kilasan memoir

Aduh......masa makin cepat berlalu. Banyak pengalaman hidup telah berlalu. Smakin matang atau semakin ak xamik port dgn keadaan sekeliling ak. Janji ak bahagia...HAkunamatata...prinsip pernah ak pegang tuk kuatkan semangat jati diri ak.
tp takut plak terpesong makne dr segi agamayer plak.

Sepanjang duk kt cni, ad satu kemusykilan ak kt cni iaitu XDE TV KE? sebesar2 kolej ni. tv cafeteria je ad. bukan ble tgk sokmo pun. time makan ble ler....ap da?
Sbb 2 mak ak risau klu pg jauh dr ketiak dier, dier tau ak xleh duk jauh kembar siam ak 2. sanggup jaga smpi pg semata nk tgk tv biarpun xde rancangan best pun asal tv.
dlu duk hostel pun, org da tau ak ilg ke mana sanggup usung bantal n sgala mcm mak nenek asal dpt duk depan tv. da sibuk kje xdela plak cakna dgn tv yer. sekadar teman kesunyian selain dpt mcm info br. ak suka termenung pk ap ntah, ak sendr xtau. (Sbb 2 ak xheran klu org ckp ak pelik)

The one-celled organism amoeba proteus
A single-celled bacteria of the type: E. coli
A human red blood cell
A plant cell from the leaf of a poplar tree The cell is one of the most basic units of life. There are millions of different types of cells. There are cells that are organisms onto themselves, such as microscopic amoeba and bacteria cells. And there are cells that only function when part of a larger organism, such as the cells that make up your body. The cell is the smallest unit of life in our bodies. In the body, there are brain cells, skin cells, liver cells, stomach cells, and the list goes on. All of these cells have unique functions and features. And all have some recognizable similarities. All cells have a 'skin', called the plasma membrane, protecting it from the outside environment. The cell membrane regulates the movement of water, nutrients and wastes into and out of the cell. Inside of the cell membrane are the working parts of the cell. At the center of the cell is the cell nucleus. The cell nucleus contains the cell's DNA, the genetic code that coordinates protein synthesis. In addition to the nucleus, there are many organelles inside of the cell - small structures that help carry out the day-to-day operations of the cell. One important cellular organelle is the ribosome. Ribosomes participate in protein synthesis. The transcription phase of protein synthesis takes places in the cell nucleus. After this step is complete, the mRNA leaves the nucleus and travels to the cell's ribosomes, where translation occurs. Another important cellular organelle is the mitochondrion. Mitochondria (many mitochondrion) are often referred to as the power plants of the cell because many of the reactions that produce energy take place in mitochondria. Also important in the life of a cell are the lysosomes. Lysosomes are organelles that contain enzymes that aid in the digestion of nutrient molecules and other materials. Below is a labelled diagram of a cell to help you identify some of these structures.
There are many different types of cells. One major difference in cells occurs between plant cells and animal cells. While both plant and animal cells contain the structures discussed above, plant cells have some additional specialized structures. Many animals have skeletons to give their body structure and support. Plants do not have a skeleton for support and yet plants don't just flop over in a big spongy mess. This is because of a unique cellular structure called the cell wall. The cell wall is a rigid structure outside of the cell membrane composed mainly of the polysaccharide cellulose. As pictured at left, the cell wall gives the plant cell a defined shape which helps support individual parts of plants. In addition to the cell wall, plant cells contain an organelle called the chloroplast. The chloroplast allow plants to harvest energy from sunlight. Specialized pigments in the chloroplast (including the common green pigment chlorophyll) absorb sunlight and use this energy to complete the chemical reaction:
6 CO2 + 6 H2O + energy (from sunlight) C6H12O6 + 6 O2
In this way, plant cells manufacture glucose and other carbohydrates that they can store for later use.
Organisms contain many different types of cells that perform many different functions. In the next lesson, we will examine how individual cells come together to form larger structures in the human body.
For more information about cells, check out:
The Cells alive! page for more pictures
Thinkquest's The Cell page for more pictures and information, including a virtual cell diagram
The Internet Bio-Ed project's Cell and Cell Division page
And the WWW Cell Biology Course

