Principles of Inheritance & Variation (Genetics) Questions and Answers

The last product in a reaction pathway often regulates the activity of the first enzyme in the branch of the pathway that is unique to its production when the concentration of the product gets very high Because the structure of the product is very likely to differ substantially from that of the the enzyme s normal substrate this type of regulation is most likely Competitive inhibition Allosteric activation Covalent modification O Allosteric inhibition O Competitive activation

What is the Ratio of phenotypes for these in B B BB b Bb

Which chromosome pair for Homo sap

DNA and RNA differ in that O A Ribose in DNA lacks a hydroxyl group B DNA is less stable than RNA OC Uracil does not occur in RNA O D RNA occurs usually in a double stranded fashion while DNA is mostly singl stranded O A and B OA B and D OA C and D

In order to synthesize DNA you need select all that apply a free 5 phosphate a free 3 OH group a free 2 OH group Odeoxyribonucleotides DNA polymerase

DNA O A Purines H bond to pyrimidines B Purines H bond to purines while pyrimidines H bond to each other C The presence of unusual bases such as hypoxanthine make the base pairing irregular non Watson and Crick D Base pairing is an important force that keeps the double helix together E An important force behind the double helix structure is the hydrophobic stacking of bases on the same strand B and E A D and E

Question 1 Not yet Identify the sites of lagging strand synthesis Select

1 For the past two decades genetic mapping has usually involved genetic markers with molecular phenotypes than genes with more traditional phenotypes Discuss some of the advantages of using molecular markers for mapping that have made them the predominant ones used for mapping Besides the assay used to determine the phenotype what other part of the standard mapping procedure might be different when molecular markers are used 2 Consider three genes in Saccharomyces cerevisiae the mutant alleles are a b and c while the wild type alleles are a b and c a and b are on different chromosomes while a and c are linked Draw the tetrads that arise under the following situations a Strains that are mutant for a but wild type for b are crossed to ones that are wild type for a but mutant for b The F1 is allowed to sporulate and the tetrads are isolated and analyzed Diagram the expected result b Strains that are mutant for a but wild type for care crossed to ones that are wild type for a but mutant for c The F is allowed to sporulate and the tetrads are isolated and analyzed Diagram the expected result if the crossover does not occur between the a and c genes

Suppose you have the following map of three genes on the same autosome Gene 1 has two possible alleles Gene 1 Wild type dominant allele A Mutant allele a Gene 2 has two possible alleles Wild type dominant allele B Mutant allele b Gene 3 has two possible alleles Wild type dominant allele C Mutant allele c Gene 2 RF between Gene 1 and Gene 2 10 25 RF between Gene 2 and Gene 3 23 75 Gene 3 The distance between two loci RF value gives the expected crossover frequency between the two loci Such crossovers include both the single AND double crossovers Suppose we obtained the following results 1 You test cross an individual of genotype AaBbCc Calculate the expected frequency of double crossovers 2 Calculate the expected single crossover frequency between Gene 1 and Gene 2 3 Calculate the expected single crossover frequency between Gene 2 and Gene 3

Your goal is to map three genes G1 G2 and G3 Assume that all three genes are located on the same autosome Gene G1 has two alleles Dominant allele X Recessive allele x Gene G2 has two alleles Dominant allele Y Recessive allele y Gene G3 has two alleles Dominant allele Z Recessive allele z You are crossing two breeding flies The female is triple homozygous wild type and the male is trip homozygous mutant 1 Write the genotypes of each of the two parents and the genotype of the F1 flies 2 Suppose we obtain the following phenotypic ratio from the F1 fly test cross Phenotype XYZ 321 Phenotype XYZ 66 Phenotype XyZ 102 Phenotype Xyz 18 Phenotype XYZ 15 Phenotype xyz 112 Phenotype xyz 59 Phenotype xyz 308

