Sabtu, 20 Desember 2008

BIOLOGY,, ABO BLOOD VERSI 2

A blood type (also called a blood group) is a classification of blood based on the presence or absence of inherited antigenic substances on the surface of red blood cells (RBCs). These antigens may be proteins, carbohydrates, glycoproteins, or glycolipids, depending on the blood group system, and some of these antigens are also present on the surface of other types of cells of various tissues. Several of these red blood cell surface antigens, that stem from one allele (or very closely linked genes), collectively form a blood group system.[1]

Blood types are inherited and represent contributions from both parents. A total of 30 human blood group systems are now recognized by the International Society of Blood Transfusion (ISBT).[2]

Many pregnant women carry a fetus with a different blood type from their own, and the mother can form antibodies against fetal RBCs. Sometimes these maternal antibodies are IgG, a small immunoglobulin, which can cross the placenta and cause hemolysis of fetal RBCs, which in turn can lead to hemolytic disease of the newborn, an illness of low fetal blood counts which ranges from mild to seve

Serology

If an individual is exposed to a blood group antigen that is not recognised as self, the immune system will produce antibodies that can specifically bind to that particular blood group antigen, and an immunological memory against that antigen is formed. The individual will have become sensitized to that blood group antigen. These antibodies can bind to antigens on the surface of transfused red blood cells (or other tissue cells), often leading to destruction of the cells by recruitment of other components of the immune system. When IgM antibodies bind to the transfused cells, the transfused cells can clump. It is vital that compatible blood is selected for transfusions and that compatible tissue is selected for organ transplantation. Transfusion reactions involving minor antigens or weak antibodies may lead to minor problems. However, more serious incompatibilities can lead to a more vigorous immune response with massive RBC destruction, low blood pressure, and even death.

ABO and Rh blood grouping

Anti-A and Anti-B, the common IgM antibodies to the RBC surface antigens of the ABO blood group system are sometimes described as being "naturally occurring", however, this is a misnomer, because these antibodies are formed in infancy by sensitisation in the same way as other antibodies. The theory that explains how these antibodies are developed states that antigens similar to the A and B antigens occur in nature, including in food, plants and bacteria. After birth an infant gut becomes colonized with normal flora which express these A-like and B-like antigens, causing the immune system to make antibodies to those antigens that the red cells do not possess. So, people who are blood type A will have Anti-B, blood type B will have Anti-A, blood type O will have both Anti-A and Anti-B, and blood type AB will have neither. Because of these so called "naturally occurring" and expected antibodies, it is important to correctly determine a patient's blood type prior to transfusion of any blood component. These naturally occurring antibodies are of the IgM class, which have the capability of agglutinating (clumping) and damaging red cells within the blood vessels, possibly leading to death. It is not necessary to determine any other blood groups because almost all other red cell antibodies can only develop through active immunization, which can only occur through either previous blood transfusion or pregnancy. A test called the Antibody Screen is always performed on patients who may require red blood cell transfusion, and this test will detect most clinically significant red cell antibodies.

The RhD antigen is also important in determining a person's blood type. The terms "positive" or "negative" refer to either the presence or absence of the RhD antigen irrespective of the presence or absence of the other antigens of the Rhesus system. Anti-RhD is not usually a naturally occurring antibody as the Anti-A and Anti-B antibodies are. Cross-matching for the RhD antigen is extremely important, because the RhD antigen is immunogenic, meaning that a person who is RhD negative is very likely to make Anti-RhD when exposed to the RhD antigen (perhaps through either transfusion or pregnancy). Once an individual is sensitised to RhD antigens their blood will contain RhD IgG antibodies which can bind to RhD positive RBCs and may cross the placenta.

Blood group systems

A total of 30 human blood group systems are now recognized by the International Society of Blood Transfusion (ISBT).[2] A complete blood type would describe a full set of 30 substances on the surface of RBCs, and an individual's blood type is one of the many possible combinations of blood group antigens. Across the 30 blood groups, over 600 different blood group antigens have been found,[4] but many of these are very rare or are mainly found in certain ethnic groups.

Almost always, an individual has the same blood group for life; but very rarely an individual's blood type changes through addition or suppression of an antigen in infection, malignancy or autoimmune disease.[5][6][7][8] An example of this rare phenomenon is the case Demi-Lee Brennan, an Australian citizen, whose blood group changed after a liver transplant.[9][10] Another more common cause in blood type change is a bone marrow transplant. Bone marrow transplants are performed for many leukemias and lymphomas, among other diseases. If a person receives a bone marrow from someone who is a different ABO type (ex. a type A patient receives a type O bone marrow), the patient's blood type will eventually convert to the donor's type.

