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| 585388186 | Two characters that appear in a 9:3:3:1 ratio in the F2 generation should have which of the following properties? | The genes controlling the characters obey the law of independent assortment. | |
| 585388187 | A sexually reproducing animal has two unlinked genes, one for head shape (H) and one for tail length (T). Its genotype is HhTt. Which of the following genotypes is possible in a gamete from this organism? | HT | |
| 585388188 | Mendel's observation of the segregation of alleles in gamete formation has its basis in which of the following phases of cell division? | Anaphase II of meiosis | |
| 585388189 | Mendel's second law of independent assortment has its basis in which of the following events of meiosis I? | Alignment of tetrads at the equator | |
| 585388190 | Given the parents AABBCc x AabbCc, assume simple dominance and independent assortment. What proportion of the progeny will be expected to phenotypically resemble the first parent? | 3/4 | |
| 585388191 | Labrador retrievers are black, brown, or yellow. In a cross of a black female with a brown male, results can be either all black puppies, 1/2 black to 1/2 brown puppies, or 3/4 black to 1/4 yellow puppies. In one type cross of black x black, the results were as follows: 9/16 black, 4/16 yellow, 3/16 brown. The genotype aabb must result in which of the following? | Yellow | |
| 585388192 | Fruit flies usually have long wings (+) but mutations in two different genes can result in bent wings (bt) or vestigial wings (vg). If a homozygous bent wing fly is mated with a homozygous vestigial wing fly, which of the following offspring would you expect? | All +bt +vg heterozygotes | |
| 585388193 | Tallness (T) in snapdragons is dominant to dwarfness (t), while red (R) flower color is dominant to white (r). The heterozygous condition results in pink (Rr) flower color. A dwarf, red snapdragon is crossed with a plant homozygous for tallness and white flowers. What are the genotype and phenotype of the F1 individuals? | TtRr - tall and pink | |
| 585388194 | Two blue budgies were crossed. Over the years, they produced 22 offspring, 5 of which were white. What are the most likely genotypes for the two blue budgies? | yyBb and yyBb | |
| 585388195 | A woman who has blood type A positive has a daughter who is type O positive and a song who is type B negative. Rh positive is a trait that shows simple dominance over Rh negative and is designated by the alleles R and r. A third gene for the MN blood group has codominant alleles M and N. Which of the following is a possible genotype for the mother? | IAi | |
| 585388196 | Which of the following provides an example of epistasis? | In rabbits and many other mammals, one genotype (cc) prevents any fur color from developing. | |
| 585388197 | What is the likelihood that the progeny of IV-3 and IV-4 will have wooly hair? | 50% | |
| 585388198 | When a disease is said to have a multifactorial basis, it means that | both genetic and environmental factors contribute to the disease | |
| 585388199 | A scientist discovers a DNA-based test for the allele of a particular gene. This and only this allele, if homozygous, produces an effect that results in death at or about the time of birth. Of the following, which is the best use of this discovery? | To design a test for identifying heterozygous carriers of the allele | |
| 585388200 | An obstetrician knows that one of her patients is a pregnant woman whose fetus is at risk for a serious disorder that is detectable biochemically in fetal cells. The obstetrician would most reasonably offer which of the following procedures to her patient? | Amniocentesis | |
| 585388201 | A man with Klinefelter syndrome (47, XXY) is expected to have any of the following EXCEPT | increased testosterone | |
| 585388202 | SRY is best described in which of the following ways? | A gene region present on the Y chromosome that triggers male development | |
| 585388203 | In birds, sex is determined by a ZW chromosome scheme. Males are ZZ and females are ZW. A recessive lethal allele that causes death of the embryo is sometimes present on the Z chromosome in pigeons. What would be the sex ratio in the offspring of a cross between a male that is heterozygous for the lethal allele and a normal female? | 2:1 male to female | |
| 585388204 | A man who is an achondroplastic dwarf with normal vision marries a color-blind woman of normal height. The man's father was six feet tall, and both the woman's parents were of average height. Achondroplastic dwarfism is autosomal dominant, and red-green color blindness is X-linked recessive. How many of their daughters might be expected to be color-blind dwarfs? | None | |
| 585388205 | A Barr body is normally found in the nucleus of which kind of human cell? | Somatic cells of a female only | |
| 585388206 | Which of the following statements is true? | The closer two genes are on a chromosome, the lower the probability that a crossover will occur between them. | |
| 585388207 | In a series of mapping experiments, the recombination frequencies for four different linked genes of Drosophilia were determined as shown in the figure. What is the order of these genes on a chromosome map? | b-rb-cn-vg | |
| 585388208 | If nondisjunction occurs in meiosis II during gametogenesis, what will be the result at the completion of meiosis? | 1/4 of the gametes will be n+1, one will be n-1, and two will be n. | |
