Featured Research

from universities, journals, and other organizations

Origin of life: Hypothesis traces first protocells back to emergence of cell membrane bioenergetics

Date:
December 20, 2012
Source:
University College London
Summary:
A coherent pathway -- which starts from no more than rocks, water and carbon dioxide and leads to the emergence of the strange bio-energetic properties of living cells -- has been traced for the first time in a major hypothesis article.

A major new hypothesis outlines a coherent pathway that starts from no more than rocks, water and carbon dioxide and leads to the emergence of the strange bio-energetic properties of living cells.
Credit: iStockphoto/Henrik Jonsson

A coherent pathway -- which starts from no more than rocks, water and carbon dioxide and leads to the emergence of the strange bio-energetic properties of living cells -- has been traced for the first time in a major hypothesis paper in Cell this week.

At the origin of life the first protocells must have needed a vast amount of energy to drive their metabolism and replication, as enzymes that catalyse very specific reactions were yet to evolve. Most energy flux must have simply dissipated without use.

So where did it all that energy come from on the early Earth, and how did it get focused into driving the organic chemistry required for life?

The answer lies in the chemistry of deep-sea hydrothermal vents. In their paper Nick Lane (UCL, Genetics, Evolution and Environment) and Bill Martin (University of Dusseldorf) address the question of where all this energy came from -- and why all life as we know it conserves energy in the peculiar form of ion gradients across membranes.

"Life is, in effect, a side-reaction of an energy-harnessing reaction. Living organisms require vast amounts of energy to go on living," said Nick Lane.

Humans consume more than a kilogram (more than 700 litres) of oxygen every day, exhaling it as carbon dioxide. The simplest cells, growing from the reaction of hydrogen with carbon dioxide, produce about 40 times as much waste product from their respiration as organic carbon (by mass). In all these cases, the energy derived from respiration is stored in the form of ion gradients over membranes.

This strange trait is as universal to life as the genetic code itself. Lane and Martin show that bacteria capable of growing on no more than hydrogen and carbon dioxide are remarkably similar in the details of their carbon and energy metabolism to the far-from-equilibrium chemistry occurring in a particular type of deep-sea hydrothermal vent, known as alkaline hydrothermal vents.

Based on measured values, they calculate that natural proton gradients, acting across thin semi-conducting iron-sulfur mineral walls, could have driven the assimilation of organic carbon, giving rise to protocells within the microporous labyrinth of these vents.

They go on to demonstrate that such protocells are limited by their own permeability, which ultimately forced them to transduce natural proton gradients into biochemical sodium gradients, at no net energetic cost, using a simple Na+/H+ transporter. Their hypothesis predicts a core set of proteins required for early energy conservation, and explains the puzzling promiscuity of respiratory proteins for both protons and sodium ions.

These considerations could also explain the deep divergence between bacteria and archaea (single celled microorganisms) . For the first time, says Lane, "It is possible to trace a coherent pathway leading from no more than rocks, water and carbon dioxide to the strange bioenergetic properties of all cells living today."


Story Source:

The above story is based on materials provided by University College London. Note: Materials may be edited for content and length.


Journal Reference:

  1. Nick Lane, WilliamF. Martin. The Origin of Membrane Bioenergetics. Cell, 2012; 151 (7): 1406 DOI: 10.1016/j.cell.2012.11.050

Cite This Page:

University College London. "Origin of life: Hypothesis traces first protocells back to emergence of cell membrane bioenergetics." ScienceDaily. ScienceDaily, 20 December 2012. <www.sciencedaily.com/releases/2012/12/121220143530.htm>.
University College London. (2012, December 20). Origin of life: Hypothesis traces first protocells back to emergence of cell membrane bioenergetics. ScienceDaily. Retrieved September 17, 2014 from www.sciencedaily.com/releases/2012/12/121220143530.htm
University College London. "Origin of life: Hypothesis traces first protocells back to emergence of cell membrane bioenergetics." ScienceDaily. www.sciencedaily.com/releases/2012/12/121220143530.htm (accessed September 17, 2014).

Share This



More Earth & Climate News

Wednesday, September 17, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Scientists Examine Colossal Squid

Raw: Scientists Examine Colossal Squid

AP (Sep. 16, 2014) Squid experts in New Zealand thawed and examined an unusual catch on Tuesday: a colossal squid. It was captured in Antarctica's remote Ross Sea in December last year and has been frozen for eight months. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Man Floats for 31 Hours in Gulf Waters

Man Floats for 31 Hours in Gulf Waters

AP (Sep. 16, 2014) A Texas man is lucky to be alive after he and three others floated for more than a day in the Gulf of Mexico when their boat sank during a fishing trip. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Researchers Explore Shipwrecks Off Calif. Coast

Researchers Explore Shipwrecks Off Calif. Coast

AP (Sep. 16, 2014) Federal researchers are exploring more than a dozen underwater sites where they believe ships sank in the treacherous waters west of San Francisco in the decades following the Gold Rush. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Isolated N. Korea Asks For International Help With Volcano

Isolated N. Korea Asks For International Help With Volcano

Newsy (Sep. 16, 2014) Mount Paektu volcano in North Korea is showing signs of life and there's not much known about it. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

    Technology News



    Save/Print:
    Share:

    Free Subscriptions


    Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

    Get Social & Mobile


    Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

    Have Feedback?


    Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
    Mobile: iPhone Android Web
    Follow: Facebook Twitter Google+
    Subscribe: RSS Feeds Email Newsletters
    Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins