MBG 2040QUIZ 1 ANSWERS.

MBG 2040 / MBG2040 QUIZ 1 ANSWERS Question 1 0 / 1 point In pea plants round seeds are dominant over wrinkled. The gene responsible for this trait exhibits typical Mendelian expression and is designated with a D for the dominant allele and with a d for the recessive allele. If two heterozygote plants are crossed (Dd x Dd) this would be considered a _ . Homozygous Cross Dihybrid Cross Heterozygous Cross Question 2 0 / 1 point In reference to the pedigree above, what is the most likely mode of inheritance for the trait indicated with solid black shapes? Homozygous Question 3 Autosomal Recessive Sex-linked 0 / 1 point When a gene mutation results in an overactive or over produced gene product this is said to be a . Hypomorphic Allele Neomorphic Allele Null Allele Question 4 A pair of chromosomes with the same array of genes, with one 0 / 1 point chromosome derived from the female parent and one derived from the male parent are called _ _. Chromosomes Sister chromatids Homozygous chromosomes ML Question 5 0 / 1 point In squash fruit colour is determined by one gene and fruit shape is determined by another independently assorting gene. The white fruit allele (W) is dominant over the yellow fruit allele (w) and the disk-shaped allele (D) is dominant over the round-shaped allele (d). If a plant has the following genotype, Wwdd, which of the following gametes would be produced? Select all that apply: WD wD dd Ww Question 6 0 / 1 point In squash fruit colour is determined by one gene and fruit shape is determined by another independently assorting gene. The white fruit allele (W) is dominant over the yellow fruit allele (w) and the disk-shaped allele (D) is dominant over the round-shaped allele (d). If a plant has the following genotype, wwDD, which of the following gametes would be produced? Select all that apply: wd WD Wd ww DD Probability Question 7 0 / 1 point In a family of four children what is the probability that the first born child is a female and the 2nd, 3rd, and 4th children are all males? Question 8 1/2 1/4 1/8 0 / 1 point A phenotypically normal couple have one child with a rare recessive disorder that is controlled by a single gene known to exhibit typical Mendelian heredity. Their second child is phenotypically normal, what is the probability that the second child is a carrier? 1/3 1/2 1/4 Pedigrees Question 9 0 / 1 point Cystic fibrosis (CF) is a rare lethal recessive genetic disorder caused by a number of mutations in a single gene where CF is dominant and cf is recessive (ie. an affected individual would be cfcf). Imagine you are a genetic counsellor advising a couple who both have a history of Cystic Fibrosis in their families. In order to assess the risk of having a child with CF (genotype: cfcf) for this couple you must first determine the probable genotypes of their family members. In the pedigree above, solid black shapes represent affected individuals with CF and open shapes represent non-affected individuals. What is the genotype of individual II-4? 1/2 CFcf, 1/2 CFCF cfcf 1/3 CFCF, 2/3 CFcf CFCF Genotypes Question 10 0 / 1 point In squash fruit colour is determined by one gene and fruit shape is determined by another independently assorting gene. The white fruit allele (W) is dominant over the yellow fruit allele (w) and the disk- shaped allele (D) is dominant over the round-shaped allele (d). A white disk shaped plant is crossed with a yellow round plant. Use the following data to determine the genotypes of the parental plants. Phenotypes of Progeny White, disk White, round Yellow, disk Yellow, round 23 19 20 22 wwDd x wwDd WWDd x wwdd Wwdd x Wwdd WwDD x wwdd Question 1 0 / 1 point When a recessive mutation results in the total loss of function in the gene product this is called a . Hypomorphic Allele Recessive Gene Hypermorphic Allele Question 2 0 / 1 point Question 3 False 0 / 1 point When two copies of an allele are required for an individual to exhibit the associated phenotype the allele is said to be . Dominant Sex-linked Heterozygous Question 4 0 / 1 point A gene located on any chromosome other than a sex chromosome is said to be . Sex-linked Recessive Dominant ML Question 5 0 / 1 point In pea plants round seeds are dominant over wrinkled. The gene responsible for this trait exhibits typical Mendelian expression and is designated with a D for the dominant allele and with a d for the recessive allele. If two heterozygote plants are crossed (Dd x Dd) what would be the expected genotypic ratio of the F1 progeny? 