In sedimentary rock from over 2.7 million years ago, the presence of cellular membrane components indicate that at least unicell
ular life was present in abundance at that time. What biomolecular structure would indicate the presence of a cell enclosed in a membrane in the fossilized rock? A) DNA and RNA B) lipids and cholesterols C) proteins and nucleic acids D) chloroplasts and mitochondria
The cell membrane is the wall of the cell which separates the cell inners to the outer environment. Cell membranes are constructed mainly from lipids and protein. The largest percentage of molecules which make up the cell membrane are phospholipids, cholesterol, and protein.
lipids and cholesterols Cell (plasma) membranes are composed primarily of a phospholipid bilayer and cholesterols embedded in that bilayer. These are some of the last structures to decompose once an organism dies, and would indicate the enclosure of cellular life in a lipid-based membrane. DNA and RNA would be found within the cell, not its membrane. Proteins and nucleic acids are also intracellular. Mitochondria and chloroplasts are organelle structures and wold not be found in a cell membrane.
