The process of cellular transport is a concept we have all learned during our high school biology classes. In a eukaryotic cell, there are two types of cellular transport. Passive transport does not utilize ATP, or adenosine triphosphate, to move molecules or waste. Instead, it uses the process of diffusion, in which substances move between the plasma membrane of the cell from high concentration of the substance to low concentration. The substances that are usually moved are small, uncharged molecules, such as carbon dioxide. In facilitated diffusion, transport proteins are used to transport charged molecules, like ions.
They are embedded in the plasma membrane of the cell and help bring substances in and out of the cell with the concentration gradient of the substance. Active transport utilizes ATP to move substances against the concentration gradient. In other words, substances are moved from low concentration to high concentration through the use of ATP. When large molecules are moved across the plasma membrane, vesicles that are formed in the membrane engulf the molecules within the cell and release the molecule outside the cell. This process is known as exocytosis. Endocytosis is the opposite of exocytosis where the cell takes in the large molecules using the vesicles formed by the plasma membrane. But how do cells know where to transport materials, how to make vesicles, and what vesicles to fuse with? The 2013 Nobel Peace Prize winners in Medicine, James E. Rothman, Randy W.
Schekman, and Thomas C. Südhof discovered the mechanism behind vesicle traffic and how cells transport materials between other cells. These three winners were able to find out the secret behind vesicular traffic in three different experiments. Schekman …
Osmosis is the diffusion of water molecules across a differentially permeable membrane from a region where water molecules are more concentrated to one where they are less concentrated. The transport of water is simple the cell being selectively permeable will allow water through it until an equilibrium is reached and at that time water will flow both in and out of the cell maintaining the equilibrium. For example a red blood cell is placed into a isotonic solution which means both the solution and the cell have the same concentration the net movement of water is zero, water however does move freely in and out of the cell to maintain the balance.b.Active TransportIn active transport a cell moves materials from an area of low concentration to an area of high concentration, this process is the opposite of osmosis or diffusion. Active transport requires energy because it is moving against the concentration gradient. In active transport the cell uses ATP to remove unwanted materials and to receive needed ones. For example a muscle cell wants potassium and wants to get rid of a sodium, the cell releases ATP to the pump proteins which results in the cell ejecting the sodium ion and at the same time another receptor cell accepts a potassium which is then released into the cell and the process is repeated until the cell is finished.
c.Facilitated TransportIn facilitated transport a molecule that cannot normally pass through into a cell use a carrier protein to gain access and exit. Basically this allows a cell to acquire molecules that cannot get through it¹s selectively permeable membrane. For example a plant cell requires glucose and the glucose will not fit through the cell membrane. A carrier protein in the plasma membrane will accelerate the movement of the glucose and allow it into the cell.Science has advanced tremendously in the last decade or so, especially in the field of cellular genetics.
Even with such great advancements many scientists find that intracellular transport is a rather complex cellular process that requires parts such as a dynamic cytoskeleton, and molecular motor protein, which are myosin, kinesin, and dynein. In addition, intracellular transport involves the movement and selecting of vesicles and proteins to particular cellular regions. Sometimes intracellular transport happens over elongated distances, “like down the nerve axon” (Lodish). Occasionally this transport is simply the movement of a vesicle through the cell cortex. Transport also incorporates the suitable delivery and localization of organelles. The mitochondria serve as an example for such system of transportation within the organelles.
Cell movement incorporates whole-cell motion, the guideline of the cell shape and extracellular attachment. Cell migration is critical for several ordinary and pathological developments, embracing: cell and tissue development, wound restoration, immune reaction, and metastases of polyps/tumors (Intracellular Transport). Within cells, membrane-bounded vesicles and proteins are habitually transported many micrometers along distinct routes in the cytosol. These are later delivered to particular addresses. Diffusion alone is not the explanation for the rate, directionality, and targets of such transport processes. According to the Pennsylvania Muscle Institute, “Early video light microscopy studies showed that these long-distance movements follow straight paths in the cytosol” (Intracellular Transport).
These are frequently found along cytosolic fibers, implying that Intracell…Cellular Respiration in Skeletal MusclesEvery day we use our skeletal muscle to do simple task and without skeletal muscles, we will not be able to do anything. Szent-Gyorgyi (2011) muscle tissue contraction in rabbit’s muscles and discovered that ATP is a source for muscle contraction and not ADP.
He proposed a mechanism to cellular respiration and was later used by Sir Hans Krebs to investigate the steps to glucose catabolism to make ATP. In this paper, I will be discussing the structure of muscle fibers and skeletal muscles, muscle contraction, biomechanics, and how glucose and fat are metabolized in the skeletal muscles. Muscle fibers are cylindrical. They have a diameter around ten to one hundred micrometers and are generally a few centimeters long. Within each muscle cells, contains basal lamina of collagen and glycoproteins. Each fiber contains a structure called excitation-contraction coupling, which is used to make sure the each contractile stimulus is quickly and equally communicated throughout the muscle fiber. The four different type of fiber types are: slow, fast and fatigue resistant, fast fatigable and fast intermediate.
Slow muscle fibers have a long twitch time, which means that they have low peak forces, and have a high resistance to fatigue. These fibers are high in oxidative enzymes and are low in glycolytic markers and ATP activity.Fast and fatigue resistant fibers are faster in contractions. Fast and fatigue resistant fibers maintains force production after contractions.
These fibers are the opposite of slow fibers, instead they have a high ATP and glycolytic activity and have a low oxidative capacity. The fast fatigable have high contractions rates and large forces, but they cannot maintain tensions…