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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, June 17, 2011

Answers to Hands on Pg 49-50

1. a)b) The daughter cell is identical to the parent cell.
c) i) It produces new cells for growth
ii) It produces new cells to replace old or dead tissues.
d) i) Presence of centrioles in an animal cell but none in plant cell.
ii) During cytokinesis, constriction of plasma membrane in an animal cell but formation of cell plate in a plant cell.
e) i) To produce more cell for growth
ii) To produce more seedlings through cloning/tissue culture.

2. a)b) Crossing over takes place at X. During this process, transferring of genes between 2 homologous chromosomes take place. This produces a new combination of genes which bring about variations.
c) Male and female gametes which are produced through meiosis have haploid number of chromosomes (n). When a male gamete (n) fuses with a female gamete (n) during fertilisation, a zygote (2n) is formed. Hence, the diploid condition is restored.
d) i) In anaphase I, the chromosomes separate but in anaphase II, the chromatids separate.
ii) Crossing over takes place in prophase I but there is no crossing over in prophase II.
iii) There is formation of bivalent during prophase I but none in prophase II.

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