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Biology Chapters 9-11

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Chromosome number and structure during G2 In a human somatic cell (normal body cell) that is in G2, what would be true about chromosome number and structure? Check all that apply.
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-These cells would be considered diploid (2n). -These cells would contain homologous chromosomes. -These cells would contain sister chromatids.
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Chromosome number and structure during G1 In a human somatic cell (normal body cell) that is in G1, what would be true about chromosome number and structure? Check all that apply.
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-These cells would be considered diploid (2n). -These cells would contain homologous chromosomes.
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__ is the longest phase of the cell cycle for most cells.
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G1
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During _________ the cell replicated its genome.
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Synthesis
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__ is a growth phase for the cell that happens after DNA synthesis has occurred.
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G2
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The process by which cellular chromosomes are divided and separated from each other is called _______.
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Mitosis
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It is during ___________ when the cytoplasm divides.
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Cytokinesis
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The resting phase of the cell cycle is called __.
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G0
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After S phase ______ __________ appear to share a common centromere.
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Sister Chromatids
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During G1, cells undergo the major portion of their ______.
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Growth
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During interphase, all eukaryotic cells synthesize large amounts of _______.
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Tubulin
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During G2, chromosomes begin to undergo ____________.
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Condensation
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The ___________ is a disk-like protein structure found at the point of constriction on the chromosome.
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Kinetochore
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Mutation in condensin gene If a gene encoding one of the proteins that is part of the condensin complex was mutated such that condensin could not bind properly with DNA, what would be the result? Check all that apply.
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– There is likely a mutation in a gene that encodes an SMC protein. – Sister chromatids will be able to separate prematurely, because condensin cannot properly associate with chromosomes.
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Cell Cycle Events INTERPHASE:
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Replicating DNA Cell prepares for division
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Cell Cycle Events PROPHASE:
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Chromosomes become visible Spindles first form
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Cell Cycle Events METAPHASE:
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Chromosomes align at equator The spindle checkpoint arrests cells in this stage
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Cell Cycle Events ANAPHASE:
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Centromeres split and move apart Sister chromatids separate
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Cell Cycle Events TELOPHASE:
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Nucleus reformation Chromosomes at poles
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Cell Cycle Events CYTOKINESIS:
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Cells divide Cleavage furrow or plate forms
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You are performing an experiment to assay phosphorylation of a substrate by a protein kinase. Based on the data in the table below, what do these experimental results suggest?
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The Substrate can undergo autophosphorylation.
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The function of adenylyl cyclase is to:
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Catalyze the conversion of ATP to cAMP.
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This type of receptor is not an enzyme itself, but is bound to an enzyme that can hydrolyze GTP to GDP. This type of receptor is referred to as _______________.
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A G Protein-Receptor.
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This type of receptor is a transmembrane receptor. It has an extracellular domain that binds to ligand, and an intracellular domain that can directly phosphorylate other proteins. This is an example of _______________.
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An enzymatic receptor.
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This type of receptor, once bound by ligand, can change conformation to allow specific substances to flow down their concentration gradient. This type of receptor is referred to as _______________.
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A channel-linked receptor.
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This type of receptor binds to hydrophobic ligands. This type of receptor is referred to as ________________.
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An intracellular receptor.
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Classify each ligand with the most likely type of receptor it will bind to. INTRACELLULAR RECEPTOR:
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-Estrogen -Progesterone -Nitric Oxide (NO) -Vitamin D
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Classify each ligand with the most likely type of receptor it will bind to. MEMBRANE RECEPTOR:
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-Insulin -Light -Extracellular Growth Factor
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When bound to ligand, this type of receptor changes conformation to allow ions to move down their concentration gradient across the membrane:
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Channel-linked receptor.
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What signaling pathway commonly makes use of a G protein to transduce the signal?
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Receptor tyrosine kinase pathways.
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A mutation in the DNA-binding domain of a steroid hormone receptor is most likely to affect what aspect of receptor function?
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The cellular response to the receptor to the nucleus.
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Ste5 binds to MAPKKK, MAPKK, and MAPK to organize the kinase cascade. What type of signaling molecule is Ste5?
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Scaffold.
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The protein Sonic Hedgehog (SHH) plays a role in specifying the identity of digits (such as fingers and toes) in mammals. Several digits arise directly from cells that both express and respond to secreted SHH. What type of signaling would this be considered?
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Autocrine.
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Many receptor tyrosine kinase pathways have MAPK as a downstream signaling component. MAPK can phosphorylate target proteins. What type of signaling molecule is MAPK?
