Sameness and Variety (Mitosis and Meiosis) 161 Example Expressed using apples, DNA replication looks like this. Observe Go look at the model of DNA on the demonstration table. We have been presenting DNA as a straight ladder, but actually it is twisted on itself like a spiral staircase. This shape is called a helix. The Chromosome Normally DNA exists as loose strands (chromatin) in the nucleus of a cell. This nuclear DNA sends a message (RNA) to the ribosomes where protein and enzymes are synthesized. When stretched out, the length of one DNA molecule in a human cell is almost 4 cm. However, the cell itself is but a tiny fraction of that size. During cell reproduction the DNA must be able to move around. So it shortens its length by tightly coiling up. In doing so, the DNA strands become wider and are visible under a microscope. Visible DNA is called a chromosome. Coiling Coiled DNA Normal DNA (chromosomes) DNA. 1. A chromosome is made up of tightly ? QUESTION 2. Explain the reason for this shape. 3. When not reproducing, DNA is found in the of a cell and exists in the form called

Sameness and Variety (Mitosis and Meiosis) 161 Example Expressed using apples, DNA replication looks like this. Observe Go look at the model of DNA on the demonstration table. We have been presenting DNA as a straight ladder, but actually it is twisted on itself like a spiral staircase. This shape is called a helix. The Chromosome Normally DNA exists as loose strands (chromatin) in the nucleus of a cell. This nuclear DNA sends a message (RNA) to the ribosomes where protein and enzymes are synthesized. When stretched out, the length of one DNA molecule in a human cell is almost 4 cm. However, the cell itself is but a tiny fraction of that size. During cell reproduction the DNA must be able to move around. So it shortens its length by tightly coiling up. In doing so, the DNA strands become wider and are visible under a microscope. Visible DNA is called a chromosome. Coiling Coiled DNA Normal DNA (chromosomes) DNA. 1. A chromosome is made up of tightly ? QUESTION 2. Explain the reason for this shape. 3. When not reproducing, DNA is found in the of a cell and exists in the form called

Biochemistry

6th Edition

ISBN:9781305577206

Author:Reginald H. Garrett, Charles M. Grisham

Publisher:Reginald H. Garrett, Charles M. Grisham

Chapter28: Dna Metabolism: Replication, Recombination, And Repair

Section: Chapter Questions

Problem 1P: Semiconservative or Conservative DNA Replication If 15N-Iabeled E. coli DNA has a density of 1.724...

See similar textbooks

Similar questions

VISUAL SKILLS If the DNA pol I in a given cell werenonfunctional, how would that affect the synthesis ofa leading strand? In the overview box in Figure 16.17,point out where DNA pol I would normally function onthe top leading strand.
1d) Whether done manually or automated, DNA sequencing gels are always made of polyacrylamide rather than agarose. Why can't agarose be used for a sequencing gel, as it is for other DNA gel electrophoresis?
During proofreading, which of the following enzymes reads the DNA? primase topoisomerase DNA pol helicase
Human Genome Replication Rate Assume DNA replication proceeds at a rate of 100 base pairs per second in human cells and origins of replication occur every 300 kbp. Assume also that human DNA polymerases are highly processive and only two molecules of DNA polymerase arc needed per replication fork. How long would it take to replicate the entire diploid human genome? How many molecules of DNA polymerase does each cell need to carry out this task?
Semiconservative or Conservative DNA Replication If 15N-Iabeled E. coli DNA has a density of 1.724 g/mL, 14N-labeled DNA has a density of 1.710 g/mL, and E. coli cells grown for many generations on 14NH4+as a nitrogen source are transferred to media containing 15NH4+as the sole N-source, (a) What will be the density of the DNA after one generation, assuming replication is semiconservative? (b) Suppose replication took place by a conservative mechanism in which the parental strands remained together and the two progeny strands were paired. Design an experiment that could distinguish between semiconservative and conservative modes of replication.
Multiple Replication Forks in E. coli II On the basis of Figure 28.2, draw a simple diagram illustrating replication of the circular E. coli chromosome (a) at an early stage, (b) when one-third completed, (c) when two-thirds completed, and (d) when almost finished, assuming the initiation of replication at oriC has occurred only once. Then, draw a diagram showing the E. coli chromosome in problem 3 where the E. coli cell is dividing every 20 minutes.
Multiple Replication Forks in E. coli I Assuming DNA replication proceeds at a rate of 750 base pairs per second, calculate how long it will take to replicate the entire E. coli genome. Under optimal conditions, E. coli cells divide every 20 minutes. What is the minimal number of replication forks per E. coli chromosome in order to sustain such a rate of cell division?
Number of Okazaki Fragments in E. coli and Human DNA Replication Approximately how many Okazaki fragments are synthesized in the course of replicating an E. coli chromosome? How many in replicating an â€œaverageâ€� human chromosome?
4a in context to taking genomic DNA from eukaryotic cells and randomly shearing it into pieces of a constant size, why do some of the genomic DNA fragments re-nature so much more quickly than other fragments
Which statements are true? Explain why or why not.1 The different cells in your body rarely havegenomes with the identical nucleotide sequence.2 In E. coli, where the replication fork travels at 500nucleotide pairs per second, the DNA ahead of the fork—in the absence of topoisomerase—would have to rotate atnearly 3000 revolutions per minute.3 In a replication bubble, the same parental DNAstrand serves as the template strand for leading-strandsynthesis in one replication fork and as the template forlagging-strand synthesis in the other fork.4 When bidirectional replication forks from adja-cent origins meet, a leading strand always runs into a lag-ging strand.5 DNA repair mechanisms all depend on the exis-tence of two copies of the genetic information, one in eachof the two homologous chromosomes
Need help fast What length of DNA (based on the number of subunits) has a potential diversity close to 3 *10^16?
Which statements are true? Explain why or why not.1 Because the DNA double helix is only 2 nm wide—well below the limit of resolution of the light microscope—it is impossible to see chromosomes in living cells withoutspecial stains.2 A fluorescent molecule, having absorbed a singlephoton of light at one wavelength, always emits it at a longer wavelength.