爱不释手（喜爱到极点而不舍得放手。形容非常喜欢。）

从前有一个读书人，他非常喜欢苏东坡的诗作， 每当抄录到苏东坡的一首诗，便反复吟咏， 爱不释手。

有一天， 他到西湖游玩，偶然间发现一块石壁上面刻有一首诗，题款人是“苏东”。 这一发现， 他高兴得像拾到宝一样，虽然题款的名字少了一个“坡”字，他肯定只是刻石的人漏刻罢了，一定是苏东坡的诗作。

他即刻拿出笔墨纸砚， 把这首诗抄录下来，然后坐在西湖边的石椅上摇头摆脑地吟咏，越吟咏越觉得有味道，越肯定它是苏东坡的作品。

有一个游人看见他这样入迷，便开口向他借来看。

“不！不行！”他生怕那游人来抢， 把手抄本捏得更紧，“我只能念给你听！”

当他把这首诗念完后，游人忽然哈哈大笑， 说道：“你虽然对苏东坡的诗作爱不释手， 但也要分清楚是不是苏东坡的作品啊！ 告诉你吧， 我叫苏东， 和苏东坡一点关系也没有，这首诗是我十年前游西湖时刻的！”

School Project

最近我的学校有一个project。这个project非常重要。如果我们没做的话，就不能毕业了， 可见得他有多么重要。 这个project是需要先在电脑上做，然后再打印出来。打印出来后不是只要交给老师就大功告成了，它还有一个更可怕的一关，就是演讲！

我向来是一个安静又不擅于演讲的人。可是， 这个project却要我在老师的面前演讲，而且不是一个老师，而是三个！面对一个老师我就已经紧张得连屎尿都流出来了， 可是却要在三个老师面前演讲啊。

而且， 我连准备都还没准备好， 都还没开始做，而且又要在这五天内赶着做。其实这个project是所有的二年级学生都必须做的。演讲的阶段一共分成三天，三天里一共分成三批人。而我却偏偏是第一批的“幸运儿”。

我希望我的这个project能够成功地渡过， 那么我就能不用再愁这一关了。

RP negative attitude

In RP, however, everyone will always skip lessons whenever they face difficult problems. I do not like people who are like that. The reason is because they do not consider what other people or what other teammates are facing. If the problem is difficult, that does not means that other teammates do not face the same difficulty. If they just skip lesson like that, this will only let the other teammates facing a more difficult situation. For those people who skip lesson halfway, I think the teachers should give them as F, so that this will teaches them a lesson. With more people, I think that there will be more brains working, there will be more helping hands around for help. Even if the teammates does not do anything as a team, at least he is still able to help out in doing some research or doing the powerpoint slides. Aman who works alone, dies alone. Therefore, in order to do things, it will always be better to have more people helping us. So that whenever we make some mistakes, the other person who knows it better will also correct us, and tell us the correct answer. With more people, we can also exchange the information that we know, or the research that we found out. The reason is because different people will know different things. Like for example, person A knows chemistry very well, person B knows physics very well, and person C knows Biology very well. Together, they are able to provide the information that they know to ech other, and exchange information, and teach each other. In this case, everyone is able to learn something new in the end of the day.Actually, I think students should not skip lessons. If they abandon the other teammates, the teammates can still join the other team for the problem. But the ones who skip, they will not be able to learn new things in the end, because the reason why we come to school is to learn new things. If we do not learn new things, we have no reason of coming to school. If the classmates do not wish to come to school, I think that they should just quit school, because there is no reason for them to come to school and not learn anything.Therefore a good teamwork is very important. When we work hard together, and make a good presentation, we are able to help each other in getting good grades too.

