Exam 3
During which phase of mitosis does the cytoplasm of a cell divide, fully separating the two daughter cells? (A) telophase (B) metaphase (C) prophase (D) cytokinesis (E) anaphase
(D) cytokinesis
Which is an example of gene therapy? (A) generating an attenuated virus to use in a live vaccine (B) altering the DNA of a mouse embryo to generate a model for a disease (C) inserting a new gene into a plant that confers drought resistance (D) replacing a disease-causing allele for a gene with a normal allele (E) inserting a new gene into bacteria so that it produces therapeutic proteins
(D) replacing a disease-causing allele for a gene with a normal allele
The cell cycle is a repeating sequence of events that leads to the duplication and division of a cell. Place the stages of the cell cycle in the order of their occurrence, from the earliest stage of cell growth through the latest stage of cell division.
Interphase Prophase Prometaphase Metaphase Anaphase Telophase Cytokinesis
What are the functions of mitotic cell division? (A) asexual reproduction (B) cell regeneration (C) organism growth (D) production of gametes
(A) asexual reproduction (B) cell regeneration (C) organism growth
Which statement describes a gene? (A) the pair of DNA sequences an organism has for a trait (B) a section of DNA in which the code for a protein is located (C) one variation of the code for a protein (D) the physical trait produced by an organism's genetic makeup
(B) a section of DNA in which the code for a protein is located
Complete the transcription of the RNA sequence using the DNA template. ATCGAC
UAGCUG
In general, what causes normal cells to become cancer cells? (A) loss of cell cycle control (B) metastasis (C) rapid cell division (D) loss of the ability to divide
(A) loss of cell cycle control
During which phase of mitosis do spindle fibers shorten, pulling sister chromatids apart from one another and toward opposite ends of the cell? (A) metaphase (B) anaphase (C) cytokinesis (D) prophase (E) telophase
(B) anaphase
What is the function of the mitotic spindle? (A) keeping sister chromatids connected (B) separating sister chromatids (C) replicating chromosomes (D) pinching a cell into two daughter cells
(B) separating sister chromatids
Diabetes is a cluster of metabolic disorders where individuals suffer from elevated blood sugar levels. To regulate their blood sugar, some diabetics must inject themselves daily with the hormone insulin, which reduces the amount of sugar in the bloodstream. Historically, therapeutic insulin has been produced by pigs and other animals. However, raising pigs and purifying their insulin for medical use is labor intensive and pig‑derived insulin can produce immune reactions in some people. Based on the techniques of biotechnology, what would be the best alternative for producing therapeutic insulin? (A) clone existing pigs to increase the number of insulin sources (B) insert the pig insulin gene into the DNA of bacteria (C) put the human gene for insulin into bacteria (D) breed pigs that produce higher insulin levels
(C) put the human gene for insulin into bacteria
During which phase of mitosis do chromosomes line up along the middle of a cell? (A) anaphase (B) cytokinesis (C) telophase (D) prophase (E) metaphase
(E) metaphase
How do the nucleus and ribosomes work together to generate a protein? (A) In the nucleus, DNA is transcribed to mRNA, which the ribosomes use as instructions to synthesize a specific protein. (B) Ribosomes produce mRNA that migrates into the nucleus and uses a gene in the DNA as instructions to synthesize a specific protein. (C) Ribosomes migrate into the nucleus, attach to a gene in the DNA, and use the gene as a transcript to synthesize a specific protein. (D) A specific gene breaks away from the DNA and exits the nucleus, allowing the ribosomes to use the gene as instructions to synthesize a protein.
(A) In the nucleus, DNA is transcribed to mRNA, which the ribosomes use as instructions to synthesize a specific protein.
What statements describe how a cell may respond at a checkpoint? (A) The cell may initiate the next phase in the cell cycle. (B) The cell may find errors and delay the cycle until the errors are corrected. (C) The cell can repeat previous stages in the cycle until an error is repaired. (D) The cell may exit the cell cycle and enter a non‑dividing state. (E) The cell cycle can skip mitosis and continue to the G1G1 phase if an error is detected.
(A) The cell may initiate the next phase in the cell cycle. (B) The cell may find errors and delay the cycle until the errors are corrected. (D) The cell may exit the cell cycle and enter a non‑dividing state.
Which statements give examples of uses for genetically‑modified organisms? (A) replacing an allele for a disorder with a healthy allele (B) creating crops with a gene for pest resistance (C) breeding spotted dogs to create a new breed (D) eliminating slower antelope as cheetahs catch them (E) using a glowing protein from jellyfish to track gene expression
(A) replacing an allele for a disorder with a healthy allele (B) creating crops with a gene for pest resistance (E) using a glowing protein from jellyfish to track gene expression
Cell division by mitosis is a mechanism of asexual cell replication. Some single‑celled organisms reproduce by cell division, and cell division enables multicellular organisms to grow and to repair damaged cells. Which is a product of cell division by mitosis? (A) two cells genetically identical to the original cell (B) daughter cells that are genetically variable (C) four genetically similar daughter cells (D) daughter cells with half the number of chromosomes
(A) two cells genetically identical to the original cell
The codon table identifies the amino acid sequence that can be translated from a human mRNA sequence. This chart can also be used to identify amino acid sequences for other organisms. Select all of the organisms that use the codon assignments shown in the codon table. (A) white shark (B) oak tree (C) cat (D) Staphylococcus aureus (E) lizard
(A) white shark (B) oak tree (C) cat (D) Staphylococcus aureus (E) lizard
Using the codon table, what conclusions can be drawn about the genetic code? (A) The 64 codons are roughly evenly distributed between the 20 amino acids. (B) Many amino acids are encoded by multiple codons. (C) There are three codons that specify the end of translation. (D) The sequence 5′ AUGAGAUCGUGA 3′5′ AUGAGAUCGUGA 3′ contains ten overlapping codons.
