REVISION WEEK

  

Week 7

hai everyone.. week 7 is the most relax week because this week only for revision. hehehe.. Last week i have got my mark for Test 1. It not so good. Why I'm so bad in biology. Actually i never get good result for biology even i like this subject. Ok let forget about the sad thing. this week we do revision for the test 1. we do this for students to know how to tackle questions especially the tricky questions. I don't know why but i think i can answer the questions when we discuss in class but i reallr blur, do not know anything in the test. ARGHH..  So stress.. 

Week 7 not only revision week but also the last week Dr. Parameswari teach us for the subject cellular and developmental biology. So here Iwant to say thank you so much Dr. because teach me so many new things. Also Thank you Dr. for the knowledge that Dr. has share with us in class.  Also Dr. you are so kind to us. i hope the next Dr. Nik that will replace Dr. is kind like Dr. 

I also want to say sorry if have make mistakes to Dr. without i notice 

After seven week i take the cellular and developmental biology think i start to like this subject. It so fun subject because i can learn many new things

I hope I can do the best for my four years in degree. I admit that degree life is very busy. for the first time i very shock because for the first day i already have so many homework. I someone who will do homework last minute but now i cannot do like that because it not will finish on time. It very a lot of work to do. So i advise to everyone who will join degree life do not practice to do homework or study last minute because you will not get to catch up. 

Lastly good luck for me and for everyone.

PLANT HORMONE

Week 6

Hello and good morning everyone. Now it my second last week writes about what i learn for my first semester for the the subject cellular and developmental biology. Yes it second last because i have assign to writes reflective journal for seven weeks and now my six weeks. So let's get started... Oh ya before we start i want to tell you that on Tuesday i do not go to class because i infected chicken pox. It so hurt and itchy. So i ask my friend what they do on the Tuesday and they say  they do the cell division cycle matching quiz, they do scl group activity: venn diagram for zygotic vs somatic embryogenesis  and quiz on plant sexual reproduction. So from that i got know that i miss two important quiz. ARGHHH.. it really stress.

I also find a little bit information about chicken pox and i want to share with you all. Chicken pox is Caused by the varicella-zoster virus (VZV), chickenpox is very contagious. Chicken pox is famous know as childhood illness because usually children will infected with this diseases. Some people say that once you infected, you will become immune to this diseases. That mean you will only infected one time in your life. But rarely have poeple infected more than one time. ok stop here about chicken pox now we continue with my assignment.

On Thursday i already recover so i go to class study as usual. On Thursday my lecture teach about plant hormones. Plants Hormones is to promote and also inhibit plant growth. In this topic we study about five plant hormones which is auxin, cytokinins, gibberellines, abscisic acid and ethylene.

function of auxin

The main function of auxin is to help plants grow. Auxin stimulates plant cells to elongate, and the apical meristem of a plant is one of the main places that auxin is produced. This makes sense because the apical meristem is also the location that all the other parts of a plant grow from - the stem, leaves, and flowers.
Auxin not only elongates cells, but it specifically elongates them in response to the environment. In response to light, auxin will elongate cells on the dark side of a stem so that the plant literally bends towards the light source. This is called phototropism, and it allows the plant to photosynthesize as much as possible, which is important because photosynthesis is how a plant makes food from light.

Auxin also elongates root cells down into the ground, while at the same time elongating cells in the stem upward. This phenomenon, called gravitropism helps the plant develop a strong underground support system and get nutrients from the ground, and it also helps it grow tall towards the sunlight.

Cytokinins are a group of hormones that promote cell division in plant roots and shoots and the growth of buds.  Functions of cytokinins is it can promote germination in some seeds in the absence of light, when the seeds normally required light for germination. Cytokinins usually work in conjunction with auxin. Cytokinins can promote axillary bud growth by over-riding the apparent inhibiting effect of auxin. this is one of the ways in which plants balance root and shoot growth.

