Cell Physiology - Assignment Example

Anatomy Homework Cell physiology Labeling 2 3. Draw and Label a phospholipid 4. Describe the characteristics of phospholipid The phospholipids are found in abundance in the cell membrane. The most definite characteristics of the molecules are the possession of bi-layers. The bi-layer exists due to the presence of hydrophilic head and a hydrophobic tail (NCBI 1). One part of the molecule is attracted to water while the other part is opposed to water (NCBI 1). The head is said to be polar while the tail is non-polar (NCBI 1). The characteristic is essential in the function of the cell membrane (NCBI 1). The character helps the lipid to show selective permeability. Moreover, the head is exposed to outside while the tail is sandwiched in inside the membrane. On the other hand, the molecules are able to move laterally in the membrane (NCBI 1). 5. Describe the role of the phospholipid in the cell membrane Phospholipid acts as an important component in the plasma membrane function. The first essential function is providing the membrane with selective permeability (NCBI 1). The selective nature occurs due to the presence of two layers that are polar and non-polar. The other vital role is the provision of adjustment in the cell membrane. The property occurs as the molecules move laterally giving the membrane the fluid mosaic model (NCBI 1). On the other hand, the molecules provide a layer in which other membrane proteins are attached (NCBI 1). 6. Draw a sample section of a cell membrane. Label all of the possible components and describe their function All the components of a cell membrane play an integral role to its function. One of such components is the cholesterol. The rigidity of the cholesterol helps the membrane in various ways (NCBI 1). Cholesterol is usually sandwiched between the phospohilipids (NCBI 1). First, cholesterol helps in membrane fluidity (NCBI 1). Once there is extreme temperature, it helps in ensuring the outer part of the membrane is less fluid and hence reducing its permeability to small molecules (NCBI 1). On the other hand, when the temperature is below normal, it prevents the membrane from freezing by increasing fluidity. Moreover, the structure is rich in proteins. One of the most valuable proteins is the integral protein. The protein helps in cell-to-cell communication, maintaining of membrane structure, and may play a role in transport of some molecules (NCBI 1). The other component of the membrane is the phospholipids layer. Phospholipids acts as an important component in the plasma membrane. The first essential function is providing the membrane with selective permeability (NCBI 1). The other notable role is the provision of adjustment in the cell membrane (NCBI 1). The property occurs as the molecules move laterally giving the membrane the fluid mosaic model (NCBI 1). On the other hand, the molecules provide a layer in which other membrane proteins are attached (NCBI 1). 7. Draw an example of each of a carrier protein. Describe the function of these proteins in the membrane and why they are needed Carrier proteins play an integral role in the cell membrane. The proteins do not extend through the membrane but exist in between in the membrane (Diwan 1). Their role is binding of substrates and moving them across the bi-layer of the membrane (Diwan 1). As a result, the membrane transport would be severely affected without the protein. 8. Draw an example of the Na+/K+ ATPase. Describe its function and why it is needed in the membrane The Na+/K+ ATPase interaction in a cell is an essential process in the membrane. The critical role is the active transport sodium and potassium ion across mammalian membrane. As a result, the cell membrane maintain membrane gradient for the two ions (Weizmann Institute of Science 1). The interaction exists in various organs in the body such as the kidney. The pump helps in control of sodium and potassium balance in the organ (Weizmann Institute of Science 1). The pump requires energy as it occurs against the concentration gradient. 