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Enzyme.
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What is the difference between Ras and the G proteins bound to G protein coupled receptors (GPCRs)?
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Ras is a small G protein and the G proteins bound to GPCRs are not small G proteins.
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Actinomycin D is a transcriptional inhibitor. If added to cells in culture, which classes of signaling pathways would likely be directly affected by this inhibitor? Select all that apply.
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-The insulin signaling pathway. -The estrogen signaling pathway.
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What is the function of a protein kinase?
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To add phosphate groups onto proteins.
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Some cancers are caused by the overexpression of receptor tyrosine kinases (RTKs). It is known that RTK signaling pathways commonly stimulate cell division. Why would the overexpression of receptor tyrosine kinases lead to cancer development?
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RTKs are activated by dimerization, caused by ligand binding. If there are too many receptors on the cell surface, it is possible that these receptors dimerize in the absence of ligand binding, thus stimulating cell division at inappropriate times.
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Some enzymatic receptors and most G protein-coupled receptors transmit the signal into the cytoplasm by utilizing other substances within the cytoplasm that are referred to as:
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Second messengers.
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In synaptic signaling, neurotransmitters are released into a space that is referred to as a:
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Chemical synapse.
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One cell sends second messengers to another cell through gap junctions. What type of signaling would this be considered?
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Direct contact.
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Many receptor tyrosine kinase (RTK) pathways lead to the activation of Ras. To activate Ras, it is necessary to recruit a guanine nucleotide exchange factor to the plasma membrane, because Ras is a membrane associated protein. Guanine nucleotide exchange factors, such as SOS, stimulate the exchange of GDP for GTP. However, SOS cannot bind directly to most RTKs. The protein Grb2 has a domain that can bind to phosphorylated tyrosines, and another domain that can bind to SOS. Therefore, Grb2 can bind to active RTKs and recruit SOS to the plasma membrane. Grb2 is an example of what kind of signaling molecule?
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Second messenger.
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Addison’s disease is a disorder that results from a reduction in production of glucocorticoids and mineralocorticoids. Individuals with Addison’s disease suffer from a variety of systemic symptoms including: muscle weakness, fever, issues with the gastrointestinal tract, and increased tanning. Considering this information, what type of signaling do you think that glucocorticoids and mineralocorticoids stimulate?
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Endocrine.
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Using a specific chemical, a cell biologist has blocked one type of channel-linked receptor in a lab rat’s liver tissue. What was the likely mechanism of the chemical she used?
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The chemical prohibits binding of a ligand to the receptor.
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What type of receptor is not an enzyme, but is directly associated with an enzyme that can hydrolyze GTP?
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G Protein-Coupled Receptor.
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You are planning to perform some protein-protein interaction studies to identify a receptor for a steroid hormone you have been working on. You start by fractionating the cell. What cell fraction would you want to work with to identify the steroid hormone receptor of interest?
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The cytoplasmic fraction.
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Your research project involves the characterization of a particular signal transduction pathway. Specifically, you have been studying a receptor tyrosine kinase and protein X, which initiates downstream events. You are certain that protein X is part of the signal transduction pathway, but have been unable to identify a direct protein-protein interaction between the receptor tyrosine kinase and the protein X. What should you do next in your attempt to identify a link between the receptor tyrosine kinase and protein X?
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Try to identify an adapter protein that can interact with both the receptor and protein X.
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A mutation that affects Ca++ binding to calmodulin is most likely to interfere with what aspect of a signal transduction pathway?
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The cellular response to the second messenger.
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What enzyme phosphorylates MAP kinase kinase?
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MAP kinase kinase kinase.
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Place the item with the class of receptor with which it is associated. RTK RECEPTOR:
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-Tyrosine Kinase -Autophosphorylation -Kinase Cascade – Extracellular Receptor
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Place the item with the class of receptor with which it is associated. STEROID HORMONE RECEPTOR:
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-Intracellular Receptor -Alters Gene Expression
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Why are phosphorylation and dephosphorylation reactions commonly used to regulate signal transduction pathways?
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The addition or removal of a phosphate group can expose or hide potential binding sites in proteins or change protein activity.
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A researcher is working to generate a new cancer drug. Thus far, he has identified a compound that can reduce the size of tumors in the lung. However, in order for the drug to work, the lung tumor has to be small. In addition, the tumor cannot have metastasized (spread to other areas of the body). Furthermore, he knows that the drug acts to prohibit the signaling from one tumor cell to another tumor cell. Given the above information, this new drug prohibits:
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Paracrine signaling between tumor cells.