Some blood types are associated with inheritance of other diseases; for example, the Kell antigen is sometimes associated with McLeod syndrome.[11] Certain blood types may affect susceptibility to infections, an example being the resistance to specific malaria species seen in individuals lacking the Duffy antigen.[12] The Duffy antigen, presumably as a result of natural selection, is less common in ethnic groups from areas with a high incidence of malaria.[13]

ABO blood group system

Main article: ABO blood group system

The ABO system is the most important blood group system in human blood transfusion. The associated anti-A antibodies and anti-B antibodies are usually "Immunoglobulin M", abbreviated IgM, antibodies. ABO IgM antibodies are produced in the first years of life by sensitization to environmental substances such as food, bacteria and viruses. The "O" in ABO is often called "0" (zero/null) in other languages.[14]


Phenotype

Genotype

A

AA or AO

B

BB or BO

AB

AB

O

OO

Rhesus blood group system

Main article: Rhesus blood group system

The Rhesus system is the second most significant blood group system in human blood transfusion. The most significant Rhesus antigen is the RhD antigen because it is the most immunogenic of the five main rhesus antigens. It is common for RhD negative individuals not to have any anti-RhD IgG or IgM antibodies, because anti-RhD antibodies are not usually produced by sensitization against environmental substances. However, RhD negative individuals can produce IgG anti-RhD antibodies following a sensitizing event: possibly a fetomaternal transfusion of blood from a fetus in pregnancy or occasionally a blood transfusion with RhD positive RBCs.

Other blood group systems

Main article: Human blood group systems

The International Society of Blood Transfusion currently recognizes 30 blood group systems (including the ABO and Rh systems).[2] Thus, in addition to the ABO antigens and Rhesus antigens, many other antigens are expressed on the RBC surface membrane. For example, an individual can be AB RhD positive, and at the same time M and N positive (MNS system), K positive (Kell system), Lea or Leb negative (Lewis system), and so on, being positive or negative for each blood group system antigen. Many of the blood group systems were named after the patients in whom the corresponding antibodies were initially encountered.

Clinical significance

Blood transfusion

Main article: Blood transfusion

Transfusion medicine is a specialized branch of hematology that is concerned with the study of blood groups, along with the work of a blood bank to provide a transfusion service for blood and other blood products. Across the world, blood products must be prescribed by a medical doctor (licensed physician or surgeon) in a similar way as medicines. In the USA, blood products are tightly regulated by the U.S. Food and Drug Administration.

Much of the routine work of a blood bank involves testing blood from both donors and recipients to ensure that every individual recipient is given blood that is compatible and is as safe as possible. If a unit of incompatible blood is transfused between a donor and recipient, a severe acute immunological reaction, hemolysis (RBC destruction), renal failure and shock are likely to occur, and death is a possibility. Antibodies can be highly active and can attack RBCs and bind components of the complement system to cause massive hemolysis of the transfused blood.

Patients should ideally receive their own blood or type-specific blood products to minimize the chance of a transfusion reaction. Risks can be further reduced by cross-matching blood, but this may be skipped when blood is required for an emergency. Cross-matching involves mixing a sample of the recipient's serum with a sample of the donor's red blood cells and checking if the mixture agglutinates, or forms clumps. If agglutination is not obvious by direct vision, blood bank technicians usually check for agglutination with a microscope. If agglutination occurs, that particular donor's blood cannot be transfused to that particular recipient. In a blood bank it is vital that all blood specimens are correctly identified, so labeling has been standardized using a barcode system known as ISBT 128.

The blood group may be included on identification tags or on tattoos worn by military personnel, in case they should need an emergency blood transfusion. Frontline German Waffen-SS had such tattoos during World War II.

Rare blood types can cause supply problems for blood banks and hospitals. For example Duffy-negative blood occurs much more frequently in people of African origin,[36] and the rarity of this blood type in the rest of the population can result in a shortage of Duffy-negative blood for patients of African ethnicity. Similarly for RhD negative people, there is a risk associated with travelling to parts of the world where supplies of RhD negative blood are rare, particularly East Asia, where blood services may endeavor to encourage Westerners to donate blood.[37]

Hemolytic disease of the newborn (HDN)

Main article: Hemolytic disease of the newborn

A pregnant woman can make IgG blood group antibodies if her fetus has a blood group antigen that she does not have. This can happen if some of the fetus' blood cells pass into the mother's blood circulation (e.g. a small fetomaternal hemorrhage at the time of childbirth or obstetric intervention), or sometimes after a therapeutic blood transfusion. This can cause Rh disease or other forms of hemolytic disease of the newborn (HDN) in the current pregnancy and/or subsequent pregnancies. If a pregnant woman is known to have anti-RhD antibodies, the RhD blood type of a fetus can be tested by analysis of fetal DNA in maternal plasma to assess the risk to the fetus of Rh disease.[38] One of the major advances of twentieth century medicine was to prevent this disease by stopping the formation of Anti-RhD antibodies by RhD negative mothers with an injectable medication called Rho(D) immune globulin.[39][40] Antibodies associated with some blood groups can cause severe HDN, others can only cause mild HDN and others are not known to cause HDN.[3]

Compatibility

Blood products

In order to provide maximum benefit from each blood donation and to extend shelf-life, blood banks fractionate some whole blood into several products. The most common of these products are packed RBCs, plasma, platelets, cryoprecipitate, and fresh frozen plasma (FFP). FFP is quick-frozen to retain the labile clotting factors V and VIII, which are usually administered to patients who have a potentially fatal clotting problem caused by a condition such as advanced liver disease, overdose of anticoagulant, or disseminated intravascular coagulation (DIC).

Units of packed red cells are made by removing as much of the plasma as possible from whole blood units.

Clotting factors synthesized by modern recombinant methods are now in routine clinical use for hemophilia, as the risks of infection transmission that occur with pooled blood products are avoided.