Cytokinins also retard leaf senescence probably by stimulating RNA and protein synthesis and delaying degradation of chlorophyll.

Gibberellins (GAs) are plant hormone that regulate growth and influence variousdevelopmental process, including stem elongation, germination, dormancy, flowering, sex expression, enzyme induction, and leaf and fruit senescences. Functions of gibberellins are gibberellins growth hormones that stimulate cell elongation and cause plants to grow taller. Gibberellins also have a role in other plant processes, such as stem elongation, germination, flowering, and fruit ripening. In humans, the pituitary gland secretes the human growth hormone at appropriate times; the plastids of a plant secrete gibberellin in a similar fashion. Once a plant releases gibberellins, its cells begin a process of elongation. Since plants are composed of single cells stacked on top of one another, this elongation of thousands of individual cells results in the overall growth of the plant.

Abscisic acid is involved in several plant functions. Plants have openings on the bottom side of their leaves, known as stomata, that take in carbon dioxide and regulate water content. Abscisic acid has been found to function in the closing of these stomata during times when the plant does not require as much carbon dioxide or during drought times when the plant cannot afford to lose much water through transpiration.Abscisic acid owes its names to its role in the abscission of plant leaves. In preparation for winter, ABA is produced in terminal buds. This slows plantgrowth and directs leaf primordia to develop scales to protect the dormant buds during the cold season.One of the crucial functions of abscisic acid is to inhibit seed germination. Abscisic acid has been found to stop a seed from germinating immediately once it has been placed in the soil. It actually causes the seed to enter a period of dormancy. This is of great benefit to the plants because most seeds are formed at the end of the growing season, when conditions would not be favorable for a new plant to sprout. The abscisic acid causes the seed to wait until the time when conditions are more favorable to grow. This ensures greater success in the plant's ability to grow and reproduce successfully.

Ethylene serves as a hormone in plants. It acts at trace levels throughout the life of the plant by stimulating or regulating the ripening of fruit, the opening of flowers, and the abscission (or shedding) of leaves

POLLINATION AND DEVELOPMENT OF PLANT EMBRYO

Week 5

Good morning everyone. we meet again for my week 5. For week 5 i learn about pollination and development of plant embryo. Actually in week 5 i have test 1 on Thursday. I feel a little bit scare because i still have so many topic to study. On Tuesday i learn about the topic i mention earlier.  

let get started...

So what is pollination???Pollination is the process by which pollen is transferred to the female reproductive organs of a plant, thereby enabling fertilization to take place. pollination have two type which is self-pollination and cross-pollination

   

Self-pollination is occur when anther and stigma is on one same flower. Meanwhile for cross-pollination the anther and stigma is on different flower. For cross-pollination occur, it need a agent to
transfer of pollen from the male reproductive organ (an anther or a male cone) of one plant to the female reproductive organ (a stigma or a female cone) of another plant. the agents can be insects and
winds.

before i start with the double fertilization i share with you life cycle of angiosperm. double fertilization occur when the pollen tube discharges two sperm into the female gametophyte within an ovule

this is the image of double fertilization.

What is double fertilization?? Double fertilization is a complex fertilization mechanism of flowering plants (angiosperms). This process involves the joining of a female gametophyte (megagametophyte, also called the embryo sac) with two male gametes (sperm). After pollen is deposited on the stigma, it must germinate and grow through the style to reach the ovule. The microspores, or the pollen, contain two cells: the pollen tube cell and the generative cell. The pollen tube cell grows into a pollen tube through which the generative cell travels. The germination of the pollen tube requires water, oxygen, and certain chemical signals. As it travels through the style to reach the embryo sac, the pollen tube's growth is supported by the tissues of the style. During this process, if the generative cell has not already split into two cells, it now divides to form two sperm cells. The pollen tube is guided by the chemicals secreted by the synergid present in the embryo sac; it enters the ovule sac through the micropyle. Of the two sperm cells, one sperm fertilizes the egg cell, forming a diploid zygote; the other sperm fuses with the two polar nuclei, forming a triploid cell that develops into the endosperm.