3:1, round:wrinkled 3:1, wrinkled:round 3:1; Dd:dd Question 6 0 / 1 point In squash fruit colour is determined by one gene and fruit shape is determined by another independently assorting gene. The white fruit allele (W) is dominant over the yellow fruit allele (w) and the disk- shaped allele (D) is dominant over the round-shaped allele (d). Two homozygous plants are crossed (WWDD x wwdd). The F1 plants are then crossed to produce F2 plants. Of 160 F2 plants approximately how many would you expect to be white and disk-shaped? 30 50 90 10 Probability Question 7 0 / 1 point A phenotypically normal couple have one child with a rare recessive disorder that is controlled by a single gene known to exhibit typical Mendelian heredity, what is the probability that a second child will have the disorder? 3/4 1/2 2/3 Question 8 A phenotypically normal couple have two children with a rare 0 / 1 point recessive disorder that is controlled by a single gene known to exhibit typical Mendelian heredity, what is the probability that a third child will have the disorder? 1/2 2/3 3/4 Pedigrees Question 9 0 / 1 point In the pedigree above individuals represented by solid black shapes have Tay-Sachs disease (tsts) a rare autosomal recessive disease that results in early death. The open shapes represent phenotypically normal individuals (TSts or TSTS). If you are a genetic councillor advising this couple (III-4 and III-5) in order to determine their risk of conceiving a child with Tay-Sachs disease you must first assign probable genotypes to their family members. What is the genotype of individual II-4? 1/2 TSts, 1/2 TSTS TSts 1/3 TSts, 2/3 TSTS Genotypes Question 10 0 / 1 point In squash fruit colour is determined by one gene and fruit shape is determined by another independently assorting gene. The white fruit allele (W) is dominant over the yellow fruit allele (w) and the disk- shaped allele (D) is dominant over the round-shaped allele (d). Two white, round plants are crossed. Use the following data to determine the genotypes of the parental plants. Phenotypes of Progeny White, disk White, round Yellow, disk Yellow, round 0 31 0 9 WwDd x WwDd WWdd x WWdd Wwdd x WWdd Question 1 0 / 1 point When studying genetic crosses the original generation from which all future progeny arises is called the _ _ generation. Parental (P) Monohybrid F2 F1 Question 2 0 / 1 point _ _ discovered the basic principles of heredity and is often referred to as the Father of Genetics. Gregor Mendel Question 3 James Watson Francis Crick Kary Mullis 0 / 1 point One version of a gene is referred to as a/an _ _. Locus Trait Gene Allele Question 4 When examining the pedigree for a rare recessive trait we can 0 / 1 point assume that individuals who mate into the pedigree are heterozygous for the recessive allele unless there is evidence to contradict this. True False ML Question 5 0 / 1 point In squash fruit colour is determined by one gene and fruit shape is determined by another independently assorting gene. The white fruit allele (W) is dominant over the yellow fruit allele (w) and the disk-shaped allele (D) is dominant over the round-shaped allele (d). If a plant has the following genotype, WWDd, which of the following gametes would be produced? Select all that apply: Wd WD WW Dd wD wd Question 6 0 / 1 point In squash fruit colour is determined by one gene and fruit shape is determined by another independently assorting gene. The white fruit allele (W) is dominant over the yellow fruit allele (w) and the disk-shaped allele (D) is dominant over the round-shaped allele (d). If a plant has the following genotype, WwDd, which of the following gametes would be produced? Select all that apply: Wd wD Dd Ww WD wd Probability Question 7 0 / 1 point A phenotypically normal couple have one child with a rare recessive disorder that is controlled by a single gene known to exhibit typical Mendelian heredity. Their second child is phenotypically normal, what is the probability that a third child would be homozygous dominant? 