Cell or Plasma Membranes

The membrane acts as a barrier that prevents most things from entering. Small molecules and water can diffuse across the membrane but most proteins and larger molecules cannot. The cell can use this advantage in combination with proteins to decide what gets in, what goes out and when that should happen.

All (mostly) membranes of the cell including those of organelles are made up of lipids, proteins and polysaccharides (like cholesterol). The lipids and proteins are called glycolipids and glycoproteins.

phospholipid bilayer, which consists of two layers of phospholipid molecules. It controls the movement of substances in and out of the cell, providing a barrier that separates the internal and external environments of the cell.

Cholesterol is a well-known steroid that is a major component of animal cell membranes. It helps maintain membrane structure and fluidity, as well as serves as a precursor for the synthesis of other important molecules like hormones.

Yes, human cells have a cell membrane. The cell membrane is a thin, semi-permeable barrier that surrounds the cell, separating its internal structures from the external environment. It plays a crucial role in maintaining the cell's shape, protecting its contents, and regulating the passage of molecules in and out of the cell.

The cell membrane is a semi-permeable barrier separating the interior of the cell from the exterior which controls what substances can move in and out of the cell.

The primary physical constituent or the cell membrane is the phospholipid bi-layer. "Floating" within this bi-layer are many different biological macromolecules including proteins and lipids. This description is often referred to as the "fluid-mosaic model."

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The Plasma Membrane is a selectively permeable membrane as it only allows entry and exit of some selected molecules into and out of the Cells.

It also prevents movement of some other materials, therefore the plasma membrane is called a selectively permeable membrane.

The membrane that surrounds the cytoplasm of a cell; it is also called the plasma membrane or, in a more general sense, a unit membrane. This is a very thin, semifluid, sheetlike structure made of four continuous monolayers of molecules. The plasma membrane and the membranes making up all the intracellular membranous organelles display a common molecular architectural pattern of organization, the unit membrane pattern, even though the particular molecular species making up the membranes differ considerably. All unit membranes consist of a bilayer of lipid molecules, the polar surfaces of which are directed outward and covered by at least one monolayer of nonlipid molecules on each side, most of which are protein, packed on the lipid bilayer surfaces and held there by various intermolecular forces. Some of these proteins, called intrinsic proteins, traverse the bilayer and are represented on both sides. The segments of the polypeptide chains of these transverse proteins within the core of the lipid bilayer may form channels that provide low-resistance pathways for ions and small molecules to get across the membrane in a controlled fashion. Sugar moieties are found in both the proteins and lipids of the outer half of the unit membrane, but not on the inside next to the cytoplasm. The molecular composition of each lipid monolayer making up the lipid bilayer is different. The unit membrane is thus chemically asymmetric.

Selective (or differential) permeability allows the cell to regulate its internal environment and maintain internal homeostasis. This is also the basis by which a neuron (nerve cell) can 'fire' and send a message along its axon - it selectively allows one electrolyte then a different electrolyte to flow across its cell membrane and change the electrochemical gradient.

An organism that can make its own food is known as an autotroph. Autotrophs use energy from sunlight (photosynthesis) or inorganic chemicals (chemosynthesis) to produce their own food, typically in the form of glucose. Plants, algae, and some bacteria are examples of autotrophs.

70 percent ethanol means it has 30 percent of water.so due to natural osmosis water can enter thr cell membrane.the ethanol thus moves inside along with water and hence has a beter penetrating power than undiluted ethanol.

Yes, protists have cell membranes. Cell membranes are present in all living cells, including those of protists, to regulate the passage of materials into and out of the cell and maintain cellular structure and function.

Cell membranes have several key functions, including controlling what substances enter and leave the cell, providing structure and support to the cell, and facilitating communication between cells. They also play a role in recognizing and interacting with other cells and molecules in the environment. Overall, cell membranes are crucial for maintaining the integrity and proper function of cells.

Cell membranes consist of a phospholipid bilayer, which is made up of two layers of phospholipid molecules. Embedded within this bilayer are proteins that help regulate the passage of ions and molecules in and out of the cell. Additionally, cell membranes may contain cholesterol molecules that provide stability and fluidity to the membrane.

A porous membrane has openings scattered on its surface of various size and frequency. This means that such membranes allow various substances to pass through. Any molecules that are larger than the membrane's openings will not pass through.

yes

Water crosses via osmosis. glucose via diffusion. Carbon dioxide needs assistance to pass through the membrane so it requires active transport.

The major types of lipids found in plasma membranes are phospholipids, cholesterol, and glycolipids. Phospholipids are the most abundant and form the structural basis of the membrane bilayer, while cholesterol helps maintain membrane fluidity and stability. Glycolipids are located on the outer surface of the membrane and play a role in cell recognition and signaling.

Yes.

While animal cells have only cell membranes, plant cells have both a cell membrane (between the cell wall and cytoplasm) and a cell wall (a cellulose wall that offsets osmotic pressure causing turgor to occur).

In most contexts radiant energy would be assumed to be made up of electromagnetic radiation, such as light. The force carrier for electromagnetic radiation is a massless fundamental particle, the photon.

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An egg cell is good at its job because it contains all the necessary components for fertilization, such as nutrients and organelles. It is also capable of recognizing and interacting with sperm cells to initiate the fertilization process. Additionally, the egg cell has a protective outer layer that helps regulate which sperm can enter and prevents multiple fertilizations.

In engineering a rigid structure is something that is analyzed as if none of the components deform, that is bend, compress or stretch. For example when analyzing a bridge made out of riveted beams to see how much force is on the joints, the assumption is often made that when there's a load on it, it doesn't deform, that is all the beams stay the same length and don't bend. This isn't exactly true in real life, but it's a good enough approximation that the force on the joints can be pretty accurately calculated.

The reason this approximation is used is that it would be extremely difficult to calculate the exact deformations and for things like bridges the margin for error in doing the design is very large. The errors caused by the rigid assumption are much smaller than the margin for safety engineered into the structure.

For designing things like a bungee jumping tower, treating the cord as a rigid structure is probably not a very good idea.