zygotic embryogenesis in plant.

somatic embryogenesis in plant.

after fertilization, occur plant embryogenesis. 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. It occurs during seed development, when the single-celled zygote undergoes a programmed pattern of cell division resulting in a mature embryo there are two type of plant embryogenesis which is zygotic embryogenesis and somatic embryogenesis.
For the zygotic embryogenesis and somatic embryogenesis we do the venn diagram in group.

here is what our group writes. hehehe.. source is from google.

This on all i learn on the week 5. on Thursday i take test 1. i think i do very bad for my test 1. i hope i can learn from my mistake. Actually week 5 is very stress week because i have so many test on week 5. Actually this topic is i hate the most in biology because it so hard for me to  understand about double fertilization. T_T  Because of that i hope i can more understand about the double fertilization. 

CELL DIVISION OF PLANT CELL AND TOTIPOTENCY

Week 4

HAI... we meet again for my week four. for the week four i learn about cell division of plant cell and totipotency. Actually about cell division and totipotency i already study it for SPM and in Asasi. It is basic about mitosis and meiosis but for totipotency i already forgot actually. Hahaha.. For what i know totepotency is the ability of single cell of plant to divide and produce all of the differentiated cells in the plant.

Before we go with the totipotency, we discuss first about cell division in plant. For the topic cell division in plant our lecture not discuss in more detail about mitosis and meiosis but we discuss about interphase. For your information interphase is the longest phase. 

In interphase we have G1 phase, S phase and G2 phase. The G1 phase, or Gap 1 phase, is the first of four phases of the cell cycle that takes place in eukaryotic cell division. In this part of interphase, the cell synthesizes mRNA and proteins in preparation for subsequent steps leading to mitosis. G1 phase ends when the cell moves into the S phase of interphase. At G1 has checkpoint 1. Cell cycle checkpoints are control mechanisms in eukaryotic cells which ensure proper division of the cell. Each checkpoint serves as a potential point along the cell cycle, during which the conditions of the cell are assessed, with progression through the various phases of the cell cycle occurring when favorable conditions are met. Currently, there are three known checkpoints: the G1 checkpoint, also known as the restriction or start checkpoint; the G2/M checkpoint; and the metaphase checkpoint, also known as the spindle checkpoint. For G1 checkpoint  is the main decision point for a cell which it must choose whether or not to divide.

S-phase (synthesis phase) is the part of the cell cycle in which DNA is replicated, occurring between G1 phase and G2 phase. Precise and accurate DNA replication is necessary to prevent genetic abnormalities which often lead to cell death or disease. then it go to G2. G2 phase, or Gap 2 phase, is the third and final subphase of Interphase in the cell cycle directly preceding mitosis. It follows the successful completion of S phase, during which the cell's DNA is replicated. G2 phase is a period of rapid cell growth and protein synthesis during which the cell readies itself for mitosis. As usually in mitosis has  4 phase which is prophase, metaphase, anaphase and telophase.

At mitosis has metaphase checkpoint. During metaphase, the kinetochore microtubules pull the sister chromatids back and forth until they align along the equator of the cell, called the equatorial plane. There is an important checkpoint in the middle of mitosis, called the metaphase checkpoint, during which the cell ensures that it is ready to divide.

 Ok we finish about cell cycle. Now we continue with totipotency. Totipotency is used in plants tissue culture. There are two pathways of regeneration: Organogenesis and Somatic embryogenesis 

Organogenesis is the development of adventitious organs or primordia( embroid) from undifferentiated cell mass(callus) in tissue culture. Use auxin and cytokinins to lead the development of shoot, root or somatic embyos.

Somatic embryogenesis is an  process in which a plant or embryo is derived from a single somatic cell or group of somatic cells. Somatic embryos are formed from plant cells that are not normally involved in the development of embryos.

