Genetics and Inheritance Quiz

What was a significant advancement in biological problem-solving introduced by Gregor Mendel during his investigations into inheritance patterns?

• He was the first to use true-breeding lines in experiments.

• He applied statistical analysis and mathematical logic for the first time in biology.

• He conducted hybridisation experiments on garden peas for exactly seven years.

• He identified the physical structure of 'factors' responsible for inheritance.

Watson and Crick's successful proposal of the complementary double-helical configuration of DNA was the result of:

• Their first serious effort, which was highly successful.

• Direct observation of the DNA molecule using advanced microscopy.

• Their second effort, based upon more experimental evidence and better appreciation of the nucleic acid literature.

• A solo discovery by James Watson in 1950 during his Ph.D. studies.

In Mendel's monohybrid cross between tall (TT) and dwarf (tt) pea plants, what specific term did he use for the discrete units that determined the height trait, which were later named genes?

• Alleles

• Genotypes

• Factors

• Phenotypes

When Mendel self-pollinated the F1 progeny (Tt) from a cross between true-breeding tall (TT) and dwarf (tt) pea plants, what was the phenotypic proportion of dwarf plants in the F2 generation?

• 1/2

• 3/4

• 1/4

• All were tall.

According to the explanation of dominance, a recessive allele typically results in a recessive phenotype because:

• It produces a normal, highly efficient enzyme.

• It blends its effect with the dominant allele to produce an intermediate phenotype.

• It produces a non-functional enzyme or no enzyme at all.

• It is always less numerous in the population than the dominant allele.

Which statement best distinguishes co-dominance, as seen in ABO blood grouping, from both dominance and incomplete dominance?

• The F1 generation shows a phenotype intermediate between the two parents.

• Only one parental trait is expressed in the F1 generation.

• The F1 generation resembles both parents, with both alleles expressing their own types of sugars.

• One allele completely masks the expression of the other.

Polygenic traits, such as human height or skin color, are characterized by being controlled by:

• A single gene product with multiple effects.

• Two genes, similar to dihybrid crosses.

• Three or more genes, taking environmental influence into account.

• Alleles that show complete dominance or recessiveness.

In the context of human skin color controlled by three genes (A, B, C) where dominant alleles (A, B, C) contribute to dark skin and recessive alleles (a, b, c) to light skin, which genotype would result in an intermediate skin color?

• AABBCC

• aabbcc

• AaBbCc

• AABBCc

Phenylketonuria, an example of a pleiotropic disorder in humans, is characterized by which of the following specific phenotypic expressions?

• Non-stop bleeding and delayed blood clotting.

• Mental retardation and a reduction in hair and skin pigmentation.

• Sickle-shaped red blood cells under low oxygen tension.

• Short stature, small round head, and a furrowed tongue.

In 1891, Henking discovered a specific nuclear structure, the 'X body', in insect spermatogenesis, noting its unequal distribution in sperm. What was his primary contribution based on this observation?

• He conclusively proved that the X body was a chromosome responsible for sex determination.

• He provided the initial clue about the genetic/chromosomal mechanism of sex determination.

• He discovered the XY type of sex determination in mammals.

• He identified the ZW sex determination system in birds.