Red blood cell compatibility

Blood group AB individuals have both A and B antigens on the surface of their RBCs, and their blood serum does not contain any antibodies against either A or B antigen. Therefore, an individual with type AB blood can receive blood from any group (with AB being preferable), but can donate blood only to another group AB individual.

Blood group A individuals have the A antigen on the surface of their RBCs, and blood serum containing IgM antibodies against the B antigen. Therefore, a group A individual can receive blood only from individuals of groups A or O (with A being preferable), and can donate blood to individuals with type A or AB.

Blood group B individuals have the B antigen on the surface of their RBCs, and blood serum containing IgM antibodies against the A antigen. Therefore, a group B individual can receive blood only from individuals of groups B or O (with B being preferable), and can donate blood to individuals with type B or AB.

Blood group O (or blood group zero in some countries) individuals do not have either A or B antigens on the surface of their RBCs, but their blood serum contains IgM anti-A antibodies and anti-B antibodies against the A and B blood group antigens. Therefore, a group O individual can receive blood only from a group O individual, but can donate blood to individuals of any ABO blood group (ie A, B, O or AB). If anyone needs a blood transfusion in a dire emergency, and if the time taken to process the recipient's blood would cause a detrimental delay, O Negative blood can be issued.

A RhD negative patient who does not have any anti-RhD antibodies (never being previously sensitized to RhD positive RBCs) can receive a transfusion of RhD positive blood once, but this would cause sensitization to the RhD antigen, and a female patient would become at risk for hemolytic disease of the newborn. If a RhD negative patient has developed anti-RhD antibodies, a subsequent exposure to RhD positive blood would lead to a potentially dangerous transfusion reaction. RhD positive blood should never be given to RhD negative women of childbearing age or to patients with RhD antibodies, so blood banks must conserve Rhesus negative blood for these patients. In extreme circumstances, such as for a major bleed when stocks of RhD negative blood units are very low at the blood bank, RhD positive blood might be given to RhD negative females above child-bearing age or to Rh negative males, providing that they did not have anti-RhD antibodies, to conserve RhD negative blood stock in the blood bank. The converse is not true; RhD positive patients do not react to RhD negative blood.

Plasma compatibility

Recipients can receive plasma of the same blood group, but otherwise the donor-recipient compatibility for blood plasma is the converse of that of RBCs: plasma extracted from type AB blood can be transfused to individuals of any blood group; individuals of blood group O can receive plasma from any blood group; and type O plasma can be used only by type O recipients.

Plasma compatibility table

Plasma compatibility table

Recipient

Donor[1]


O

A

B

AB

O

Y

Y

Y

Y

A


Y


Y

B



Y

Y

AB




Y

Table note
1. Assumes absence of strong atypical antibodies in donor plasma

Rhesus D antibodies are uncommon, so generally neither RhD negative nor RhD positive blood contain anti-RhD antibodies. If a potential donor is found to have anti-RhD antibodies or any strong atypical blood group antibody by antibody screening in the blood bank, they would not be accepted as a donor (or in some blood banks the blood would be drawn the product would be appropriately labeled); therefore, donor blood plasma issued by a blood bank can be selected to be free of RhD antibodies and free of other atypical antibodies, and such donor plasma issued from a blood bank would be suitable for a recipient who may be RhD positive or RhD negative, as long as blood plasma and the recipient are ABO compatible.

Universal donors and universal recipients

With regard to transfusions of whole blood or packed red blood cells, individuals with type O negative blood are often called universal donors, and those with type AB positive blood are called universal recipients; however, these terms are only generally true with respect to possible reactions of the recipient's anti-A and anti-B antibodies to transfused red blood cells, and also possible sensitization to RhD antigens. Exceptions include individuals with hh antigen system (also known as the Bombay blood group) who can only receive blood safely from other hh donors, because they form antibodies against the H substance.[43][44]

Blood donors with particularly strong anti-A, anti-B or any atypical blood group antibody are excluded from blood donation. The possible reactions of anti-A and anti-B antibodies present in the transfused blood to the recipients RBCs need not be considered, because a relatively small volume of plasma containing antibodies is transfused.

By way of example; considering the transfusion of O RhD negative blood (universal donor blood) into a recipient of blood group A RhD positive, an immune reaction between the recipient's anti-B antibodies and the transfused RBCs is not anticipated. However, the relatively small amount of plasma in the transfused blood contains anti-A antibodies, which could react with the A antigens on the surface of the recipients RBCs, but a significant reaction is unlikely because of the dilution factors. Rhesus D sensitization is not anticipated.

Additionally, red blood cell surface antigens other than A, B and Rh D, might cause adverse reactions and sensitization, if they can bind to the corresponding antibodies to generate an immune response. Transfusions are further complicated because platelets and white blood cells (WBCs) have their own systems of surface antigens, and sensitization to platelet or WBC antigens can occur as a result of transfusion.

With regard to transfusions of plasma, this situation is reversed. Type O plasma can be given only to O recipients, while AB plasma (which does not contain anti-A or anti-B antibodies) can be given to patients of any ABO blood group.