Factors that affect cellular totipotency are source of explant, nutrient media and constituents, and culture environment.

the topic of cell division of plants cell and totipotency i learn on tuesday and on Thursday i have virus, viroid and prion's quiz. I just manage to get 12 out of 20. it so awfull. ARGHHH.... 

Thats all i want to share with you all about topic that i learn this week.  This week is more light because i just need to revise back what i have study in the past years but also there is a few new knowledge that i get from this topic. But for the quiz on virus. viroid and prions is not good at all. I must study more because next week i will have test 1. I hope i can answer the test 1 well. 

GOODBYE EVERYONE... Wish me LUCK on my test...

HISTORY OF LIFE PART 2, CELL THEORY PROKARYOTES, VIRUS, VIROID, PRION, ENDOSYMBIOSIS

WEEK 3

HAI EVERYONE... As you can see at the title i known that this week i have learn 6 topic for my third week. ARGHHHH!!!! It so many right . But actually all of the topic is just short topic. 

Ok without wasting time i start with the first one which is history of life part 2. In earth all living things are classified by characteristics into six kingdoms of life. 

 

As you cab see from the picture the six kingdoms are archeabacteria, eubacteria, protista, fungi, plantae and animalia. Archeabacteria also known as archae and eubacteria also known as true bacteria are unicellular and prokaryotic meanwhile the other four are eukaryote.

     

    

                     

I want to ask you all, do you known what is Taxonomy? Taxonomy is the science of biological classification-identification, nomenclature (naming the organisms) and making into system. Also do you known what is the important of classification? classification system help us to clarify relationship among organisms, help us remember organisms and their trait and  also enable us to communicate clearly the identity of organisms being studied. 

Caralus Linnaeus  was the first to develop and publish the first comprehensive and consistent classification system for both animal and plant. He emphasized morphological characteristic as the basis for arranging the specimen in a collection. each species is given a unique scientific name. Each unique name is a binomial (Genus + species). For example Homo sapien. Homo is genus and always capitalized. sapien is species and do not need to capitalized. Both name must be underline or written in italics.

Linnaeus was arranged species in an ascending series of inclusive categories or taxa. 

the end for history of life part 2. it look easy right but when my lecture give quiz for us about history of life to answer it, i found it really difficult. i take so long time to answer it and when we discuss the answer, i got so many wrong. i must study more about this chapter.

For the cell theory prokaryotes i study about the scientist who discover cell. Robert Hook who the first discovered cell  while looking through a slice of cork. Anton Van Leeuwenhoek used his hand made microscope to view samples from a pond and discovered single cell organisms. Matthias Jakob Schleiden and Theodore Schwan say all living thing are made up of cell. the cell is the basic unit of life in all living things. Rudolph Carl Virchow say new cells arise from the pre-existing cells (cell division). Lastly Louis Pasteur prove that spontaneous generations does not occur. Then lecture we sit in group and do the venn diagram that illustrates the similarities and differences between eubacteria and archeabacteria. 

this one is we discuss with lecture

this one what we do/write. all sources from google. hahaha..

Viruses

then we study about viruses. virus is very tiny. we cannot see virus through light microscope. we must use more advance microscope to see virus. virus is no membranes, cytoplasm, ribosome or other cellular compenents. they cannot grow or move. virus move through ride dust and the dust be carried by wind. virus can only reproduce inside a host cell such as animal and bacteria (intracellular parasites). virus has two major part which is DNA and RNA. the nuclei acid is surrounded by a protective protein coat called capsid. Some of them also surrounded by envelope (made of lipid and protein)  

         

virus has two way to reproduce. First Lytic Cycle. lytic cycle will harm the host cell because the virus vill kill the host cell. Second is Lysogeny Cycle that do not harm the host cell because the virus do not kill the host cell.

