Week 7 - Plant hormones and Summary

This is the last week of our class with Dr. Parameswari. During our last class, we had discussed the answer for our test paper and also lecture on hormones in plant. There are 5 hormones that are important in plant growth which are auxin,cytokinins, gibberellins, abscisic acid and ethylene. Each are very important for each part of the growth of the plants. 

Throughout these 7 weeks, I learnt a lot of new things in the lecture class. The topic that I really interested in is the history of life. Since I was small, I am so curious that how life started, how do the earth have the first living things, how are they going to live in that kind of environment, how do they obtain food, which animal is the first living organism that found in earth, do the earht have plants or animal first. After this lecture, I found the answer to all my question. It is so fun to learn about new things, about something that I have been so curious about it. Besides the last few topic was mainly on plant, originally I always doesn't like chapter or topic on plant when I was studying in secondary school or form 6, simply because I cannot imagine how things work on them. I'm a human being I can roughly understand how blood flow in my body, how my brain function, where is my heart and how my heart beats. However while studying plant it takes so much of my time to really understand them, how pollination occur, how it transfer the pollen and how the male gametes is transfer to the female ovum. After the lecture class with Dr. Parameswari, I can now understand more, I don't just memorize the ways or important part for exam, because now I understand plant. 

Moreover I have fun doing scl activites, where it makes us understand more on the topic that we had covered and also have the opportunity to work together with our course mate. I really like the scl activities, because only lecturing sometimes is very hard for me to concentrate, as I had gone to different classes before and it is really tiring and hard to pay attention. Scl activities give me the chance to know the topic well by letting me do my own research on internet. When answering the question, I’ll ask myself whether I really understand it by determining it with whether I can answer the entire question in scl activities. If I don’t I have a chance to revise and study on my own so that I can participate in the scl activities and contribute to my group.

Besides that, writing reflective journal every week after the lecture class also help me in my studies. When I am writing for reflective journal I’ll study the topic beforehand, I will also do some further research on things or ideas that are new and interesting to me. This makes me understand further on the topic, and increase my knowledge. Study in universities is not just about getting a good grade, universities is also a place or a pathway for us to enter the real society. Hence getting more knowledge is very important. Besides in further understanding the subject or topic, I can know what I’m interested in doing, I’ll have an idea on what course I would like to be major in or what kind of job I’ll like to do in the future time. 

The next class will be with Dr Nik, I look forward to the next class as we going to study more about human body. I think I will enjoy the following class till the end of this sem. 

Week 6 - Totipotency and Reproduction in Plant

This week we continue with last week topic, which is about the cell division in plant cell, mainly focusing on totipotency. There are four ways for an explants (for example, a piece of leaves) to form it’s shoots and roots :

i.                     Direct organogenesis – The explants will be differentiated directly to form its shoots and roots.

ii.                   Direct somatic embryogenesis –The explants will form an embryo, and the embryo will then developed into shoots and roots.

iii.                  Indirect organogenesis – The explants will form callus, a groups of undifferentiated cells and then it will develop to form organs such as roots or shoots

iv.                 Indirect somatic embryogenesis – The explants will first form callus, the callus then develop into an embryo, and then shoots and roots will be formed from the embryo.

This are the ways where tissue culture is carry out. In this topic I learn that it is very important to know the ratio or auxin and cytokinin in order to let the explants or callus to develop it shoots or roots. Auxin will be stimulating the growth of shoots, while cytokinin stimulates the growth of roots. The correct amount is needed to determine the degree of shoot and/or root formation in tissue culture. A high ratio of cytokinin to auxin favours shoot production, whereas a high auxin to cytokinin ratio favours root production. Intermediate levels of both hormones enhance callus formation. Besides that we should know that when the plants have undergoes tissue culture, we cannot transfer it immediately to exposure of sun. This is because during tissue culture, they had adapted to the environment where the humidity is high and the sun exposure is low. Directly bringing the tissue-cultured plant will causes the plant to be dehydrated and die. Moreover there are some factors that need to be considered when we are doing tissue culture, such as the air flow, fresh media and also sufficient food for the plant. No stress should be given to the plants, as stress will lead to the increase or hormone ethylene, excessive of this hormone will cause the retardation of growth. Next there are also factors need to be considered and decide when totipotency is carry out such as sources of explants, age of explants, the size of explants, energy sources, the season where the plant will grow and etc. However there are many successful cases for tissue culture, there is still a problem to tissue culture woody plant. Hence woody plant is known as recalcitrous.

