SCIENCE/BIOLOGY IMPORTANT QUESTIONS BLOOD-BLOOD GROUP
► Blood is a kind of fluid connective tissue.
► Blood is the softest tissue in the body.
► Blood is slightly alkaline, an average pH 7.4 (7.35+.1)
► Acidity of blood makes heamoglobin carry less oxygen.
► An average adult person has about 4-6 litres of blood.
► The study of blood is called haematology.
► Temperature of blood is 100.4°F.
► The process by which blood cells are formed is called haemopoiesis or haematopoiesis.
Blood -Plasma (55%) -Blood corpuscles (45%)
Blood corpuscles (45%) – (99%) RBC or Erythrocyte cellsRBC (.2%) WBC OR Leucocyte cells – (.8%) Blood or Platelets
►Fluid part of blood after removal of corpuscles is plasma.
► It is colloidal Mixture and yellow in colour (due to bilirubin)
► It contains Urea, sugar, cholesterol and bilirubin.
► Plasma proteins cqnstitate about 8% major plasma proteins are albumin, globulin,
prthrombin and fibrinogen.
► Prothrombin and fibrinogen are essential for blood clotting.
Red Blood corpuseles (RBC)
► RBCs of mammals (man) are round, biconcaue and non- nucleated except camel and llama.
►RBCs of comel, llama , fisb, amphibians , reptiles birds are oval, biconvex and nucleated.
► Musk deer has the smallest RBCs.
►The instrument used to RBC is haemocytometer.
► Red colour of RBC due to presence of haemglobin.
►Haemglobin facilitates 02 transport.
Number of RBC
Man=5.5 million /c.c Women=4.5 million /c.c
Child=7.0 million /c.c →
►Number of RBC increases as we go at high altitude.
► Life span of mammalian RBC is about 120 days..
► Daily destruction of RBC is 2.5 % in man.
► Lifespan of frog’s RBC is about 100 days.
- Spleen – spleen is called “graveyard of RBC”.
- It is also called “blood bank” of animal body. Serum – Plasma – plasma protein (dotting factor)
- It is used in preparation of Vaccine.
- In 1798 Edward Jenner made Ist smallpox vaccination.
Amount of haemoglobin
- Man = 15 gm / 100 ml of blood Woman = 13.5 gm / 100 ml of blood
- Child = 16.5 gm / 100 ml of blood
Anemia– It is loss of O2 carrying capacity by blood when amount of hemoglobin becomes 11 gm or less per 100 ml of blood.
White Blood Corpuscles (WBC) Or Leucocytes
► Leucocytes are devoid of hemoglobin so it is colorless.
► It is irregular in shape i.e. amoeboid, nucleated.
► The total Leukocyte count is normally 5000-7000 per cubic centimeter of blood.
►Ration of RBC: WBC is 600: 1.
► It leucocytes number increase up to 12000/cc or more than it is called Leukemia (Blood
► It number decrease than it is called Leucopenia.
► WBC produced from yellow bone marrow while RBC produced from Red bone marrow.
► It plays important mole in immune system. Life span of WBC is 3 to 4 day (but it may be
several days to year).
► It is found only in mammals.
► It is also called thrombocyte like cells. It is formed in bonemarrow,
► It is without nucleus and secrete thromboplastin which help in blood clotting.
Size = 2.3 um Number = 2.5 to 3.5 lacs/cc of blood.
Life span = 3-7 days.
► In dengue fever ,blood platelets number decreases largely.
► Blood groups are found in man and apes.
► Blood group was first discovered by karl Landsteiner in 1900. He discovered A,B & O blood
group and known as “Father of Blood group”.
► AB’blood group was discovered by Van Decastello and sturle (1902).
Characteristics of Human Blood Groups
Blood Group – Antigen – Antibodies In Plasma
A A b
B B a
AB AB X
O X ab
► Persons of ‘O’blood group are called Universal donars, as they can donate blood to all.
► Person of ‘AB’ blood group are called as universal recipients, as they can receive blood from
Rh – factor or Rhesus factor
- Rh factor was first of all reported in RBC of a Rhesus monkey by Landsteiner and Weiner in 1940.
- It is an antigen found on the surface of RBC.
- If Rh factor absent than Rh-blood group.
- Percentage of Rht people in India is 97% of the population:
Erythroblastofoetalis occure when father is Rht and mother is Rh. To escape from this problem Rh anti D (Rhogam) vaccine should given with in 48 hours after birth of child.