Bio 151 Unit 2 Quiz Questions And Answers Rated 100% !!!

Alternate splicing does which of the following? - ANS Allows partly different proteins to be translated from a single transcript Which of the enzymes below cannot catalyze the formation or breakdown of phosphodiester linkages? - ANS helicase 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 A bacteriophage has the coat proteins of a T2 phage and the DNA for a t4 phage. If this phage infects a bacterium, it will take over the bacterium's cell machinery and make more phages. If this occurs, the new phages produced in the host bacteria cell would have: - ANS the protein and DNA of a T4 When lactose binds to the Lac operon repressor protein, the repressor - ANS stops repressing transcription from the Lac operon Transcription uses ____; Replication uses ____; Translation uses ____ - ANS Terminator; DNA ligase; start codon An inhibitor of exocytosis will block which of the following processes? - ANS release of digestive proteins modified in the Golgi to the outside of the cell The concentrations of cyclin-dependent kinases are ____ just before the cell cycle checkpoint they regulate and ____ after that checkpoint has passed. - ANS unchanged; unchanged Insulin, a protein hormone, is secreted using exocytosis from specialized cells in the pancreas. What path does the insulin protein take from synthesis to the outside of the cell? - ANS Rough ER vesicle Golgi apparatus vesicle exterior of cell In eukaryotes, the ____ of the mitotic spindle often span the entire region between the two poles containing ____. - ANS microtubules; centrosomes Microtubules and their associated motor proteins are responsible for: - ANS the movement of chromosomes What is glycosylation? - ANS the addition of sugars to proteins Which of the following signal sequences would you expect to find in the polypeptide that will eventually allow facilitated diffusion of Ca2+? - ANS a transmembrane anchor signal Which of the following signal sequences would you expect to find in the polypeptide that would eventually fold to become a histone protein? - ANS an amino terminal secretion signal peptide A eukaryotic cell undergoing mitosis contains the least amount (mass) of DNA during which phase of the mitotic cell cycle? - ANS G1 phase In a eukaryotic cell, where can protein synthesis occur? - ANS In the cytoplasm and the rough endoplasmic reticulum When cargo moves in the plus direction versus the minus direction along microtubules, different motor proteins are used for each different direction? - ANS True Human trisomy for the X chromosome is better tolerated than trisomy for the autosomes because - ANS extra X chromosomes turn into Barr bodies A human zygote contains 45 chromosomes instead of the usual 46. This can be caused by: - ANS nondisjunction during a meiotic cell division producing either egg or sperm Meiosis I separates ____, and meiosis II separates ____. - ANS homologous chromosomes; sister chromatids A heterozygotes 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 Mendel used true-breeding strains of peas. Which true-breading strains of peas would have been easier to produce from plants whose genotypes were unknown? - ANS recessive allele Which of the following represent the ratio of offspring phenotypes from a 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 allele of the gene? - ANS 1:0 A human zygote contains 69 chromosomes instead of the usual 46. This can be caused by: - ANS incomplete cytokinesis during spermatogenesis after meiosis I. 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. Which of the following represents the expected ratio of offspring phenotypes from the cross of an individual who is heterozygous for the alleles of two genes and another individual who is homozygous recessive for alleles of both genes? Assume the genes are on separate pairs of autosomes. - ANS 1:1:1:1 A man can pass on an X-linked allele to his sons. - ANS False A human cell has more DNA molecules during metaphase of meiosis I than during metaphase of mitosis. - ANS False A normal cell in the G1 phase of the cell cycle is considered to be haploid because the DNA has yet to be replicated into sister chromatids. - ANS False What did Chargaff's experiment prove? - ANS %A=%T, %C=%G What did the Avery, Griffith, and Hershey-Chase experiments each (independently) show? - ANS genetic material is DNA What are the bonds that are formed between complementary nucleotides on opposite strands of the double helix? - ANS hydrogen bonds How many origins of replication do prokaryotes have? How many origins of replication do eukaryotes have? - ANS one; many What happens when unwinding the DNA double helix creates supercoiling? - ANS Topoisomerase cuts the strands, allows them to unwind, and rejoins them How does primase work? - ANS primase is a specialized kind of RNA polymerase only used in DNA replication; RNA polymerase can start copying a template without a free 3'-OH; lays down a primer that consists of a short RNA stretch of 10-12 nucleotides for DNA polymerase RNA primers are synthesized by - ANS primase How does lagging strand replication work? - ANS DNA is synthesized from 5' to 3' direction and lagging strands go 3' to 5'; discontinuous and creates Okazaki fragments consisting of RNA primers plus DNA; RNA primers removed by DNA polymerase and replaced with DNA; DNA ligase joins adjacent DNA fragments