DNA and RNA are the key molecules of living cells. DNA plays a vital role
in storing and transmitting the hereditary information that constitutes
the "operating instructions" of living cells; how to construct the functional
and structural proteins that perform vital cell functions, control
developmental pathways, and basically "build" the organism. RNA is ... Show More
Oct 2009
Lecture 15: The Chemistry of Life
What is the basic chemistry of living organisms? We introduce the requirements for metabolism (raw
materials and energy), the ATP/ADP energy cycle in cells, auto- and
heterotrophs, photosynthesis and chemosynthesis, and the role played by
liquid water. The goal of today's lecture ... Show More
45m 4s
Oct 2009
Lecture 13: What is Life?
How do we define life? This lecture reviews the six basic criteria
for living systems described by biologists: order, reproduction, growth and
development, energy utilization, reaction to environment, and evolution
that characterize life. The last third of the lecture is an admit ... Show More
46m 16s
Mar 2022
Comment calculer l'âge d'une étoile ?
La durée de vie d'une étoile peut nous renseigner sur sa composition et sur l'existence éventuelle de la vie dans le cosmos. mais, en dehors du Soleil, il est assez difficile de déterminer l'âge d'une étoile.
L'importance de la masse
En évaluant, grâce à la radioactivité, l'âge d ... Show More
1m 58s