Next, we study about reproduction in plant. There are 2 types of reproduction which are asexual (budding, rhizomes etc. ) and sexual. Sexual reproduction is the fusion of male and female gametes, where asexual doesn’t involves the fusion of gametes.

Sexual Reproduction

During embryogenesis, the zygote has suspensor which is important for the plant growth. Without it, it will not grow. There is four types of tissue culture, which are embryo culture, organ culture, callus culture and cell culture. If we use anther in culturing this plant we will get a haploid plant.

Embryogenesis of dicotyledon plant - where the heart at the heart stage is visible.

Beside the lecture, we discuss again about our Trainee Scientist, our topic is on transport mechanism in cell membrane. We are asked to prepare on our proposal, listing the learning outcomes, activities that we are doing and also questionnaire. The Trainee Scientist program basically is to gain interest of primary student on science subjects. In order to do that, we need to prepare interesting activities, hands on to involve them in it. Besides this is also to inspire them, to make them understand more about the fun of learning sciences, that science is really interesting.I really looking forward for this Trainee Scientist program, where I get the opportunity to inspire the younger generation, make them love science and they might be a successful scientist in the future.

Week 5 - Endosymbiosis

In this class I've learned what is endosymbiosis and what organelles had undergoes this endosymbiosis process. Endosymbiotic theory suggest that the large host cell and ingested bacteria become dependent on one another for survival, resulting in a permanent relationship. Besides, eukaryotes arose from a symbiotic relationship between various prokaryote, hetetrophic which is aerobic bacteria became mitochondria and cyanobacteria (photosynthetic) became chloroplast.

Next we are asked to determined whether mitochondria and chloroplast are originated from prokaryotes. Firstly, I really didn't expect that this organelles originally are from either prokaryote or eukaryote. I thought that the cell somehow already have those organelles, through evolution or they are born having those organelles. But after this class I realize that it is not. They undergo a process call endosymbiosis which they enter the cell through endocytosis and become a part of the cell. Mitochondria and chloroplast are originated from prokaryotes, due to some of the reasons.

1. The DNA of this organelles are circular which is the same as prokaryotes.

2. The size of the ribosomes is 70s, is the same as prokaryotes. While eukaryotes is 80s.

3. Mitochodria, chloroplast and prokaryotes replicated through binary fission. 

There is also other factors such as size. Hence all this characteristics show mitochondria and chloroplast are originated from prokaryotes. 

Next we learn about cell cycle. In form 5 and form 6 I learn about interphase, mitosis and meiosis. That's the only thing I've learned before. Last time we only cover a little about interphase, I actually dont really know what the cell do during that phase. In this class I just knew that there are a lot of stages before the cell are ready for mitosis. There are Gap 1, synthesis stage and Gap 2. Gap 1 and Gap 2 is basically the preparation for the cell before they enter the mitosis stage. While the synthesis stage are the stage where the DNA is replicated. Each stages needed a specific enzyme for them to work, the enzyme in Cyclin together with the Cyclin Dependent Kinase. 

The new next term that I learned is totipotency, the ability of any cells to form the organism back at favorable conditions. Scientist use this theory to make test tube plants, to replant a plant by just using the plant cell. For example, the leaf is dediferentiate into callus ( a group of undifferentiated cells), then it will re-differentiate into embryo, shoots and roots, forming a new plant. That's all for week 5.

Week 4 - Cell Theory

This week the Topic that I learned is about Cell Theory and Prokaryote. We are given a task to be done before the class on the scientist that had contribute to the cell theory. There are 4 main scientist that had contributed to cell theory. I really look up to them, because without them, we will not be able to differentiate the different type of organism. We wouldn't know what made up of the organism, what causes the illness, how the system and things work in our body. The first scientist is Robert Hooke, he discovered the word 'cell', he examined thin slices of cork and discovered empty spores contained by walls. Next we learn about Anton Van Leeuwenhoek who upgraded the magnification of the microscope from  20x-30x to capacity of 270x. With this great invention we can examined many microorganism that cannot see by our naked eyes under the microscope. Besides he also discovered "animacules". This is the new word that I learned which is little animals for example amoeba. Besides Anton Van Leeuwenhoek also discovered bacteria from a sample of saliva from his mouth in the year of 1683. The 3rd scientist that I had look upon is Theodor Schwann, I remember this guy from my STPM text book, where he discovered the Schwann cells in peripheral nervous system. He came out with a cell theory that cells are organism and all organisms consist of one or more cells or cell is the basic structure for all organism. The last scientist is Rudoplh Virchow, where he came out with the cell theory stating that all living things come from other living things, the origin of cells was the division of pre-existing cells.

