Eject waste

Respire

Die

Cells

List the conditions needed to support life.

i)     Air

ii)    Food

iii)  Water

iv)  Shelterà this factor is not necessary for all living things. Eg. Plants grow well under sunlight without shelter.

v)   Adapt to changes

vi)  Warmthà not all animals need warmth to survive.. Eg. Cold-blooded animals do not need wanrmth to survive.

Air

Food

Water

Suppose you are given some unknown pellets or powdered substances. How are you going to carry out experiments to find out if the unknown substancs are living things.

·      Which characteristics of the living thing are you using in the experiment?

All living things are made up of cells (my group’s)

Another characteristic would be living things respire.

·      How would you carry out the experiment?

    Look at the pellets or powdered substances through a microscope to find out if cells are present and at the same time, we can observe and take note of their behaviour and movement (my group's).  

Put the pellets and powdered substance into a container and compare the oxygen level before and after putting them in. If the oxygen level has decreased, it means that respiration had been undergone.

Put the pellets and powdered substance into a container with a cup of lime water. If the limewater has turned chalky, it means that respiration had been undergone and carbon dioxide is given out during the process.

·      What kind of evidence will you collect to show that it is a living thing?

The presence of cells. (my group’s)

The increase in the amount of carbon dioxide and decrease in the amount of oxygen.

Why are these liquids chosen?

Waterà All living things needs water to survive. So if the water poured in the petri dish decreases as time passes, that shows that it is a living thing.

Glucose àGlucose is a form of food or energy for living things which is one of the conditions needed for the survival of living things. Thus, if the glucose poured in the petri dish decreases as time passes, that shows that it is a living thing.

Salt water à

	Physical apperance	Before ten minutes,	After ten minutes
Substance A	Is made up of different sizes of stones which are in different shades of brown. It stinked with a rotten smell.	Most of the substance A rests at the bottom of the test tube while the water stays on top of substance A. The water has turned a brownish. I think some of Substance A has dissolved into the water.	Substance A almost looked the same but the water turned more murkier which means more of substance A has been disolved into the water.
Substance B		Substance B dissolved in the water and turned the water into a creamy colour. Some of the substance are resting at the bottom of the test tube,	Water in test tube B turned murkier due to more of the substance B disolving in the water.
Substance C	is made up of big, round and translucent and has a slight bad smell.	Substance C got bigger as it was put into the water. I think it is due to the absorbtion of water by subsatnce C. The water became translucent.	Substance C got very big and could not be seen clearly in water as both were colourless.
Substance D	Is made up of small, round, black and brown balls. It does not have any smell.	Most of substance D sunk to the bottom of the test tube while the rest floated on the water. The water stayed clear.	All of the Substance D sunk to the bottom of the test tube.
Substance E	Is made up of different shades of brown balls. It has a very slight bad smell.	Substance E spreaded itself well around the water but still did not dissolve into the water.	More of Substance E sunk to the bottom of the test tube.