Viroid

Now we continue with Viroid. Scientist found the viroid when they were trying to figure out why potatoes sometimes grew in weird shape. 

Viroids is small circular RNA molecules without a protein coat. Viroids infect plants and viroid induced disease lead to dramatic economic losses in agriculture and horticulture worldwide.

Prions

A prion is an infectious agent composed entirely of protein material, called PrP (short for prion protein), that can fold in multiple, structurally distinct ways, at least one of which is transmissible to other prion proteins, leading to disease that is similar to viral infection.

   

Prion diseases, also known as transmissible spongiform encephalopathies (TSE's) are a group of progressive neurodegenerative conditions. These illnesses exist in both animals and humans. Scrapie, a disease affecting sheep and goats, was the first prion disease to be identified in the 1730s.

Endosymbiosis 

on Thursday we study about endosymbiosis. Before we do group activity first. For group activity we must do venn Diagram  that illustrates the similarities and differences between mitochondria and chloroplast.

 Then after the activity we study about endosymbiosis. From my understanding endosymbiosis is the process that form mitochondria and chloroplast. Endosymbiosis occur when cyanobacteria ate pathogen, the cyanobacteria form membrane around the pathogen and after a long time it become mitochondria and chloroplast inside the cells. Because of that mitochondria and chloroplast have two plasma membranes and alergic to antibiotic. Until now no one known the pathogen that was eaten by the cyanobacteria is not parsed. 

So many already i write for this week. But i still want to say that chapter this week is the most interesting. i got many new knowledge. ok bye2 everyone until we meet again on my next chapter.. GOOD NIGHT... 

HISTORY OF LIFE PART1

WEEK 2

HELLO EVERYONE..... we meet again for my second week.  I'm sure you all wondering right why I write week 1 for the past one and week 2 for this one. Actually this is my assignment for subject cellular and developmental biology. This assignment was called as reflective learning journal blog.
The purpose of the assignment assign to us are to show student ability to communicate in writing, to give opportunity to students to share activities and what they feel during study the subject of cellular and developmental biology. So today i will share with you all what i learn in week 2. In week 2 i learn about History of Life Part1.

Scientist say that the diversification of life started 3.8 billions ago and 3.3 billions ago the earliest unicellular life/ bacteria/ stromatolites/ cyanobacteria exists. But how did life begin? Life begin from molecules to cell. the first cell exist from abiotic synthesis of small organic molecules and then the small organic molecules bonding to each other and form macromolecules. packaging macromolecules into protobionts.

 Protobionts is an aggregation of organic molecules, surrounded by a membrane, that abiotically coalesces into resemblances of living matter; thought to be the precursors of prokaryotic cells. From protobionts the first RNA was produced. Yup from here you can known that RNA come first before DNA. WHY??? Because DNA can only copy themselves with the help of enzymes but single RNA strand can copy in solution containing nucleotides without enzymes. Also,  RNA has the molecule called ribozymes that can make complementary copies of short stretches of their own or other short pieces of RNA. Because of this resulting the self-replication molecules. All of this happen because of chemical evolution. For the chemical evolution occur there are 4 requirement:
1) little or no oxygen.
2)source of energy to form organic molecules-early earth was a place of high energy.
3) Availability of chemical building blocks such as CO2, N2, CO and water vapour.
4) sufficient time for molecules tp accumulate and react.
In history of life it not valid if we not talk about 'Prebiotic Broth Hypothesis". this hypothesis proposes that organic molecules formed near earth's surface-in a sea of organic soup or on rock or clay surfaces.

