WEEK 7: SUMMARY

We already finished all the topics that need to be covered by Dr.Parameswari. On this week 7, we just discussed our test paper that we did on week 5. She gave the tips on how to understand the questions and how to answer it. On the last test, I admit that some of the questions were tricky and there are a lot of answers that i got wrong. I need to push myself on the next coming test. I love to study about biology but sometimes I lost my focus. About Dr.Parameswari's classes, I found it fine and interesting. At first, i need to adapt with the skill of teaching from her. Dr. Parameswari will not give all the information. She wants her students to find the information and not just waiting for someone else to give it to you. She also encourage all her students to use their critical thinking and not totally depend on the lecture notes. After this, Dr. Nik will continue the lecture on other topics and I would like to say thank you to Dr.Parameswari for all the knowledge that have been given and I also want to apologize if I did something wrong. I hope we can see each other again and I want to make her proud soon.

WEEK 6: THE REGULATION OF DEVELOPMENTAL AND DIFFERENTIATION HORMONES

This is the last topic that has been taught by Dr. Parameswari. In this topic, we have been introduced five main types of hormones which are auxin, cytokinin, gibberellins, abscisic acid and ethylene. Auxin is a plant hormone which causes the elongation of cells in shoots and is involved in regulating plant growth. Cytokinins are a class of plant growth substances that promote cell division. Next, gibberellins are plant growth hormones that regulate growth and influence various developmental processes, including stem elongation, germination, dormancy, flowering, sex expression, enzyme induction and leaf and fruit senescence. For abscisic acid, it helps in promoting bud dormancy and the last one is ethylene. Ethylene is the only hormone forms in gas and it controls fruit ripening, flower wilting and leaf falls. These are the simple points that I got from this topic.

 I have doing a quiz about this topic and I really sad because I got a lower marks. It just a simple question about all these hormones and straight forward questions but I cannot answer it!!! This is all because I did not read the notes first.. hmm..

WEEK 5: POLLINATION AND DEVELOPMENT OF PLANT EMBRYO

On this week, we were introduced more detailed on the pollination in plants. The structure of plant’s reproductive organs. For female, it is called ovule that consists of a megasporangium, megaspore and one or more protective interguments. For male, it is called anther that consists of microsporangium. Plants will go through either self-pollination or cross-pollination. If the flower’s structures are separated, it will undergo cross-pollination and if the structures are together, it will undergo self-pollination, but even though the structures stay together in the flower, it can  undergo cross-pollination because the anther is shorter than the stigma so it cannot pass the pollen grains to the stigma.

Plant embryogenesis is the process that produces a plant embryo from a fertilized ovule by asymmetric cell division and the differentiation of undifferentiated  cells into tissues and organs. Plant embryogenesis can be divided into two which are zygotic embryogenesis and somatic embryogenesis. Zygotic embryogenesis is a fertilization of female and male gametes results in the formation of embryo and later the seed. While somatic embryos are formed from plant cells that are normally not involved in the development of embryos.

 The species of flowers can be spread by the agents such as bees and even the winds.

This is some points that I learned in this topic but of course there are other important points. To be honest, I really do not like to study about plants. For me, human’s body is more interesting than plant’s structure but I try to enhance my interest on plants. I also think that plant studies are difficult and people who want to further their studies on plants need to have a deeply passion about plants.

 

WEEK 4: ENDOSYMBIOSIS THEORY AND DIVISION CYCLE OF PLANT CELL AND TOTIPOTENCY

In the next class on week 4, we went through endosymbiosis theory. from this theory i learned how mitochondria and chloroplast presence in eukaryotic cells. the ancestry of mitochondria and chloroplast are proteobacterium and cyanobacteria.
mitochondria also got its own circular DNA and reproduces independently the cell in which it is found. Chloroplast also contains its own DNA and are able to grow and reproduce independently within the cells of plants and other protista that conduct the complex chemistry in photosynthesis.

http://www.fossilmuseum.net/Evolution/Endosymbiosis.htm

For the totipotency in plants, it really caught my attention because before this since in school, i really do not like whatever kind of topics that related to plants. It makes me bored and hardly to pay attention but on this topic I can see the flow of the development in plants from cell and then become callus. Finally it grows into whole plant. From the tissue culture, the plant can undergo either organogenesis or somatic embryogenesis. in organogenesis, the cell will develop become shoot or root first. Then, it grows further become the whole plant. while in somatic embryogenesis, there is no fusion between gametes and the plant is developed from somatic cells. organogenesis can be divided into two which are direct organogenesis and indirect organogenesis. Somatic embryogenesis also can be divided into two. Direct somatic embryogenesis and indirect somatic embryogenesis. 





