EasyBio > Heredity > DNA and Polypeptide Synthesis > Construct appropriate representations to model and compare the forms in which DNA exists in eukaryotes and prokaryotes (ACSBL076)
Comparison between Eukaryotic and Prokaryotic DNA
| Feature | Prokaryotic DNA | Eukaryotic DNA |
|---|---|---|
| 1. Location | Freely found in cytoplasm in a region called nucleoid. | Is contained within a membrane bound nucleus. |
| 2. Packaging | Are not bounded with histone proteins and thus DNA does not form tightly coiled structures. | DNA is bound to histone and non-histone proteins that helps the DNA to form a tightly coiled and packed structure so that a large amount of DNA can reside in the nucleus. |
| 3. Shape of Chromosome | Chromosomes are circular in shape and can form loops since they are not tightly packed. | Chromosomes are linear. |
| 4. Genome | Compact and contains very little repetitive DNA and no introns. | Contains large amounts of repetitive DNA and intron. |
| 5. Chromosome Number | Have only one principal chromosome which may have multiple copies. | Contains variant number of chromosomes depending on the type of organism. |
| 6. Number of Nucleotide Base Pair | Ranges from 160, 000 to 12.2 million. | Can vary depending on the type of organism. For example, humans have 23 pairs of chromosomes containing about 2.9 billion base pairs. |
| 7. Replication Process | Relatively simple and speedy (2000 base pairs/second) and during the process only a single origin, replication fork and bubble is formed. Prokaryotic Replication takes about two proteins to initiate. | Is more complex and slower (100 base pairs/second) and during the process, multiple origins, replication forks and bubbles can be formed. Takes about multiple protein sub units to initiate. |
| 8. Presence of extra- chromosomal DNA | Contains extra chromosomal DNA known as plasmid. | Does not contain plasmid but different cell organelles such as mitochondria and chloroplast have their own DNA. |
| 9. Information Content | Prokaryotic DNA is organized in segments called operons which code for multiple proteins. | Eukaryotic DNA contains genes and each gene codes for a single protein. Sometimes, multiple genes can code for the same protein as well. |
Note: Introns are sequences of DNA which do not code for protein.
Extract from HSC Biology Stage 6 Syllabus. © 2017 Board of Studies NSW.
