Download EBIO 1210 Exam Study Guide: Cell Division and Genetics and more Exams Biology in PDF only on Docsity!
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How many chromatids and chromosomes are present in this cell? - ans8 chromosomes and 8 chromatids Which sentence below about cancer cells is false? - ansAll cells become synced and cease dividing at the same time at the same point in the cell cycle. This cell is in which phase of mitosis? - ansPrometaphase Which best describes how density-dependent inhibition functions? - ansProtein-protein interactions on the surfaces of adjacent cells cause them to stop dividing. This cell is in which phase of mitosis? - ansTelophase Which roman numeral(s) indicate(s) when a cell is undergoing mitosis? - ansIII and IV You would find ________in animal cells, but they aren't present in plant cells. - ansCentrioles The cell shown below is in which phase of mitosis? - ansProphase During mitosis, what causes the chromosomes to move toward the opposite poles? - ansmotor proteins of the kinetochore and spindle pole motor move the chromosomes along the spindle fibers Humans have - ans23 pairs of chromosomes, one set of 23 from each parent The event that is not part of mitosis is the - ansdoubling of the DNA content. Where would the effects be observed if a drug that could inhibit the action of the non- kinetochore microtubules was given to cells prior to division? - ansformation of cleavage furrow and cytokinesis During Anaphase I - ansHomologous chromosomes separate and migrate to opposite poles Which of these most accurately describes the frequency of crossing over in meiosis in mammalian cells? - ansIt happens at least 1-2 times for each chromosome pair This contributes to genetic variation in species that reproduce sexually. - ansrandom fertilization If an egg from a sexually reproducing species contains 16 chromosomes, what is the diploid number for that species? - ans This cell is in - ansProphase 1 If the parent cell contained 32 chromosomes, how many would be present in the daughter cell of meiosis I? - ans This cell is - ansin metaphase 1 of meiosis A pair of homologous chromosomes would include - anstwo sister chromatids that have synapsed I. Prophase I V. Prophase IIII. Metaphase I VI. Metaphase IIIII. Anaphase I VII. Anaphase IIIV. Telophase I VIII. Telophase IIDuring which of the phases listed above would you expect to see the centromeres of sister chromatids splitting? - ansVII Independent assortment of chromosomes is involved. - ansThis is true for meiosis I only. During which part of meiosis do the daughter cells become haploid? - ansAt the end of meiosis 1 Which is true regarding anaphase 1 versus anaphase 2 of meiosis? - anssister chromatids separate in mitosis only If the parent cell contained 32 chromosomes, how many would be present in the daughter cell of meiosis II? - ans
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Crossing a plant that is homozygous for long stems and a plant that is homozygous for short stems produces all pea plants with long stems in the F1 generation. This example demonstrates - ansdominance Having unattached earlobes is dominant while having attached earlobes is recessive. When a person with attached earlobes mates with a person heterozygous for unattched earlobes, what is the chance that their child will have attached earlobes? - ans50% All of the traits Mendel studied in pea plants followed the principle of independent assortment, so what does this indicate? - ansAll of the genes controlling the traits behaved as if they were on different chromosomes. In a cross between an individual that is heterozygous and an individual that homozygous recessive for a single trait, what is the chance they will produce an offspring with the homozygous recessive phenotype? - ans2/ ______ genes are inconsistent with the law of independent assortment. - ansLinked Plants that have the dominant allele T for bark thickness have thick bark and homozygous recessive (tt) plants have thin bark. There is also a gene B in these plants that determines whether the plants will have any bark at all, and the homozygous recessive plants (bb) don't have bark. In a cross of two plants that are heterozygous for both traits, what fraction of the F1 offspring would be predicted to have thick bark? - ans3/ For an individual with the genotype DdGg, which of the gamete genotypes listed below would be possible? - ansDg A true-breeding pea plant with green peas is crossed with a true-breeding pea plant with yellow peas. Why are all of the seeds of all of the offspring yellow? - ansThe yellow allele is dominant to the green allele. Some members of a family shown in the pedigree have the dominant trait, W. A dark square or circle shows that the individual has at least one dominant W allele. What is the chance that the male individual number II-4 is WW? - ans A true-breeding pea plant has red flowers located axially and another true-breeding pea plant has white flowers that are located terminally. When