Lecture 3: Prokaryotic and Eukaryotic Cells. Plant Cell TABLE 3.2 DIFFERENCE BETWEEN ANIMAL AND PLANT CELLS. Differences between prokaryotic and eukaryotic. Eukaryotic cells contain many membrane-enclosed, large, complex organelles in the cytoplasm whereas prokaryotic cells do not contain these membrane-bound organelles. This is a key difference because it allows a high level of intracellular division of labor and contributes to the greater complexity characteristic of eukaryotic cells.

Differences Between Eukaryotic and Prokaryotic Cells Prokaryotic cells are quite simple in structure. They have no nucleus, no organelles and a small amount of DNA in the form of a single, circular chromosome. Eukaryotic cells on the other hand, have a nucleus, multiple organelles and more DNA arranged in multiple, linear chromosomes. Telstra Join Me Software T54 Wot there.

Steps in DNA Replication DNA replication begins at a specific spot on the DNA molecule called the origin of replication. At the origin, enzymes unwind the double helix making its components accessible for replication. Each strand of the helix then separates from the other, exposing the now unpaired bases to serve as templates for new strands. A small segment of RNA – ribonucleic acid – is added as a primer, then new nucleotide bases that complement the unpaired bases can be assembled to form two daughter strands next to each parent strand.

This assembly is accomplished with enzymes called DNA polymerases. When the process is complete, two DNA molecules have been formed identical to each other and to the parent molecule. Similarities Between Prokaryotic and Eukaryotic DNA Replication The steps for DNA replication are generally the same for all prokaryotic and eukaryotic organisms.

Unwinding the DNA is accomplished by an enzyme named DNA helicase. Manufacturing new DNA strands is orchestrated by enzymes called polymerases. Both types of organisms also follow a pattern called semi-conservative replication.

In this pattern, the individual strands of DNA are manufactured in different directions, producing a leading and a lagging strand. Lagging strands are created by the production of small DNA fragments called Okazaki fragments that are eventually joined together. Both types of organisms also begin new DNA strands with a small primer of RNA. Differences Between Prokaryotic and Eukaryotic DNA Replication Differences between prokaryotic and eukaryotic DNA replication are largely related to contrasts in size and complexity of the DNA and cells of these organisms. The average eukaryotic cell has 25 times more DNA than a prokaryotic cell. In prokaryotic cells, there is only one point of origin, replication occurs in two opposing directions at the same time, and takes place in the cell cytoplasm.

Introductory Sociology Biltong Pdf Creator. Eukaryotic cells on the other hand, have multiple points of origin, and use unidirectional replication within the nucleus of the cell. Prokaryotic cells possess one or two types of polymerases, whereas eukaryotes have four or more.

Replication also happens at a much faster rate in prokaryotic cells, than in eukaryotes. Some bacteria take only 40 minutes, while animal cells such as humans may take up to 400 hours. Robyn Hitchcock Globe Of Frogs Raritan. In addition, eukaryotes also have a distinct process for replicating the telomeres at the ends of their chromosomes. With their circular chromosomes, prokaryotes have no ends to synthesize.

Lastly, the short replication in prokaryotes occurs almost continuously, but eukaryotic cells only undergo DNA replication during the S-phase of the cell cycle.

Location Prokaryotes lack nuclei and other organelles, which are specialized, membrane-bound compartments, whereas eukaryotes do have them. In fact, the word 'eukaryote' means 'true nucleus.' In eukaryotes the cell's genome is located in the nucleus. Transcription thus occurs in the nucleus, and the mRNA transcript is subsequently exported through nuclear pores (pores in the nuclear envelope) to the cytoplasm for translation. By contrast, prokaryotic transcription and translation are not spatially or temporally segregated. Initiation of Transcription Promoter elements are short sequences of DNA that bind to a cell's transcriptional initiation factors. Prokaryotes have three promoter elements: one that is upstream of the gene being transcribed, one that is 10 nucleotides downstream of it and one that is 35 nucleotides downstream.