3.2.1 Flashcards
How many chromosomes do most prokaryotes have?
One single circular chromosome that consists of a loop of DNA containing all of the genes needed by the organism.
Why is prokaryotic DNA referred to as “naked DNA”
It is not wrapped in proteins.
What are plasmids?
Small extra DNA molecules that are found in prokaryotes.
They are not found in eukaryotes. They typically contain extra genes that are beneficial but not essential to the cell’s life.
How are plasmids used by biologists?
Since plasmids can replicate independently from chromosomes, they can easily be transferred from one organism to another. Plasmids are often used by biologists to artificially transfer genes between species.
How are prokaryotic chromosomes replicated?
Their replication involves the formation of a replication bubble and is bidirectional. This was proven by Cairn’s images.
What are eukaryotic chromosomes?
They are linear DNA molecules wrapped around histone proteins.
During interphase what appearance do eukaryotic chromosomes have under a TEM?
They have a string of beads appearance because DNA gets wrapped around histone proteins forming nucleosome beads.
How do the different types of eukaryotic chromosomes differ?
They differ in length and position of the centromere.
How many types of chromosomes do humans have?
23
How many total chromosomes do humans have?
46
How would you find a gene if you knew its location was 3p22.1
You’d know the gene was on the 3rd chromosome, it would be on the short arm as indicated by the “p” and the position on the arm would be the 2nd region, band 2, sub-band 1.
