The largest molecule known to date is a protein called titin. Titin is found in muscle cells and plays a role in muscle contraction. It is a giant protein with an extremely long molecular chain. The full chemical name of titin is quite lengthy, but it is often referred to as titin for simplicity.
Titin has an enormous size relative to many other molecules. Its molecular weight can range from around 3 to 3.7 million Daltons (a unit used to measure molecular mass). To put this into perspective:
Compared to a human cell: Titin is significantly larger than a typical human cell. Human cells, such as muscle cells, are microscopic in size, typically ranging from 10 to 30 micrometers (0.01 to 0.03 millimeters). In comparison, titin's size is measured at the molecular scale, with a length of around 1 micrometer (0.001 millimeters).
Compared to an atom: Atoms are the fundamental units of matter and are much smaller than molecules. The size of an atom can vary depending on the element, but typically atoms have a diameter on the order of picometers (10^(-12) meters). In contrast, titin is composed of thousands of amino acid residues, making it much larger than an individual atom.
It's worth noting that there are other large molecules found in nature, such as DNA molecules, which can have significant lengths. However, in terms of sheer molecular weight and length, titin currently holds the record as the largest known molecule.