In a given strain of fly you are studying the inheritance of the body color and wing surface that are assumed to be autosomal traits Assume that each trait is controlled by a single gene with two alleles B and b alleles for the body color gene and W and w alleles for the wing surface gene The parental cross is between a true breeding female fly with yellow body smooth wing and a true breeding male fly with red body and wrinkled wings All the F1 flies have a red body and smooth wings a Taking the dominance pattern into account write the allele phenotype correspondence for body color and wing shape using the symbol B b for body color and W w for wing surface for example B yellow body b red body b Write the parental genotypes female and male and the genotype of the F1 flies c Crossing several pairs of F1 offspring i In the F2 offspring what is the expected red body smooth wings red body wrinkled wings yellow body smooth wings yellow body wrinkled wings ratio ii Suppose that the data below represents the actual numbers you obtain from the cross Compare it to your expected ratio in part i and provide a clear explanation for the discrepancy in case it does not match your expectation Body Color Red Yellow Red Yellow Body Color Wing Surface Red Yellow Red Yellow Smooth Smooth Wrinkled Wrinkled d Assuming the loci of the two genes are on the same chromosome In order to evaluate the distance between the loci you perform a few crosses between the F1 offspring flies and flies with yellow body and wrinkled wings Using the data from the following table calculate the distance between the genes for body color and wing surface Wing Surface Number Smooth Smooth Wrinkled Wrinkled 300 150 150 0 Number 396 102 98 404

In sweet peas two genes called A and B control the expression of the purple pigment in the petals This is the pathway White Pigment Enzyme from gene A Blue Pigment Enzyme from gene B Purple Pigment a Assuming the first reaction is disrupted in a pure breeding plant what would be the color of the petals b Assuming the second reaction is disrupted in a pure breeding plant what would be the color of the petals c Crossing the plants in part a and b what will be the color of the petals in F1 d Crossing the plants in F1 what ratio of purple blue white plants would you obtain in F2

2 In many mammals including rabbits there is a hair texture known as angora in which the hair is long and soft Angora rabbits are highly prized for the quality of their fur A rabbit breeder has four rabbits an angora male an angora female a short haired male and a short haired female The sex of the rabbits is not relevant to the solution He made the following crosses with the outcomes shown Angora female X angora male Angora female X short male Short female X angora male a Which phenotype is dominant all angora all short 4 short and 5 angora b What are the genotypes of each of the parents c If the short female and the short male were mated to each other what fraction of the offspring is expected to have short hair d Even for experts the sex of rabbits is very difficult to determine but the breeder wants to keep the males and females separate as much as possible When the mating in part C is performed a litter of five rabbits is born What is the probability that at least

5 In a sequence of double stranded DNA 2 000 000 of the total bases consists of the base T what is the number of base C A 1 000 000 B 2 000 000 C 4 000 000 D not enough information for an answer 5 Which enzyme functions in elongating the new RNA strand and is considered the primary enzyme for transcription A DNA polymerase B helicase C single stranded binding protein D RNA polymerase

1 The following DNA template indicates the first 7 base pairs for the beta amyloid pro cell membrane of neural cells Complete the double stranded DNA molecule by adding the complementary bases This would represent DNA replication TAC CTA CGT CTT DNA Template color the 7 rectangles in light blue TAC CTA CGT 2 Transcription 2 Transcription Step DNA is copied into mRNA After the DNA strand opens at the hydrogen bonding between complementary bases to expose the template of the gene it is copied onto RNA by the enzyme RNA polymerase to eventually make the mRNA molecule This mRNA molecule will be used as the template to assemble the amino acids during protein synthesis Complete the Transcription step below by writing the complementary RNA nucleotides from the DNA template Note DNA A T G C RNA A U G C RNA copy color the 7 rectangles in orange AAA CTT TCT AAA GTG TCT GTG

20 Which one of the following statements does not apply to a prokaryote and its genome a the genetic material is in the form of a DNA histone protein complex b prokaryotes are generally haploid c its linkage group is often circular d there is only one linkage group present e all of these are correct statements 21 In which of the following situations will the genotypic ratio and the phenotypic ratio not be the same a monohybrid test cross b incomplete dominance c monohybrid cross d co dominance e dihybrid test cross