| 585925953 | Which of the following statements describes genomic imprinting? | It explains cases in which the gender of the parent from whom an allele is inherited affects the expression of that allele. | |
| 585925954 | Mitochondrial DNA is primarily involved in coding for proteins needed for electron transport. Therefore in which body systems would you expect the most mitochondrial gene mutations to be exhibited? | Nervous and muscular systems | |
| 585925955 | A certain kind of snail can have a right-handed direction of shell coiling (D) or left handed coiling (d). If the direction of coiling is due to a protein deposited by the mother in the egg cytoplasm, then a Dd egg-producing snail and a dd sperm-producing snail will have offspring of which genotype(s) and phenotype(s)? | 1/2 Dd: 1/2 dd; all right coiling | |
| 585925956 | In his transformation experiments, what did Griffith observe? | Mixing a heat-killed pathogenic strain of bacteria with a living nonpathogenic strain can convert some of the living cells into the pathogenic form. | |
| 585925957 | For a science fair project, two students decided to repeat the Hershey and Chase experiment, with modifications. They decided to label the nitrogen of the DNA, rather than the phosphate. They reasoned that each nucleotide has only one phosphate and two to five nitrogens. Thus, labeling the nitrogens would provide a stronger signal than labeling the phosphates. Why won't this experiment work? | Amino acids (and thus proteins) also have nitrogen atoms; thus, the radioactivity would not distinguish between DNA and proteins. | |
| 585925958 | Replication in prokaryotes differs from replication in eukaryotes for which of these reasons? | Prokaryotic chromosomes have a single origin of replication, whereas eukaryotic chromosomes have many. | |
| 586858163 | An Okazaki fragment has which of the following arrangements? | 5' RNA molecules, DNA nucleotides 3' | |
| 586858164 | To repair a thymine dimmer by nucleotide excision repair, in which order do the necessary enzymes act? | endonuclease, DNA polymerase I, DNA ligase | |
| 586858165 | The leading and the lagging strands differ in that | the leading strand is synthesized in the same direction as the movement of the replication fork, and the lagging strand is synthesized in the opposite direction | |
| 586858166 | What is the function of topoisomerase? | relieving strain in the DNA ahead of the replication fork | |
| 586858167 | Which would you expect of a eukaryotic cell lacking telomerase? | a reduction in chromosome length | |
| 586858168 | Using RNA as a template for protein synthesis instead of translating proteins directly from the DNA is advantageous for the cell because | RNA acts as an expandable copy of the genetic material | |
| 586858169 | A peptide has the sequence NH2-phe-pro-lys-gly-phe-pro-COOH. Which of the following sequences in the coding strand of the DNA could code for this peptide? | 5' TTT-CCC-AAA-GGG-TTT-CCC | |
| 586858170 | Which of the following is true for both prokaryotic and eukaryotic gene expression? | RNA polymerase binds to the promoter region to begin transcription | |
| 586858171 | A part of the promoter, called the TATA box, is said to be highly conserved in evolution. Which might this illustrate? | Any mutation in the sequence is selected against | |
| 586858172 | Introns are significant to biological evolution because | their presence allows exons to be shuffled | |
| 586858173 | Alternative RNA splicing | can allow the production of proteins of different sizes from a single mRNA | |
| 586858174 | In an experimental situation, a student researcher inserts an mRNA molecule into a eukaryotic cell after he has removed its 5' cap and poly(A) tail. Which of the following would you expect him to find? | The molecule is digested by exonucleases since it is no longer protected at the 5' end. | |
| 586858175 | Accuracy in the translation of mRNA into the primary structure of a polypeptide depends on specificity in the | both C and D C) attachment of amino acids to tRNAs D) bonding of the anticodon to the codon | |
| 586858176 | A part of an mRNA molecule with the following sequence is being ready by a ribosome: 5' CCG-ACG 3' (mRNA). The following charged transfer RNA molecules (with their anticodons shown in the 3' to 5' direction) are available. Two of them can correctly match the mRNA so that a dipeptide can form. The dipeptide that will form will be | proline-threonine | |
| 586858177 | A mutant bacterial cell has a defective aminoacyl synthetase that attaches to a lysine to tRNAs with the anticodon AAA instead of phenylalanine. The consequence of this for the cell will be that | proteins in the cell will include lysine instead of phenylalanine at amino acid positions specified by the codon UUU. | |
| 586858178 | Choose the answer that has these events of protein synthesis in the proper sequence. | A small ribosomal subunit binds with mRNA, an aminoacyl-tRNA binds to the A site, a peptide bond forms between the new amino acid and a polypeptide chain, tRNA translocates to the P site, tRNA leaves the P site, and the P site remains vacant | |
| 586858179 | When does translation begin in prokaryotic cells? | as soon as transcription has begun | |
| 586858180 | Why might a point mutation in DNA make a difference in the level of a protein's activity? | It might substitute an amino acid in the active site. | |
| 586858181 | What is the effect of a nonsense mutation in a gene? | It introduces a premature stop codon into the mRNA. |