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G protein-coupled receptors are the largest family of cell surface receptors. Each receptor passes through the plasma membrane how many times?
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Seven times.
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Growth of new blood vessels is stimulated by vascular endothelial growth factor (VEGF). This ligand binds to the VEGF receptor, which leads to the dimerization and autophosphorylation of this receptor on cytoplasmic tyrosines. What type of receptor is the VEGF receptor?
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Enzymatic receptor.
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The cell surface receptors that can act only indirectly on plasma membrane-bound enzymes or ion channels are called:
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G protein-coupled receptors.
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The EGF-receptor is a receptor tyrosine kinase that binds to epidermal growth factor (EGF). In response to EGF binding, the EGF-receptor stimulates a signaling pathway that involves Ras. Ultimately, this signaling pathway leads to the upregulation of factors that promote cell division. As a result, in response to EGF, cells that express the EGF-receptor undergo cell division to produce more cells. If an inhibitor that inhibited all G proteins was added to cells, how would this affect the ability of these cells to respond to EGF?
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While the receptor would dimerize and autophosphorylate in the presence of the inhibitor, downstream signaling would be prevented because the inhibitor would affect Ras activity.
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You have identified a novel cytoplasmic protein. Through sequence analysis you are able to identify the presence of a number of serine/threonine phosphorylation motifs. Based on these data, you hypothesize that this protein may be a substrate for what kind of enzyme?
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A protein kinase.
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Leptin is a circulating hormone that is produced by fat cells and plays a role in body metabolism and obesity. It normally binds to receptors in the brain and inhibits appetite. Studies have demonstrated that when obese mice that are leptin deficient are injected with leptin they quickly lose their excess weight. Interestingly, however, many overweight people have high levels of leptin in their bloodstream. Why do you think that the high levels of leptin in obese individuals are insufficient to curb their appetite?
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Obese people who have high levels of leptin may have a leptin receptor with decreased sensitivity.
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The protein SOS is a guanine nucleotide exchange factor for Ras. SOS helps facilitate the exchange of GDP for GTP. What would be the effect of a mutation that inhibits the interaction between SOS and Ras?
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GDP would remain bound to Ras, thereby preventing Ras activation.
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You are leading a team of researchers at a pharmaceutical company. Your goal is to design drugs that help fight cancer. Specifically, you want to focus on drugs that bind to and inactivate certain proteins, thereby halting cell cycle progression. One of your team members suggests targeting the retinoblastoma (Rb) protein and inhibiting this protein. Will this approach be successful? Why or why not?
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This approach will not be successful. Rb is tumor-suppressor protein, and functions to inhibit the action of a number of cell cycle regulatory proteins. A drug designed to inactivate the Rb protein would essentially create the same situation as in as a cell that lacks both copies of the Rb gene. Lack of Rb activity would release the inhibition of cell cycle regulatory proteins, thereby promoting cell cycle progression, rather than halting it.
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Place the description of the binary fission stage in the correct sequence of events.
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1 – Site Specific DNA Replication 2 – Replication Enzymes Spread Out 3 – Replication Terminus Formed 4 – Chromosome Duplication 5 – DNA Partitioning 6 – FtsZ Protein Activity 7 – Septum Completion and Pinching
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Growth factor receptors are typically found in the:
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Cell Membrane.
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If the protein retinoblastoma is ________, it can bind to and ________ the Myc protein.
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– Dephosphorylated – Inactive
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The growth factors illustrated in this system are positive regulatory growth factors. Why are they considered ‘positive’ growth factors.
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They increase the rate of cell proliferation.
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How does myc become active?
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It dissociated from Rb.
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Mutations in the protein retinoblastoma (Rb) are often associated with cancer in the eye. What mutation might lead to cancer?
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A mutation that prevents Rb from becoming phosphorylated.
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The success of DNA replication is assessed during the ______ phase.
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S
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The cell cycle is regulated by checkpoints during the _______ phases.
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G1, G2, and M
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A eukaryotic cell that receives a “go-ahead” signal at the G1 checkpoint of the cell cycle will:
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Complete the cycle and divide.
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A cell that is in an environment that has an abnormally low pH will NOT pass which checkpoint?
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G1
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DNA repair enzymes will be highly active during what phase of the cell cycle?
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G2
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The proteins ________ work together to free the transcription factor that is bound by the retinoblastoma protein.