Conversion

In April 2007 a method was discovered to convert blood types A, B, and AB to O, using enzymes. This method is still experimental and the resulting blood has yet to undergo human trials.[45][46] The method specifically removes or converts antigens on the red blood cells, so other antigens and antibodies would remain. This does not help plasma compatibility, but that is a lesser concern since plasma has much more limited clinical utility in transfusion and is much easier to preserve.

History

The two most significant blood group systems were discovered during early experiments with blood transfusion: the ABO group in 1901[47] and the Rhesus group in 1937.[48] Development of the Coombs test in 1945,[49] the advent of transfusion medicine, and the understanding of hemolytic disease of the newborn led to discovery of more blood groups, and now 30 human blood group systems are recognized by the International Society of Blood Transfusion (ISBT),[2] and across the 30 blood groups, over 600 different blood group antigens have been found,[4] but many of these are very rare or are mainly found in certain ethnic groups. Blood types have been used in forensic science and in paternity testing, but both of these uses are being replaced by genetic fingerprinting, which provides greater certitude.

Cultural beliefs regarding blood types

The Japanese blood type theory of personality is a popular belief that a person's ABO blood type is predictive of their personality, character, and compatibility with others. It was a serious scientific hypothesis which was proposed early in the 20th century, which gained currency within the Japanese public. This theory has long since been rejected by the scientific community. (For a proponent, see Masahiko Nomi). This belief has been carried over to a certain extent into other parts of East Asia, including South Korea and China. In all these places, asking someone their blood type is considered as normal as asking their astrological sign. It is also common for Japanese-made video games (especially role-playing games) and the manga series to include blood type with character descriptions.

The blood type diet is a diet created by an American author who claims that people can improve their health by modifying their food intake and lifestyle according to their ABO blood group and secretor status.[50] This diet theory includes some references to differences in personality between ABO blood types, but not to the extent typical of the Japanese theory.


BIOLOGY,, ABO BLOOD VERSI 1

A B O Blood

A blood type (also called a blood group) is a classification of blood based on the presence or absence of inherited antigenic substances on the surface of red blood cells (RBCs). These antigens may be proteins, carbohydrates, glycoproteins, or glycolipids, depending on the blood group system, and some of these antigens are also present on the surface of other types of cells of various tissues. Several of these red blood cell surface antigens, that stem from one allele (or very closely linked genes), collectively form a blood group system.

Blood types are inherited and represent contributions from both parents. A total of 30 human blood group systems are now recognized by the International Society of Blood Transfusion (ISBT).

Many pregnant women carry a fetus with a different blood type from their own, and the mother can form antibodies against fetal RBCs. Sometimes these maternal antibodies are IgG, a small immunoglobulin, which can cross the placenta and cause hemolysis of fetal RBCs, which in turn can lead to hemolytic disease of the newborn, an illness of low fetal blood counts which ranges from mild to seve.




Blood Group :

Human blood group can be separated into 3 kinds :

1. The blood group of system A, B, AB, and O

2. The blood group of rhesus system

3. The blood group of MN system



1. The blood group of system A, B, AB, and O

Based on the pessence or not agglutinogen, human body group is separated into 4 group of A, B, AB and O. Agglutinogen is substance in red blood cell that it still can be coagulated by agglutinin. Meanwhile agglutinin is substance in blood plsma that cause coagglution in agglutinogen.

a. If someone in red blood cell contains agglutinogen A and blood serum can make agglutinin b, the person has blood group A. The formula of blood group is (A, b)

b. If someone in red blood cell contains agglutinogen B and blood serum can't make agglutinin a, the person has blood group B. The formula of blood group is (B, a)

c.If someone in red blood cell contains agglutinogen a and b but blood serum can make agglutinin, then that person has blood group AB. The formula of blood group is (AB, -)

d.If someone in red blood cell dowsn't contains agglutinogen but the serum of blood has blood group O. The formula of blood group is (-, ab)

Blood type (or blood group) is determined, in part, by the ABO blood group antigens present on red blood cells.



The ABO system is the most important blood group system in human blood transfusion. The associated anti-A antibodies and anti-B antibodies are usually "Immunoglobulin M", abbreviated IgM, antibodies. ABO IgM antibodies are produced in the first years of life by sensitization to environmental substances such as food, bacteria and viruses. The "O" in ABO is often called "0" (zero/null) in other languages.

Phenotype

Genotype

A

AA or AO

B

BB or BO

AB

AB

O

OO





Based on that thing can be conclused that:

  1. The blood tasted has blood group A if mixed by serum of agglutinin a coagulates, while if it mixed by serum of agglutinin b it does not coagulate.

  2. The blood tasted of blood group B if mixed by serum of agglutinin a does not coagulate, while if it mixed by serum of agglutinin b coagulates.

  3. The blood tested has blood group A if it mixed by serum of agglutinin a and b will coagulate.

  4. The blood tested has blood group O if it mixed by serum of agglutinin a and b will not coagulate.


Commonly blood transfusion is done in the following condition.

  1. When body is lost of much blood and surgery.

  2. In burning body.

  3. In accident and body is hurt badly

  4. Suffering chronical suffer

  5. Acute lack of blood

.



Blood Group of Rhesus System

Golongan Darah Sistem Rhesus

Blood grouping based on rhesus system (Rh) is found in 1940 by Landsteiner and Wiener.

a) Positive rhesus (Rh+), if his blood group coagulates if given anti-Rh serum.

