Advertisement Upgrade to remove ads

RNA world hypothesis

the idea that RNA systems self-replicated in previous ages and evolved into the current genetic duplication processes we have now

chemical natural selection

ribosome replication not accurate, select for ribosome variants that are better at linking nucleotides

Semi-autonomous organelles

mitochondria and chloroplasts; contains come of their own DNA, RNA, and ribosomes, reproduce in cells by fission, resemble free-living bacteria


produce chemical energy from sugars and other compounds


in plants and some protists, site for energy production from sunlight


theory for semi-autonomous organelles


organisms living together in direct and intimate contact


strands of chromosomes


sites of rRNA synthesis, assembly of large & small ribosomal subunits

nuclear pore

active transport complex of many types of proteins

Please allow access to your computer’s microphone to use Voice Recording.

Having trouble? Click here for help.

We can’t access your microphone!

Click the icon above to update your browser permissions above and try again


Reload the page to try again!


Press Cmd-0 to reset your zoom

Press Ctrl-0 to reset your zoom

It looks like your browser might be zoomed in or out. Your browser needs to be zoomed to a normal size to record audio.

Please upgrade Flash or install Chrome
to use Voice Recording.

For more help, see our troubleshooting page.

Your microphone is muted

For help fixing this issue, see this FAQ.

Star this term

You can study starred terms together

NEW! Voice Recording