Introduction Structures/Functions Prokaryotes vs. Eukaryotes Types Reproduction Theory Glossary Credits

Within cells there is an intricate network of organelles that all have unique functions. These organelles allow the cell to function properly. Arranged below according to location (nucleus, cytoplasm, and surface) is a description of common organelles. You may click on the organelle's name in the list below to directly reach the feature on that structure.
Cell wallCentriolesChloroplastsChromosomesCytoskeletonEndoplasmic reticulumNuclear membrane
NucleolusGolgi apparatusLysosomeMitochondriaPlasma membraneRibosomesVacuoles

One or more per cell
Spherical shape
Denser than surrounding cytoplasm
Chromosomes- Usually in the form of chromatin- Contains genetic information- Composed of DNA- Thicken for cellular division- Set number per species (i.e. 23 pairs for human)
Nuclear membrane- Surrounds nucleus- Composed of two layers- Numerous openings for nuclear traffic
Nucleolus- Spherical shape- Visible when cell is not dividing- Contains RNA for protein manufacture

Collective term for cytosol and organelles contained within
Colloidal suspension
Cytosol mainly composed of water with free-floating molecules
Viscosity constantly changes
Centrioles- Paired cylindrical organelles near nucleus- Composed of nine tubes, each with three tubules- Involved in cellular division- Lie at right angles to each other
Chloroplasts- A plastid usually found in plant cells- Contain green chlorophyll where photosynthesis takes place
Cytoskeleton- Composed of microtubules- Supports cell and provides shape- Aids movement of materials in and out of cells
Endoplasmic reticulum- Tubular network fused to nuclear membrane- Goes through cytoplasm onto cell membrane- Stores, separates, and serves as cell's transport system- Smooth type: lacks ribosomes- Rough type (pictured): ribosomes embedded in surface
Golgi apparatus- Protein 'packaging plant'- A membrane structure found near nucleus- Composed of numerous layers forming a sac
Lysosome- Digestive 'plant' for proteins, lipids, and carbohydrates- Transports undigested material to cell membrane for removal- Vary in shape depending on process being carried out- Cell breaks down if lysosome explodes
Mitochondria- Second largest organelle with unique genetic structure- Double-layered outer membrane with inner folds called cristae- Energy-producing chemical reactions take place on cristae- Controls level of water and other materials in cell- Recycles and decomposes proteins, fats, and carbohydrates, and forms urea
Ribosomes- Each cell contains thousands- Miniature 'protein factories'- Composes 25% of cell's mass- Stationary type: embedded in rough endoplasmic reticulum- Mobile type: injects proteins directly into cytoplasm
Vacuoles- Membrane-bound sacs for storage, digestion, and waste removal- Contains water solution- Contractile vacuoles for water removal (in unicellular organisms)

Cell wall- Most commonly found in plant cells- Controls turgity- Extracellular structure surrounding plasma membrane- Primary cell wall: extremely elastic- Secondary cell wall: forms around primary cell wall after growth is complete
Plasma membrane- Outer membrane of cell that controls cellular traffic- Contains proteins (left, gray) that span through the membrane and allow passage of materials- Proteins are surrounded by a phospholipid bi-layer.
Organelle Links
Cells and Organelleshttp://www.life.uiuc.edu/bio100/lessons/cells_and_organelles.html
The Insides of Cellshttp://kauai.cudenver.edu:3010/0/nutrition.dir/organelle.html
Structures and Function of Organelleshttp://esg-www.mit.edu:8001/esgbio/cb/organelles.html
Why Are There Organelles?http://iip.ucsd.edu/Step/projects95/cellular.Organelles/WHY.HTM
Cellular Organelleshttp://iip.ucsd.edu/Step/projects95/cellular.Organelles/CELLS.HTM
Microfilaments and Microtubules--The Cytoskeletonhttp://www-class.unl.edu/bios201/group6/cytoskel.html
Eukaryotic Cell Membrane or Plasma Membranehttp://www.bio.mtu.edu/campbell/eukaryot.htm
The Nucleus, Nucleolus, Nuclear Envelope, and everything you ever wanted to know about DNA (but were afraid to ask)http://www-class.unl.edu/bios201/group6/nucleus.html
Lysosomeshttp://www-class.unl.edu/bios201/group6/lyso.html
The Rough and Smooth Endoplasmic Reticulumhttp://www-class.unl.edu/bios201/group6/er.html
The Endoplasmic Reticulumhttp://lenti.med.umn.edu/~mwd/back/cell_www/chapter2/ER.html
The Golgi Bodieshttp://www-class.unl.edu/bios201/group6/golgi.html
Centrioleshttp://www-class.unl.edu/bios201/group6/centrio.html
Mitochondriahttp://www-class.unl.edu/bios201/group6/mitochon.html