Rhesus positif (Rh+), apabila darahnya menggumpal jika diberi serum anti-Rh.

b) Negative rhesus (Rh-), if his blood group foes not coagulate if given anti-Rh serum.

Rhesus negative (Rh-), apabila darahnya tidak menggumpal jika diberi serum anti-Rh.


MN System Blood Group

Golongan Darah Sistem MN

Blood grouping based on MN system is found by Landsteiner and Levine through experiment by using serum for several person who their blood groups are different.

Based on MN system blood group is divided into three those are:

  1. Blood group M if his blood coagulates and if given anti-M serum.

Golongan darah M apabila darahnya menggumpal jika diberu serum anti-M

  1. Blood group N, if his group coagulates if given anti-N serum.

Golongan darah N, apabila darahnya menggumpal jika diberu serum anti-N.

  1. Blood group MN is his blood coagulates if given anti-M and N serum.

Golongan darah MN apabila darahnya menggumpal jika diberi serum anti-M dan N.



Rabu, 05 November 2008

nEw tAsk.......

1. Perbedaan nama Domain dengan URL
  • URL adalah metode penamaan situs di internet yang banyak digunakan di WWW.URL menjelaskan tipe dokumen, nama komputer tempat dokumen disimpan direktori / subdirektori dokumen, dan nama dokumen.
  • Domain adalah identitas komputer di internet yang disebut juga dengan alamat web, akhiran nama domain disebut TLD ( Top level domain)

2. Fungsi HTML
  • untuk membuat text judul utama
  • untuk membuat text sub judul
  • Sebagai bahasa kode untuk ditafsirkan web browser menjadi tampilan halaman web


3. Tipe-tipe koneksi internet
  • Dial-up (Connection) : istilah teknologi informasi dalam bahasa Inggris yang mengacu kepada akses Internet dengan menggunakan jalur telepon tetap atau telepon bergerak.
  • Wi-Fi merupakan kependekan dari Wireless Fidelity, memiliki pengertian yaitu sekumpulan standar yang digunakan untuk Jaringan Lokal Nirkabel (Wireless Local Area Networks - WLAN) yang didasari pada spesifikasi IEEE 802.11.4. Jenis Informasi yang didapat dari internet
  • Broadband : sebuah istilah dalam internet yang merupakan koneksi internet transmisi data kecepatan tinggi. Ada 2 jenis broadband yang umum yaitu DSL dan kabel modem.5. Situs-situs interaktif tentang edukasi
  • Internet satelit : Hubungan ini menggunakan sebuah satelit di orbit geostationary untuk meneruskan data dari perusahaan satelit ke setiap pelanggan.
  • DSL : dari bahasa Inggris Digital Subscriber Line adalah satu set teknologi yang menyediakan penghantar data digital melewati kabel yang digunakan dalam jarak dekat dari jaringan telepon setempat.

4. Jenis Informasi yang didapat dari internet
  • Pendidikan : membantu dan mempermudah siswa maupun guru dalam mencari informasi tentang pendidikan dan ilmu-ilmu pengetahuan lainnya dan mempermudah komunikasi antara guru dengan siswa melalui situs-situs internet.
  • Ekonomi : Membantu masyarakat dalam mengembangkan usaha-usaha atau bisnis-bisnisnya. Misalnya : membuat iklan hasil produksi melalui salah satu situs di internet. Serta memberikan informasi tentang harga saham dan kurs rupiah, sehingga para investor dapat memantau usahanya.
  • Kebudayaan : Mempermudah mencari budaya-budaya daerah lain dan dapat mengembangakan budaya sendiri melalui internet.
  • Pariwisata : mengetahui tempat-tempat wisata di seluruh dunia yang menarik beserta dengan akomodasinya.
  • Politik : Mempermudah mencari informasi-informasi yang berhubungan dengan bidang politik. Misal : Pemilu

5. Situs-situs interaktif tentang edukasi :
  • Wikipedia
  • Edukasi
  • nationalgeographic.com

Senin, 01 September 2008

Laporan TIK

  1. Nama Warnet
  2. Alamat
  3. Jumlah komputer
  4. Tarif per jam
  5. Waktu buka
  6. Topologi jaringan
  7. Media transmisi
  8. piranti jaringan
  9. sistem operasi
  10. ISP
  11. Bandwidth
  12. Cara koneksi ke internet
  13. Billing
  14. Browser
  15. Fasilitas
  16. Kelebihan dan kekurangan warnet

Kamis, 21 Agustus 2008

TuGaS TIK, GaneCa haL.42

1. Apa yang kamu ketahui tentang ISP (Internet Servive Provider) ?
ISP adalah perusahaan yang menawarkan jasa pelayanan untuk berhubungan dengan internet. Untuk mengakses internet, kita cukup menghubungi melalui komputer dan modem, selanjutnya ISP akan mengurus detail-detail yang diperlukan untuk berhubungan dengan internet, termasuk biaya koneksi tersebut.

