BIO 3

id there are 20 chromatids in a cell, how many centromeres are there
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id there are 20 chromatids in a cell, how many centromeres are there
10
A group of cells is assayed for DNA content immediately following mitosis and is found to have an average of 8 picograms of DNA per nucleus. those cells would have - picograms at the send of the s phase and - picograms at the end of G2
16;16
A particular cell has has as much DNA as some other cells in a mitotically active tissue. the cell in question is most likely in
G1
Which of the following are primarily responsible for cytokinesis in plant cells but not in animal cells
Golgi-derived vesicles
define genetics
study of heredity and variation
define heredity
transmission of traits to next generation
define variation
differences that offspring shoe from parents and siblings
define gene
sequence of DNA encoding a protein
define allele
alternative version of a gene
define locus
location of gene on the chromosome
define mutationchange in the nucleotide sequenceThe chromosomes each have two chromatids joined at the centromere. what process led to the formation of the two chromatidsthe two chromatids were formed by replication of the DNA within a single chromatid during S phasediploid cells may undergo either mitosis or meiosis, can haploid cellsnoA cross between homozygous purple-flowered and homozygous white-flowered pea plants results in offspring with purple flowers. This demonstratesdominaceMendel's observation of the segregation of alleles in gamete formation has its basis in which of the following phases of cell division?Anaphase I of meiosisImagine crossing a pea heterozygous at the loci for flower color (white versus purple) and seed color (yellow versus green) with a second pea homozygous for flower color (white) and seed color (yellow). What genotypes of gametes will the first pea produce?four gamete types: white/yellow, white/green, purple/yellow, purple/greenA women who has blood type A positive has a daughter who is type O positive and s son who is type B negative. Rh positive is a trait that shows simple dominance over Rh negative and is designated by the alleles R and r, respectively. Which of the following is a possible partial genotype for the sonI(B) iHow many unique could be produced through independent assortment by an individual with the genotype AaBbCCDdEE8Given the parents AABBCc x AabbCc, assume simple dominance for each trait and independent assortment. what proportion of the progeny will be expected to phenotypically resemble the first parent3/4red-green color blindness is sex-linked recessive trait in humans. two people with normal color vision have a color blind son. what the genotypes of the parentsXN Xn and XN YThe human genome is minimally contained in which of the followingEvery human celldefine genomethe complete set of an organism's genesat which stage of mitosis are chromosomes usually photographed in the preparation of a karyotypemetaphasea certain organism is diploid, has either blue or orange wings as the consequence of its genes on chromosome 12, and has either long or short antennae as the result of a second gene on chromosome 19, as shown in the figure 12: either ------I--- blue ------I--- orange 19: either --I------- long --I------- shortone chromosome 12 with one blue gene and one chromosome 19 with one long genewhy did f1 offspring of Mendels classic pea cross always look like one of the two parental varietiesone phenotype was completely dominant over the otherwhy did Mendel continue some of his experiments to the F2 or F3 generationto observe whether or not a recessive trait would reappearBlack fur in mice (B) is dominant to brown fur (b) short tails (T) are dominant to long tails (t). what fraction of the progeny of crosses BbTtxBBtt will be expected to have black fur and long tails1/2In certain plants, tall is dominant to short. if a heterozygous plant is crossed with a homozygous tall plant, what is the probability that the offspring will be short0The frequency of heterozygosity for the sickle-cell anemia allele is unusually high, presumably because this reduces the frequency of malaria. such a relationship is related to which of the followingDarwins explanation of natural selectionWhen Thomas Hunt Morgan crossed his red-eyed F1 generation flies to each other, the F2 generation included both red- and white-eyed flies. remarkably, all the white-eyed flies were male, what was the explantation for this resultthe gene involved is on the X chromosomeSRY is best described in which of the following waysa gene region present on the Y chromosome that triggers male developmentRed-green color blindness is a sex-linked recessive trait in humans. two people with normal color vision have a color-blind son. what are the genotypes of the parentsXC Xc and XC YAt which phases is is preferable to obtain chromosomes to prepare a karyotypelate prophase or metaphaseWhich enzyme catalyzes the elongation of a DNA strand in the 