they are crossed, all F1 offspring have red flowers located axially. The alleles for flower location and flower color assort independently. Out of 1000 crosses, approximately how many of the F2 progeny would have white flower color and terminal flower location? - ans If there is a phenotype ratio of 9:3:3:1 in the F2 generation, we know that - ansall answers are correct Which of the examples below demonstrates polygenic inheritance? - ansskin pigmentation in humans Shaded circles or squares in the pedigree below indicate that the individual has pancreatic cancer. The number listed for the individual indicates that individual's age when they were diagnosed. The woman in generation IV indicated by the shaded circle has the cancer and wants to know if she can figure out the risk for her children. Which of these would be advised for her to answer her questions?1. genetic counseling2. prenatal diagnosis if she gets pregnant3. testing her to see if she has the allele4. testing to her children's' potential father for the allele - ans1, 2, and 4 only
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When red-eyed F1 generation flies crossed with each other, the F2 generation included both red- and white-eyed flies but all the white-eyed flies were male. Why is this? - ansThe gene involved is on the X chromosome. Which choice best describes what SRY is? - ansa gene region present on the Y chromosome that triggers male development Where in cell division is a chromosome lost, resulting in an embryo with 45, X after fertilization?I. an error in anaphase III. an error in anaphase IIIII. an error of the first postfertilization mitosisIV. an error in pairing - ansI, II, III, or IV Which choice defines a syndrome? - ansa group of traits typically found in conjunction with a particular chromosomal aberration or gene mutation For humans, clear differentiation by gender occurs after the second month of gestation, rather than at fertilization. Which of the choices is the first event in this process? - ansactivation of SRY in male embryos and masculinization of the gonads In which way did Sturtevant demonstrate the existence of four pairs of chromosomes in Drosophila? - ansDrosophila genes cluster into four distinct groups of linked genes. Which choice describes the theory if inheritance as it stood in the early 20th Century? - ansMendelian genes are at specific loci on the chromosome and in turn segregate during meiosis. Colorblindness is X-linked recessive and achondroplasia, a form of dwarfism, is autosomal dominant. A man with achondroplasia and normal vision marries a colorblind woman of normal height. The man's father was over 6 feet tall and both of the woman's parents were of average height. How many of the daughters of this couple would be expected to have both achondroplasia and colorblindness? - ansnone What is it called when a chromosome breaks and a fragment of it joins a homologous chromosome? - anstranslocation Which choice is true of linkage? - ansThe closer any two given genes are on a chromosome, the lower the chance that crossing over will happen between them. Why does recombination between linked genes occur? - ansCrossovers between the genes lead to chromosomal exchange. How many chromosomes would an individual with trisomy 21 have in their somatic cells? - ans In humans, color blindness is a sex-linked recessive trait. If a couple that both have normal color vision have a color-blind son, what are the parents' genotypes? - ansXNXn and XNY The diagram below shows a map of four genes on a chromosome.Between which two genes on this chromosomes would you expect to find the highest frequency of recombination? - ansA and G The loci of 3 genes (X, Y and Z) are being mapped. Each gene has two alleles; one of them results in a phenotype that is very different compared to the wild type. The unusual allele of gene X is inherited with the unusual allele of gene Y or Z about 50% of the time. However, the unusual alleles of genes Yand Z are inherited together 14.4% of the time. Which of the following describes what is happening? - ansGene X is assorting independently of genes Y and Z
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The tortoiseshell phenotype is normally seen only in female cats because... - ansa male inherits only one allele of the X-linked gene controlling hair color. Females are not affected by sex-linked traits as frequently as males because... - ansmales are hemizygous for the X chromosome. Which statement is true of aneuploidies? - ans45, X is the only known human live-born monosomy. Duchenne muscular dystrophy is caused by a recessive allele on the X chromosome. The muscles of affected individuals weaken over time because they are missing or have decreased levels of the protein dystrophin. The condition is usually fatal before the individual reaches adulthood. What is the likelihood that a woman will have this disorder? - ansIt is very rare that an affected male would mate with a carrier female. Colorblindness is X-linked