ASU BIO-181 Quiz 7 with correct Answers

The migratory neural crest cells: - ANSWER-Form neural and non-neural structures in the periphery. Which of the following is a protein produced by a regulatory gene? - ANSWER-Repressor The formation of the fertilization membrane requires an increase in the availability of: - ANSWER-Calcium ions From earliest to latest, the overall sequence of early development proceeds in which of the following sequences? - ANSWER-Acrosomal reaction → cortical reaction → synthesis of embryo's DNA begins → first cell division Transcription of structural genes in an inducible operon _____. - ANSWER-starts when the pathway's substrate is present A human zygote undergoes its first cell division: - ANSWER-24 hours after fertilization The vegetal pole of the zygote differs from the animal pole in that: - ANSWER-The vegetal pole has a higher concentration of yolk Genomic imprinting, DNA methylation, and histone acetylation are all examples of: - ANSWER-Epigenetic phenomena Two potential devices that eukaryotic cells use to regulate transcription are: - ANSWER-DNA methylation and histone modification. Contact of a sperm with signal molecules in the coat of an egg causes the sperm to undergo: - ANSWER-The acrosomal reaction A transcription unit that is 8,000 nucleotides long may use 1,200 nucleotides to make a protein. This is best explained by the fact that - ANSWER-many noncoding stretches of nucleotides are present in mRNA. In eukaryotes, general transcription factors: - ANSWER-Bind to other proteins or to a nswerssequence element within the promoter called the TATA box. Fertilization normally: - ANSWER-Reinstates diploidy Which of the following genes map out the basic subdivisions along the anterior-posterior axis of the Drosophila embryo? - ANSWER-Segmentation genes One hereditary disease in humans, xeroderma pigmentosum (XP), makes homozygous individuals exceptionally susceptible to UV-induced mutation damage in the cells of exposed tissue, especially skin. Without extraordinary avoidance of sunlight exposure, patients soon succumb to numerous skin cancers. Which of the following best describes this phenomenon? - ANSWER-Inherited inability to repair UV-induced mutation. The product of the bicoid gene in Drosophila provides essential information about: - ANSWER-The anterior-posterior axis The lactose operon is likely to be transcribed when - ANSWER-The cyclic AMP and lactose levels are both high within the cell. The tryptophan operon is a repressible operon that is: - ANSWER-Turned off whenever tryptophan is added to the growth medium. Which of the following correctly displays the sequence of developmental milestones? - ANSWER-Cleavage → morula → blastula → gastrula Embryonic lethal mutations result in: - ANSWER-Phenotypes that are never born/hatched. In positive control of several sugar-metabolism-related operons, the catabolite activator protein (CAP) binds to DNA to stimulate transcription. What causes an increase in CAP? - ANSWER-Decrease in glucose and increase in camp From earliest to latest, the overall sequence of early development proceeds in which of the following sequences? - ANSWER-Cleavage → gastrulation → organogenesis Which of the following experimental procedures is most likely to hasten mRNA degradation in a eukaryotic cell? - ANSWER-Removal of the 5' cap At the time of implantation, the human embryo is called a: - ANSWER-Blastocyst If a Drosophila female has a homozygous mutation for a maternal effect gene, _____. - ANSWER-all of her offspring will show the mutant phenotype, regardless of their genotype In a newly fertilized egg, the vitelline layer: - ANSWER-Hardens to form a protective cover. Your brother has just purchased a new plastic model airplane. He places all the parts on the table in approximately the positions in which they will be located when the model is complete. His actions are analogous to which process in development? - ANSWER-Pattern formation Gases are exchanged in a mammalian embryo in the: - ANSWER-Chorion In humans, identical twins are possible because: - ANSWER-Early blastomeres can form a complete embryo if isolated. The outer-to-inner sequence of tissue layers in a post-gastrulation vertebrate embryo is: - ANSWER-Ectoderm → mesoderm → endoderm Cells move to new positions as an embryo establishes its three germ tissue layers during: - ANSWER-Gastrulation In animals, embryonic stem cells differ from adult stem cells in that: - ANSWER-Embryonic stem cells are totipotent, and adult stem cells are pluripotent. Which of the following sets of materials are required by both eukaryotes and prokaryotes for replication? - ANSWER-Double-stranded DNA, four kinds of dntps, primers, origins As an embryo develops, new cells are produced as the result of: - ANSWER-Cell division Steroid hormones produce their effects in cells by _____ - ANSWER-binding to intracellular receptors and promoting transcription of specific genes During fertilization, the acrosomal contents: - ANSWER-Digest the protective jelly coat on the surface of the egg. A human blastomere is: - ANSWER-An embryonic cell that is much smaller than the ovum. For a repressible operon to be transcribed, which of the following must occur? - ANSWER-RNA polymerase must bind to the promoter, and the repressor must be inactive. An Okazaki fragment has which of the following arrangements? - ANSWER-5' RNA nucleotides, DNA nucleotides 3' A new DNA strand elongates only in the 5' to 3' direction because - ANSWER-DNA polymerase can only add nucleotides to the free 3' end.