(B) Many amino acids are encoded by multiple codons. (C) There are three codons that specify the end of translation.
Select the examples of genetically modified organisms (GMOs). (A) a wild white‑tailed deer hunted for meat (B) a rice crop modified to contain more iron (C) a farm‑raised chicken kept for laying eggs (D) a wild sunflower harvested for seeds (E) a farm‑raised salmon engineered to grow faster
(B) a rice crop modified to contain more iron (E) a farm‑raised salmon engineered to grow faster
The segment of DNA is unwound in preparation for transcription. 5′ GTGCTGGTA 3′ 3′ CACGACCAT 5′⟵template strand Identify the mRNA transcript that would be produced from this DNA sequence. (A) 5′ CACGACCAT 3′ (B) 5′ GTGCTGGTA 3′ (C) 5′ GUGCUGGUA 3′ (D) 5′ CACGACCAU 3′ (E) 5′ ACAUCAACG 3′
(C) 5′ GUGCUGGUA 3′
Which description is the best definition of recombinant DNA? (A) DNA that composes the genome of a cell that is the product of multiple rounds of self‑fertilization. (B) DNA that contains segments of DNA as well as segments of RNA within a single genome. (C) DNA that is composed of a combination of DNA nucleotides from two or more organisms. (D) DNA that contains both the template strand and the newly synthesized DNA strand within a single double‑helix molecule.
(C) DNA that is composed of a combination of DNA nucleotides from two or more organisms.
During the cell cycle, the cell must pass through several checkpoints that confirm that the cell is ready to progress to the next phase of the cycle. If the requirements of one phase have not been met, the cell cannot proceed to the next phase. These checkpoints help control the rate of cell division. If a mutation disables one of these checkpoints, what is most likely to happen? (A) Cells proceed through phases of the cell cycle in the wrong order. (B) The cell cannot proceed to the next phase of the cycle and must remain in the current phase. (C) The cell begins dividing too often, forming a tumor. (D) The cell stops dividing, entering the G0 (Gap 0) phase.
(C) The cell begins dividing too often, forming a tumor.
Why does radiation therapy increase the risk of cancer reoccurring? (A) Radiation causes cells to break away from the tumor and persist to reestablish the tumor. (B) Radiation disrupts the cell cycle checkpoints, causing cells to divide uncontrollably. (C) Radiation therapy leaves scar tissue, which is prone to developing tumors. (D) Exposure to radiation can damage the DNA of normal cells, which can contribute to cancer.
(D) Exposure to radiation can damage the DNA of normal cells, which can contribute to cancer.
The statements describe either advantages or disadvantages of genetically‑modified crops. Match each statement to the appropriate category. Often produces higher crop yields than traditional crops GMO crops have unknown impact on human health Pest-resistant crops decrease the cost of farming Pest-resistant crops may harm unattending organisms Salt-resistant crops are more hardy than traditional crops Cross pollination can transfer genes to traditional crop varieties Often have added vitamins to increase crop nutrition Generation and spread of resistant weeds
Advantages: Often produces higher crop yields than traditional crops Pest-resistant crops decrease the cost of farming Salt-resistant crops are more hardy than traditional crops Often have added vitamins to increase crop nutrition Disadvantages: GMO crops have unknown impact on human health Pest-resistant crops may harm unattending organisms Cross pollination can transfer genes to traditional crop varieties Generation and spread of resistant weeds
The variety of bananas typically eaten in North America and Europe do not contain seeds and thus cannot reproduce. The plants that grow these bananas are clones of a single parent plant that have been derived through natural selection and selective breeding. In the 1950s, the Gros Michel banana was the most common banana and was nearly eradicated by disease. As a result, the most common variety today is the Cavendish banana. Due to increasingly devastating diseases that attack the cloned Cavendish bananas, researchers in Belgium have created banana cultivars that are resistant to disease. However, many countries do not wish to use these resistant bananas because they are genetically modified organisms, also called GMOs. Select the arguments for GMO bananas. (A) GMO bananas can be generated that produce seeds for ease of planting. (B) Banana clones are infertile and cannot readily hybridize with resistant cultivars. (C) Inserting the resistance gene is more precise than hybridization. (D) There is no difference between GMO and traditional Cavendish bananas. Select the arguments against GMO bananas. (A) Little data on other GMO foods exist. (B) GMO bananas can be patented and can outcompete local varieties. (C) Little is known regarding human health and GMO bananas. (D) GMO bananas will reduce the genetic diversity in the current banana cultivar.
Select the arguments for GMO bananas. (B) Banana clones are infertile and cannot readily hybridize with resistant cultivars. (C) Inserting the resistance gene is more precise than hybridization. Select the arguments against GMO bananas. (B) GMO bananas can be patented and can outcompete local varieties. (C) Little is known regarding human health and GMO bananas.