2.Tulislah 7 nama ISP yang kamu ketahui !
  • RADNET, Jakarta
  • PT Cyberindo Aditama
  • Pasific Link
  • Asia Pasific Internet Company
  • PT Telesindo Media Utama
  • APJII-IIx
  • PT Infotek Mitrasejati
3. Apa Telkomnet instan termasuk ISP? Jelaskan !
Iya, karena Telkomnet instan merupakan alternativ kedua setelah account dari ISP yang digunakan untuk mengakses internet dengan PC di rumah tanpa berlangganan dan Telkomnet instan merupakan perusahaan di Indonesia

4. Tulislah 5 macam persyaratan yang harus dipenuhi supaya dapat melakukan instalasi Dial-up Connection.
  • Komputer
  • Modem
  • Saluran telepon
  • Driver modem
  • Account dari ISP


5. Jelaskan peran ISP dalam mengakses internet !
  • Menghubungkan pelanggan ke Gateway ke internet terdekat
  • Memberi tempat untuk homepage
  • Menghubungkan seorang user ke layanan informasi
  • Menyediakan proteksi penyebaran virus bagi pelanggannya
  • Menyediakan modem untuk dial-up

Senin, 18 Agustus 2008

TUGAS TIK,, BUKU GANECA HAL 33


1. Sebutkan beberapa cara penyambungan kabel UTP pada konektor RJ-45 dan fungsinya!
Penyambungan kabel UTP ada 2, yaitu :







2. Sebutkan 3 kelebihan topologi star dibanding topologi bus!
  • Tiap komputer dapat menggunkan jaringan tanpa menunggu perintah server
  • Pemasangan stasiun sangat mudah dan tidak mengganggu bagian jaringan lain
  • Kontrol terpusat
  • Kemudahan deteksi dan isolasi kesalahan
  • Kemudahan pengelolaan jaringan

3. Sebutkan bahan-bahan untuk membentuk jaringan komputer dengan topologi bus?
  1. Kabel UTP
  2. Swicth
  3. Konektor RJ-25
  4. LAN card dan Repeater (Jika diperlukan untuk jarak yang jauh)

4. Sebutkan manfaat jaringan komputer lokal!
  • File yang keluar masuk ke server dapat dikontrol
  • Pertukaran file dapat dilakukan dengan mudah
  • proses backup data menjadi lebih mudah dan cepat
  • pemakaian printer dapat silakukan oleh semua client
  • File-file dapat disimpan pada server sehingga data dapat diakses dari semua client
  • resiko kehilangan data oleh virus komputer menjadi lebih kecil
  • Apabila salah satu client terhubung dengan modem maka semua atau sebagian komputer pada jaringan lokal dapat mengakses ke jaringan internet atau mengirim faksimili melalui satu modem

5. Sebutkan 2 persyaratan minimal untuk koneksi internet dengan saluran komunikasi telepon!
  • Adanya saluran telepon dan modem
  • Adanya ISP (Internet Server Provider) sebagai penyedia layanan internet





Senin, 28 Juli 2008

TUGAS TIK

PENGERTIAN INTERNET

Istilah INTERNET berasal dari bahasa Latin inter, yang berarti “antara”. Secara kata per kata INTERNET berarti jaringan antara atau penghubung. Memang itulah fungsinya, INTERNET menghubungkan berbagai jaringan yang tidak saling bergantung pada satu sama lain sedemikian rupa, sehingga mereka dapat berkomunikasi. Sistem apa yang digunakan pada masing-masing jaringan tidak menjadi masalah, apakah sistem DOS atau UNIX..

Jadi, definisi INTERNET ialah “jaringannya jaringan”, dengan menciptakan kemungkinan komunikasi antar jaringan di seluruh dunia tanpa bergantung kepada jenis komputernya.

Kesimpulannya :
Definisi INTERNET : Internet merupakan hubungan antar berbagai jenis komputer dan jaringan di dunia yang berbeda sistem operasi maupun aplikasinya di mana hubungan tersebut memanfaatkan kemajuan media komunikasi (telepon dan satelit) yang menggunakan protokol standar dalam berkomunikasi yaitu protokol TCP/IP.

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PENGERTIAN INTRANET

Intarnet adalah jaringan komputer-komputer yang saling tersambung digunakan suatu sistem organisasi. Misalnya: jaringan komputer-komputer PT. Telkom seluruh Indonesia. Jadi dibilang “internet” khusus. Intranet berfungsi mengkomunikasikan komputer satu dengan yang lain, persis seperti internet tetapi layanannya terbatas, tidak seluas dan seberagam di internet.





MANFAAT INTERNE
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Berikut adalah beberapa manfaat penggunaan teknologi informasi :
•arus informasi tetap mengalir setiap waktu tanpa ada batasan waktu dan tempat;
•kemudahan mendapatkan resource yang lengkap,
•aktifitas pembelajaran pelajar meningkat,
•daya tampung meningkat,
•adanya standardisasi pembelajaran,
•meningkatkan learning outcomes baik kuantitas/kualitas
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PERANGKAT KERAS INTERNET


1.Enternet

Enternet merupakan system jaringan yang di buat dan di patenkan perusahaan Xerox.Enternet adalah implementasi metode CSMA/CD (Carrier Sense Multiple Access With Collision Detection)yang di kembangkan tahun 1960 pada proyek Wireless ALOHA di Hawai University di atas kabel coaxial.Standarisasi system enternet di lakukan sejak tahun 1978 oleh IEEE.kecepatan tranmisi data di enternet sampai saat ini adalah 10 sampai 100 Mbps.saat ini yang umum ada di pasaran adalah Enternet berkecepatan 10 Mbps yang biasa di sebut seri 10 base .