recessive and achondroplasia, a form of dwarfism, is autosomal dominant. A man with achondroplasia and normal vision marries a colorblind woman of normal height. The man's father was over 6 feet tall and both of the woman's parents were of average height. They have a daughter who has achondroplasia and normal color vision. What is the chance that she is heterozygous for both genes? - ans100% If nondisjunction of one chromosome occurs in one of the daughter cells during meiosis II, what would be the result at the completion of meiosis? - ansOne-fourth of the gametes descended from cell X will be n + 1, 1/4 will be n - 1, and 1/2 will be n. How could a man with normal vision be the father of a daughter who has the sex-linked form of red-green color-blindness? - ansHe can't (unless there is a mutation). What percentage of the time would a daughter be expected to inherit an X-linked recessive allele from her father? - ans100% A scientist isolates, purifies, and combines in a test tube a variety of component needed for DNA replication. When DNA is added to the mixture, replication occurs, but each DNA molecule consists of a normal strand paired with many segments of DNA, each just a few hundred nucleotides long. What component is missing? - ansDNA ligase What causes histone proteins to bind so tightly to DNA? - ansHistones are positively charged, and DNA is negatively charged. Which sequence of events would be used for inserting DNA into a plasmid and inserting the plasmid into bacteria? I. Transform bacteria with a recombinant DNA molecule.II. Cut the plasmid DNA using restriction enzymes.III. Extract plasmid DNA from bacterial cells.IV. Hydrogen-bond the plasmid DNA to nonplasmid DNA fragments.V. Use ligase to seal plasmid DNA to nonplasmid DNA. - ansIII, II, IV, V, I Which choice below would be consistent with the rules of base pairing in a DNA sample? - ansA + G = C + T Which choice below is true for any sample of double-stranded DNA? - ansA + C = G + T In replacing a nucleotide with nucleotide excision repair, which choice below represents the order in which the enzymes would work to accomplish this? - ansendonuclease, DNA polymerase I, DNA ligase Scientists use the Taq polymerase for performing PCR because... - ansit is heat stable and can withstand the heating step of PCR.
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A scientist is trying to insert a gene into a plasmid and has a preparation of genomic DNA that has been cut with restriction enzyme X. The gene she wants to insert has sites on both ends for cutting by restriction enzyme Y. She has a plasmid with a single site for Y, but not for X. The strategy should be to - anscut the DNA again with restriction enzyme Y and insert these fragments into the plasmid cut with the same enzyme. DNA synthesis can only progress in the 5' to 3' direction because - ansDNA polymerase can add nucleotides only to the free 3' end. Which statement provides evidence that RNA probably evolved before DNA? - ansDNA polymerase uses a primer that is usually made of RNA. A transcription unit in a eukarotic cell that is 9,000 nucleotides long might use 1, nucleotides to make a protein consisting of about 400 amino acids. This is because - ansthere are many stretches of non-coding nucleotides present in eukaryotic DNA. How would a point mutation in DNA affect the level of a protein's activity? - ansIt may cause substitution of a different amino acid in the active site. In which direction does RNA polymerase move along the DNA? - ans3' to 5' along the template strand What amino acid sequence will be generated, based on the following mRNA codon sequence?5' AUG-UCU-UCG-UUA-UCC-UUC 3' - ansmet-ser-ser-leu-ser-phe The question refers to the simple metabolic pathway in the figure:If substances A, B, and C are all necessary for growth, a strain that has a mutation in the gene that encodes enzyme A would be able to grow on which of the following media? - ansminimal medium supplemented with nutrient B only The enzyme polynucleotide phosphorylase can assemble nucleotides randomly into a polynucleotide polymer. If polynucleotide phosphorylase is added to a solution of ATP, GTP, and UTP. How many artificial mRNA 3 nucleotide codons could be made? - ans Which mutation would be most likely to have a harmful effect? - ansa single nucleotide insertion near but downstream of the start of the coding sequence A sample of nucleic acid was analyzed and found to contain 37% A, 22% G, 16% C and 25%T. This sample probably contains - anssingle stranded DNA Which statement best describes a codon? - ansa triplet in the same reading frame as an upstream AUG A scientist isolates the gene for a trait and the corresponding mRNA. However, she finds that the mRNA has 500 fewer bases than the gene. Did she isolate the wrong mRNA? - ansNo, the final mRNA contains only exons so it should be shorter than the gene. The nitrogenous base adenine can be found in all members of which of the groups below? - ansDNA, ATP, RNA RNA polymerase in prokaryotes is made up of several subunits. Most of the subunits are the same for the transcription of any gene, but the one known as sigma varies considerably. Which statement describes the most probable advantage of such variability in RNA polymerase? - ansIt would allow the polymerase to recognize different promoters under certain environmental conditions. What mutation is the most likely to result in a phenotypic change? - ansdeletion of a single nucleotide in an exon that codes for an active site