Besides I learn about the 3 traditional cell theory :
1. All living things are made up of cells.
2. All living cells come from pre-existing cells.
3. Cell is the basic unit of life.
And there is 3 modern cell theory:
1. Studies of biochemistry and metabolism proves that energy flow occur within all cells.
2. Cells contain hereditary information (DNA) that is passed from one cell to another cell during cell reproduction.
3. All cells are basically same in chemical composition and metabolic activities in organisms of similar species.

We also learn about prokaryotes and eukaryotes, stating down the similarities and differences. This is something that I had learned so is not something special to me. But I am quite interested with the next sub-topic which is viruses, prions and viroids. These are exception of cell theory, because they cannot be consider as a living things, they are not the basic unit of life but they can spread, attack and function like it is a living things. Besides viruses, prions and viroids, subcellular organelles such as mitochondria and multinucleated cells such as muscle cells are also exception of cell theory.

I think viruses, prions and viroids is very interesting, they are such a small molecule or organism, but they can do a lot of harm to humans, animal and also plant. This topic is also new to me. Viruses carries genetic material in protein that are called virus code where they code for protein that contain virus and spread to the all part of the body. Attacking the original or normal cell in the body by using the process Lytic cycle and Lysogeny cycle. Where as prions are infectious protein that will infect the normal prion protein by changing it shapes and conformation. This will lead to abnormal protein that will clogged and causes diseases such as mad cow. The next one is viroids which infect plants. Viroids causes the plants to have abnormal shapes. For example potato plants that is affected by viroids produced potato that is small and long. This will cause a big loss to the farmer that brings down the economy.

I enjoy the topic on the virus and prions. Maybe I'll consider myself in taking virology. If I were to do the class again, I'll nicely write down the points on lecture, and write a notes to myself after the class ended. This will help me remember better on the topic.

Mers Virus

Week 3 - History of Life

This week the topic that I had learned to " Origin of Life". How did life begin? It so caught my attention that how life begin, just like when they ask which come first, the egg or chicken? In this class we learn about how did all the organism came from and where are we from. Below is what  I had learned for this topic

4 billion years ago, earth is not formed. When the planet cooled down, the earth layers is formed. The atoms hydrogen gas (H2), oxygen gas (O2), Methane (CH4), Carbon dioxide(CO2) and Nitrogen (N2) are formed. Chemical evolution happen where the inorganic compound were evolved to organic compound, with the stimulation such as hydrothermal vents, volcanoes and lightning. This chemical evolution is know as prebiotic broth hypothesis which is also proved by the scientist Miller and Urey. How did the organic compound start to form and evolved to more complex organism? First the inorganic compound is stimulates by external forces such as volcanoes or ultraviolet radiation to form organic compound. The oxygen level of the earth is increasing. In the second stage the newly formed organic compound polymerized to produce macromolecules. The larger macromolecules are protein and nucleic acid. In the third stage aggregation of prebiotic molecules form protobiont. Protobionts have the ability to maintain it's chemical properties in the cell. Protobionts also have the ability to replicates and carries out simple metabolism. where this two is the key properties of life. Next the first biological catalyst in RNA, from the theory of origin of life. RNA is the first genetic material and not DNA. Why? This is because RNA have the ability to copy themselves without the presence of enzyme. RNA molecules called ribozymes can involve in many catalytic process, such as make complementary copies of short pieces of RNA. Protobionts contain RNA, with this features it can grow and split, distributing the copies of their heridity macromolecules to their offsping. Besides that, mutation can also occurs in copying RNA which start the biotic diversity. Later on DNA take over as the genetic material as it is more stable and easy packing.

Chemoheterotrophs is the first prokaryotes that can be found in earth, they consume organic molecules for energy and carbon. It takes ATP formed abiotically, as the ATP is losed, natural selection favour those early prokaryotes that can regenarate ATP from ADP to be use as energy. This result the evolution of glycolysis which is fermentation without need of oxygen.

The first autotrophs could be photoautotroph, it used light to derive H2S to fix CO2 into sugar, this process doesn't need the presence of oxygen as well. Cynobacteria is the first photoautotrophs that used light to drive electrons from H20 instead of H2S to fix CO2. O2 is released in this process, hence the releasing of O2 change the atmosphere dramatically. This cause the extinction of many anaerobic organism, natural selection favor those early prokaryotes that able to tolerate O2. This result in aerobic respiration. The change in the atmospheric forced diverse adaptations including cellular respiration which produce energy using O2.

