Vitamin D production begins when a precursor molecule is exposed to ultraviolet light in the skin.
UV or ultraviolet light
mitochondria
Glucose, a six-carbon molecule, is the starting molecule for glycolysis.
glucose
exposed to a rough surface
Molecule
Glucose
The citric acid cycle begins with acetyl-CoA and ends with oxaloacetate.
1834Charles Babbage begins build his "Analytical Engine", precursor to the computer. It uses read-only memory in the form of punch cards.
Physical weathering begins the moment a rock body is uplifted and fractured, or exposed to the atmosphere, along with it's differences in temperature, sunlight, and water.
When blood is exposed to oxygen, it turns red. In your body, it is really blue.
When one strand of the DNA molecule is unzipped, the exposed bases become available for complementary base pairing. This process allows an enzyme called DNA polymerase to build a new complementary strand by adding nucleotides according to the base pairing rules (A with T and C with G).