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A peptide has the sequence NH2-phe-pro-lys-gly-phe-pro-COOH. Which of the following sequences in the coding strand of the DNA could code for this peptide? - ans5' TTT-CCC- AAA-GGG-TTT-CCC There isn't a tRNA that enters the A site when a ribosome reaches a stop codon on the mRNA. If the translation reaction stopped at this point, which of these could be isolated? - ansan assembled ribosome with a polypeptide attached to the tRNA in the P site A triplet of bases in the template strand of DNA is 5' ACT 3'. The corresponding codon for the mRNA transcribed is - ans3' UGA 5'. In order for a eukaryotic gene to be engineered into a bacterial colony to be expressed, what must be included in addition to the coding exons of the gene? - ansa bacterial promoter sequence An error in transcription causes an alteration in the formation of one tRNA molecule in a cell and the altered tRNA can still attach to the same amino acid (Phe). But its anticodon loop now has the sequence AAU, which binds to the mRNA codon UUA (which usually specifies the amino acid leucine, Leu). How will translation be affected in this cell? - ansThere will be very little effect because the one altered tRNA will compete with many "normal" ones. The TATA box, which is part of the promoter, is highly conserved in evolution. Which of the following would this illustrate? - ansAny mutation in the sequence is selected against. Which statement is false? - ansThe genetic code is overlapping A transfer RNA (#1) attached to the amino acid glutamine enters the ribosome. The glutamine binds to the growing polypeptide on the other tRNA (#2) already in the ribosome.Where does tRNA #2 move to after this bonding of glutamine to the polypeptide? - ansE site refer to the simple metabolic pathway in the figure to answer the question.Using Beadle and Tatum's hypothesis, how many genes are necessary for this metabolic pathway? - ans Accurately translating mRNA into the primary sequence of a polypeptide depends on specificity in the - ansbonding of the anticodon to the codon and the attachment of amino acids to tRNAs. Alternative RNA splicing... - ansallows production of proteins of different sizes and functions from one mRNA. The functioning of enhancers is an example of - anstranscriptional control of gene expression. The phenomenon in which RNA molecules in a cell are destroyed if they have a sequence complementary to an introduced double-stranded RNA is called - ansRNA interference. Which of the following best describes siRNA? - ansa short double-stranded RNA, one of whose strands can complement and inactivate a sequence of mRNA Allolactose, an isomer of lactose, is formed in small amounts from lactose. An E. coli cell is presented for the first time with the sugar lactose (containing allolactose) as a potential food source. Which of the following occurs when the lactose enters the cell? - ansAllolactose binds to the repressor protein. Researchers are looking for better treatments for breast cancer. For a particular DNA microarray assay (DNA chip), cDNA has been made from the mRNAs of a dozen patients' breast tumor biopsies. The researchers will be looking for a - anspattern shared among some or all of the samples that indicates gene expression differing from control samples.
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In eukaryotes, general transcription factors - ansbind to other proteins or to a sequence element within the promoter called the TATA box. A geneticist introduces a transgene into yeast cells and isolates five independent cell lines in which the transgene has integrated into the yeast genome. In four of the lines, the transgene is expressed strongly, but in the fifth there is no expression at all.Of the lines that express the transgene, one is transcribed but not translated. Which of the following is a likely explanation? - ansno AUG in any frame When DNA is compacted by histones into 10-nm and 30-nm fibers, the DNA is unable to interact with proteins required for gene expression. Therefore, to allow for these proteins to act, the chromatin must constantly alter its structure. Which processes contribute to this dynamic activity? - ansmethylation and phosphorylation of histone tails Which of the following would not be true of cDNA produced using human brain tissue as the starting material? - ansIt would contain sequences representing all the genes in the genome. Which of the following is a protein produced by a regulatory gene? - ansrepressor