 
I do not know how come I like this topic but on the other topics that related to plants, I gave a little focus on it. Maybe this topic, I can understand it well but not the others. So I need to give more effort on the other topics as well.

http://www.slideshare.net/avinashsharma40/somatic-embryogenesis-27-march-15-300-pm

WEEK 3: HISTORY AND EVOLUTION OF LIFE ON EARTH PART II AND PROKARYOTIC CELLS, VIRUS, VIROID,PRION

 In this part II of history and evolution of life on earth, we learned about systematics, taxonomy and classification. Evolution produces biodiversity of organisms. What is Systematics? Systematics is the study of biological diversity and its evolution. Taxonomy, a subdivision of systematics is the science of biological classification- identification, nomenclature and making into a system. This classification systems help to clarify the relationship among organisms. It also helps us to remember organisms and their traits. This system enable us to communicate clearly about the identity of organisms being studied. If there is no classification system, it will make the communication between scientists or people who studied in this field become difficult as there will be miscommunication in order to differentiate one organism from another species. There are many ways to classify the animals by seeing their forms, colour, size, chemical structure and genetic make up but now focus is more on molecular similarities, proteins, DNA and genes. Caralus Linnaeus, a Swedish botanist was first to develop and publish the first comprehensive and consistent classification system for both plants and animals. Each species is given a unique scientific name. For this semester, the syllabus for cell biology class and microbiology class are almost the same. In microbiology class, we also learned about taxonomy, classification and so on. What I can relate to this topic from microbiology class is about the scientific name. From the scientific names of a microbe, we can know its shape, who is the founder of the microbe, what kind of nutrient that it gets, and what diseases can be caused by the microbe. It is really useful and interesting. I got really excited actually when the first time I knew that we can get those information from the name of the microbes.

Furthermore, there are 7 taxa which are kingdom, phylum, class, order, family, genus and species. Next, we learned about phylogenetics which is the study of evolutionary relationships among and between species. The relationships usually presented as a phylogenetic tree or cladogram. Each branch of the cladogram is called as clade. Classic phylogenetics dealt mainly with physical or morphological features. Modern phylogeny uses information extracted from genetic material which is mainly DNA and protein sequences.

Other than that, we studied about prokaryotic cells, virus, viroid and prions. First of all, we read about the discovery of cell. The first person who discovered cell was Robert Hooke while looking at a slice of cork. He described cells as tiny boxes or honey combs. He also thought cells only existed in plants and fungi. On 1673, Anton van Leeuwenhoek used his hand microscope to view samples from a pond and discovered single cell organisms. There are three basic cell theory which are:

1) All living things are made up of cells.

2) The cell is the basic unit of life in all living things.

3) New cells arise from the pre-existing cells.

     

     After that, there are four additional statements which are   the cell contains hereditary information which is passed on from cell to cell during cell division,  all cells are basically the same in chemical composition and metabolic activities,  all basic chemical and physiological functions are carried out inside the cells and  cells activities depends on the activities of subcellular structures within the cell.

I have been learning about prokaryotes and eukaryotes since in secondary school and the basic about the cells. In the lecture, I have been introduced more details about the structure of the cells such as the materials that made up the cell wall, the important to distinguish between gram positive and negative bacteria, the features of the cell membrane and the structure of nucleoid region in bacteria. The new things for me are virus, viroid and prion. 

 

Viruses can be classified according to their genetic, shape, symmetry of the capsid, presence and absence of envelope and type of the host. Viruses reproduce in 2 ways, lytic cycle and lysogeny cycle. Lytic cycle is virus will lysis and rupture the host and distribute its particle. In lysogeny cyle, the virus will grow together with the host. Then, DNA’s virus enters the host and integrate the host chromosome. For viroid, it is a small circular RNA molecules without a protein coat. It infects plant and lead to dramatic economic losses in agriculture and horticulture worldwide. The last one is prions. Prion is an infectious agent that is composed primarily of protein.

 

 It propagates by transmitting a mis-folded protein state. This mis-folded protein can lead to mad cow disease and Alzheimer.