Miller-Urey's experiment(1953)

In the 1950's, biochemists Stanley Miller and Harold Urey, conducted an experiment which demonstrated that several organic compounds could be formed spontaneously by simulating the conditions of earth early atmosphere.They designed an apparatus which held a mix of gases similar to those found in Earth's early atmosphere over a pool of water, representing Earth's early ocean. Electrodes delivered an electric current, simulating lightning, into the gas-filled chamber. After allowing the experiment to run for one week, they analyzed the contents of the liquid pool. They found that several organic amino acids had formed spontaneously from inorganic raw materials. These molecules collected together in the pool of water to form coacervates. Their experiments, along with considerable geological, biological, and chemical evidence, lends support to the theory that the first life forms arose spontaneously through naturally occuring chemical reactions.

The early Earth was has little oxygen but then become more oxygen because
the existence of  cyanobacteria. Cyanobacteria is the first photoautotrophs that used light to drive electron from water instead of H2S to fix CO2 into sugar. This is because the evolution of prokaryotes that act like chloroplast.  It happen about 2.5 billions ago and it caused the extinction of many anaerobic organisms  and  evolution of aerobic respiration-evolution of prokaryotes that act like mitochondria.

Okey the end for the part 1. For the first time i study about history of life it very confusing but with the help from my friends i think i understand about it a bit. And then our lecture give us a group work to make mind-map for this chapter make me become more understand about this chapter. Thanks to our lecture i can known about our prior existence in more detail... THANK YOU.  That all for today.. thank you. and wait for my third week.. bye2..

INTRODUCTION TO DARWIN'S THEORY

WEEK 1

Hello everyone...  on 5/9/2016 i officially become biology's cell and molecule student. Yeeaayyy... i'm so happy because this is my first choice. So my first week on Tuesday 6/9/2016 i start my first lesson for subject cellular and developmental biology. This first week i study about the introduction of Darwin's theory. so, here today i want to share about the Darwin theory with you all. 

Who is Darwin??? Charles Robert Darwin  was an English naturalist and geologist, best known for his contributions to the science of evolution. He proposed and demonstrated that all species of life have evolved over time from common ancestor through the process he called natural selection. 

Before i continue with the Darwin's theory, i will let you know first what is evolution and the ideas on evolution prior to Darwin. Evolution is change through time. It help us to understand history of life.  Before Darwin, there is a few ideas on evolution such as Aristotle(384-322 B.C) that arranged organisms from simple to complex and visualized them as not perfect but moving to perfectness, Jean Baptiste Lamarck(1744-1829) that say evolution occurred by the inheritance of acquired characteristics. Organisms are subject to a force which moves them from simplicity to complexity and environmental forces fine-tune them to fit their biological niche more efficiently. Lastly Charles Lyell that were give the idea of evolution to Darwin through his book entitled "Principle of Geology".

Before Darwin become naturalist, he was medic student but when he saw for the first time surgery that without sterile, Darwin was not comfortable with surgery and he also not  comfortable with the sight of blood, he had a fairly queasy stomach.  Darwin is known as the "Father of Evolution". he developed his theory after taking trip on a ship called the HMS Beagle. when he saw the coral reef formation, unusual plants and animals and the Galapagos animal such as swimming lizard, the famous marine iguanas and  the giant turtles intrigued Darwin to begins to form his theory of life evolving.  His evolution theory was supported by  fossil evidence, anatomical evidence, biochemical evidence, DNA sequences and embryology. According to Darwin the evolution was occurs by the process of natural selection also known as survival of the fittest. In natural selection there are artificial selection, variation, adaptation and mutation. Alfred Russell Wallace who is published the book of Darwin theory that entitled "The Origin of Species".

That all from me about Darwin's Theory. I think  so many already i share with you all about Darwin Theory. For all of you to more understand about the Darwin's Theory you can check it at http://www.hhmi.org/biointeractive/endless-forms-most-beautiful

For me study About Darwin's Theory is very fun even sometimes i think it's weird but for study something you must be open minded. Also from this theory you will find out why in this Earth there are so many species of animals and plants and some of them are very different and some of the also are look alike.

For the introduction to Darwin's theory i will end here and i hope we can see again for my next blog. Meet again you all. GOOD NIGHT....