2/3 1/3 1/4 1/2 Question 8 0 / 1 point In a family of two children what is the probability that of having one girl and one boy? 1/16 1/4 1/2 1/8 Pedigrees Question 9 0 / 1 point In the pedigree above individuals represented by solid black shapes have Tay-Sachs disease (tsts) a rare autosomal recessive disease that results in early death. The open shapes represent phenotypically normal individuals (TSts or TSTS). If you are a genetic councillor advising this couple (III-4 and III-5) in order to determine their risk of conceiving a child with Tay-Sachs disease you must first assign probable genotypes to their family members. What is the genotype of individual II-8? TSts 1/3 TSTS, 2/3 TSts TSTS 1/2 TSts, 1/2 TSTS Genotypes Question 10 0 / 1 point In squash fruit colour is determined by one gene and fruit shape is determined by another independently assorting gene. The white fruit allele (W) is dominant over the yellow fruit allele (w) and the disk- shaped allele (D) is dominant over the round-shaped allele (d). Two white disk shaped plants are crossed. Use the following data to determine the genotypes of the parental plants. Phenotypes of Progeny White, disk round White, round Yellow, disk Yellow, 89 31 27 11 WWdd x WWDd WwDd x Wwdd Wwdd x Wwdd WwDd x WwDd WwDd x wwDd Question 1 0 / 1 point When two genes are located on separate chromosomes the alleles are randomly distributed to each gamete. This phenomenon is assumed in basic Mendelian genetics and is called . Mendelian Genetics Linked Assortment Random Distribution Independent Assortment Question 2 0 / 1 point When examining a pedigree for a recessive trait we can assume that individuals who mate into the pedigree are not carriers if the recessive allele is rare. True False Question 3 A is defined as a segment of DNA which codes for a polypeptide or other functional molecule; the unit of heredity. Chromosome Locus Gene Allele Question 4 0 / 1 point 0 / 1 point When studying genetic crosses the first set of progeny in the cross are called the _ _ generation. F1 F2 Parental (P) Heterozygous ML Question 5 0 / 1 point In squash fruit colour is determined by one gene and fruit shape is determined by another independently assorting gene. The white fruit allele (W) is dominant over the yellow fruit allele (w) and the disk-shaped allele (D) is dominant over the round-shaped allele (d). If a plant has the following genotypes WwDD, which of the following gametes would be produced? Select all that apply: DD WD Wd Ww wD wd Question 6 0 / 1 point In squash fruit colour is determined by one gene and fruit shape is determined by another independently assorting gene. The white fruit allele (W) is dominant over the yellow fruit allele (w) and the disk- shaped allele (D) is dominant over the round-shaped allele (d). Two homozygous plants are crossed (WWDD x wwdd). The F1 plants are then crossed to produce F2 plants. Of 160 F2 plants approximately how many would you expect to be yellow and round? 10 30 50 90 Probability Question 7 0 / 1 point A phenotypically normal couple have one child with a rare recessive disorder that is controlled by a single gene known to exhibit typical Mendelian heredity. What is the probability that the father is a carrier? 1 1/4 2/3 1/2 Question 8 0 / 1 point Polydactyly is a dominant trait that is characterized by having extra digits. A man with 6 fingers on his left hand marries a phenotypically normal woman. Their first child is also phenotypically normal. What is the probability that a second child will have be polydactyly? 75% 50% 25% There is not enough information to determine. 100% Pedigrees Question 9 0 / 1 point In the pedigree above individuals represented by solid black shapes have Tay-Sachs disease (tsts) a rare autosomal recessive disease that results in early death. The open shapes represent phenotypically normal individuals (TSts or TSTS). If you are a genetic councillor advising this couple (III-4 and III-5) in order to determine their risk of conceiving a child with Tay-Sachs disease you must first assign probable genotypes to their family members. What is the genotype of individual III-7? 1/3 TSTS, 2/3 TSts TSts TSTS 1/4 TSTS, 1/2 TSts, 1/4 tsts Genotypes Question 10 0 / 1 point In squash fruit colour is determined by one gene and fruit shape is determined by another independently assorting gene. The white fruit allele (W) is dominant over the yellow fruit allele (w) and the disk- shaped allele (D) is dominant over the round-shaped allele (d). A white disk shaped plant is crossed with a yellow, round plant. Use the following data to determine the genotypes of the parental plants. Phenotypes of Progeny White, disk White, round Yellow, disk Yellow, round 46 51 0 0 WWDd x wwdd WwDD x wwdd WwDd x wwdd Wwdd x WWdd WwDd x WwDd