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Cyclin and cyclin dependent kinase
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Mutated forms of the Rb protein:
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Do not bind to E2F thereby promoting uncontrolled cell division.
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The protein ________ checks for damaged DNA, thereby acting as a “quality control” for the cell.
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p53
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What mutation would allow the cell to divide when it should not and could possibly lead to cancer?
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None of these will lead to cell proliferation.
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Which mutation would allow the cell to pass the G1 checkpoint when it should not?
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A mutation in Rb, preventing it from associating with E2F.
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A pregnant mother recently had an ultrasound that indicated massive defects in the formation of her unborn baby’s heart. Other oddities were noted in the spinal cord region, the kidneys, and the formation of the facial features. She had an amniocentesis to examine the baby’s karyology, and it was noted that there was a deletion of a small piece of one chromosome. The doctors advised her that her that she would likely miscarry. The devastated parents consult you as a genetic advisor on the likelihood that a future pregnancy would end similarly. What advise do you give this unfortunate couple?
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The mutation was probably a germ line mutation that only affected a single egg or sperm, so they should try to have more children.
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Which of the following represents the correct order of the phases of the cell cycle?
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G1 -> S -> G2 -> M
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The division of the cytoplasm is called:
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Cytokinesis.
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Which of the following represents the correct order of the phases of mitosis?
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prophase -> metaphase -> anaphase -> telophase
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Which statement about mitosis and cytokinesis is TRUE?
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At the end of cytokinesis there are two daughter cells with a normal complement of diploid genetic material.
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Using the chart at the beginning of the animation and your knowledge of cells, what stage of the cell cycle do most cells spend the majority of their lives?
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G1
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During the G2 phase, the cell is preparing for mitosis. Using your knowledge of cellular organelles and molecules, Which molecule is produced in the highest quantity during the G2 phase?
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Tubulin, the microtubule protein.
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Cohesin complexes:
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hold a chromosome’s sister chromatids together.
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The arms of the sister chromatids dissociate from each other during ________ of mitosis.
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Prophase
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The sister chromatids of a chromosome fully separate during ________ of mitosis.
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Anaphase
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If the cohesin proteins failed to degrade during the metaphase/anaphase transition?
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Daughter cells would not have a complete set of chromosomes, and there would be two copies of the chromosomes that are present.
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When does cohesin first associate with the sister chromatids?
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During S phase.
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Which of the following events do NOT occur in prophase of mitosis?
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Chromosomes are replicated.
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Which of the following statements about microtubules during anaphase is TRUE?
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Those attached to chromosomes shorten, while those that are unattached elongate.
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Why do chromosomes condense during prophase?
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So that they will not be damaged when they are moved around the cell.
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How does cytokinesis differ between plants and animals?
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In animals two separate daughter cells are formed, in plants two daughter cells are formed but they share a single plasma membrane.
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Docetaxel is a drug that is used in the treatment of cancer. It interferes with cell division by inhibiting microtubule depolymerization. Specifically, what effect will this have on mitosis?
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It will prevent sister chromatids from separating during anaphase.
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Place the characteristic with the correct corresponding structure. HOMOLOGOUS CHROMOSOMES:
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– Maternal and paternal pairs – In humans, there are 23 pairs of these – Numbered in a karyotype
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Place the characteristic with the correct corresponding structure. SISTER CHROMATIDS:
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– Attached to each other by cohesin – Replica of single chromosome – Formed during interphase – Separated during mitosis
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If the gene encoding one of the proteins that forms cohesin were mutated such that cohesin could not perform its normal function, what would be the consequence? Check all that apply.
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– Microtubules could not reassemble to form the mitotic spindle. – Chromosomes would not be able to properly align at the metaphase plate. – The separation of sister chromatids would not likely occur specifically during anaphase A.
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Place the appropriate characteristic with the corresponding type of cytokinesis. ANIMAL CELL CYTOKINESIS:
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– Cleavage furrow – Constricting belt of actin – Centrioles separate
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Place the appropriate characteristic with the corresponding type of cytokinesis. PLANT CELL CYTOKINESIS:
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– Cell plate – Fusion of vesicles – Lack lusters
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The ______ checkpoint is the primary point of the cell cycle that is influences by external signals.
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G1/S
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The ________ checkpoint ensures that all of the chromosomes are attached to microtubules.
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Spindle
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The ________ checkpoint assesses whether DNA is damaged, and also whether DNA replication has completed.
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G2/M
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Passage through checkpoints is controlled by __________ enzymes.