马来人的无情

很久以前， 我的父亲在一间工厂工作。他当时为了赚多一点钱， 便加了夜班。而他第一次加夜班时， 有好几位马来人也在工厂里， 只有我父亲一个华人。另一天早上，有贵重的东西不见了。他们一起联合起来说看见我的父亲偷那个东西。最后丢了饭碗。
你们说我身为他的家人，听见了能不气吗？

在我的班上， 有一个中国学生。他几乎每天都被同班的马来学生欺负。他们取笑他， 作弄他， 推他， 打他。身为华人的我能不气吗？ 如果你们是在新加坡或是在马来西亚， 这种种族之战很普通。虽人不是公开示意，可是却感受得到种族对彼此的不满。 况且，我们华人没有做什么伤天害理的事。事发者通通都是由马来人先开始。

MCB problem 6 quiz

1)

a) A normal cell with no genetic defects was exposed to large amounts of a DNA-damaging chemical (chemical X) for 5 minutes. After a few hours, the cell died. Based on what you had learnt today, account for the death of the cell. (5 marks)


b) Some environmental pollutants (e.g. cigarette smoke) can cause adducts to form on DNA. These are organic molecules that bind to DNA, causing a bulge in the molecule. Suggest how these adducts can interfere with cell replication. (5 marks)






a) The reason why the cell will die is because the DNA has been denatured. In today's lesson, we learned that there can be many possible ways of DNA denaturing. Firstly, it could be due to a foreign molecule attaching to the bases, and not allowing the DNA polymerase or helicase to pass through the DNA for transcription or for replication. Secondly, it could be that there is a cross link, which causes pyrimidine dimers to occur. These cross link can be caused by the UV rays emitting photons to the DNA. When this occurs, the sugar-phosphate backbone will also get distorted too. In this case, it is able to repair when the photolyase are able to remove the pyrimidine dimers. Thirdly, it will cause the sugar-phosphate backbone to break. In this case, the DNA ligase IV is able to join the sugar-phosphate backbone back. Forthly, it is the Base mismatch. The DNA glycosylase can recognize the mismatch base site and remove its base. Then, the endonuclease removes neighboring nucleotides, and the gap is filled by DNA polymerase I and DNA ligase.
The death of the cells could be due to the fact that the cell do not have enough immunity. Like for example maybe it does not have enough of the repairing mechanism. Like for example, in the problem statement, we could see that the one with a lack of DNA ligase IV cannot survive very long. Therefore, it does not have the ability to do faster repairing. Also, the damage rate is more than the repair rate, therefore, the rate of survival will keep dropping.
b) In cell replication, helicase will firstly go through the DNA, and it will split the double strand into a single strand, and therefore it will start reading a single strand coding, and therefore it will then replicate mRNA. In order to replicate mRNA, the helicase needs to go though the DNA, and with the molecule obstructing the pathway, the helicase might not be able to split the double strand.
Also, in the replication process, where the DNA will replicate from a single strand to a double strand by the DNA polymerase III. The DNA Polymerase III will not be able to read the complete sequence of the DNA, and with the molecule obstructing the reading, it will not be able to go on to complete the full strand coding, therefore the DNA sequence will not be complete.

MHC

a) In the MHC Class I, the antigenic proteins which enters the Antigen Presenting Cell will firstly undergo degradation by a protein called protease. After degrading, it will be transported by TAP, and then the antigenic peptide will be loaded onto the Class I MHC Molecule. The MHC then move to the cell surface and display the antigenic peptide. The T killer cell bind onto the MHC molecule, and the killer T cell will then be activated, and then it will be able to kill the infectious foreign particles directly.

b) In the MHC Class II, when the antigens enter the Antigen Presenting Cell, phagosomes are formed, and the phagosomes containing the antigens are merged with the lysosome. Then, the MHC class II molecules migrate into the phagolysosome where the antigen is being degraded, and the invariant chain is removed for peptide binding. The Class II MHC molecule then moves to the cell surface, and present the antigenic peptide to the helper T-cell, and it will help to activate immune cells to fight against the foreign infectious particles.

DNA Folding (School revision)

1) Firstly, the long strand double helix DNA coil a few rounds around the octomer histones. The octomer histones are positively charged.

2) In order to stabilise the DNA being uncoiled from the octomer histone, another protein called the H1 histone will attached onto the DNA and the octomer like a scotch tape, to stabilise it. The ending product is called nucleosome.

3) DNA continued to form more and more nucleosomes. After that, these nucleosomes in a long chain will coil itself like a spring shape. It will then be known as solenoid.

4) The solenoid then attach to another protein called scaffold to form loops. That is called the loop solenoid.

5) It then made up into chromosomes.

(WARNING: Information may be incorrect. If there are any incorrect information, or anything more to add, please give comments. )