Cell or Plasma Membranes

Cell membranes are selectively permeable because they allow certain substances to pass through while blocking others. This selectivity is achieved through the presence of proteins and channels that regulate the movement of specific molecules into and out of the cell. The lipid bilayer structure of the membrane also plays a role in determining which substances can cross based on their size, charge, and solubility.

Cell membrane depolarization is caused by the influx of positively charged ions, such as sodium ions, through ion channels in the membrane. This influx of positive charge reduces the voltage difference across the membrane, leading to depolarization.

The term for the changes that take place in cells as they develop is called differentiation. It causes cells that are not very specialized to become cells that are very specialized.

The lipid layer that forms the foundation of cell membranes is primarily composed of molecules called phospholipids. Phospholipids have a hydrophilic (water-attracting) head and hydrophobic (water-repelling) tails, allowing them to align in a bilayer structure to create the cell membrane.

Phospholipids are a crucial component of cell membranes, forming a lipid bilayer that provides structure and acts as a barrier to control what enters and exits the cell. They also play a role in cell signaling and as precursors for various signaling molecules.

The membrane-covered compartment of eukaryotic cells are called vesicles. The vesicles are developed when a part of the membrane nips off.

The plasma membrane would fit into the general function category of "barrier protection and selective permeability." It serves as a barrier to separate the inside of the cell from the external environment while selectively allowing certain substances to pass through.

A phospholipid is placed in water, it spontaneously folds upon itself to create a double layer. This reaction is also the foundation for fluid mosaic model of membrane structure. The internal membranes compartmentalize reactions to stop interference.

on the outer layer of the cell

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The membrane is found around the edge of a cell - it encases the cell and controls what goes in and out of it. In plants, the membrane is protected by a thick cell wall.

It is because of the make up of the membrane. Most of the bilayer is hydrophobic; therefore water or water-soluble molecules do not pass through easily. Other do pass through easily.

A cell controls what moves through the membrane by means of membrane proteins embedded in the phospholipid bilayer.

No, not all molecules can diffuse through all cell membranes. The ability of a molecule to diffuse through a cell membrane depends on its size, charge, and solubility in lipids. Small, non-polar molecules can generally pass through the lipid bilayer of cell membranes via simple diffusion, while larger, polar molecules may require specific transport mechanisms.

The plasma membrane of a muscle fiber is called the sarcolemma. It surrounds the muscle cell and is responsible for controlling the passage of substances in and out of the cell, as well as transmitting signals for muscle contraction. The sarcolemma is essential for maintaining the integrity and function of the muscle fiber.

Yes, a cell membrane can have bumps on it known as microvilli. Microvilli are small, finger-like projections that increase the surface area of the cell membrane, allowing for more efficient absorption of nutrients or secretion of substances.

The cell membrane needs proteins, lipids, and carbohydrates to maintain its structure and function properly. It also requires a balanced environment of ions and nutrients inside and outside the cell to support various cellular processes. Additionally, the cell membrane needs to be intact to regulate the movement of substances in and out of the cell for proper communication and functioning.

A cell membrane is composed of a phospholipid bilayer, which consists of two layers of phospholipid molecules oriented with their hydrophobic tails facing inward and their hydrophilic heads facing outward. Various proteins, cholesterol molecules, and other components are embedded within or attached to the phospholipid bilayer, providing structural support and enabling various functions such as transport, signaling, and cell adhesion. The cell membrane is selectively permeable, allowing certain substances to pass through while restricting others.

Membrane organelles in a eukaryotic cell include the nucleus, endoplasmic reticulum, Golgi apparatus, mitochondria, lysosomes, peroxisomes, and vacuoles. These organelles are surrounded by lipid bilayers that separate their internal environment from the cytoplasm.

Water moves across plasma membranes due to "Osmosis". Water may also move through the plasma membrane by flowing down a gradient from outside the cell into the inside of the cell since there is a less concentration of of water inside the cell (there are more things in the cell other than water such as proteins, hormones, and other substances).

Phospholipids have polar and nonpolar ends. The polar ends face the outside of the cell or inwards towards the cytoplasm and the non polar lipid parts face toward the inside of the lipid bilayer of the membrane. Most phospholipids are made of a glycerol molecule attached to two fatty acids and a phosphate group. (Some phospholipids do not use glycerol and instead use a ceramide.) The phosphate group can be attached to inositol, choline, ethanolamine, and glucose. When attached to glucose it can form a lipid-carbohydrate anchor for carbohydrates that stick off of the cell membrane. Phosphoinositol is used in an important signaling pathway for cells by breaking down into diacyglycerol and phophoinositol phosphate. Also one of the fatty acids attached to phosphoinositol is arachidonic acid which is removed from phosphoinositol in order to make prostaglandins and leukotrienes. Hope that helps.

Cell membranes usually allow water, gases (such as oxygen and carbon dioxide), and small uncharged molecules to enter a cell. Larger molecules or charged ions may require specific transport proteins or channels to cross the membrane.

The size of a plasma membrane can vary depending on the type of cell it is in. Typically, it is about 7-10 nanometers thick and can extend for micrometers in length and width.

intrinsic

Of or relating to the essential nature of a thing; inherent.

Anatomy. Situated within or belonging solely to the organ or body part on which it acts. Used of certain nerves and muscles.

[Middle English intrinsique, inner, from Old French intrinseque, from Late Latin intrīnsecus, inward, from Latin, inwardly.]

Situated entirely within, or pertaining exclusively to, a part.

i. factor - see intrinsic factor.

i. host determinants - characteristics peculiar to the host that affect the spread and occurrence of a disease.

i. nerve - some evidence exists for the presence of autonomous nerves, without connection to the CNS, in the adventitia of small arteries and arterioles.

i. pathway, i. system - see coagulation pathways.

i. protein - see membrane proteins.

extrinsic

Not forming an essential or inherent part of a thing; extraneous.

Originating from the outside; external.

[Latin extrīnsecus, from outside : exter, outside; see exterior + -im, adv. suff. + secus, alongside.]

Of external origin.

e. allergic alveolitis - see hypersensitivity pneumonitis.

e. factor - see extrinsic factor.

e. incubation period - the period between infection of the arthropod insect vector and the vector's ability to infect the next vertebrate host.

e. pathway - see coagulation pathways.

e. protein - see membrane proteins.

Molecules that are charged or polar, such as ions, glucose, and amino acids, diffuse through cell membranes by facilitated diffusion. This process relies on carrier proteins or channel proteins to help facilitate the movement of these molecules across the membrane.

The cell will die.

The cell membrane/plasma membrane is a semipermeable lipid bilayer common to all living cells. It contains a variety of biological molecules, primarily proteins and lipids, which are involved in many cellular processes, and also serves as the attachment point for both the intracellular cytoskeleton and, if present, the cell wall.

If it ruptures all cell organelles will leak out due to the difference of osmotic pressure and will result in the eath of the cell.

Cell membranes are primarily composed of lipids (such as phospholipids and cholesterol) and proteins. These components work together to form a flexible yet selectively permeable barrier that surrounds the cell and regulates the movement of substances in and out of the cell.

No, viruses do not have a cell membrane. They are considered acellular entities that consist of genetic material (DNA or RNA) encapsulated in a protein coat called a capsid. Viruses require a host cell to replicate and do not have the ability to carry out cellular functions on their own.