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My name is Poon Cheng Moh. I have been teaching biology in SMK(P) Raja Zarina, Port Klang for 26 years. I sincerely hope that this blog on SPM Biology will be useful to both teachers and students.

Friday, May 8, 2015

How a cell cycle works



• The chromosomes in the nucleus condense and become more tightly coiled.
• Each chromosome now consists of a pair of sister chromatids joined together at the centromere.
• In the cytoplasm, the spindle fibres begin to form and extend between the centrioles.
• Each pair of centrioles then migrates to lie at the opposite poles of the cell. The chromatids are attached to the fibres of the spindle by their centromeres.
• At the end of prophase, the nucleolus disappears and the nuclear membrane disintegrates.

• Metaphase begins when the centromeres of all the chromosomes are lined up on the metaphase plate, an imaginary plane across the middle of the cell.
• The mitotic spindle is now fully formed.
• The two sister chromatids are still attached to one another at the centromere.
• Metaphase ends when the centromere divide.

• During anaphase, the two sister chromatids of each chromosome separate at the centromere.
• The sister chromatids are pulled apart to the opposite poles by the shortening of the spindle fibres.
• Once separated, the chromatids are referred to as daughter chromosomes.
• By the end of anaphase, the two poles of the cell have complete and equivalent sets of chromosomes.

• Begins when the two sets of chromosomes reach the opposite poles of the cell.
• The chromosomes start to uncoil and revert to their extended state (chromatin).
• The chromosomes become less visible under the microscope.
• The spindle fibres disappear and a new nuclear membrane forms around each set of chromosomes.
• The nucleolus also reforms in each nucleus.
• The process of mitosis is now completed.

Tuesday, March 10, 2015



KERTAS 3 (4551/3A)
Jenis instrumen
Ujian Amali
Jenis item
Item subjektif : Item berstruktur
Bilangan soalan
2 soalan (Jawab semua)
Jumlah Markah
30    (Wajaran 16.7%)
Cara Memberi Respons
Ditulis pada ruang dalam kertas soalan
Tempoh Ujian
1 jam 45 minit (Termasuk 15 minit masa    merancang)
·        Kemahiran proses sains
·        Kemahiran manipulatif
Pemarkahan secara analitikal dan holistik berdasarkan rubrik penskoran
Cakupan Konteks
Bidang pembelajaran Tingkatan 4 dan    Tingkatan 5

Monday, June 9, 2014


CHAPTER 10 – TRANSPORT IN PLANT (PEKA using microscope)

1. Aim/ Objective : To study the function of xylem tissues in flowering plant.

2. Problem Statement: Do xylem tissues transport water?

3. Hypothesis : Xylem tissues transport water.

4. Variables
Manipulated : Types of vascular tissues, xylem tissues and phloem tissues
Responding : Red stain on the xylem tissues
Fixed : Types of plant / balsam plant // types of staining / eosin

5. Material : Eosin , balsam plant , distill water
Apparatus : White tile , conical flask , pen-knife ( scalpel ), glass slide , cover slip , microscope , forceps

6. Technique :
Observing and identifying the presence of red stain on the xylem tissues using microscope and then drawing and labeling the xylem tissues.

7. Procedure :
1. Roots of the balsam plant are washed under running tap water to get rid of the soil.
2. The balsam plant is then placed in a conical flask containing 200 ml of eosin.
3. The balsam plant is placed under bright situation for 30 minutes. After 30 minutes, the balsam plant is removed from the conical flask, then the roots are washed under running water to get rid of the excess eosin.
4. Two parts of the plant, the roots and the stem are observed.
5. A pen-knife (scalpel) is used to cut a thin cross section of the roots.
6. The section is mounted in a drop of water on a microscopic slide and is covered with a cover slip.
7. The section is examined under a microscope using low power objectives lens.
8. Diagram of the cross section of the roots is drawn.
9. The structures that are stained red with eosin are shaded and labeled.
10. Steps 6-9 are repeated for the stem.

8. Result :
The Cross Section Root And Stem Of A Balsam Plant

(a) Root

(b) Stem

Magnification: 10 x 40

Discussion :
Xylem tissues in the root and stem are stained red with eosin.
Phloem tissues in the root and stem are not stained red with eosin.
Xylem tissues transport water and phloem tissues do not transport water.

9. Conclusion : Xylem tissues transport water. Hypothesis is accepted