Q&A - PSLE Science

[tisha]

tianzhu:

tisha:

Which of the following statements are true?
A. Chlorophyll is only found in the leaves.
B. Leaves capture chlorophyll to make food.
C. Oxygen is not needed in the process of photosynthesis
D. Gaseous exchange can only take place through the stomata.

(1) A and C only
(2) A and D only
(3) B and C only
(4) C and D only

Hi tisha

Good Morning.

A and B are offside.

C is true; oxygen is a product of photosynthesis.

D may not be completely true, but in primary science, students learned that plant respire through openings called stomata.It would be better if only had been left out in the option.

Therefore, given the four choices, I‘d go for option (4) ------ C and D only. That’s the closest answer.

Best wishes

A very good morning to you tianzhu. Thanks a lot for the answer. I still have one doubt though, why did you rule out option A. :?

[ParentingChildren]

Hi Tisha,


Depending on the plant, chlorophyll can also be found in parts other than the leaves. For example, some cacti have their chlorophyll in their stems.

[tisha]

ParentingChildren:

Hi Tisha,


Depending on the plant, chlorophyll can also be found in parts other than the leaves. For example, some cacti have their chlorophyll in their stems.

Thank you. Now it is clear.

[tianzhu]

tisha:

A very good morning to you tianzhu. Thanks a lot for the answer. I still have one doubt though, why did you rule out option A. :?

Hi

Option like A, Chlorophyll is only found in the leaves usually appears in exams to confuse students.

If you do a search on Google, you’ll realise that chlorophyll can be found on the stems of plants as well as some algae. A good example has been given by ParentingChildren.

Options involving “absolute words” such as “only”, “always” or “never” are less likely to be correct.

Best wishes.

[chrisu]

Understand that the 2011 PSLE Science followed the 2008 Science syllabus; would like to know is the Phases of the Moon (especially calculating the dates of the phases of the moon) still in this year PSLE syllabus? Saw some science questions in \"Road to PSLE\" on Phases of the Moon in 2008.


Thank you.

[tianzhu]

chrisu:

Understand that the 2011 PSLE Science followed the 2008 Science syllabus; would like to know is the Phases of the Moon (especially calculating the dates of the phases of the moon) still in this year PSLE syllabus? Saw some science questions in \"Road to PSLE\" on Phases of the Moon in 2008.


Thank you.

Hi

The topic on Day and Night cycles is not in the new syllabus.

You may wish to confirm it with your kid's teacher.

Best wishes

http://www.moe.gov.sg/education/syllabuses/sciences/files/science-primary-2008.pdf

http://www.punggolpri.moe.edu.sg/cos/o.x?c=/wbn/pagetree&func=view&rid=15664

[Belle2011]

Amy wants to find out whether plants with red leaves could make food. She plucked a red leaf from a potted plant and carried out an experiment.

The steps given below are NOT in order:
A) Soak the leaf in a boiling tube of warm alcohol.
B) Put a few drops of iodine on the leaf.
C) Wash the leaves in a beaker of water.
D) Put the leaf in boiling water for 20 seconds.

(a) What are the correct order to carry out the experiment?
(b) Why was the leaf soaked in warm alcohol?
Why was the leaf put in boiling water for 20 seconds?

Thank-you.

Cheers,
Belle.

[janet88]

chrisu:

Understand that the 2011 PSLE Science followed the 2008 Science syllabus; would like to know is the Phases of the Moon (especially calculating the dates of the phases of the moon) still in this year PSLE syllabus? Saw some science questions in \"Road to PSLE\" on Phases of the Moon in 2008.


Thank you.

Er...this sun and moon thing is no longer in P6 syllabus.
Other than the must-haves PSLE Science reference (Marshall Cavendish) and Science Ultimate (EPH), are there any assessment book which are of help in the preparation please ? Thanks.

[tianzhu]

Belle2011:

Amy wants to find out whether plants with red leaves could make food. She plucked a red leaf from a potted plant and carried out an experiment.

The steps given below are NOT in order:
A) Soak the leaf in a boiling tube of warm alcohol.
B) Put a few drops of iodine on the leaf.
C) Wash the leaves in a beaker of water.
D) Put the leaf in boiling water for 20 seconds.

(a) What are the correct order to carry out the experiment?
(b) Why was the leaf soaked in warm alcohol?
(c) Why was the leaf put in boiling water for 20 seconds?

Thank-you.

Cheers,
Belle.

Hi

Let me try.

a)The procedures are:

D) Put the leaf in boiling water for 20 seconds.
A) Soak the leaf in a boiling tube of warm alcohol.
C) Wash the leaves in a beaker of water.
B) Put a few drops of iodine on the leaf.

Please craft your answer around these points; I think they should be sufficient.

b)The green colour of chlorophyll will mask the result of the iodine test if iodine solution were to simply drop onto the leaf surface. Hence, the leaf needs to be decolourised i.e., the chlorophyll needs to be removed. --- decolours the leaf

c)The leaf surface is tough and may be impermeable to iodine solution. Boiling the leaf in hot water helps to soften it by killing the cells and breaking down the cell walls and cell membranes. This enables the green colouring to be extracted. --- kills the leaf

Best wishes

[tianzhu]

janet_lee88:

Other than the must-haves PSLE Science reference (Marshall Cavendish) and Science Ultimate (EPH), are there any assessment book which are of help in the preparation please ? Thanks.

Hi

I think one will be overwhelmed by the sheer volumes of science assessment books in Popular. There are so many new titles this year.

Just like going to an economical rice stall where there are so many dishes, sometimes having too many choices is also a problem.

If I may add, past years papers from top schools is also a must have.

Best wishes