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What is the reason that cells exchange materials with the environment around them?
to get rid of wastes and take in nutrients
What is the flexible covering of cells allowing exchange of materials between the cell and its environment?
the selectively permeable cell membrane
It is the Endoplasmic Reticulum(ER)
The ER (endoplasmic reticulum), both smooth and rough, move material within the cell
The Endoplasmic Reticulum
So they can have food oxygen and other things from the environment
Respiration. The main job of blood is to perform external and internal respiration, in the lungs and the tissues. This main job is called gas exchange.
to get rid of waste
It takes place across the cell membrane
A cell's contents are enclosed by a bilayer of phospholipid molecules, each of which has a head group attracted to water and a tail repelled by it. This bilayer is called a m…embrane and regulates traffic into and out of the cell. There are five types of transport across membranes in cells: diffusion, facilitated diffusion, active transport, cotransport and endocytosis/exocytosis. Diffusion Facilitated and Active Transport Diffusion is the motion of solutes from a region of high concentration to areas of low concentration; over time, diffusion causes solutes to become evenly distributed throughout a liquid, much as a drop of dye added to a glass of water will eventually diffuse throughout the water. Cotransport, Endocytosis and Exocytosis Urea, carbon dioxide, water and oxygen are among the substances that can diffuse across cell membranes. Charged ions and many other important substances like glucose either do not diffuse across the membrane or do so very slowly. In facilitated transport, a carrier protein embedded in the membrane acts like a revolving door to permit substances concentrated on either side of the membrane to flow to the other. In active transport, by contrast, a protein uses energy to actively pump a substance across the membrane.Cotransport is a form of active transport where a membrane-embedded protein uses a concentration gradient of one substance to power the cross-membrane transport of another. If, for example, the cell pumps hydrogen ions out, it could create a high extracellular concentration of hydrogen ions and use this gradient to power inward transport of another molecule like sucrose. In endocytosis, the cell membrane envelops food particles or other molecules and takes them in as a membrane-enclosed sac. Exocytosis is the reverse of endocytosis.
Cell membranes must control the exchange of nutrients, waste, water, and communication signals. Whether it's one cell or many cells, each cell is completely surrounded by …a protective membrane.