5' --> 3' directionDNA polymerase IIIWhat is the function of topoisomeraserelieving strain in the DNA ahead of the replication forktoo repair a thymine dimer by nucleotide excision repair, in which order do the necessary enzymes actendonuclease, DNA polymerase I, DNA LigaseAn Okazaki fragment has which of following arrangements5' RNA nucleotides, DNA nucleotides 3'Which of the following statements describes the eukaryotic chromosomesit consists of single linear molecule of double-stranded DNA plus proteinsCinnabar eyes is a sex-linked recessive, characteristic in fruit flies. If a female having cinnabar eyes is crossed with a wild-type male, what percentage of F1 males will have cinnabar eyes100%In his transformation experiments, what did Griffith observeMixing a heat-killed pathogenic strain of bacteria with a living nonpathogenic strain can convert some of the living cells into the pathogenic formIn trying to determine whether DNA or protein is the genetic material, Hersey and Chase made use of which of the following factsDNA contains phosphorus, whereas protein does notAfter mixing a heat-killed, phosphorescent strain of bacteria with a living nonphosphorescent strain you discover that some of the living cells are now phosphorescent. which observation would provide the best evidence that the ability to fluoresce is a heritable traitdecedents of the living cells are also phosphorescentSomatic cell vs. Gametegametes: one set of chromosomes- 23 somatic cells- two sets of chromosmes-46true-breedingterm used to describe organisms that produce offspring identical to themselves if allowed to self-pollinateHybridizationBreeding technique that involves crossing dissimilar individuals to bring together the best traits of both organismsmonohybrid crossA cross between individuals that involves one pair of contrasting traitsdihybrid crossA cross between individuals that have different alleles for the same geneMendel's Law of Segregationthe two copies of a gene segregate from each other during transmission from parent to offspringMendel's Law of Independent Assortmentgenes found on different chromosomes are sorted into sex cells independently of one anothercomplete dominancea relationship in which one allele is completely dominant over anotherincomplete dominanceSituation in which one allele is not completely dominant over another alleleCo-dominancesituation in which both alleles of a gene contribute to the phenotype of the organismPleiotropyThe ability of a single gene to have multiple effects.EpistasisA type of gene interaction in which one gene alters the phenotypic effects of another gene that is independently inherited.Which of these is a way that sexual life cycle increases genetic variation in a speciesby allowing crossing overMales are more often affected by sex-linked traits than females becausemales are hemizyogous for the X chromosomeswhen we see chiasmata under a microscope, that kets us know which of following has occurredprophase 1cinnabar eyes is a sex-linked recessive characteristic in fruit flies. if a female having cinnabar eyes is crossed with a wild-type male, what percentage of the F1 males will have cinnabar eyes100%After mixing a heat-killed, phosphorescent strain of bacteria with a living nonphosphorescent strain, you discover that some of the living cells are now phosphorescent. Which observations would provide the best evidence that the ability to fluoresce is a heritable trait?descendants of the living cells are also phosphorescentThe elongation of the leading strand during DNA synthesisdepends on the action of DNA polymeraseEukaryotic telomeres replicate differently than the rest of the chromosomes. this is a consequence of which of the followinggaps left at the 5' end of the lagging strandAn okazaki fragment has which if the following arrangements5' RNA nucleotides, DNA nucleotides 3'Which of the following statements describes the eukaryotic chromosomesit consists of single linear molecule of double-stranded DNA plus proteinsThe enzyme telomeres solves the problem of replication ay the ends of linear chromosomes by which methodadding numerous short DNA sequences such as TTAGGG, which form a hairpin turnwhich enzyme catalyzes the elongation of a DNA strand in the 5' --> 3' directionDNA polymeraseexperiments with cohesions have found thatcohesions are protected from cleavage at the centromere during meiosis 1Which of the following helps to hold the DNA strands apart while they are being replicatedsignle-brand binding proteinsafter telophase 1 of meiosis, the chromosomal makeup of each daughter cell ishaploid, and the chromosomes are each composed of two chromatidsWhich of the following can be determined directly from X-ray diffraction photographs of crystallized DNAthe diameter of the helixCytosine makes up 42% of the nucleotides in a sample of DNA from an organism. approximately what percentage of the nucleotides in this sample will be thymine8%To repair a thymine dimer by nucleotide excision repair, in which order do the necessary