The mitotic cell divisions in the early embryo ofD. melanogaster occur very rapidly (every eightminutes).a. If there were one bidirectional origin in the middleof each chromosome, how many nucleotides wouldDNA polymerase have to add per second to replicate all the DNA in the longest chromosome(66 Mb) during the eight-minute early embryoniccell cycles? (Assume that replication occurs duringthe entire cell division cycle.)

The mitotic cell divisions in the early embryo ofD. melanogaster occur very rapidly (every eightminutes).a. If there were one bidirectional origin in the middleof each chromosome, how many nucleotides wouldDNA polymerase have to add per second to replicate all the DNA in the longest chromosome(66 Mb) during the eight-minute early embryoniccell cycles? (Assume that replication occurs duringthe entire cell division cycle.)

Biology: The Dynamic Science (MindTap Course List)

4th Edition

ISBN:9781305389892

Author:Peter J. Russell, Paul E. Hertz, Beverly McMillan

Publisher:Peter J. Russell, Paul E. Hertz, Beverly McMillan

Chapter10: Cell Division And Mitosis

Section: Chapter Questions

Problem 1ITD: Biologists have long been interested in the effects of radiation on cells. In one experiment,...

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The mitotic cell divisions in the early embryo ofD. melanogaster occur very rapidly (every eightminutes).a. If there were one bidirectional origin in the middleof each chromosome, how many nucleotides wouldDNA polymerase have to add per second to replicate all the DNA in the longest chromosome(66 Mb) during the eight-minute early embryoniccell cycles? (Assume that replication occurs duringthe entire cell division cycle.)b. In fact, many origins of replication are active oneach chromosome during the early embryonic divisions and are spaced approximately 7 kb apart. Calculate the average rate (per second) with whichDNA polymerase adds complementary nucleotidesto a growing chain in the early Drosophila embryo,making the same assumption as in part (a)
The size of one copy of the human genome is approximately 3 billion base pairs, and it contains about27,000 genes organized into 23 chromosomes.a. Human chromosomes vary in size. What wouldyou predict is the size of the average chromosome?b. Assuming that genes are spread evenly amongchromosomes, how many genes does an averagehuman chromosome contain?c. About half of the DNA in chromosomes containsgenes. How large (in base pairs) is an averagehuman gene?
a. Manually, using a pencil, draw a cell in anaphase II from an organism in which 2n = 2 and each chromosome is metacentric. b. Given that each G1 nucleus from this organism contains 16 picograms of DNA, how many picograms of chromosomal DNA would you expect in the cell shown here?
Carbon Copy (CC), the first cat produced from aclone, was created from an ovarian cell taken from hergenetic donor, Rainbow, a calico cat. The diploid nucleusfrom the cell was extracted and then injected into an enucleatedegg. The resulting zygote was then allowed to developin a petri dish, and the cloned embryo was implanted inthe uterus of a surrogate mother cat, who gave birth to CC.CC’s surrogate mother was a tabby (see the photo below).Geneticists were very interested in the outcome of cloninga calico cat because they were not certain if the cloned catwould have patches of orange and black, just orange, orjust black. Taking into account the Lyon hypothesis, explainthe basis of the uncertainty. Would you expect CC to appearidentical to Rainbow? Explain why or why not.
a micrograph of chromosomes from a normalhuman cell. If you created this kind of image using a cell from aperson with Down syndrome, what would you expect to see?
In a turtle species, a diploid cell in the G1 phase of the cell cycle contains 22 picograms of DNA (picogram is a measure of the total mass of the DNA present). How much DNA is present in a cell of the same species at prophase II of meiosis (prophase of the second meiotic division)?
. Genomes A, B, and C all have basic chromosomenumbers (x) of nine. These genomes were derivedoriginally from plant species that had diverged from each other sufficiently far back in the evolutionarypast that the chromosomes from one genome can nolonger pair with the chromosomes from any other genome. For plants with the following kinds of euploidchromosome complements, (i) state the number ofchromosomes in the organism; (ii) provide terms thatdescribe the individual’s genetic makeup as accurately as possible; (iii) state whether or not it is likelythat this plant will be fertile, and if so, give the number of chromosomes (n) in the gametes.a. AABBCb. BBBBc. CCCd. BBCCe. ABCf. AABBCC
Chromosome 3 in orangutansdiffers from chromosome 3 in humansby two inversion events that occurredin the human lineage (Figure Q4–2).Draw the intermediate chromosomethat resulted from the first inversionand explicitly indicate the segmentsincluded in each inversion.
Somatic cells of chimpanzees contain 48 chromosomes.How many chromatids and chromosomes are present at: (a) anaphase of mitosis, (b) anaphase I ofmeiosis, (c) anaphase II of meiosis, (d) G1 priorto mitosis, (e) G2 prior to mitosis, (f) G1 prior tomeiosis I, and (g) prophase of meiosis I?How many chromatids or chromosomes are presentin: (h) an oogonial cell prior to S phase, (i) a spermatid, (j) a primary oocyte arrested prior to ovulation,(k) a secondary oocyte arrested prior to fertilization,(l) a second polar body, and (m) a chimpanzee sperm?
Replication and segregation of eukaryotic chromosomesrequire three functional elements: replication origins, a centromere, and telomeres. How would a chromosome be affected ifit lacked (a) replication origins or (b) a centromere?
For S phase to be completed in a timely manner, DNA replication must be initiated from multiple origins in eukary-otes. In S. cerevisiae, what role do S phase CDKs and DDKs play to ensure that the entire genome is replicated once andonly once per cell cycle?
Cleavage blastomeres are totipotent. Differentiate this property from the terms pluripotent, unipotent, multipotent. Give examples to prove your point. Examples totipotent pluripotent unipotent multipotent