Molecular Biology II Flashcards
Dr. Karl Landsteiner discovered ABO blood group via _____, they observed agglutination and there’s something within the red blood cells
mixing cells and serum,
The most important blood group in transfusion
practice, main blood group in our RBCs
ABO GROUP
The most important blood group in transfusion
practice, main blood group in our RBCs
ABO GROUP
Individuals have antibodies in their serum
against the antigens absent from the RBCs.
When incompatible, it may result in destruction
of donor RBCs or ____
Transfusion reactions
ABO inheritance follow simple
mendelian genetics
ABO is inherited via ____ in expression.
Codominant
The ABO genes are inherited from
one from each parent
The A,B, or O gene is located on ____
Chromosome 9
Group O gene is considered an
amorph
The O gene is considered an ____, meaning it produces no functional glycosyltransferase.
“amorph” (nonfunctional)
O blood type results from inheriting ___
two recessive O alleles (OO)
Use Punnett squares to visualize inheritance patterns
1, 2, Offspring Genotype, Blood Types,
A A AA, AO A
A B AB, AO, BO AB, A, B
A O AO A
B B BB, BO B
B O BO B
O O OO O
Formation of ABH Antigens: Involves Three Genes from Different Loci:
• ABO Gene
• Hh Gene
• Se Gene (Secretor Gene)
These genes (ABO, Hh, Se) code for _____, enzymes that add specific sugars to a precursor substance
glycosyltransferases
Formation of ABH Antigens begins during the ___ of fetal life and persists throughout life.
second month of fetal life
glycosyltransferases, enzymes add specific sugars to a precursor substance_____ to form ABH antigens
paragloboside or glycan
Type A: ____ is added.
N-acetylgalactosamine
Type B: ____ is added
Galactose
ABH antigens are synthesized by adding specific sugars to precursor substances. These precursors are forms of
glycans (carbohydrate chains).
Type 1 Precursor is characterized by a ___ linkage between ___ and ____
β-1 to 3 linkage between galactose and N-acetylglucosamine.
Type 2 Precursor is characterized by a __ linkage between galactose and N-acetylglucosamine
β-1,4
serves as the base structure for the glycosyltransferases encoded by the ABO genes to add specific terminal sugars
Terminal galactose
RBC ABO antigens are constructed from
Type 2 precursor
A and B genes depend on the
H gene action (Chromosome 19)
H antigen is present/ expressed
HH, Hh
rare; doesn’t have H antigen; no expression
hh
hh is also called: ___ because it was first discovered in Bombay (Mumbai) India
“Bombay phenotype”
H gene is linked ______ from ABO genes meaning that the genes that encodes for type A, B, O are different from each other
linked independently
The ABO gene is located on ____ and
consist of ___ exons and spans about __ to ___ kb
chromosome 9, seven exons, 18 to 20 kb
Last two exons (6 and 7) of the ABO gene encode for the ___ of the ___
catalytic domain of the ABO glycosyltransferases (most in 7)
is a sequence that codes something
Exon
doesn’t code for anything, that’s why it is deleted in the mature RNA.
intron
The H gene is also known as
FUT1
The H gene (also known as “FUT1”) codes for _____ that adds the sugar “_____” to the terminal galactose of type 2 precursor, forming the H antigen
1, 2 Fucosyl transferase, adds fucose
1, 2 Fucosyl transferase adds the sugar “Fucose” to the ___ thus forming the H antigen
terminal galactose of type 2 precursor
The Se gene is also known as
FUT2
The se gene codes for 1,2 Fucosyl transferase that adds the sugar Fucose to terminal galactose of a ____, thus forming the ____
type 1 precursor, forming the H antigen in secretions
The A gene codes for ____ which joins the sugar ___ to the terminal galactose of an H antigen
1, 3 N-acetylgalactosaminyl transferase joins sugar “N-acetyl-D-galactosamine”
The B gene codes for _____ which adds “____” to the terminal galactose of an H antigen
1,3 galactosyl transferase which adds “Galactose”
H gene → codes for _____ + adds ___ → terminal galactose of ____ precursor = H antigen
H gene — codes for 1, 2 Fucosyl transferase +
adds fucose — terminal galactose of type 2
precursor = H antigen
A gene → codes ____ joins _____ → terminal galactose of an H antigen = A antigen
1, 3 N-acetylgalactosaminyl transferase joins N-acetyl-D-galactosamine
B gene → codes for ____ + adds ___ → terminal galactose of an H antigen = B antigen
1,3 galactosyl transferase
results from any mutation in an A or B transferase gene that causes loss of glycosyltransferase activity and nonfunctional enzyme
Group O phenotype
Most common Group O phenotype
Group 001
(Group 001) results from a single nucleotide deletion early in the gene near the
N-Terminus
Deletion in (Group 001) causes a ____ and a ____ product with no enzyme activity.
frameshift and a truncated product
group O02 deletion and mutation
nucleotide deletion and nine point mutations
Blood type that has many H antigen is Group ___
Group O
ABO Antigens are Carbohydrate structures
composed of
glycoproteins and glycolipids
RBC membrane proteins carry over ____ A or
B or H antigens
2 x 10^6
RBC membrane proteins carry over 2 x 10^6 A or
B or H antigens mostly located on the ____ membrane protein called ___
major integral membrane protein called Band 3.
ABO antigens can be found on other tissues like:
- Platelets
- other endothelial and epithelial cells of: lungs, gut, urinary and reproductive tracts
Group B is found usually in ___
African Americans and
Asians (11% in Whites, 20% in Blacks)
most common blood group. found in asians
Group A and Group O found in Asians (40-45% in whites, 50% in blacks)
rarest blood group
Group AB
Basic antigenic material of ABO
H antigen
H antigen is found in greatest concentrations on the
RBCs of group ___ individuals
group O individuals
H antigen is detected by an anti-H antiserum made up of lectin ___
‘Ulex europeus”
ABH antigens are found on secretions of people
with the __ phenotype
secretor phenotype (Se)
secretes A, B, H antigen in saliva, sweat, urine, milk, tears
SeSe, Sese
non secretors
sese
test to determine if you are secretor gene is
ABH TEST
Inheritance of “hh” gene, therefore no “H
substance”
BOMBAY PHENOTYPE
BOMBAY PHENOTYPE is first reported by __ in bombay india
Dr. Bhende in 1952
The person can inherit A or B genes BUT has no
H-substance, therefore no ABH antigens.
BOMBAY PHENOTYPE
BOMBAY PHENOTYPE is caused by a mutation in the ___ which produces Silenced gene
FUTl gene
Bombay serum contains:
Anti-A
Anti-B
Anti-AB
Bombay phenotype is an ____ that reacts at ___
IgM that reacts at 37C
Phenotypes where RBCs completely lack H
antigens or have only small amounts of H antigen
present
PARA-BOMBAY PHENOTYPES
lacks the H antigen
bombay
little presence of H antigen.
para-bombay
In parabombay RBCs express weak forms of A and B antigens which are only detected in ____
elution techniques.
