Biology 240 Unity of Life Practice exam for Exam 3 Dr James Alexander Which of the following is a characteristics of all viruses A a nucleic acid DNA or RNA is present B a protein coat capsid C cell wall of lignin D answers A and C are both correct E answers A and B are both correct Simple small infectious particles consisting of small naked RNA molecules are A bacteria B prokaryotes C viroids D viruses E prions In the eukaryotic nucleus the structure that consists of DNA coiled around a core of eight histone proteins is called the A histone complex B microsphere C chromosome D Barr body E nucleosome The concept of dominance states that A The alleles of a gene locus separate during gamete formation B Hereditary units from male and female parents are blended in offspring C Different gene loci sort out independently of each other during gamete formation D Genes on one chromosome separate from each other in meiosis E Offspring that are heterozygous for a trait will exhibit only the dominant trait in the phenotype the recessive trait will not be observed in the heterozygote Alleles A are the result of hybridization B are present only in the F generation C are alternative competing forms of a gene at one gene locus D always occur in a 3 1 ratio E are different phenotypes 2 The chances that a child being heterozygous for a trait if both parents are heterozygous is A 0 B 25 C 50 D 75 E 100 RNA differs from DNA in that A RNA contains deoxyribose as its sugar B RNA has two phosphates instead of one bound to it C RNA contains uracil instead of thymine D answers A and C are both correct E answers A B and C are all correct Answer the following two questions on the following information In a flower there are two alleles one codes for white flowers W one codes for pink flowers P Initially you do not know which is dominant or which is recessive A white flowered plant is crossed with a pink flowered plant Both were from true breeding lines and both are considered to be homozygous All of the F offspring from the cross are white 1 Which phenotype is dominant A White B Pink What is the genotype of all the F offspring A WW B WP C PP D White E Pink 1 An individual with the genotype aaBBCc can form genetically different kinds of gametes A 8 B 4 C 3 D 2 E 1 When DNA is replicated the new strand of DNA is copied in a direction A 5 to 3 B 3 to 5 C 5 to 1 D 1 to 5 E 2 to 5 Using the genetic code which will be given to you identify a possible sequence of nucleotides in the DNA template strand that codes for the following polypeptide sequence Phe Pro Lys A UUU CCC UUU B GAA CCC CTT C AAA ACC TTT D CTT CGG GAA E AAA GGG TTT A particular triplet of bases in the coding sequence of DNA is TTT The anticodon on tRNA that binds to the mRNA codon is A AAA B GGG C CCC D UUU E TTT If R is dominant to r the offspring of a cross RR x rr will A display the same phenotype as the RR parent B display the same phenotype as the rr parent C have the same genotype as the RR parent D have the same 1 genotype as the rr parent E two of the above answers are correct A normal chromosome has genes A through H arranged as follows the represents the location of the centromere A B C D E F G H After a chromosomal mutation had taken place the chromosome is arranged as follows A B C D E E F G H What type of chromosome mutation occurred A deletion B reciprocal translocation C inversion D duplication E recombination The trp operon of E coli a bacterium which is normally turned on is an example of A an oppressed operon B a translatable operon C an inducible operon D a repressible operon E a removable operon The genotypic ratio of the F1 progeny of a cross P generation Aa x Aa is A 1 1 B 9 3 3 1 C 3 1 D 1 2 1 E 15 1 A couple who are both normal but are both carriers of the gene for cystic fibrosis a recessive trait have two children who have cystic fibrosis The probability that their next child will be normal is A 0 B 25 C 50 D 75 E 100 Which of the following statements is are false A The genotype at least in part determines the phenotype B The phenotype determines genotype C A genotype is the organism s genetic makeup D Alleles are different forms of the same gene E Two of the above statements are false Albinism is an autosomal recessive trait A woman and her husband show the normal phenotype but each had an albino parent What is the probability that their first child will be an albino A 0 B 25 C 50 D 75 E 100 In cats there are three possible alleles at the B locus They are as follows B black color b chocolate brown color b cinnamon reddish brown color The B allele is dominant over both b and b and b is dominant over b If you crossed a chocolate cat who had a cinnamon parent with a heterozygous black cat possessing the cinnamon allele what phenotypic ratio would you expect to see in their offspring A 75 cinnamon 25 black B 75 black 25 chocolate C 50 black 50 cinnamon D 50 black 50 chocolate E 50 black 25 chocolate 25 cinnamon 2