enzymes actendonuclease, DNA polymerase I, DNA ligaseall cell cycle checkpoints are similar in which waythey give the go-ahead signal to progress to the next checkpointThe leading and lagging strands differ in thatthe leading strand is synthesized in the same direction as the movement of the replication fork, and the lagging strand is synthesized in the opposite directionwhy did mendel continue some of his experiments to the F2 or F3 generationto observe whether or not a recessive trait would reappearthe beginning of anaphase is indicated by which of the followingcohesion is cleaved enzymaticallywhat do we mean when we use the term monohybrid crossa monohybrid cross involves organisms that are heterozugous for one characterwhich of the following is the best statement of the use of the addition rule of probabilitythe probability that either one of two independent events will occurwhich of the following investigations was/ were responsible for the following discoveryErwin chargraffIn his work with pneumonia-causing bacteria and mice Griffith found thatsome substance from pathogenetic cells was transferred to nonpathogenic cells, making them pathogenicwhen crossing an organism that is homozygous recessive for a single trait with a heterozygous what is the chance of producing an offspring with the homozygous recessive phenotype50%how do we describe transformation in bacteriaassimilation of external DNA into a cellwhat is the basis for the difference in how the leading and lagging strand of DNA molecules are synthesizedDNA polymerase can join new nucleotides only to the 3' end of a growing strandYou briefly expose bacteria undergoing DNA replication to radioactively labeled nucleotides. When you centrifuge the DNA isolated from the bacteria, the DNA separates into two classes. One class of labeled DNA includes very large molecules (thousands or even millions of nucleotides long), and the other includes short stretches of DNA (several hundred to a few thousand nucleotides in length). These two classes of DNA probably representleading strands and okazski fragmentsRefer to the life cycles illustrated in the figure which of the life cycles is (are) for animalsI onlyaltering patterns of gene expression in prokaryotes would most likely serve the organisms survival un which of the followingallowing the organism to adjust to changes in environmental conditionsmales are most often affected by sex-linked traits than females becausemales are hemizygous for the X chromosomein a nucleosome, the DNA is wrapped aroundhistonesA couple has a child with Down syndrome. The mother is 39 years old at the time of delivery. Which of the following is the most probable cause of the child's condition?one member of the couple underwent non adjunction in gamete productionwhat is the function of topoisomerasereliving strain in the DNA ahead of the replication forkWhat was the most significant conclusion that Gregor Mendel drew from his experiments with pea plants?traits are inherited in discrete units, and are not the results of "blending"Red-green color blindness is a sex-linked recessive trait in humans. Two people with normal color vision have color-blind son. What are the genotypes of the parents?XNxn and XNYlabrador retrievers are black, or yellow. In a cross of a black female with a brown male, results can be either all back puppies, 1/2 black to 1/2 brown, or 3/4 black to yellow 1/4 yellow. these results indicate which of the following?epistasis is involvedcompared to most prokaryotic cells, eukaryotic cells typically havemore DNA molecules and larger genomesIn cats, black fur color is caused by an X-linked allele; the other allele at this locus causes orange color. The heterozygote is tortoiseshell. What kinds of offspring would you expect from the cross of a black female and an orange male?tortoiseshell females; black maleshumans produce skin cells by mitosis and gametes by meiosis. the nuclei of skin cells produced by mitosis will havetwice as much DNA as the nuclei of gametes produced by meiosisWhen Thomas Hunt Morgan crossed his red-eyed F1 generation flies to each other, the F2 generation included both red- and white-eyed flies. Remarkably, all the white-eyed flies were male. What was the explanation for this result?the gene involved is in the X chromosomereplication in prokaryotes differs from replication in eukaryotes for which of the following reasonsprokaryotes chromosomes have a single origin of replication, whereas eukaryotic chromosomes have manywhy did the F1 offspring of Mendels classic pea cross always look like one of the two parental varietiesOne allele was dominantA new DNA strand elongates only in the 5' to 3' direction becauseDNA polymerase can only add and nucleotides to the free 3' endwhich of the following occurs in meiosis but not in mitosissynapsis of chromosomeswhat is meant but the description "anitparallel" regarding the strands that make up DNAthis 5' to 3' direction of one strand runs counter to the 5' to 3' direction of the other strand