Q&A - PSLE Science

[tianzhu]

atutor2001:

However, an immediate question came to my mind - Why can a plucked leaf continue to carry out photosysnthsis?

Hi atutor2001

Glad you find it interesting. I came across this article while doing some readings for this question.

http://www.mathsheuristics.com/mathsHeuristics_flyer.pdf --- Please refer to question at pg 2.

I don’t have any answer to your question now, but will do some further reading.

Meanwhile let’s hear what others have to say.

Best wishes

[atutor2001]

Hi tianzhu


Actually the "apple question" is still bothering me. If some of the cells in a plucked leaf is alive, then some of the cells in a "pluck apple" will probably also be alive. That leads to my frustration of whether is the leaf or apple, as a whole, considered to be alive i.e. living thing.

Have tried googling but so far couldn’t find any satisfactory answer. Hope you can hit one. Thanks.

Regards

[tianzhu]

atutor2001:

Actually the \"apple question\" is still bothering me.

Hi atutor2001

Hope this article helps.
http://www.scholastic.ca/education/science_place/downloads/alive_tg_on.pdf

Have fun.

Best wishes

[atutor2001]

Hi tianzhu


Thanks

[Full.010894Cream]

an interesting article on leave disk indeed!!


BTW, what's the conclusion on the 'apple'? :?

[atutor2001]

Hi Full.Cream


Most of the articles indicated that picked apple is dead. Those that said that it is still alive concluded so because they had included the seeds as part of the apple. However, the definition of fruit (apple is a fruit) does not include the seeds as part of a fruit. (A fruit is the fleshy part that protects the seeds and helps in seed dispersal.)

When I tried to match the 7 characteristics of a living thing to a picked apple, most of the characteristics do not match. So I have accepted and concluded that a picked apple is DEAD

[Full.010894Cream]

atutor2001:

Hi tianzhu


A very interesting article indeed. Thank you.

However, an immediate question came to my mind - Why can a plucked leaf continue to carry out photosysnthsis?

My guess is that the cells of in a plucked leaf are \"alive\" for quite a number of days. That brings my thought to the term \"alive\". Is it right to say that the cells are \"alive\" or should it be \"functional\" or some other biological term. Thanks in advance.

Regards

What happens when a human dies? In the context of first aid, the cells start to die after abt 4mins due to the deprivation of oxygen (IIRC).

SO when we pluck the leaves from the plant, the cells in the leaves are still very much alive. Couple with the fact that it is submerged in water and also able to photosynthesize, it'll lose very little water and also produce oxygen to sustain live at the cell level. Therefore its state of 'aliveness' is prolonged. Acceptable reasoning?

[atutor2001]

Full.Cream:

What happens when a human dies? In the context of first aid, the cells start to die after abt 4mins due to the deprivation of oxygen (IIRC).

SO when we pluck the leaves from the plant, the cells in the leaves are still very much alive. Couple with the fact that it is submerged in water and also able to photosynthesize, it'll lose very little water and also produce oxygen to sustain live at the cell level. Therefore its state of 'aliveness' is prolonged. Acceptable reasoning?

Ya agreed.

Now I ask myself this question when deciding whether something is alive or dead - Is live processes (i.e. respiration, absorption of water, nutrient..., excretion, ..) still in progress? If yes then it is a living thing.

[Full.010894Cream]

well, I wld not consider a plucked leaf a living thing coz we shdn’t go to the celol level to determine what is a living thing.

[glchua]

For any plucked fruit, physiological processes are still happening. A banana still ripens, mangoes give off heat if you encase it. An apple is thus still living.


If a dismembered plant is immediately considered dead, then grafting is not possible as a farming technique.

This is also true of dismembered parts of an animal. The tissue is still alive.

The apple is considered dead when it starts to rot. Respiration ceases, defense ceases, and microbes take over.

Sorry, just my opinion.