Cell biology (also called cellular biology or formerly cytology, from the Greek kytos, "container") is an academic discipline that studies cells – their physiological properties, their structure, the organelles they contain, interactions with their environment, their life cycle, division and death. This is done both on a microscopic and molecular level. Cell biology research encompasses both the great diversity of single-celled organisms like bacteria and protozoa, as well as the many specialized cells in multicellular organisms like humans.

Knowing the components of cells and how cells work is fundamental to all biological sciences. Appreciating the similarities and differences between cell types is particularly important to the fields of cell and molecular biology as well as to biomedical fields such as cancer research and developmental biology. These fundamental similarities and differences provide a unifying theme, sometimes allowing the principles learned from studying one cell type to be extrapolated and generalized to other cell types. Hence, research in cell biology is closely related to genetics, biochemistry, molecular biology and developmental biology.

Contents 1 Processes 1.1 Movement of proteins 1.2 Other cellular processes 2 Internal cellular structures 3 Techniques used to study cells 4 See also 4.1 Notable cell biologists 5 References 6 External links 6.1 Online cell biology textbooks

Processes

Movement of proteins

Each type of protein is usually sent to a particular part of the cell. An important part of cell biology is the investigation of molecular mechanisms by which proteins are moved to different places inside cells or secreted from cells.

Most proteins are synthesized by ribosomes in the cytoplasm. This process is also known as protein biosynthesis or simply protein translation. Some proteins, such as those to be incorporated in membranes (known as membrane proteins), are transported into the endoplasmic reticulum (ER) during synthesis. This process can be followed by transportation and processing in the Golgi apparatus. From the Golgi, membrane proteins can move to the plasma membrane, to other subcellular compartments, or they can be secreted from the cell. The ER and Golgi can be thought of as the "membrane protein synthesis compartment" and the "membrane protein processing compartment", respectively. There is a semi-constant flux of proteins through these compartments. ER and Golgi-resident proteins associate with other proteins but remain in their respective compartments. Other proteins "flow" through the ER and Golgi to the plasma membrane. Motor proteins transport membrane protein-containing vesicles along cytoskeletal tracks to distant parts of cells such as axon terminals.

Some proteins that are made in the cytoplasm contain structural features that target them for transport into mitochondria or the nucleus. Some mitochondrial proteins are made inside mitochondria and are coded for by mitochondrial DNA. In plants, chloroplasts also make some cell proteins.

Extracellular and cell surface proteins destined to be degraded can move back into intracellular compartments upon being incorporated into endocytosed vesicles. Some of these vesicles fuse with lysosomes where the proteins are broken down to their individual amino acids. The degradation of some membrane proteins begins while still at the cell surface when they are cleaved by secretases. Proteins that function in the cytoplasm are often degraded by proteasomes.