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Cdk
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A new small molecule drug inhibits the function of the APC/C. If this drug were applied to cells undergoing the cell cycle, what do you think would be the result? Check all that apply.
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– Securin would not be destroyed in these cells. – These cells would not be able to undergo Anaphase A. – These cells would not be able to degrade mitotic cyclins. – These cells would not be able to exit mitosis.
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Estimates are that p53 is mutated in 50% of all human cancers. If the gene that encodes p53 is mutated such that p53 is non-functional, what processes would be affected? Check all that apply.
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– The ability to halt the cell cycle in response to DNA damage. – The ability to repair DNA damage. – The ability to stimulate cell death processes if the cell is irreparably damaged.
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The structure that divides the bacterial cell in two is termed the:
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Cross septum.
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How many generations does it take for a single bacterial cell to become 256?
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8
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The generation time of Mycobacterium tuberculosis is:
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12 hours.
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Which of the graphs below represent the population growth of bacteria?
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C
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The generation time for the five bacterial species mentioned in the animation are shown below. Which of these bacteria would be the best organism for scientists to use to study genetics, and why?
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Escherichia coli, because many generations can be examined in a short period of time.
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In streptococci, why is new cell wall only produced in certain regions of the daughter cells?
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These bacteria possess cell wall from the parent, and only need to produce new cell wall in certain regions.
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Which of the following statements about the mitotic spindle is TRUE?
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Kinetochore microtubules in the mitotic spindle attempt to connect to kinetochore proteins in the centromeres of the condensed chromosomes.
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You are assembling a model of a chromosome, but begin having some trouble when you get to the step of forming chromatin loops. If you are unable to resolve this problem, what step of chromosome structure would you be unable to achieve?
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Rosettes
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The two copies of each type of chromosome found in normal somatic (body) cells in an organism, throughout the cell cycle, are called:
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Homologous chromosomes.
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These structures are held together by cohesin:
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Sister chromatids.
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If there are 32 sister chromatids in a normal somatic cell, what is the haploid number for that cell?
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8
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A somatic cell from a garden pea normally contains 14 chromosomes. How many sister chromatids would that cell contain during G1 of the cell cycle?
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What is the sequence of events in a typical eukaryotic cell cycle?
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G1 to S to G2 to mitosis to cytokinesis.
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The stage of the cell cycle during which the cytoplasm divides to form two cells is called:
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Cytokinesis
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A duplicate copy of all of the hereditary information contained in the nucleus of eukaryotic cells is made during what stage of the cell cycle?
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S
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If a cell has 32 chromosomes prior to S and undergoes mitosis followed by cytokinesis, each new daughter cell will have how many chromosomes?
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32
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What is the portion of the cell cycle during which the chromosomes are invisible under the light microscope because they are not yet condensed?
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Interphase
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During what stages of the cell cycle are sister chromatids bound together by cohesin?
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S, G2, prophase, metaphase.
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If a chromosome contains a mutation such that it cannot bind to the kinetochore complex, what would be the consequence?
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That chromosome would not be able to bind to the mitotic spindle.
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This is the stage of mitosis characterized by the alignment of the chromosomes in a ring along the inner circumference of the cell:
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Metaphase
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This stage of mitosis is characterized by the disassembly of spindle apparatus, the reestablishment of the nuclear membrane, and the decondensation of the chromosomes:
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Telophase.
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In prophase, ribosomal RNA synthesis stops when the chromosomes condense, and as a result:
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the nucleolus disappears.
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What happens during Anaphase B?
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The spindle poles move apart.
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The drug Taxol, or Paclitaxel, is used to treat patients with a variety of cancers, including breast, lung and ovarian cancers. The drug works by stabilizing microtubules, and preventing their disassembly. The goal of the drug is to prevent dividing cells from being able to complete mitosis. As a result, cancerous cells can no longer divide. In a cell treated with Taxol, at what stage of mitosis will the cells arrest?
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Prior to metaphase
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If a cell was capable of bypassing metaphase and going directly from prometaphase to anaphase, what is the most likely consequence of this?
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The resulting daughter cells would have different numbers of chromosomes.
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Plant cells typically achieve cytokinesis by:
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forming a cell plate across the middle of the cell.
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The progress of the eukaryotic cell cycle is regulated primarily by what proteins?
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Cyclins.
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You are examining the effect of maturation-promoting factor (MPF) in sea urchin cells, which have a diploid number of 36. If you fuse a dividing sea urchin cell with a G1 arrested oocyte, what would be the outcome?
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The G1 cell would enter mitosis, but would likely arrest at the spindle checkpoint because the chromosomes have not been properly replicated.
