Exam 14: Mendel and the Gene Idea

Albinism (without melanin pigmentation) is a recessive trait. A man and woman who both have normal pigmentation have one child out of three who has albinism. What are the genotypes of this child's parents?

Which of the following statements correctly describes how Mendel accounted for the observation that traits had disappeared in the F₁ generation and then reappeared in the F₂ generation?

Radish flowers may be red, purple or white. A cross between a red-flowered plant and a white-flowered plant yields all-purple offspring. The part of the radish we eat may be oval or long, with long being the dominant trait. If true-breeding red long radishes are crossed with true-breeding white oval radishes, the F1 will be expected to exhibit which of the following phenotypes?

Mendel's law of independent assortment has its basis in which of the following events of meiosis I?

Feather colour in budgies is determined by two different genes, Y for pigment on the outside of the feather, and B for pigment on the inside of the feather. YYBB, YyBB, or YYBb is green; yyBB or yyBb is blue; YYbb or Yybb is yellow; and yybb is white. Two blue budgies were crossed. Over the years, they produced 22 offspring, five of which were white. What are the most likely genotypes for the two blue budgies?

A black guinea pig crossed with a guinea pig with albinism produced 12 black offspring. When the albino was crossed with a second black animal, six blacks and six albinos were obtained. What is the best explanation for this genetic situation?

A sexually reproducing animal has two unlinked genes, one for head shape (H) and one for tail length (T). Its genotype is HhTt. Which of the following genotypes is possible in a gamete from this organism?

Mendel crossed yellow-seeded and green-seeded pea plants and then allowed the offspring to self-pollinate to produce an F₂ generation. The results were as follows: 6,022 yellow and 2,001 green (8,023 total). Which of the following statements correctly describes the relationship of the allele for green seeds to the allele for yellow seeds?

A gene for the MN blood group has codominant alleles M and N. If both children in a family are of blood type M, which of the following situations is possible?

Which of the following statements about independent assortment or segregation is correct?

Gene S controls the sharpness of spines in a type of cactus. Cacti with the dominant allele, S, have sharp spines, whereas homozygous recessive ss cacti have dull spines. At the same time, a second gene, N, determines whether or not cactuses have spines. Homozygous recessive nn cactuses have no spines at all. A cross between a true-breeding sharp-spined cactus and a spineless cactus would produce ________.

Which of the following calculations require the use of the addition rule of probability?

Which of the following statements best describes the addition rule of probability?

In humans, ABO blood types refer to glycoproteins in the membranes of red blood cells. There are three alleles for this autosomal gene: IA, IB, and i. The IA allele codes for the A glycoprotein, The IB allele codes for the B glycoprotein, and the i allele doesn't code for any membrane glycoprotein. IA and IB are codominant, and i is recessive to both IA and IB. People with type A blood have the genotypes IAIA or IAi, people with type B blood are IBIB or IBi, people with type AB blood are IAIB, and people with type O blood are ii. If a woman with type AB blood marries a man with type O blood, which of the following blood types could their children possibly have?

Which of the following inheritance patterns describes the ability of a single allele to have multiple phenotypic effects?

Mendel's observation of the segregation of alleles in gamete formation has its basis in which of the following phases of cell division?

Why did all of the F₁ offspring of Mendel's classic pea cross always look like one of the two parental varieties?

Which of the following statements correctly explains the fact that all seven of the pea plant traits studied by Mendel obeyed the principle of independent assortment?

What is the probability of producing the genotype AABBCC in a cross of individuals who both possess this genotype: AaBbCc?

In a particular plant, leaf colour is controlled by gene locus D. Plants with at least one allele D have dark green leaves, and plants with the homozygous recessive dd genotype have light green leaves. A true-breeding, dark-leafed plant is crossed with a light-leafed one, and the F₁ offspring is allowed to self-pollinate. The predicted outcome of the F₂ is diagrammed in the Punnett square shown in the figure, where 1, 2, 3 and 4 represent the genotypes corresponding to each box within the square. - Which of the boxes marked 1-4 correspond to plants with a heterozygous genotype?