Bio 151 exam 2, Seth Blair, Questions And Answers

Alternate splicing does which of the following - ANS Allows partly different proteins to be translated from a single transcript In analyzing the number of different bases in a single-stranded messenger RNA, which rule is correct A + U = G + C A + T = C + U None of the other answers are correct. A = G - ANS None of the other answers are correct The role of snRNA is to - ANS help splice out introns from DNA Why does DNA replication require the enzyme primase - ANS Primase builds an RNA primer so that DNA polymerase has a free 3' end to attach nucleotides to RNA polymerase - ANS Transcription Promoter - ANS Transcription Initiator tRNA - ANS Translation Okazaki fragments - ANS replication The enzyme that breaks hydrogen bonds between nucleotide bases during DNA replication is - ANS Helicase A eukaryotic chromosome has only one origin of replication - ANS False A human cell has more DNA molecules during metaphase of meiosis I than during metaphase of mitosis - ANS False Meiosis I separates ________________, and meiosis II separates __________________ - ANS homologous chromosomes, sister chromatids A heterozygote contains two different alleles of the same gene. Just before meiosis begins the two different alleles are found on: - ANS a pair of homologous chromosomes Which of the following represents the expected ratio of offspring phenotypes from the cross of an individual who is homozygous for the dominant allele of an autosomal gene with an individual who is heterozygous for the dominant and recessive alleles of the gene - ANS 1:0 You examine the chromosomes of a somatic cell in G2 from a diploid animal in which 2n = 10. Which of the following is NOT true about the chromosomes in this cell? - ANS There are 20 chromosomes present We have a pea plant that is heterozygous for two traits - height and seed color. The plant is tall and yellow, which are dominant phenotypes; short and green are recessive phenotypes. We will let this plant self-fertilize, and see what kind of offspring this plant produces. This is a dihybrid cross; we are tracking two traits - T (tall) to denote height and Y (yellow) to denote seed color. The plant is heterozygous for both traits so the plant is TtYy What type of gametes will a TtYy plant produce? Commas in the answers separate types of gametes. TT, tt, YY, yy - ANS TY, Ty, tY, ty 9:3:3:1 When a single base is deleted from an exon of a gene encoding a protein, this most often leads to a _______ mutation. - ANS frameshift The lac operon controls the production of beta-galactosidase and lactose permease proteins. A mutation in the lac repressor protein that prevented it from binding lactose would likely cause the cell to: - ANS never produce the beta-galactosidase and lactose permease proteins irrespective of whether lactose is present or absent Where does splicing of pre-mRNA to make mature mRNA occur - ANS In the nucleus The genetic makeup of a particular individual is its - ANS genotype Cystic fibrosis (CF) is a disease based on mutations in the CF transmembrane conductance regulator (CFTR) gene. The codon sequence for part of the CFTR mRNA is: 5' -ACC-ATT-AAA-GAA-TTT-AAT-ATC-ATT-GGT-GTT-TCC- 3' ...where ACC codes for the amino acid threonine, which is the first amino acid encoded by the region of the gene shown. In some individuals with cystic fibrosis, the equivalent codon sequence is: 5' -ACC-ATT-AAA-GAA-AAT-ATC-ATT-GGT-GTT-TCC- 3' Which of the following statements about this mutation is true - ANS his is a deletion mutation