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During meiosis I, the 2 kinetochores of sister chromatids fuse and kinetochore microtubules from one pole of the cell attach to the fused kinetochore. This is important because it ensures that during anaphase I:
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Sister chromatids are pulled towards the same pole of the cell.
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How does chromatid cohesion differ in mitosis and meiosis?
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Cohesion between sister chromatids is maintained during anaphase I of meiosis but not during anaphase of mitosis.
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Consider meiosis starting with a diploid cell where 2n=6. If DNA replication were not suppressed between meiotic divisions, the final result would be:
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Suppose you have a multicellular eukaryotic organism that is composed entirely of haploid cells. This organism would produce gametes by the process of:
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Mitosis
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Mutations can occur in any cell of the human body that contains DNA. However, only mutations in ________ can be passed on to the next generation.
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Haploid
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A cell biologist examines a diploid cell from a kangaroo during prometaphase of mitosis and determines that 32 chromatids are present. The role of fertilization in this animal is to (Check all that apply).
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A cell biologist examines a diploid cell from a barley plant during prometaphase of mitosis and determines that 28 chromatids are present. The role of meiosis in this plant is to (Check all that apply).
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A new drug is discovered which disrupts the process of synapsis. This drug is most likely to affect
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Cell division in germ-line cells
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A geneticist examines the karyotype of a diploid cell from a particular species of frog and determines that 12 chromosomes are present. If a germ-line cell from this species divides by meiosis, then at the end of meiosis I each cell will have (Check all that apply.)
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– 12 chromatids – 6 chromosomes
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Nondisjunction is the failure of homologous chromosomes to separate during meiosis I, or the failure of sister chromatids to separate during meiosis II or mitosis. As a result, both homologous chromosomes or both sister chromatids migrate to the same pole of the cell. This produces daughter cells with an imbalance of chromosomes. If 22 pairs of homologous chromosomes segregate normally during meiosis I in humans (n=23) but we have nondisjunction of 1 pair, then at the end of meiosis II we will have:
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Nondisjunction is the failure of homologous chromosomes to separate during meiosis I, or the failure of sister chromatids to separate during meiosis II or mitosis. As a result, both homologous chromosomes or both sister chromatids migrate to the same pole of the cell. This produces daughter cells with an imbalance of chromosomes. A cell biologist examines the final products of meiosis in a rabbit cell (2n=44) and finds 2 cells with 22 chromosomes, 1 cell with 24 chromosomes and 1 cell with 20 chromosomes. Most likely this was caused because
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Which of the following is not haploid?
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Meiosis results in a reassortment of maternal chromosomes (inherited from the mother) and paternal chromosomes (inherited from the father.) If 2n=6 for a given species, what is the probability that a gamete will receive 1 maternal chromosome and 2 paternal chromosomes?
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In animals, cells that will eventually undergo meiosis to produce the gametes are set aside early in the course of development. These cells are called:
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Germ-line cells.
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The number of chromosomes per cell is reduced from two sets to one set during:
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Meiosis I.
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Which of the following events occur during prophase I?
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Breakdown of nuclear envelope, condensation of chromosomes, and movement of centrosomes.
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How many bivalents are formed in a cell with 20 chromosomes at the beginning of meiosis I?
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10
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Which of the following events occur during anaphase I?
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Separation of homologous chromosomes.
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How can you compare the complement of DNA in an interphase (G1) diploid cell and a cell that has just completed meiosis I?
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They have the same amount of DNA, but the meiotic cell has half as many chromosomes.
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What event in meiosis I leads to the cell becoming haploid rather than the separation of sister chromatids?
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Formation of bivalents lead to spindle fibers from opposite poles attaching to homologous chromosomes.
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In life cycles that alternate between haploid and diploid stages, _____ acts to reduce the number of chromosomes per cell from two sets to one set.
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Meiosis
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In life cycles that alternate between haploid and diploid stages, _____ acts to double the number of chromosome per cell from one set to two sets.
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Fertilization
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In life cycles that alternate between haploid and diploid stages, _____ acts to keep the number of chromosomes per cell the same.
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Mitosis
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In animals, a single diploid cell called a _____ divides by mitosis to give rise to all the cells of the adult body.
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Zygote
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During fertilization, each haploid _____ contains the entire genetic contribution from one of the two parents.
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Gamete
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Cells that have one set of chromosomes are called _____.
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Haploid
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Cells that have two sets of chromosomes are called ______.
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Diploid