In today's Science lesson, we went through answers in worksheets that we had done in the past few weeks. I feel that this will help me in my revision as it allows us to recall back what we had learnt. I also had gained some new knowledge after the lesson.
3 Thoughts:
1) There are two types of methods used in desalination. The first is distillation and the second method is reverse osmosis. In reverse osmosis, some steps are almost similar to the method of filtration as there is a presence of partially-permeable membrane which its function is similar to the function of filter paper used in the filtration. Both filter paper and partially-permeable membrane only allow certain substances to pass through.
2) I learnt that sublime means change in state directly from solid to gas, without even turning into the liquid state. One example is the solid iodine. To separate a small amount of substance, which sublimes to the effect of heat, from a mixture, we must first heat the mixture in an evaporating dish with an inverted filter funnel placed above the dish. The substances will then be formed on the wall of the inverted filter funnel.
3) I now know that concentrated means to remove any inessential substances. Example, if you want to get concentrated syrup means that you want more of the syrup and less amount of water.
2 Questions:
1) Reverse osmosis or distillation is a better method to obtain NEWater?
2) Can the partially-permeable membrane used in reverse osmosis be replaced with a stronger and firmer filter paper?
1 Useful application:
1) Such new knowledge will help me to understand how NEWater is obtained from the method of reverse osmosis.
(Reverse osmosis) (Subliming)
Sources: Google Images
For today's science lesson, we went through the notes on DNA and answered a few questions on it. We also had completed some parts on the cells worksheet. I felt that the questions were quite challenging!
3 Thoughts:
1) Letters in DNA has a special name which is called nitrogenous bases. Each of the letters is attached to a molecule of sugar while a phosphate molecule will attach to the sugar molecule. As both sugar and phosphate molecule is attached to one another, the sugar-phosphate will form the backbone of DNA.
2) I have learnt that nucleotide, which is a building block of DNA, is formed when the each of the bases, sugars and phosphates are linked together.
3) When the double stranded DNA is twisted like a spiral staircase with a hollow interior, it is called DNA double helix. The DNA is covered with proteins, chromatin and chromatids which will then form chromosome. Chromatin wound around the proteins so as to help join the DNA and prevent it from breaking.
2 Questions:
1) Will there be an ending in DNA strand?
2) Won't the DNA break if both the proteins and chromatin are removed?
1 Useful application:
1) With the help of the descriptions of a DNA, we can roughly know how a DNA strand looks like. We are also able to understand what surround the DNA and their functions in helping the DNA.
(DNA strands)
Sources: Google Images
