Cell or Plasma Membranes

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.

Yes, the plasma membrane is composed of a phospholipid bilayer, which is a double layer of phospholipid molecules arranged with their hydrophobic tails facing inward and their hydrophilic heads facing outward towards the extracellular and intracellular environments.

Yes, both plant and animal cells have a plasma membrane. The plasma membrane is a semi-permeable barrier that surrounds the cell and controls the movement of substances in and out of the cell.

The Plasma Membrane encases the cell and all of the organelles within it, it regulates what goes in and out of the cell. It also protects it from harmful objects i.e. viruses, harmful chemicals, from entering the cell and possibly destroying it from within.

Plant cells do have cell membranes, which are covered by the cell walls.

It is the plasma membrane of a cell. The plasma membrane is a phospolipid bilayer, but because the phospsolipids are amphipathic, and because the lipid tails of each are turned into one another it is considered a trilamina. Hydrophilic Head of the inner layer + lipid tails of each layer + Hydrophilic Head of the outer layer.

Proteins do not pass through cell membranes freely because they are large molecules that cannot easily fit through the membrane's lipid bilayer. Instead, proteins are typically transported into or out of cells through specific channels or transport proteins in a process called facilitated diffusion or active transport.

Because the animal cells contain cholesterol as the major sterol in the plasma membrane whereas in plant cells the plasma membrane contain stigmasterol as the major sterol. How could you not know this? Are you a 1st grader?

oxygen and carbon dioxide

Surface carbohydrates on the cell membrane play a key role in cell recognition, adhesion, and communication with other cells. They are involved in immune response, cell signaling, and are also important for forming glycoproteins and glycolipids on the cell surface. These carbohydrates are diverse and can vary between cell types, serving as markers that help cells identify and interact with one another.

The cell membrane confines cell contents and regulates the entry and exit of materials. It acts as a selectively permeable barrier, allowing certain compounds to pass while preventing others from entering or exiting the cell.

The Golgi apparatus is the organelle that forms vesicles, known as secretory vesicles, that fuse with the plasma membrane. These vesicles contain proteins or lipids that are then released outside the cell.

A cell membrane's function for an animal cell is, it gives the cell its shape, strength, holds cell together, and controls what goes in and out of the cell. For a plant cell it just, holds cell together, and controls what goes in and out of the cell.

The main molecules that form the plasma membrane are phospholipids, cholesterol, glycolipids, proteins, and carbohydrates. These molecules are arranged in a bilayer structure, with the hydrophilic heads facing the external and internal environments and the hydrophobic tails facing each other.