do chloroplast n leucoplast &chromoplast all have DNA and ribosome.do all of them self replicate?

Answer 1

sorry but fortitud--- and sumit are totally and absolutely wrong about the replication.

the plastids (leucoplasts, chloroplasts, chromoplasts...) are capable of selfreplication, but they do it seldom, because they are mature forms of plastids. Normally the plastids replicate in the form of unspecialized "young"proplastids that mature into the form of eucoplasts, chloroplasts, chromoplasts... as if they literally ripen. these mature plastids can turn into one another if necessary (sometimes they do it regularly - chloroplasts in unripe rosehips turn into red chromoplasts, chloroplasts in leaves that are left in dark turn into etioplasts) and when challenged to do so, they replicate. but especially chromoplasts and plastids packed full of storage materials are difficult to replicate.

so plastids can replicate (like how else would fortitud.. and sumit expect them to originate?) but they normally do it BEFORE they mature. same goes for mitochondria. many organisms mature mitochondria replicate like hell - the mitochondria count per cell is very changeable - mitochondrias tend to die off or multiplicate according to how much energy is currently needed .

yes, both plastids and mitochondria are supposed to be endosymbionts, thats correct just like fortitudinous says. like their ribosomes are more similar to bacterial ribosomes than to eukayrotic ones, etc,

Answer 2

Maryam......this is fortitudinousskeptic again. I really think you should start emailing me these questions. I have time. I have a botany degree and I teach chemistry among other things and I have a strong background in biochemistry and genetic engineering, but I don't get a chance to use those skills much anymore. I'd enjoy the chance.
Anyway.........an attempt to answer this question off the top of my head. I'm wondering what the professor's question was initially. First off.......I'm thinking maybe he/she is asking you what subcellular organelles have those characteristics. Mitochondria DO. Mitochondria have their own DNA, referred to as mitochondrial DNA or mDNA. When cells divide the many mitochondria in the cell are separated into the two daughter cells. Mitochondrial DNA evolves faster because of technical reasons, and is only inherited from mothers in animals. That makes some specific kinds of DNA studies useful. Mitochondria do not, I believe, have their own ribosomes, but I'd have to check for sure. Ribosomes are involved in protein synthesis.
I do not think that chloroplasts, leukoplasts, and chromoplasts have their own DNA and ribosomes. I do not believe they self-replicate. Mitochondria do, though, and most scientists believe that mitochondria actually started out as bacteria that lived in foreign cells and got so deep into a mutualistic relationship that they're now one with their "host" cells. I will have to check on the other subcellular organelles, though. Off the cuff, though, I believe the answer is "yes" for mitochondria and "no" for the others.

Answer 3

Replication is required. Theoretically it is not required to be *self*-replication, pratically it is always selfreplication. DNA is not required. As rocks and minerals do not replicate themselves they can not evolve.

Answer 4

all have DNA and ribosome but they do not self-replicate