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Genetics-lecture 7- Blood

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winniesmith1's version from 2017-06-12 16:57

Section 1

Question Answer
What percentage of body weight is blood8% (5.6kg)
What does blood doIt is a transport protein (oxygen, carbon dioxide, nutrients, wastes). Immunity.
Name problems/diseases of bloodAnaemia, leukaemia, AIDS, sickle-cell disease.
What are the functions of bloodTransportation, regulation, protection, restriction.
Describe transportation* Respiratory substances, oxygen and carbon dioxide. * Nutritive substances, products of digestion. * Excretory substances, e.g. excess water and salt.
Describe regulation* Hormones and regulatory molecules to target tissues. * pH and electrolyte composition of interstitial fluid. * Thermoregulation, stabilization of body temperature.
Describe protection* Defence against toxins and pathogens * Clotting of damaged vessels
Describe restriction* of fluid losses at injury sites
Describe the composition of bloodMade up of 55% plasma and 45% formed elements. In plasma 91% is water, 7% protein and 2% other solutes. Formed elements consists of up to 400,000 platelets, 5-9 thousand white blood cells and 4.2- 6.2 million red blood cells.
Describe red blood cells/erythrocytesBy concave shape. (Mature cells) do not contain a nucleus, contain haemoglobin in cytoplasm (>200 million Hb molecules). Lifespan of approx hundred and 120 days. Have antigens on surface.
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Section 2

Question Answer
What is an antigenany substance that the body regards as foreign (genetic element, virus, bacterium, toxin)
What is an antibodya disease fighting protein developed by the body in response to the presence of an antigen
What is agglutinationreaction between antibodies and antigens clumping of cells.
What is a multiple allelic set A character controlled by multiple alleles of a given gene
Although a gene may have multiple alleles in a population, a diploid individual must have only two of these alleles, one at the same locus on each homologous chromosome.
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Section 3

Question Answer
What are blood groups determined byantigens (agglutinogens) on surface of RBCs
What results when antibodies (agglutinins) bind to RBC antigensAgglutination (clumping) or haemolysis (rupture) of RBCs.
How many different blood grouping systems are thereMore than 15 commonly used (ABO, Rh, MNSs etc)
who discovered the ABO blood groupKarl Landsteiner (1900)
What did karl landsteiner discoverA, B and O. Student discoverered AB (1902) Reciprocal antibodies are consistently and predictably present in the sera of normal people whose RBC lack the corresponding antigen(s). Awarded nobel prize.
Describe the ABO blood group system-4 Major ABO Blood Types: A, B, AB, O. -Multiple Alleles at the same locus: A, B and O. -A & B are co-dominant and O is recessive to both A and B. -Blood type identified by antigens on RBC membrane. -Antigens are recognised as non-self and solicit formation of antibodies.
Type A blood has what antigens presenttype A antigens on RBC membranes and antibodies for type B blood in blood serum (vise versa for B)
Describe red blood cell membranesBilipid membrane. External surface of RBC membrane is coated with a diverse array of glycoproteins, complex carbohydrates, and lipoproteins, imparting antigenic structure to the membrane
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Section 4

Question Answer
Describe the biochemistry of A, B, H antigensABO antigens are located on RBCs, lymphs, platelets, tissue cells, bone marrow and solid organs. Inheritance results in expression. Antigens ARE NOT direct products of the genes. Genes code for TRANSFERASE which causes transfer of monosaccharide molecule onto a precursor substance on the RBC.
What are human blood groups formed fromcomplex groups of polysaccharides on the surfaces of erythrocytes. These carbohydrates are attached to glycoproteins and glycolipids on the surfaces of red blood cells where they act as specialised antigenic determinants.
What is the difference between A,B and Othe presence and type of only one monosaccharide
What do all ABO carbohydrate structures have in commonoligosaccharide foundation
What does type A add to foundationN-acetylgalactosamine
What does type B add to foundation galactose
Which blood group is known as the 'universal donor' and whyType O blood and because it contains no antigens and can be transfused to any of the other blood types.
Which blood group is known as a universal recipient and whyType AB and because it produces no antibodies so can receive any type of blood
Which is the rarest blood groupAB
Which is the most abundant blood groupO (distribution of blood groups maps lecture 7 pgs 20-22)
What are secretorspersons who have A,B and/or H in secretions.
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Section 5

Question Answer
Describe Rh blood group (named after rhesus monkey)-Multiple Genes (3 loci, C, D, E, C& E are co-dominant, D is dominant). -Antigen D most important. Antigen d has not been found! -Inherited trait: Dominant (Rh+ve is dominant over Rh-ve) 86% of White European are Rh (D) positive.
How and why is Rh different to ABO no spontaneous production of anti -Rh antibodies!!
Why is Rh group clinically very important -If Rh negative woman has Rh positive child and blood types mix, the woman will form antibodies against Rh positive blood. -In the future these antibodies will cause agglutination of the Rh positive blood --> (erythroblastosis fetalis) or hemolytic disease of the newborn (HDN). (Also for parentage testing, blood transfusion and population studies)
Describe erythroblastosis fetalisMaternal Rh-Negative RBC, Fetal RH-positive RBC. Maternal anti-Rh antibodies are produced and cross the placenta, cause agglutination of fetal Rh-positive RBCs, leading HDN.
Describe MNSs blood group2 separate blood group systems. M & N locus and the S & s locus are linked and found on chromosome 4: -Genes produce TWO distinct antigens on the RBC membrane. -One with MN specificity and one with Ss specificity. -Co dominant (2 allelesīƒ  Three Phenotypes/genotypes eg MM, MN and NN. -Ss is also co-dominant!
What is the use of MNSs blood groupClinically not very important. Useful for forensic, paternity testing and evolution and genetic variation studies.
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Section 6

Question Answer
Blood type ORh+ 37%. Rh- 7%. Total 44%
Blood type ARh+ 35% Rh-7% Total 42%
Blood type BRh+ 8% Rh- 2% Total 10%
Blood type ABRh+ 3% Rh- 1% Total 4%
D (Rhesus)Rh+ 83%. Rh- 17%
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