Other cellular processes

• Cell division - a eukaryotic cell process resulting in the formation of daughter cells; there are two major types, that of mitosis and meiosis, asexual reproduction and sexual reproduction, respectively.
• Cell signaling - Regulation of cell behavior by signals from outside.
• Active transport and Passive transport - Movement of molecules into and out of cells.
• Adhesion - Holding together cells and tissues.
• Transcription and mRNA splicing - gene expression.
• Cell movement: Chemotaxis, Contraction, cilia and flagella
• DNA repair and Cell death
• Metabolism: Glycolysis, respiration, Photosynthesis
• Autophagy - The process whereby cells "eat" their own internal components or microbial invaders

Internal cellular structures

• Organelle - term used for major subcellular structures
• Chloroplast - key organelle for photosynthesis
• Cilia - motile microtubule-containing structures of eukaryotes
• Cytoplasm - contents of the main fluid-filled space inside cells
• Cytoskeleton - protein filaments inside cells
• Ribosome - RNA and protein complex required for protein synthesis in cells
• Endoplasmic reticulum - major site of membrane protein synthesis
• Flagella - motile structures of bacteria, archaea and eukaryotes
• Golgi apparatus - site of protein glycosylation in the endomembrane system
• Membrane lipid and protein barrier
• Lipid bilayer - fundamental organizational structure of cell membranes
• Vesicle - small membrane-bounded spheres inside cells
• Mitochondrion - major energy-producing organelle by releasing it in the form of ATP
• Nucleus - holds most of the DNA of eukaryotic cells and controls all cellular activities

Techniques used to study cells

Cells may be observed under the microscope. This includes the Optical Microscope, Transmission Electron Microscope, Scanning Electron Microscope, Fluorescence Microscope, and by Confocal Microscopy.

Several different techniques exist to study cells.

• Cell culture is the basic technique of growing cells in a laboratory independent of an organism.

cells as they divide and migrate ken

• Immunostaining, also known as immunohistochemistry, is a specialized histological method used to localize proteins in cells or tissue slices. Unlike regular histology, which uses stains to identify cells, cellular components or protein classes, immunostaining requires the reaction of an antibody directed against the protein of interest with the tissue or cell. Through the use of proper controls and published protocols (need to add reference links here), specificity of the antibody-antigen reaction can be achieved. Once this complex is formed, it is identified via either a "tag" attached directly to the antibody, or added in an additional technical step. Commonly used "tags" include fluorophores or enzymes. In the case of the former, detection of the location of the "immuno-stained" protein occurs via fluorescence microscopy. With an enzymatic tag, such as horse radish peroxidase, a chemical reaciton is carried out that results in a dark color in the location of the protein of interest. This darkened pattern is then detected using light microscopy.

• Gene knockdown mutates a selected gene
• Transfection introduces a new gene into a cell, usually an expression construct
• PCR can be used to determine how many copies of a gene are present in a cell
• In situ hybridization shows which cells are expressing a particular RNA transcript
• DNA microarrays identify changes in transcript levels between different experimental conditions
• Computational genomics is used to find patterns in genomic information ^[1]

Purification of cells and their parts

Purification may be performed using the following methods:

• Flow cytometry
• Cell fractionation
  • Release of cellular organelles by disruption of cells.
  • Separation of different organelles by centrifugation.
• Proteins extracted from cell membranes by detergents and salts or other kinds of chemicals.
• Immunoprecipitation.

Kelas, gambar ape tue? betul ker? gune utk ape ek? Knape selalu sinomin bile bulan mei?

isy...risau aku bile pikir n tenung lilin ni...mau terbakar aku dibuatyer. Mampu ke ak nk jd lilin ni....slalu jd tiang lampu time kwn dating adla, tak pun klu ak admirer, dier da ad org lain (jd consultant berbayar air mata frust
menonggeng -hah poyo betul aku mengaku).

Ak xsangka walaupun masih awal utk mengaku aku akan jd lilin. Tapi syukur Alhamdullillah... jalan yang ditentukan Illahi adalah terbaik dalam hidup aku. Smoga jadi bekalan amalan utk masa depan abadi. Itupun klu ak bg ilmu yng betul dan dipratik oleh orang yang betul ke jalan yang betul. Fuh...cam berfalsafah plak tp bile blajar falsafah pendidikan ak da pening dgn ayat yang agak berbelit walaupun senang straight da point da jer!

Hehe...bile tengok cerita GTO n Gokusen, nk jer ak jd cam mereka bukan skema tp ble dibawa brunding sbagai sahabat untuk membina semangat menjadi modal insan yang lahir dari guru Versatil & Holistik