BSC Exam 2 Review Session, Quiz Question, and Practice Test with correct answers 2024.

Departure from 1:1:1:1 ratio of F1 gametes in dihybrid cross indicates ______________. - answers-linkage __________ classes are always most numerous or equal to _____________. - answers-1. Parental 2. Recombinant Crossing over (genetic recombination) is a random event that will only result in equivalent parental and recombinant phenotype ratios if genes are_______________________. - answers-independently assorting Dihybrid test cross of independently assorting genes produces a ___________ progeny ratio (Aa Bb X aa bb) - answers-1:1:1:1 Dihybrid test cross of completely linked genes produces a ________ progeny ratio (AB/ab X ab/ab) - answers-1:1 Dihybrid test cross of genes on the same chromosome that are sometimes but not always separated by crossing over in meiosis produce _____________________ progeny ratios - answers-intermediate In moths, the allele for black body, b, is recessive to the normal body color allele b+. The allele for purple eyes, p, is recessive to normal eyes, p+. A doubly heterozygous female (b+p+/bp) is test-crossed to a purple-eye, black body male (bp/bp) and we get the following progeny phenotypes: 90 wild-type 10 normal body & purple eyes 10 black body & normal eyes 90 black body & purple eyes 1) Which are the recombinant classes of offspring? - answers-Normal body and Purple Eyes Black Body and Normal Eyes In moths, the allele for black body, b, is recessive to the normal body color allele b+. The allele for purple eyes, p, is recessive to normal eyes, p+. A doubly heterozygous female (b+p+/bp) is test-crossed to a purple-eye, black body male (bp/bp) and we get the following progeny phenotypes: 90 wild-type 10 normal body & purple eyes 10 black body & normal eyes 90 black body & purple eyes What are the genotypes of the pure-breeding parents of the heterozygous female? - answers-b+p+/b+p+ and bp/bp In moths, the allele for black body, b, is recessive to the normal body color allele b+. The allele for purple eyes, p, is recessive to normal eyes, p+. A doubly heterozygous female (b+p+/bp) is test-crossed to a purple-eye, black body male (bp/bp) and we get the following progeny phenotypes: 90 wild-type 10 normal body & purple eyes 10 black body & normal eyes 90 black body & purple eyes What is the map distance between the 2 genes? - answers-10 map units ________________ proposed that recombination frequencies (RF) could be used as a measure of physical distance between two linked genes - answers-A. H. Sturtevant A particular virus with DNA as its genetic material has the following proportions of nucleotides: 20% A, 35% T, 25% G, and 20% C. How can you explain this result? - answers-The virus contains single stranded DNA If AB/AB is crossed to ab/ab, and the F1 heterozygotes are test crossed, what percent of the test cross progeny will be ab/ab if the two genes are linked and 10 m.u. apart? - answers-45% In humans, the gene A and gene B loci are 20 m.u. apart. If an AB/ab woman marries with an ab/ab man, what is the probability that their first child will only show dominant trait for gene A? - answers-10% The pairwise map distances for four linked genes are as follows: A-B = 22 m.u. B-C = 7 m.u. C-D = 9 m.u. B-D = 2 m.u. A-D -20 m.u. A-C = 29 m.u. What is the order of these four genes? Assume m.u. (map units) are accurate. - answers-ADBC You are looking at the sequence of a region of the leopard genome that is 300 base-pairs in length. You determine the sequence of one of the DNA strands and count 50 adenine nucleotide bases. How many cytosine nucleotides will there be in the double stranded molecule? - answers-100 You are looking at the sequence of a region of the leopard genome that is 300 base-pairs in length. You determine the sequence of one of the DNA strands and count 50 adenine nucleotide bases. How many pyrimidines will there be in the double stranded molecule? - answers-150 Which of the following DNA sequences is complementary to the sequence listed below?5'-ATAGCAC-3' - answers-5'-GTGCTAT-3 When DNA is being replicated: Correct Answer: Nucleotides are added to the _____ end of the growing DNA strand. - answers-3 ' Compare the wild-type sequence 5' AGCCTAC 3' with the following sequence 5' AGGCTAC 3' . - answers-Transversion and Nucleotide Base Substitution A complementation group is a group of mutations: - answers-That are in the same gene and do not complement each other. A true-breeding line of snapdragons with violet flowers and shiny leaves is cross to a true-breeding line with white flowers and dull leaves. The F1 plants all have violet flowers and dull leaves. The F1s are test-crossed to plants with white flowers and shiny leaves, producing the following F2 progeny: violet dull 8 violet shiny 42 white dull 42 white shiny 8 What is the genetic distance between the genes for flower color and leaf shininess? - answers-16 map units Two genes, Avocet and Bacara, are known to be 24 map units apart. A true-breeding Avocet Bacara animal is crossed to a true-breeding nonavocet nonbacara. All of the progeny are Avocet Bacara. These F1s are crossed to nonavocet nonbacara. How many of the F2 progeny will have an Avocet Bacara phenotype? - answers-38% Genes C and D are 70 map units apart on the same chromosome. In the following cross: C d / c D x c d / c d, what fraction of t - answers-25% A true-breeding line of snapdragons with violet flowers and shiny leaves is cross to a true-breeding line with white flowers and dull leaves. The F1 plants all have violet flowers and dull leaves. The F1s are test-crossed to plants with white flowers and shiny leaves, producing the following F2 progeny: What classes are the parental classes? violet dull 8 violet shiny 42 white dull 42 white shiny 8 - answers-violet shiny and white dull A dihybrid produces equal numbers of 4 different gamete types. This indicates that: - answers-the two genes are more than 50 map units on the same chromosome or they are on different chromosomes 5' and 3' represents __________ - answers-the polarity of sugar molecules in DNA A double-stranded DNA molecule contains 21% cytosine. What percentage of the bases are thymine? - answers-29% DNA replication begins at the space between A and C nucleotide of the template strand below. 5' GGTCCGAA CAGACGTA 3' What are the first 5 nucleotides incorporated into the newly synthesized strand? - answers-5' GUUCG 3' What phenotype would you expect to find in a cell that contained a mutation in the gene for telomerase? - answers-The cell's chromosomes would grow shorter at each S-phase. During DNA replication, DNA polymerase adds a __ to the __ of the newly synthesized strand. - answers-nucleoside monophosphate, 3' end DNA replication occurs by a _______________ mechanism; this term refers to the fact that each new DNA molecule contains one old and one new strand - answers-semiconservative You are an Okazaki fragment. In what order do the following enzymes synthesize you and modify you? a. primase - DNA polymerase I - DNA polymerase III - ligase b. DNA polymerase III - primase - DNA polymerase I - ligase c. primase - DNA polymerase III - DNA polymerase I - ligase d. DNA polymerase I - DNA polymerase III - ligase - primase e.DNA polymerase III - primase - DNA polymerase I - ligase - answers-c. primase - DNA polymerase III - DNA polymerase I - ligase Genes on the same chromosome are said to be __________. - answers-syntenic