11
votes
1answer
395 views

Is there an advantage to linear chromosomes?

The DNA copying enzymes have a hard time working to the end of a chromosome. For circular chromosomes this is not a problem, since there is not a sharp 'end'. However, for a linear chromosome, without ...
1
vote
3answers
1k views

Evolutionally speaking, why do humans have 46 chromosomes

In humans, each cell normally contains 23 pairs of chromosomes, for a total of 46. Monkeys, chimpanzees, and Apes have 24 pairs (twenty-four pairs), for a total of 48. What caused humans to have 46? ...
15
votes
4answers
705 views

Why are there exactly four nucleobases in DNA?

Does someone know why DNA is composed of four nucleobases? In particular, is there an explanation for the number? Why four and not two, or eight?
5
votes
2answers
108 views

Are there other mechanisms for mutation besides imperfect DNA replication?

I was reading http://www.askamathematician.com/2012/05/q-is-quantum-randomness-ever-large-enough-to-be-noticed/ and saw: [...] the evolution of entire species can be changed by a single mistake ...
22
votes
3answers
2k views

Why do eukaryotic organisms have introns in their DNA?

We touched on introns and exons in my bio class, but unfortunately we didn't really talk about why Eukaryotes have introns. It would seem they would have to have some purpose since prokaryotes do not ...
5
votes
1answer
136 views

What is the benefit for cells having the ATP production regulated in mitochondria compared to being from the nucleus?

Mitochondria have their own DNA and appear to be loosely connected to the nucleus and it role. Why are the functions of mitochondria not in the nucleus? Why doesn't the nucleus control the ...
11
votes
1answer
179 views

Abiogenesis: Beyond the research journals as a lead in to discussions on evolution

I just came across this abstract: Aminoacyl-tRNA synthetases (aaRSs) are responsible for creating the pool of correctly charged aminoacyl-tRNAs that are necessary for the translation of genetic ...