BioSc 231 General Genetics Exam 4 Name Multiple Choice 1 point each Polyploid plants found in nature usually have even numbers of chromosomes because organisms having odd numbers A exhibit altered mitosis B exhibit altered growth C have low fertility D are not viable Pollen from one species with a genome represented by CC germinates on the stigma of another related species with a genome represented by DD and sexually fertilizes the ovule Most of the resulting plants are sterile but some of the resulting offspring undergo chromosome duplication resulting in fertile plants The genomes of the fertile offspring are best represented by A CC B DD C CCDD D CDD E CCD In a mammal no Barr bodies are observed How many X chromosomes does the organism have A 0 B 1 C 2 D 3 E 4 Euploidy is A a chromosome number that is not an exact multiple of the haploid number B an example of aneuploidy C a chromosome number that is an exact multiple of the haploid number D the addition of an extra copy of a particular chromosome E the absence of a particular copy of a chromosome The basic diploid chromosome number in Rye Secale cereale is 14 A new species of rye is found that has 28 chromosome species This species is said to be A haploid B diploid C triploid D tetraploid E pentaploid When an allotetraploid AABB is backcrossed to one of its progenitor species BB a sterile progeny is produced The genomic composition of this sterile individual can be best represented by A AB B ABB C AA D BB E AAB When an organism gains one extra copy of a chromosome but not a complete haploid set the conditions is known as A polyploidy B euploidy C aneuploidy D triploidy It was once thought that the karyotype was related to criminal disposition because it led to aggressive behavior due to excessive maleness A XO B XY C XXY D XYY E YY Consider a species with a diploid 2n number of 12 chromosomes How many chromosomes would be found in a trisomic body cell A 6 B 7 C 12 D 13 E 18 A base change resulting in a codon specifying an amino acid which is different than in the wild type polypeptide A Missense B Silent C Nonsense D Synonymous E Frameshift Mosaicism is due to A X inactivation B chromosome duplication C chromosome deletion D somatic mutations E gametic mutations When a diploid organism undergoes one or more rounds of endoreduplication resulting in a gain of more than one complete haploid set of chromosomes the resulting cells are best described as A polyploid B triploid C aneuploid D trisomic Type of mutation in which a purine is substituted for a purine A Transition B Transversion C Frameshift D Conversion E Inversion A type of microorganism that can exist on minimal medium A Conditional B Autotroph C Auxotroph D Prototroph A biochemical mutant that must be supplied with a particular nutrient for growth would be described as a n A Conditional B Lethal C Auxotroph D Prototroph E Autotroph A base change that changes a codon for an amino acid to a stop codon A Missense B Silent C Nonsense D Synonymous E Frameshift A bacterial histidine mutant was plated on minimal medium and a single colony grew You decide to sequence the histidine biosynthetic gene of the revertant and discover that the original mutation is still present This colony must have been able grow due to a A forward mutation B suppressor mutation C auxotrophic mutation D back mutation E back mutation OR suppressor mutation A cell is exposed to EMS a mutagen that causes guanine to mispair with thymine and allowed to undergo a few rounds of DNA replication The mutational event caused by this mutagen will be A AT to CG B GC to AT C AT to TA D AT to GC E GC to CG A new E coli mutant was tested for auxotrophy The mutant grows on minimal medium M arginine R histidine H M H alanine A M R H A but not on M or on M R A The mutant requires A Arginine B Histidine and alanine C Histidine D Arginine and alanine E Alanine The fluctuation test of Luria and Delbruck studying resistance to bacteriophge T1 infection established that A T1 phage was a mutagen B Mutations could arise prior to the time they were selected C The mutation rate varies greatly from experiment to experiment D In E coli the number of mutants per clone was relatively constant Himalayan rabbits have an appearance similar to Siamese cats in which their body is primarily a light cream color but have patches or black at their extremities This coloration is due to a mutation within a black pigment gene The type of mutation in this gene is described as A Conditional B Lethal C Auxotroph D Autotroph How many different trisomics could be formed in a plant with a diploid number of 16 A 1 B 8 C 16 D 24 E 32 E coli cells were spread on an agar plate producing 1000 colonies The colonies are replica plated on three agar plates containing the antibiotic kanamycin and one agar plate without antibiotics All of the colonies are able to grow on the agar plate without antibiotic but only 4 colonies are able to grow on each of the agar plates containing kanamycin You notice that the four colonies that grew on each of the kanamycin containing plates are in the exact same position This demonstrates A how to screen for environmental mutagens B that mutations occur in prokaryotes as well as in eukaryotes C that in some cases mutations are caused by the selective agent itself D that mutations occur in the absence of the selective agent E a direct correlation between the amount of the selective agent used and the number of resistant mutants one hit relationship Turner syndrome in humans is caused by which chromosomal conditions A 47 XXY B 47 21 C 45 X D 47 XYY Exposure to gamma radiation leads to severe damage to DNA The bacterium Deinococcus radiodurans is able to survive exposure to levels of gamma radiation that would kill any other known organism This organism is able to survive because A it is covered with a very thick cell wall that blocks radiation B it produces its own mutagens that quickly revert mutations that result from radiation exposure C it has several very efficient DNA repair systems D it has hundreds of copies of its chromosome so it has a good chance of at least one surviving A hybrid allotetraploid species 2n 40 was backcrossed to one of the suspected parents 2n 20 When the F 1 underwent meiosis the prophase chromosome configuration was examined If the guess about the suspected parent is correct what would the chromosome configuration look like A 20 pairs B 20 pairs and 10 singles C 30 singles D 10 pairs and 10