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BIO Final Exam
Question | Answer |
---|---|
Which of the following defines a genome? | The complete set of an organism's GENES and other DNA sequences. |
Which of the following is true of a species that has a chromosome number of 2n=26? | A gamete from this species has 13 chromosomes. |
In a plant's sexual life cycle___ | Gametophytes produce GAMETES by MITOSIS |
Homologous chromosomes___ | Carry information for the SAME traits |
The human X and Y chromosomes____ | Include genes that determine an individual's sex |
Which of the following happens at the conclusion of meiosis I? | Homologous chromosomes of a pair are separated from each other. |
Sister chromatids separate from each other during___ | Mitosis and Meiosis II |
Crossing over normally takes place during which of the following processes? | Meiosis I |
Independent assortment of chromosomes is a result of ___ | The random way EACH PAIR of homologous chromosomes lines up at the metaphase plate during meiosis I |
When homologous chromosomes cross over, what occurs? | Corresponding segments of DNA on HOMOLOGOUS chromosomes are exchanged. |
How is natural selection related to sexual reproduction as opposed to asexual reproduction? | Sexual reproduction results in many new gene combinations, some will lead to BETTER adaptation to the environment. |
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 |
Mendel accounted for the observation that traits that had disappeared in the F1 generation reappeared in the F2 generation by proposing that ___ | Traits can be dominant or recessive, and the recessive traits were obscured by the dominant ones in the F1 |
Phenylkenonuria is a genetic disorder that results in the inability to metabolize the amino acid phenylalanine. It is inherited as an autosomal recessive. Two parents who do not have PKU have a daughter with PKU. | pp |
The daughter from questions 16 and 17 goes on to marry a man w/o PKU. They have 3 children, all without PKU. What is the father's genotype? | Cannot be determined based on this information. |
Which of the following describes the ability of a single allele to have multiple phenotypic effects? | Pleiotropy |
Which of the following is an example of multifactorial inheritance? | Skin pigmentation in humans |
Which of the following provides an example of epistasis? | In rabbits and many other mammals, one genotype prevents any fur color from developing. |
Cytosine makes up 24% of the nucleotides in a sample of DNA from an organism. Approximately what percentage of the nucleotides in this sample will be thymine? | 26% |
What is meant by the description "antiparallel" regarding the strands that make up DNA? | One strand runs 5' - 3' and the other strand runs 3'-5' |
Which enzyme catalyzes the elongation of a new DNA strand in the 5'-3' direction? | DNA polymerase |
Eukaryotic telomeres replicate differently than the rest of the chromosome. This is a consequence of which of the following? | Gaps left at the 5' end of the lagging strand |
A new DNA strand elongates only in the 5'to 3' direction because___ | DNA polymerase begins by adding nucleotides at the 5' end of the template |
What is the function of topoisomerase? | Relieving strain in the DNA ahead of the replication fork |
What is the role of DNA ligase in the elongation of the lagging strand during DNA replication? | It joins Okazaki fragments together. |
What is a telomere? | The ends of linear chromosomes |
A particular triplet of bases in the template strand of DNA is AGT. The corresponding codon for the mRNA transcribed is___ | UCA |
The genetic code is essentially the same for all organisms. From this, one can logically conclude which of the following? | A gene from an organism can theoretically be expressed by any other organism |
In the process of transcription | RNA is synthesized |
What was Beadle and Tatum's hypothesis? | Every enzyme came from a gene |
What does it mean when we say the genetic code is redundant? | More than one codon can specify the addition of the same amino acid |
According to the central dogma, what molecule should go in the blank? DNA-____-Proteins | mRNA |
A ribozyme is | an RNA with catalytic activity |
Alternative RNA splicing ___ | Can allow the production of proteins of different sizes and functions from a single mRNA |
Which one of the following statements about RNA processing is true? | Introns are cut out before mRNA leaves the nucleus. |
Translation requires___ | mRNA, tRNA, rRNA |
How does termination of translation take place? | A stop codon is reached |
A nonsense mutation in a gene ___ | Introduces a premature stop codon into the mRNA |
Which of the following DNA mutations is most likely to damage the protein it specifies? | A base-pair deletion |
A single base substitution mutation is least likely to be deleterious when the base change results in___ | A codon that specifies the same amino acid as the original codon |