2007-08-02 06:45:52 · 5 answers · asked by Anonymous in Science & Mathematics ➔ Biology
In humans there are the ABO blood groups. A person can be type A, type B, type O or type AB. The blood types A, B and AB carry antigens on the cells. If a person has a certain blood type, they will generally have antibodies against other blood types (except for type O) and will reject the blood. For instance, if someone is blood type A, then they will have antibodies against the B antigen, so they will reject blood given to them if it is B or AB and will accept blood types A or O. There is also the Rhesus factor (Rh) which makes the blood type Rh+ or Rh-, so the blood type A person above could be A positive (A+) or A negative (A-). Blood type O carries no antigens, so the recipient won't reject the blood as long as the Rh factor is matched between donor and recipient. Specifically, blood type O- is considered to be universal donor, because it carries no antigens with which the recipient's body will react.
2007-08-02 07:00:59 · answer #1 · answered by N E 7 · 0⤊ 0⤋
Each type of blood carries antigens that are incompatible with other blood types that recognize the other blood type as an invading tissue and attack the other blood types cells. For example blood type A carries antigens that attack cells of blood type B and the same thing goes for blood type B. Blood type AB can accept both A and B because it doesn't contain antigens for either A or B. Blood type O is normally accepted by all blood types because it has no antigens.
2007-08-02 16:11:14 · answer #2 · answered by S M 2 · 1⤊ 0⤋
All the types of blood cells (AB RH+/- etc) have different chemical markers on them. Type O- for example lacks them. If you get blood from a person with different chemical markers than you, your immune system thinks its an invader and attacks it. This can be lethal.
Blood from donors that lack these common markers when given to someone that has them is OK. If you do the reverse it will cause rejection. So you can give O- blood to a AB+ person, but if you give B- blood to a O- person bad things happen. That's why O- its the universal donor.
2007-08-02 13:58:21 · answer #3 · answered by dna man 2 · 0⤊ 0⤋
Blood is a mixture of living cells and chemicals. Some in a supply of blood are incompatible with the ones in a different supply of blood. When they are mixed the result is a clumping and destruction of cells in the blood of the person receiving that blood which can cause their death.
What blood type you have depends on your parents and may be a characteristic of the ethnic group that they belong to.
2007-08-02 13:53:58 · answer #4 · answered by Rich Z 7 · 0⤊ 0⤋
when it comes to blood it is basic math you can always put a negative in a positive but never a positive in a negative
2007-08-02 13:54:23 · answer #5 · answered by lydiajw 2 · 0⤊ 0⤋