20) A friend of yours has type A blood. If her mother has type AB blood and her
ID: 268818 • Letter: 2
Question
20) A friend of yours has type A blood. If her mother has type AB blood and her father has type B blood, what is the genotype of the father? A) IBIA B) 1BB C)1B E) None of the above 21) Sickle-cell disease shows incomplete dominance, with the heterozygote showing sicklecell tzait and the homozygous recessive showing sickle.cell discase. If two parents with sickle cell-trait have offspring what is the chance of an offspring being normal? A) 100% B) 75% C)50% D) 25% E)0% 22) If allele A is dominant to a and allele B is dominant to b, what is the expected ratio in phenotypes of the cross: AaBbx AaBb? (Note: do this cross and then find the best answer.) A) 4:3:1 B) 8:4:2:2 D) 9:3:3:1 E) 2:2 23) The alleles of a gene are found at A) the same locus on non-homologous chromosomes B) different loci on homologous chromosomes C) different loci on non-homologous chromosomes D) the same locus on homologous chromosomes E) the same locus on different autosomes 24) Using a six-sided die, what is the probability of rolling a 5 followed by a 6? A) 1/6 x 1/6 -1/36 D) 1/6 E) 1/12Explanation / Answer
20)
Mother is AB= IAIB
Freind is A= IAI
Father is B= IBI
If father was IBIB,then friend of yours would have one IB from his father. In that case the genotype of friend would have been IA IB and blood type AB. But as the friend is blood type A, then genotype of father is IBI.
21.D)9.3.3.1
AaBb X AaBb
AB
Ab
aB
ab
AB
AABB
AABb
AaBB
AABb
Ab
AABb
AAbb
AABb
Aabb
aB
AaBB
AaBb
aaBB
aaBb
ab
AaBb
Aabb
aaBb
aabb
23D) the same locus on homologous chromosome.
24. 1/6 X 1/6= 1/36
Genotypes which will give same phenotype are grouped together.
AABB/AABb/AaBb=9
AAbb/Aabb=3
aaBb/aaBB=3
aabb=1
AB
Ab
aB
ab
AB
AABB
AABb
AaBB
AABb
Ab
AABb
AAbb
AABb
Aabb
aB
AaBB
AaBb
aaBB
aaBb
ab
AaBb
Aabb
aaBb
aabb
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