BIO 148 Exam 2 Questions With All Correct Answers Verified Answers 2025 Marking Scheme New Update

BIO 148 Exam 2 Questions With All Correct Answers Verified Answers 2025 Marking Scheme New Update Which of the following is part of a DNA molecule (i.e. is made up of DNA nucleotides)? 1. Promoter 2. Switch 3. Gene 4. 5' cap 5. Activator - Answer- 1, 2, and 3 only A doctor is trying to identify the mutant gene that causes her patient to be colorblind. To do this she takes a swab of the patient's cheek cells to send off for DNA sequencing. Did she sample the correct cells? - Answer- Yes, because both cells have the same genes RNA polymerase ________ - Answer- Synthesizes a nucleic acid that is complementary to the template strand For most multicellular organisms, how can the cells of a single organism have different shapes and actions? - Answer- They express different genes An individual has a mutation in the gene that encodes a switch activator protein. The mutation prevents the activator protein from binding to the switch that controls the expression of the lactase gene. What will the ultimate outcome of this mutation be? - Answer- The lactase gene will not be transcribed so the mRNA will not be translated Within the eukaryotic cell, transcription occurs in the __________ and RNA splicing occurs in the _____. - Answer- Nucleus; nucleus The DNA molecules in eye cells contain which of the following? -a.) Genes that encode eye color and skin color, and switches that control both eye color and skin color -b.) Genes that encode eye color and skin color, and switches that control eye color only (not skin color) -c.) Genes and switches that encode eye color only (not skin color) -d.) Genes that control eye and skin color, but not switches for either of these genes. - Answer- -A: Genes that encode eye color and skin color, and switches that control both eye color and skin color Which of the following is a part of a DNA molecule? -a.) Promoter -b.) Switch -c.) Gene - Answer- -A: Promoter -B: Switch -C: Gene How might a single base change (substitution) in the sequence of an exon affect the protein encoded by the gene? - Answer- -A single amino acid could change -The length of the polypeptide could change -It is possible that the change would have no effect on the protein Which of the following contains information that determines the amino acid sequence of the protein encoded by this gene? -a.) The gene's promoter -b.) Nucleotides between +1 and the start codon -c.) Nucleotides in exons - Answer- -C: Nucleotides in exons A possible sequence of nucleotides in the template strand of DNA that would code for a portion of a polypeptide with the amino acid sequence Phe-Ile would be _____. -a.) 3' TTG-CTA 3' -b.) 3' AAC-GAC 5' -c.) 3' AUG-CTG 3' -d.) 3' AAA-AAT 5' -e.) 3' AAA-TAA 5' - Answer- -E: 3' AAA-TAA 5' mRNA in eukaryotes - Answer- It is produced in the nucleus, contains untranslated sequences and is translated in the cytoplasm What determines the tertiary structure of proteins? - Answer- Genes determine the amino acid sequence of the protein, which determines its tertiary structure Which of the following mutations is the most likely to be deleterious? -a.) A switch mutation that leads to increased fertility in females -b.) A missense mutation that enhances the function of a protein -c.) A frameshift mutation in an essential gene -d.) A silent mutation in an essential gene - Answer- -C: A frameshift mutation in an essential gene A gene that codes for the BIO148 Protein is expressed in the liver and kidneys of an animal. An animal is born with a mutation that prevents the expression of the BIO148 Protein in kidney, but does not prevent its expression in liver. Where is this mutation most likely located? - Answer- In a gene switch Which of the following is translated? -a.) The 5' cap -b.) The +1 nucleotide -c.) The promoter -d.) Exons - Answer- -D: Exons What is used by ribosomes during translation? - Answer- mRNA Two distantly related species (like a cow and a yeast) will - Answer- Have many genes that differ between the two species Two members of the same species will - Answer- Share all the same genes, but may contain different alleles Artificial selection - Answer- It can change the heritable characters and the frequency of alleles in a population over time Why has resistance to a wide variety of insecticides, antibiotics, and herbicides has recently evolved in hundreds of insects, bacteria, and plants? - Answer- Humans are altering the environments of these organisms, and the organisms are evolving by natural selection For a population to evolve through natural selection - Answer- There must be heritable variation in the population True or false: A mutation in the protein-coding region of PitX1 that inactivated the protein product would have the same effect on fitness as the pelvic switch mutation - Answer- False The fish in which the pelvic switch mutation originally occurred had a pelvis. What statement accurately describes why? - Answer- The mutation occurred in germ line cells that gave rise to gametes The Pitx1 gene in stickleback fish is normally expressed in the pituitary, jaw, and pelvis. Assume that a fish inherits a mutation that inactivates the pelvic switch. You isolate DNA from pituitary, jaw, and pelvic tissue. In the DNA of which tissues would you expect to find the pelvic switch mutation? - Answer- All tissues What restates the fact that rifampin resistance in M. tuberculosis is an adaptation? - Answer- Rifampin resistance is a heritable trait that increases the fitness of bacteria in Rifampin compared to susceptible bacteria. Scientists know that a single genetic mutation gives rise to blue eyes. This mutation arose around 10,000 years ago and spread throughout European populations. What would be a possible explanation for the origin of the blue eye allele? - Answer- DNA polymerase inserted an incorrect base during replication of a cell that gave rise to gametes.