Science Department
April 2015
Grade 7
Name ______
The Blood
(Revision sheet)
Read the paragraphs below then answer the questions that follow
All humans can be typed for the ABO blood group. There are four principal types: A, B, AB, and O.
There are two antigens (A and B) and two antibodies (anti-A and anti-B) that are mostly responsible for the ABO types.
An antigen is found on a red blood cell, it is what determines the type of blood group a person is.
An antibody is a protein that fight antigens that are different than the body’s antigens (antigens coming from outside the body).
The specific combination of these antigens and antibodies determines an individual's blood type.
An example is if a person is blood type A then his red blood cells have antigen Abut has the opposite antibody which is anti-B.
Complete the boxes below:
Some people donot have antigens on their red blood cells (neither antigen A nor antigenB) these are known as blood group O. These people have both antibodies anti-A and anti-B.
Others may have both antigens A and B and no antibodies not anti-A noranti-B these are known as blood group AB.
Complete the boxes below:
Why is it important to know your blood group?
Sometimes people need blood transfusion. If anyone is transfused with incompatible blood (doesn’t match his blood type) it may lead to his death.
This is a Red blood cell with antigens on it.
This is what an Anti-A antibody looks like
When an antigen combines with its antibody , for example Antigen A with antibody A they combine together and the red blood cells are destroyed.
Therefore it is important when transfusing blood to know the blood type and which types are compatible to prevent the destruction of blood cells causing death.
Erythrocyte = Red Blood Cells
Remember:
- Antigens tell us the blood type
- Antibodies fight antigens so they are always the opposite of our blood group.
Looking at the table above we realize that:
- Anti B cannot attack antigen A on RBCs of blood group A.
- Anti B can attack antigen B which are on RBCs of blood group B.
- Anti A cannot attack antigen B on RBCs of blood group B.
- Anti A can attack antigen A which are on RBCs of blood group A.
- Blood group AB has no antibodies and therefore do not attack any blood cells entering.
- Blood group O on the other hand has both antibodies A and B and therefore they attack any blood group with antigens (A or B).
Using the table and the information above complete the boxes below (the first one has been done for you)
Blood group AB are known to be universal recipients because they can receive blood from anyone but only donate to themselves (AB).
Blood group O are known to be universal donors because they can donate blood to anyone but only receive from themselves (O).
When an antigen attaches to its antibody they form clusters called antigen antibody complex, which settles down and may block capillaries.
When theantigen antibody complex form clusters this process is called agglutination.
In the lab when we test for blood typing we add the antibody to the blood sample from the person tested to check for the antigen.
In the sample above we added anti-A antibody to the blood which combined with the antigen A causing agglutination which shows in the first circle.
The blood did not agglutinate in the second circle with the anti-B which means the blood does not have antigen B.
This means that this blood is blood group A.
For the blood samples below circle the correct answer
- When we added Anti-Athe blood (Agglutinates -- Does not agglutinate) this means that this blood (has –does not have) antigen A.
- When we added Anti-B the blood (Agglutinates -- Does not agglutinate)this means that this blood (has –does not have) antigen B.
- This is blood group ______
- When we added Anti-Athe blood (Agglutinates -- Does not agglutinate) this means that this blood (has –does not have) antigen A.
- When we added Anti-B the blood (Agglutinates -- Does not agglutinate) this means that this blood (has –does not have) antigen B.
- This is blood group ______
- When we added Anti-Athe blood (Agglutinates -- Does not agglutinate) this means that this blood (has –does not have) antigen A.
- When we added Anti-B the blood (Agglutinates -- Does not agglutinate) this means that this blood (has –does not have) antigen B.
- This is blood group ______
Question one
- How many blood types do we have in the ABO system?
______
- What part of the red blood cell determines your blood type?
______
- Why is it important to know your blood type?
______
- Complete the table below
Blood group / Antigens / Antibodies
A
B
AB
O
- Complete the sentences below
- An antigen is found on the surface of ______.
- An antibody is a ______that fights the ______.
- The ______determines the blood group.
- When the antigen combines with its antibody to form an ______
______complex in a process called ______.
- Blood group ______is known as a universal donor while blood group ______is known as a universal recipient.
- Look at the example then complete in the same pattern:
- Antigen A + ___Anti-A___ causes agglutination.
Antigen A + ___Anti-B___ does not cause agglutination.
- Antigen B + ______causes agglutination.
Antigen B + ______does not cause agglutination.
- Complete the table below
Blood group / Receives blood from (can take from) / Donates blood to
(can give to)
A
B
AB
O
- In the lab the lab technician received 4 blood samples to test for blood grouping.
Look at the diagrams below and determine the blood group of each sample.
This means no agglutination
This means agglutination is seen
The letter on the test tubes indicate the Antibody used so
In this test tube anti A has been added to the blood sample
In this test tube anti B has been added to the blood sample
Now look at the samples and determine the blood types:
Anti A shows ______
Anti B shows ______
Then this is blood group ______
b.
Anti A shows ______
Anti B shows ______
Then this is blood group ______
c.
Anti A shows ______
Anti B shows ______
Then this is blood group ______
d.
d
Anti A shows ______
Anti B shows ______
Then this is blood group ______