Functions Of A Cell Membrane

P1: Outline the function of the main cells of the body. Cells are the main structure of the body as they all come together to form one cell. They are very important because without them, we wouldn’t be able to live. The cells carry out numerous of chemical reaction that we wouldn’t have heard of or even felt and it is simply done it on its own. Cells make up all the organs in the body.

Diffusion happens when molecules that are confined in a certain amount of space are given more space. This causes the molecules to move apart from the high concentration areas to lower concentration areas down the gradient. Osmosis is the

A cell is the basic unit of life, essential to maintaining the physiology of the larger organism. In animals, certain organelles metabolize food into energy, and then uses the energy for repair, growth and reproduction. Similarly, chloroplasts in plant cells transform sunlight into energy, a process known as photosynthesis.

diffusion is one of the passive transport processes. it is used in oxygen entering a cell and carbon dioxide leaving a cell. diffusion is the movement of particles such as atoms or molecules from a high concentration place in an area of a low concentration. this shows that they diffuse down the concentration gradient. the concentration gradient is a gradual change in the concentration of solutes in a solution as a function of distance through a solution. in biology a gradient results from an unequal distribution of particles across the cell membrane. When this happens solutes move along the concentration gradient until the concentration of the

Some molecules can pass into the cell by facilitated diffusion. This is passive due to the nature of diffusion and because the solute is moving down its

The cell membrane consists of eight distinctive parts that each have their own unique structure and function. The phospholipid bilayer is an integral part of the cell membrane because it is the external layer of the cell membrane and composes the barriers that isolate the internal cell components and organelles from the extracellular environment. It is composed of a series of phospholipids that have a hydrophobic region and a hydrophilic region. These regions are composed of the hydrophilic heads and the hydrophobic tails of the phospholipids, this organization of the polar heads and nonpolar tails allows the heads of the cell to form hydrogen bonds with water molecules while the tails are able to avoid water. The phospholipid bilayer also has many important functions within the cell, it gives the cell shape, provides protection, and it is selectively permeable which allows it to only let very specific molecules pass through its surface. The phospholipid bilayer is an important structure because it prevents harmful and unwanted molecules from entering the cell and isolates organelles which helps to maintain the internal environmental homeostasis of the cell.

All cells in the human body are surrounded by a plasma membrane made up of lipids and proteins which form a barrier. The proteins and lipids in the membrane occupy different roles. The lipids create a semipermeable barrier and the proteins are part of a cross membrane transport. To pass through the membrane a substance goes through a transport known as diffusion. Diffusion is movement of molecules from a high area of concentration to an area of low concentration. There are two different forms of diffusion. One example of diffusion is known as simple diffusion, an unassisted movement of dissolved substances through a selectively permeable membrane (Marieb pg. 54). The

Introduction: Cell membranes contain many different types of molecules which have different roles in the overall structure of the membrane. Phospholipids form a bilayer, which is the basic structure of the membrane. Their non-polar tails form a barrier to most water soluble substances. Membrane proteins serves as channels for transport of metabolites, some act as enzymes or carriers, while some are receptors. Lastly carbohydrate molecules of the membrane are relatively short-chain polysaccharides, which has multiple functions, for example, cell-cell recognition and acting as receptor sites for chemical signals.

active transport – journeys against the concentration gradient. Molecules go from low to high levels of concentration. Requires the use of ATP.

Diffusion occurs in various areas of the body whereas, humans will experience diffusion in the kidneys, lungs, intestines and many more places. Diffusion is the movement of molecules or ions from a higher to lower concentration; occurring because solutes moving are not evenly distributed. However to achieve this equilibrium, solutes will move down a concentration gradient. Resulting in facilitated diffusion which is a type of diffusion using carrier and channel proteins to carry out its functions being a passive transport. This is where molecules or ions cross from a high concentration to a low concentration only requiring membrane proteins.

All cells contain membranes that are selectively permeable, allowing certain things to pass into and leave out of the cell. The process in which molecules of a substance move from an area of high concentration to areas of low concentration is called Diffusion. Whereas Osmosis is the process in which water crosses membranes from regions of high water concentration to areas with low water concentration. While molecules in diffusion move down a concentration gradient, molecules during osmosis both move down a concentration gradient as well as across it. Both diffusion, and osmosis are types of passive transport, which do not require help.

In order for cells and organisms to “live” they need to perform certain tasks such as produce energy through respiration, send messages, maintenance and reproduction. To enable the cell to do so, it contains within small structures called organelles, each organelle is different and carries out a specific function.

As molecules move about randomly at high speeds, they collide and bounce off one another, changing direction with each collision. For a given temperature, all matter has about the same average kinetic energy. Smaller molecules tend to move faster than larger molecules because kinetic energy is directly related to both mass and velocity (KE 1⁄2 mv2). When a concentration gradient (difference in concentration) exists, the net effect of this random molecular movement is that the molecules eventually become evenly distributed throughout the environment—in other words, diffusion occurs. Diffusion is the movement of molecules from a region of their higher concentration to a region of their lower concentration. The driving force behind diffusion is the kinetic energy of the molecules themselves. The diffusion of particles into and out of cells is modified by the plasma membrane, which is a physical barrier. In general, molecules diffuse passively through the plasma membrane if they are small enough to pass through its pores (and are aided by an electrical and/or concentration gradient) or if they can dissolve in the lipid portion of the membrane (as in the case of CO2 and O2). A membrane is called selectively permeable, differentially permeable, or semipermeable if it allows some solute particles (molecules) to pass but not others. The diffusion of solute particles dissolved in water through a selectively permeable membrane is

The plasma membrane is an assortment of phospholipids, cholesterol molecules, proteins, and carbohydrates. Phospholipids make up the basic structure of a cell membrane. A single phospholipid molecule has two different ends: a head and a tail. The head end contains a hydrophilic phosphate group. This means that this part of the bilayer is water-loving and thus will be in contact with water. The tail end is made up of two strings of hydrogen and carbon atoms called fatty acid chains. These chains are hydrophobic or do not like to mingle with water molecules.)The phospholipids of a cell membrane are arranged in a double layer called the lipid bilayer. The hydrophilic phosphate heads

Biomembranes play an essential role in regulating an extensive variety of cellular processes by providing an active two-dimensional lipid framework within which biochemical reactions can occur. The structure and dynamic lateral organization of these membranes selectively modulate the activity of membrane associa¬ted proteins, such as receptors and channels.1–3 Biomembranes are complex structures which are responsible for the entity of cytosolic organelles and cells. Besides a structural role, membrane components play a key role in communications between the extra- and intracellular environments, serving as messengers in signal transduction and recognition processes. The main constituents - lipids and proteins in biological membranes stay together predominantly by non-covalent interactions. Covalent interactions are also absent between lipids within membranes, resulting highly dynamic properties these assemblies. Lipids are amphipathic molecules that self-assemble into continuous double layer arrangement in aqueous environment, where polar head groups have tendency to interact with the water while hydrophobic moieties to self-associate via hydrophobic interactions. Although phospholipid molecular species vary greatly in eukaryotic cell membranes, they predominantly belong to four main lipid types: Phosphatidylcholine (PC), phosphatidylserine (PS), phosphatidyl-ethanolamine (PE) and sphingomyelin (Sph). Asymmetric distribution of these components between extra-cellular