Question
A couple have four children whose blood groups are $A, B$ and $A B$. What is the likely combination of the parents’ genotypes?
A. $\quad I^A i$ and $\mathrm{I}^{\mathrm{B}} \mathrm{i}$
B. ||$^A i$ and ||$^B$
C. $\left.\left.\quad\right|^A\right|^B$ and ii
D. $\left.||^A\right|^A$ and $\left|I^B\right|^B$
Answer/Explanation
Ans:A
Question
The pedigree chart shows the inheritance of hemochromatosis, a genetic disease which causes an excessive accumulation of iron in the body.
What can be deduced about this genetic disease from the pedigree chart?
A. It is sex-linked.
B. It is autosomal dominant.
C. It is autosomal co-dominant.
D. It is autosomal recessive.
Answer/Explanation
Ans: D
Question
Huntington’s disease is an autosomal dominant genetic disease. What are the chances of two parents that are heterozygous for the gene having a child with Huntington’s disease?
A. 25%
B. 50%
C. 75%
D. 100%
Answer/Explanation
Ans: C
Question
What is a difference between two alleles of a gene?
A. Their positions on homologous chromosomes
B. Their amino acid sequence
C. The characteristic they influence
D. Their base sequence
▶️Answer/Explanation
D
Question
Chromosome numbers vary between species. Which statement refers to humans?
A. An egg cell has 22 autosomes.
B. A sperm cell has 23 autosomes.
C. An egg cell has two X chromosomes.
D. A zygote has two autosomes
▶️Answer/Explanation
A
Question
Scientists sequenced the genes in each chromosome of chimpanzees (Pan troglodytes) and humans (Homo sapiens). The graph shows the mean divergence between the genes of these species by chromosome.
What can be deduced from this data?
A. Autosomes are more similar than Y chromosomes.
B. There is the same number of chromosomes in humans and chimpanzees.
C. Humans are more closely related to chimpanzees than to other species.
D. Smaller chromosomes are more similar than larger chromosomes.
▶️Answer/Explanation
A
Question
The pedigree chart shows the inheritance of three generations of Duane syndrome, a condition caused by a dominant allele that affects alignment of the eyes.
If individuals II:1 and II:2 had a third child, what is the probability that the child would have Duane syndrome?
A. 25 %
B. 50 %
C. 75 %
D. 100 %
▶️Answer/Explanation
B
Question
Which statements are characteristics of alleles?
I. Alleles differ significantly in number of base pairs.
II. Alleles are specific forms of a gene.
III. New alleles are formed by mutation.
A. I and II only
B. I and III only
C. II and III only
D. I, II and III
▶️Answer/Explanation
C
Question
The system of sex determination in chimpanzees (Pan troglodytes) is the same as in other mammals. A chimpanzee has 48 chromosomes in the nuclei of its body cells.
What can be deduced from this information?
A. The sex of the chimpanzee
B. The number of genes in each chromosome
C. Whether non-disjunction has occurred
D. The number of autosomes in a diploid cell
▶️Answer/Explanation
D