Bermacam macam jenis 10 base diantaranya adalah 10 base 5,10 base 2 ,10Base T,dan 10 base F yang akan di terangkan lebih lanjut kemudian .pada metode CSMA|CD,sebuah host komputar yang akan mengirim data ke jaringan pertama-tama memastikan bahwa jaringan sedang tidak di pakai untuk transfer dari dan oleh host komputer lainnya.jika pada tahap pengecekan di temukan transmisi data lain dan terjadi tabrakan (collision),maka host komputer tersebut di haruskan mengulang permohonan(request)pengiriman pada selang waktu berikutnya yang di lakukan secara acak (random).Dengan demikian ,jaringan efektif bisa di gunakan secara bergantian.untuk menentukan di posisi mana sebuah host komputer berada ,maka tiap – tiap perangkat enternet diberikan alamat (address) sepanjang ).Dengan demikian ,jaringan efektif bisa di gunakan secara bergantian.untuk menentukan di posisi mana sebuah host komputer berada ,maka tiap – tiap perangkat enternet diberikan alamat (address) sepanjang ).Dengan demikian ,jaringan efektif bisa di gunakan secara bergantian.untuk menentukan di posisi mana sebuah host komputer berada ,maka tiap – tiap perangkat enternet diberikan alamat (address) sepanjang 48 bit yang unik hanya satu di dunia.informasi alamat di simpan dalam chip yang biasanya nampak pada saat komputer di star dalam urutan angka berbasis 16(heksadesimal).sepanjang 48 bit angka agar mudah di mengerti di kelompokan masing –masing 8 bit untuk menyatakan bilangan berbasis 16 seperti 00:40:05:61:20:e6,tiga angka di depan adalah kode perusahaan pembuat chip tersebut.chaip di atas dibuat oleh ANI Comunications Inc.berdasarkan adres internet,setiap protocol komunikasi (TCP/IP,IPX,dan appli Talk,)berusaha memanfaatkan untuk informasi masing – masing host komputer jaringan.

10Base5

System 10Base5 menggunakan kabel coaxial berdiameter 0,5 inch(10MM)sebagai media penghubung berbentuk bus.biasanya kabelnya berwarna kuning dan pada kedua ujung kabelnya dkonsentrator sehingga mempunyai resintrasi sebesar 50 ohm.jika menggunakan 10 base5,1 segmen jaringan bisa sepanjang maksimal 500 m.bahkan,jika sepanjang penghubung (repeater)sebuah jaringan bisa mencapai panjang maksimum 2,5 km.

Antara NIC (Network Interface card)yang ada di komputer(DTE,Date terminal equipment )dengan media transmisi bust (kabel coaxial)-nya diperlukan sebuah transceifer (MAU ,medium Attachment unit).Antar MAU di buat jarak minimal 2,5 m dan setiap segmen hanya mampu menampung sebanyak 100 unit .konektor yang di pakai adalah konektor 15 pin

2. 10 Base2

Seperti pada jaringan 10Base5 ,10 Base2 mempunyai struktur berbentuk bus .hanya saja yang digunakan lebih kecil,berdiameter 5mm dengan jenis twistedpair.tidak di perlukan MAU karena MAU telah ada di dalam NIC –nya sehingga bisa menjadi lebih ekonomis.karenanya jaringan ini di kenal dengan sebutan Cheapernet.di bandingkan dengan jaringan 10base5,panjang maksimal sebuah segmennya menjadi lebih pendek,sekitar 185m,dan bisa di sambung sampai 5 segmen menjadisekitar 925m sebuahsegmen hanya mampu menampung tidak lebih dari 30 unitkomputer saja. Pada jaringan inipun di perlukan konsentrator yang membuat ujung-ujung media transmisdi busnya menjadi beresitasi 50ohm.

3.10 baseT

Berbeda dengan jaringan di atas 10 baseT berstruktur bintang atau star.tida di perlukan MAU karena sudah tersedia di dalam NIC-nya.sebagai pengganti konsetrator dan repeater di hub karena jaringan berbentuk star.panjang sebuah segmen 100m,dan setiaphub bisa di hubungkan untuk memper panjang jaringan sampai 4unit sehingga maksimal komputer tersambung bisa mencapai 1024 unit.

Menggunakan konektor modular jackRJ -45 dankabel jenis UTP (Unshielgeg Twistd Pair) seperti kabel telvon di rumah-rumah.saat ini kabel UTP yang banyak di gunakan adalah jenis kategori 5 karena bisa mencapai kecepatan transmisi 100mbps.










