Gen Bio 1: EXAM 3

Halploid

A human cell with a total of 23 chromosomes is:

B. The DNA analyzed contains tandem repeats.

After using PCR on the same region from two individuals, you notice that each person's DNA yielded pieces of different sizes. Which answer option is the most likely explanation? A. This is a result of point mutation. B. The DNA analyzed contains tandem repeats. C. A mistake was made during gel electrophoresis. D. A mistake was made during PCR. E. None of the other answer options is correct.

D. are highest in viruses.

Mutation rates per nucleotide per replication: A. are higher in organisms with larger genomes. B. are lower in organisms with larger genomes. C. are similar across all organisms. D.are highest in viruses. E. are highest in bacteria.

A. somatic; germ-line

Mutations that affect only the individual in which they occur are called _____ mutations; _____ mutations are passed from parent to offspring. A. somatic; germ-line B. somatic; point C. point; germ-line D. germ-line; somatic E. germ-line; heritable

FALSE

Okazaki fragments are ligated to form a continuous DNA molecule after replication is completed. true false

B. results in two daughter cells that are genetically identical.

Reproduction by mitotic cell division: A. reduces the number of chromosomes by half. B. results in two daughter cells that are genetically identical. C. does not require the replication of chromosomes. D. involves the formation of gametes.

D.to package DNA in eukaryotic chromosomes

What is the function of histone proteins? A. to organize the microtubules that make up the spindle B. to attach sister chromatids together C. to connect chromosomes to the mitotic spindle D.to package DNA in eukaryotic chromosomes

E. to synthesize a strand of DNA using DNA as a template

What is the function of the enzyme DNA polymerase? A. to synthesize a strand of mRNA using mRNA as a template B. to synthesize a strand of mRNA using DNA as a template C. to synthesize a polypeptide using DNA as a template D. to synthesize a strand of DNA using a polypeptide as a template E. to synthesize a strand of DNA using DNA as a template

C. The cells would be smaller than normal.

What would happen to the daughter cells if the G2 phase of the parent cell is shortened? A. The cells would not undergo cytokinesis. B. The cells would be missing chromosomes. C. The cells would be smaller than normal. D. The cells would be larger than normal.

E. ribosomes

Which of the answer options is not needed for DNA replication? A. nucleotides B. None of the answer options is correct. C. DNA D. enzymes E. ribosomes

E. 4

For any single-nucleotide polymorphism (SNP), what is the maximum number of alleles possible? Please choose the correct answer from the following choices, and then select the submit answer button. A. 1 B. 2 C. 3 D. any number, depending on the SNP E. 4

oncogenes

Genes that promote cancer are called:

D. This mutation likely benefited the human population against some other related pathogen.

Genetic studies have identified an allele (Δ32) that seems to provide protection against HIV. Which would explain the reason why our population has this mutation? A. Our bodies are designed to protect us against a myriad of pathogens, and the immune system was preparing for future viruses like HIV. B. This mutation is very likely a neutral mutation. C. This mutation was likely induced in the genome by the presence of HIV virus. D. This mutation likely benefited the human population against some other related pathogen.

C. They phosphorylate proteins that allow passage through cell cycle checkpoints.

How do CDKs promote cell division? A. They regulate the activity of cyclins. B. They change the ability of microtubules to polymerize. C. They phosphorylate proteins that allow passage through cell cycle checkpoints. D. They cause cyclin levels to increase and decrease. E. They bind to DNA.

A. 12; 12; 6; 6; 3

It is estimated that a human cell in G1 phase of the cell cycle contains 6 picograms of DNA in its nucleus. If you measure the DNA content at various stages of mitosis and meiosis, what amounts of DNA can be expected in nuclei at the following stages? prophase mitosis: _____; prophase I meiosis: _____; prophase II meiosis: _____; telophase mitosis: _____; telophase meiosis II: _____. A. 12; 12; 6; 6; 3 B. 12; 24; 6; 12; 6 C. 12; 12; 3; 6; 3 D. 6; 6; 3; 6; 3 E. 6; 12; 3; 6; 3

D. Cytokinesis does not occur.

Muscle cells in the mammalian heart are multinucleate, meaning that multiple nuclei are present in the cytoplasm of individual large cells. Predict what is different about the cell cycle in a muscle cell. A. The G1 and G2 phases are extended. B. S phase happens twice. C. M phase is inhibited. D. Cytokinesis does not occur.

E. hotspots.

Sites in the genome that are more susceptible to mutations than others are called: A. noncoding DNA. B. genes. C. risk factors. D. mutation spots. E. hotspots.

D. These structures represent crossing over between non-sister chromatids.

Suppose you analyze a time-lapse video of a cell under a microscope and you observe what appears to be crosslike structures within a bivalent. Which of the answer choices is an interpretation of this observation? A. The cell is probably from a plant that has four sets of chromosomes, rather than only two sets. B. The cell has completed S phase and is ready to begin cell division. C. The chromatids are the result of crossing over prior to the initiation of Prophase 1 of meiosis. D. These structures represent crossing over between non-sister chromatids.

C. The chromatids represent a bivalent and the cell is probably in Prophase I of meiosis.

Suppose you analyze a time-lapse video of a cell under a microscope, and you observe what appears to be four chromatids tightly aligned along their lengths. Which of the answer choices is an interpretation of this observation? A. The cell has completed S phase and is ready to begin cell division. B. The chromatids are the result of crossing over prior to initiation of Prophase 1 of meiosis. C. The chromatids represent a bivalent and the cell is probably in Prophase I of meiosis. D. The cell is probably from a plant that has four sets of chromosomes, rather than only two sets.

A. a point mutation is when a base pair is changed to a different base pair, whereas an SNP is when the base pair differs among individuals in a population.

The difference between a single-nucleotide polymorphism (SNP) and a point mutation is that: A. a point mutation is when a base pair is changed to a different base pair, whereas an SNP is when the base pair differs among individuals in a population. B. an SNP can be corrected by various repair mechanisms, whereas a point mutation cannot. a point mutation can be corrected by various repair mechanisms, whereas an SNP cannot. C. an SNP becomes permanently incorporated into the genome whereas a point mutation does not. D. a point mutation becomes permanently incorporated into the genome, whereas an SNP does not.

D. origin of replication.

The point at which DNA synthesis is initiated is called the: A. start codon. B. primase. C. primer. D. origin of replication. E. replication fork.