Cell membranes contain and protect the contents of the cell. They are active in signaling other cells, and proteins embedded in their matrix regulate the cell's chemistry by selectively absorbing and secreting chemicals. Many single-celled organisms, such as amoebae, use their flexible membranes for locomotion and food gathering.
Cell membranes are extremely flexible structures that play many roles in the life of a cell. They are the only structures found in all cells, regardless of species, and serve as the attachment point for many intracellular structures such as cell walls and cytoskeletons, as well as extracellular structures such as cilia.Learn More
The cytoplasm was discovered in 1835 by three biologists, George E Palade, Albert Claude and Christian de Duve. It was Robert Hooke who discovered the cell in 1831 and laid down the fundamentals for the study of the cell.Full Answer >
The National Science Foundation explains that viruses infect host cells by piercing the cells' outer membranes, digesting the walls and injecting virus DNA into the cells. While many viruses remain dormant under extreme conditions, such as freezing temperatures, they may come to life in the right conditions and enter another organism's cells.Full Answer >
The major difference between active and passive transport is that passive transport does not require the application of external energy, while active transport does. Both processes move molecules across the cell membrane, but passive transport always takes advantage of existing concentration gradients to allow a natural diffusion of molecules.Full Answer >
A sperm cell delivers its DNA to and fertilizes eggs, according to the National Center for Biotechnology Information. The BBC points out that this genetic material is contained in 23 chromosomes, which combine with the 23 chromosomes found in the female sex cell to make 23 pairs of chromosomes that contain all the genes for the new embryo.Full Answer >