Please help me understand the cell with the following questions: 1. A subgoal in
ID: 262950 • Letter: P
Question
Please help me understand the cell with the following questions:
1. A subgoal in our "build-a-cell" design challenge is to create a boundary that separates the "inside" of the cell from the environment "outside". This boundary needs to serve multiple functions that include: act as a barrier by blocking some compounds from moving in and out of the cell; be selectively permeable in order to transport specific compounds into and out of the cell; receive, sense, and transmit signals from the environment to inside of the cell; project "self" to others by communicating identity to other nearby cells.
2. Eukaryotic cells contain membrane-bound organelles that effectively separate materials, processes, and reactions from one another and from the cytoplasm. How can a eukaryotic cell transport compounds from their place of origin (could be the cytoplasm) to where they are needed (could be the nucleus)?
3. The cell membrane must simultaneously act as a barrier between "IN" and "OUT" and control specifically. Which substances enter and leave the cell and how quickly and efficiently they do so?
Explanation / Answer
1) The lipid bilayer of the cell membrane separates the inside of the cell from outer environment. It acts as a barrier and permits the transport of selected solutes across it.Further transport is possible due to presence of transporter molecules and channel proteins on the membrane. Receptors that detect ligands or stimuli from the environment helps in transporting signals into the cell.
2) Compunds synthesised inside the cell pocess a unique sequence or signal peptides (in the case of proteins) that directs them to its target. These compounds are transported to its destination depending on the presence of these signals.
3)Plasma membrane bear lipid entities. Hence any hydrophobic molecules and small polar molecules can diffuse through the lipid bilayer depending on their concentration gradient.Ions and large polar molecules cross by passive or active transport. Water and other hydrophilic molecules pass through channel proteins across the membranes. To transport some molecules against their concentration gradient, energy is utilized. This forms the active transport. Process of exocytosis is used to transport out bulk molecules from the cell to outside and this is used in cell secretions. While receptor mediated endocytosis allow cell to take in bulk molecules from outside.