CARA KERJA MODEM

Komputer yang terhubung dengan saluran telepon hampir bisa dipastikan memerlukan modem. Nama "modem" sendiri merupakan kependekan dari "Modeluator - Demodulator".
Modem mengubah sinyal menjadi bentuk yang bisa dikirimkan melalui saluran telepon. Alat ini akan memodulasi (istilah modulasi ini bisa anda bayangkan seperti membungkus atau mengubah) sinyal digital dari komputer menjadi sinyal analog, yang merupakan jenis sinyal yang bisa dikirimkan melelui saluran telepon.
Modem akan mengubah atau (melakukan demodulasi) sinyal tersebut kembali ke bentuk digital agar bisa dibaca oleh komputer.
Apaan tuh digital, analog, tidaak jelas. Digital itu sinyal yang hanya memiliki 2 nilai yaitu 1 atu 0 aja, atau dalam bahasa listriknya on atau off, ada tegangan dan tidak ada tegangan. Gitu.
Nah kalau analog itu, sinyal yang nilainya kontinyu, misalnya sinyal suara yang melalui kabel ke speaker atau earphone mp3 kamu. Kalau sinyal yang dikirim ke earphone kamu itu sinyal analog, kamu bukannya mendengan suara lagu Bunga Citra Lestari tapi cuman suara rrrrrrrr gitu doang, tergantung frekuensinya.





CARA PENYAMBUNGAN MODEM

Beberapa cara untuk penyambungan modem antara lain :

1. Menggunakan hubungan "peer to peer"
2. Menggunakan koneksi USB & ethernet pada modem
3. Menggunakan active hub
4. Menggunakan wireless router



1. Menggunakan hubungan "peer to peer"
Hubungan "peer to peer" adalah hubungan antar 2 komputer lewat suatu media tertentu. Pilihan media tersebut dan kebutuhan peralatan sesuai pilihan media adalah:
· Ethernet (dengan koneksi RJ-45)
1. Ethernet port pada kedua komputer yang akan dihubungkan.
2. Kabel ethernet yang dicross; Bisa dipesan di toko komputer yang menyediakan peralatan networking; Kabel ini berbeda dalam penyambungan jalurnya dibandingkan kabel network biasa.
· Firewire
1. Firewire port pada kedua komputer yang akan dihubungkan.
2. Kabel firewire dengan ujung konektor yang sesuai dengan port firewire pada kedua komputer; Konektor firewire memang mempunyai dua tipe yaitu yang kecil dan yang besar; Yang besar biasanya terdapat pada komputer dekstop dan yang kecil pada komputer notebook.
Pilih salah satu koneksi tersebut dan konfigurasikan TCP/IP dari koneksi tersebut (ethernet atau firewire) pada komputer yang terhubung langsung ke internet (kita sebut saja komputer server) sehingga IP komputer tersebut adalah 192.168.1.1
Kemudian konfigurasikan TCP/IP dari komputer client (komputer yang akan dihubungkan ke komputer server) sehingga IP komputer tersebut menjadi 192.168.1.x di mana x adalah nilai pilihan anda sendiri antara 2-254; Subnet mask 255.255.255.0; Gateway 192.168.1.1
2. Menggunakan koneksi USB & ethernet pada modem
Dalam hal ini, kita memanfaatkan fasilitas dari modem (ADSL atau cable TV) yang mempunyai fasilitas koneksi USB dan ethernet. Dengan demikian, anda akan memerlukan:
1. Modem (ADSL atau cable TV) yang mempunyai port ethernet dan USB
2. Kabel ethernet atau RJ-45 (biasanya sudah disediakan dari modem tersebut)
3. Kabel USB (juga biasanya sudah disediakan dari modem tersebut)
4. Satu komputer yang mempunyai port ethernet
5. Satu komputer yang mempunyai USB port
Hubungkan komputer pertama ke modem dengan ethernet, lalu konfigurasikan (IP, DNS, dll) sesuai dengan informasi dari si penyedia layanan internet (ISP) tersebut.
Install USB driver dari modem tersebut ke komputer kedua, lalu hubungkan komputer tersebut ke modem lewat USB. Kemudian konfigurasikan (IP, DNS, dll) sesuai informasi dari ISP yang dipakai.
Biasanya digunakan automatic IP dan DNS
3. Menggunakan active hub
Anda perlu menyediakan:
1. Modem yang mempunyai koneksi ethernet
2. Active hub atau switch ethernet
3. Kabel network/ethernet untuk menghubungkan active hub ke modem
4. Komputer-komputer yang mempunyai port ethernet
5. Kabel network/ethernet sesuai dengan jumlah komputer yang dipakai
Hubungkan active hub ke modem, kemudian hubungkan semua komputer yang active hub tersebut.
Konfigurasikan semua komputer sehingga menggunakan automatic IP dan DNS, kecuali kalau ada informasi tertentu dari ISP
4. Menggunakan wireless router
Kalau anda membutuhkan koneksi wireless, maka pilihan ini memang anda perlukan. Anda punya dua pilihan:
1. Modem yang mempunyai kapabilitas wireless router
2. Wireless router yang akan dihubungkan ke modem.
Tentu saja semua komputer yang digunakan harus mempunyai kapabilitas wireless atau Wifi.
Biasanya, modem akan dikonfigurasi dengan IP 192.168.1.1 dengan DHCP aktif, sedangkan router dikonfigurasi dengan IP 192.168.2.1, juga dengan DHCP aktif.
Pastikan wireless router tersebut menggunakan enkripsi (WEP, WPA, dll), lalu catat key yang sudah di-generate.
Kemudian masing-masing komputer bisa langsung dihubungkan ke router tersebut dengan memasukkan key sewaktu diminta oleh koneksi wireless tersebut.