Cyanobacteria - The first of bacteria that release oxygen to earth

The next class we learned the topic of Systematic, Taxonomy & Classification, before this. I had encountered with this topics. The new things that I had learned was Archaebacteria and Eubacteria. Archaebacteria is an ancient bacteria which can live in extreme environment, while eubacteria is a true bacteria. Both of it have diff cell wall components and some other differences. That is all I had learned for Week 3, which is really new for me. I will further look into this topics to make myself more understand and know them.

History of life 

Week 2 - Evolution + Selection

This week, I had prepared for the class by watching the video " Endless Forms Most Beautiful". We discuss with Dr. Parameswari about the video in the class. It's a video about the evolution, mostly about the story of Charles Darwin, the evidence of evolution and the ideas proposed by Charles Darwin. Before this I have learned about the finches in Galapagos island. From this video, it open up my views that there are not only the finches that prove the ideas of evolution. There are different animals for example, swimming lizard, giant tortoise and seals. First the theory of evolution was proved by the formation of coral discovered by Darwin. Besides there are fossils that found by Darwin in Galapagos island that show evidence of common ancestry among species, which are the fossils of giant sloth and almadillo - the "Gigantic Guinea Pig".
  
The giant sloth.

 From the aspect of Biogeography, the animals of Galapagos island were similar to animals from the South American mainland but it is different from the animals on the other island that have similar environment. Next, there are natural selection which contribute to evolution. Increasing genetic variation and environment effect on that variation form the basis for natural selection. After thousand of generations, the organism that have the advantage with survive preservation will be more favorable. There are few factors that causes variation in different places, there are population size, mutation rate and reproduction rate.



After we have done discussing the video, we are given another video to watch on Selection in Action.  Next we did SCL activites, on the topic on the evidence of evoluion in Darwin's time. It's mostly question about the video. There is this new things that I had encountered with during the SCL activities which are the new technology that further understand the concept of evolution. For instance, there are DNA sequence analysis, Pseudogenes ( lost its function but is still being inherited), Homeobox genes ( involved in development, especially in embryo development) and protein comparisons.

Next , the second class of the week we talk about the second video " Selection in Action". There are two types of selection :
a. Artifical selection, the breeding of plants oranimals to produce desirable traits.
b. Natural selection, a process whereby organisms better adapted to their environment tend to survive and produce more offspring. It works at physical level but not genetic level hence it doesn't change the genetic of an organism.
The mechanism of natural selection are struggle of survival, overproduction, adaptation of each organism and also descent with more modification. All this factors will lead to the variations of organism and causing the evolution to happen.
From this class I learned new word which is Heretability, which means the ability of a trait to be pass down to the next generation.

Next we drew and came out with a comic strip showing the process of evolution. My group decided to draw an evolution on rabbits which have different color. Below are the comic strips that we had prepared.

That's all for the second week. 

Week 1 - Evolution

8 of September is my first class to Cell and Development Biology. I feel excited and curious on what are we going to learn here. My lecturer for this course is Dr. Parameswari Namasiwayam, where she will teach the upper half of the subject and Dr. Nik Mohd Afizan Nik Abdul Rahman for the second half of this subject. Today I only get to meet Dr. Parameswari and she gaves us the introduction of this subject, the exam scheme and things we need to prepare for her class. So we are informed how is the marks given for us for the first semester which is listed below:
Test 1          : 10%
Test 2          : 10%
Scl               : 40%
Final Exam : 40%
Moreover we are told that we need to write reflective journal using blogging. Which is very new to me, it's a new way of learning where I get to revise on the topics that the lecture had taught us, reflecting on things I had learned before or new things that I had just encounter with. I really think this a good way for us to get to understand ourselves on whether we truly understand the topics or not.


Charles Darwin (1809-1882)

The first topic for this subject is Theory of evolution and Charles Darwin. I have actually learn a little about evolution and heard of Charles Darwin. Whenever I heard of Charles Darwin it only remind me of the Galapagos island and the finches that he discovered, that is the only thing I learn about Charles Darwin in my STPM.
                          

Evolution is very interesting it change through a long period of time. Whenever I saw evolution I will think of the picture where the monkey slowly transform its physical appearance to become a human being. This is basically defines what evolution is, many people might not able to believe this happen but according the those scientist, their research has proven that evolution did happen.

We are asked to watch the video " Endless Forms Most Beautiful" after this first class. The contents are mostly about the ideas proposed by Darwin in Origin of Life, the evidence of evolution and mechanism of evolution. We are asked to discuss about the video on the next class.

So this is basically my first class for this subject Cell and Development Biology. It is so different from secondary school where we are ask to prepare ourselves before the class, get to know the topic and learn it before the class. I think this is a really good way for us to learn a new thing, rather than just being spoon fed by the lecture.