The title of this presentation is an acrostic that lists the six elements needed for life: Sulfur, Phosphorus, Oxygen, Nitrogen, Carbon and Hydrogen.
Life on this planet has a very old history. It has emerged from a primeval soup; cooked with the Sun for the last 4.6 billion years.
“Earth’s prebiotic oceans—different from their modern counterparts—would have formed a “hot dilute soup” in which organic compounds could have formed. J.D.Bernal, a pioneer in x-ray crystallography, called this idea biopoiesis or biopoesis, the process of living matter evolving from self-replicating but non living molecules,”
Ancient oceans were very hot. And barren. No life. But they were huge cauldrons; with the proper conditions to cook with CHNOPS. 4.6 billions of years ago, amino-acids–building blocks of life–were emerging. But how these elements happen in the first place? The subject is a matter of heated debate in the modern scientific community, but recently NASA came across this interesting piece of data:
In March, 2009, researchers at NASA’s Goddard Space Flight Center in Greenbelt, Md., reported the discovery of an excess of the left-handed form of the amino acid isovaline in samples of meteorites that came from carbon-rich asteroids. This suggests that perhaps left-handed life got its start in space, where conditions in asteroids favored the creation of left-handed amino acids. Meteorite impacts could have supplied this material, enriched in left-handed molecules, to Earth. The bias toward left-handedness would have been perpetuated as this material was incorporated into emerging life.
Another elegant approach towards the origin of life, in an experiment 60 years old this year:
Asteroids could’ve brought amino acids. Hot, primordial, oceans boiled (remember the emergent properties of water); lightning storms cooked electric. Are we made out of star stuff? Where these elements the result of The Big Bang?
[Put on your headphones and Google—or better yet: retrieve from Youtube–the song Solstice (Current Value Remix for Seniors; original version for 10th grade). Listen to the song. Look for the lyrics. Write a short essay (100 words) on the song (10 point value; it can replace a blog participation).]
On this spinning rock, macromolecules have emerged. And they are strange: they can replicate. Information is carried in their chemistry—in their molecular arrangements—in their bonds—5-Carbon sugars.
DNA replicates. It can be read, reread, edited, transcripted, mutated, sliced. All this happens because amino-acids—23 of them—combine in ways that make horns, hemoglobin, muscle tissue, etc.
Plants can do this in their cells; the same mechanics are embedded in our own DNA. Thanks to these remarkable properties–possible only through the chemical interactions between CHNNPS elements–plants pumped a very important element to the atmosphere; these elements ignite flames; they were believed to be phlogiston (the prefix “phlo” refers to flammable).
Oxygen is highly reactive as well, and it’s responsible for trillions of controlled explosions going on in our cells; right now.
Oxygen–versatile element–makes fire possible, it makes Cellular Respiration possible.
Another element famous for its versatility is Carbon. It can combine in its pure form in various ways, forming what we know as allotropes. These can be bucky balls–they travel through space–; graphite (your pencils are made of this); graphene; diamonds; even whole planets.
A lot more can be said about the origin and nature of life. But this presentation aims to spark your curiosity about biochemistry, abiogenesis, and, to some extent, cosmology–we are part of the Cosmos.
This video is by science commentator and physicist, Neil Degrasse Tyson; a good coda–ending–to this blog post, which will be revisited– many times–during the school year:
This blog post is for both: 10H and AP Biology. The content of this presentation will be evaluated on future assessments—i.e. tests, quizzes, quizams, etc. Textbooks for this presentation are: Modern Biology, Campbell 7th through 9th, and Study Guide for Modern Biology.
Unit I: The Foundations of Biology
Chapters 2 (Chemistry of Life) and 3 (Biochemistry)
The film presented on class, Nova: Hunting for Elements, can be used to review concepts discussed here.
Homework: Chapter 3 of your Study Guides for Tuesday 10th of September.
Unit: Intro to Biology.
Chapters 3 (The Chemical Context of Life) and 4(Carbon and The Molecular Diversity of Life).
Labs I (Bonds and models) and II (Emergent Properties of Water) are important for the discussion of this presentation. Concepts 3.1, 3.2, and 4.1 are aligned with this blog post.
Homework: One participation—comments, replies, etc.—on this blog post. (Refer to the rubric given by the teacher on how to comment).