9. Compare and contrast the cytoplasm and the extracellular fluid There exist various compartments of the fluid in a cell. In a cell, some fluid occurs inside the cell while other occurs outside the cell. Fluid that exists in a cell is known as cytoplasm or intracellular while one that occurs outside is known as extracellular fluid. Cytoplasm occurs within the compartment of a cell (Naveen 1). The fluid is bounded by the cell membrane. Most of the metabolic reaction takes place within the fluid. The composition is usually water with traces of ions such as sodium. The fluid also has proteins. In contrast, the extracellular fluid occurs outside the cells (Naveen 1). The fluid helps in facilitation of cells and tissues. The main role is to supply nutrients to other organelles found within the cytosol (Naveen 1). The fluid does not contain protein. Moreover, the fluid contains a large amount of ions. 10. Draw an example of a cell in each of the following. Explain the effect of each on the cell Hypotonic solution In this solution, there is less amount of solute outside the cell. As a result, concentration is high inside the cell as compared to the outside. Therefore, a cell placed in the solution gains water and increases in size (Biologymad 1). Sometimes, such cell may burst due to accumulation of the excess amount of water. Hypertonic solution In this solution, the outer environment has a high amount of solute concentration as compared to inside the cell. Consequently, a cell placed in such a solution looses water (Biologymad 1). Eventually, the cell shrinks and crenated due to water leaving to the outside environment (Biologymad 1). . Isotonic solution The solution is described as being stable. Both inside the cell and outside have the same level of concentration of solutes (Biologymad 1). As a result, a cell placed in such a solution has equal movement of water (Biologymad 1). Therefore, the cell maintains its original shape and size (Biologymad 1). Part 2 Neural Conduction 1. 2. 3. Using the diagrams above as a reference describe in detail the process of signal conduction from a neuron to its target organ. Draw a diagram and include all structures, ions, chemicals and their movements The nervous system plays a significant role in control and management of the body through its neuron. The process is achieved in nerves where impulses are generated and moved across the axon. The process is achieved through maintaining different charge in and out of the membrane in a neuron. The difference that is created in a normal membrane is known as membrane potential (RSC 1). On the other hand, the membrane potential keeps on changing in a neuron (RSC 1). This is achieved through continuous entry and exit of ions across the membrane (RSC 1). In a normal circumstance, the membrane of a neuron has a negative charge in its environment as compared to its outer part. At this state, the membrane is said to be in resting potential (RSC 1). The resting potential is achieved through variation of different ions. Some of the major ions in the process include potassium, sodium, and calcium. Inside the membrane, the concentration of potassium ion is high as compared to concentration of sodium and calcium ions in the outside (RSC 1). In this state, the movement of potassium ion in the axon is at ease as compared to other ions. Therefore, there is free flow of the potassium ions to the outside and the inner part of cell become negative due to little presence of positive ions. Ultimately, a balance is achieved between K+ ions entering and leaving the cell. The process leads to generation of resting potential (RSC 1). On the other hand, the properties change once the neuron becomes agitated. As a result, the membrane potential is altered, and the cell is said to be depolarized (RSC 1). At the site of stimulation, the permeability changes favoring entry of sodium ions inside the axon. As a result, the inner part becomes more positive ultimately leading to action potential. The state remains until the permeability of the Na+ reduces due to excess sodium ions (RSC 1). However, the permeability of potassium ions increases and the flow continues until resting potential is achieved (RSC 1). The concentration of ions is restored at its initial state and hence the membrane is repolarized (RSC 1). The process is repeated until the impulse reaches the synapse. The transfer of impulse in the site is repeated as in the axon (RSC 1). The ions facilitating the process are Ca++ and Na+. Moreover, the process is also facilitated by acetylcholine. The nerve impulse depolarizes the membrane on reaching the pre-synaptic membrane. As a result, there is change in electric potential at the site of interaction(RSC 1). On the other hand, the permeability changes in favor of calcium ions. The effect is the fusion of synaptic vesicle with the inner part of the membrane triggering the release of acetylcholine in the gap . In addition, the acetylcholine moves across the synaptic cleft via diffusion and joins with the receptor molecules on the postsynaptic membrane (RSC 1). The attachment of the molecule leads to depolarization of the membrane (RSC 1). As a result, permeability changes in favor of Na+. Consequently, a new action potential is generated. Works Cited Biologymad. “The Cell Membrane.” Biologymad.com. Web 20 February 2013. < http://www.biologymad.com/cells/cellmembrane.htm>. Diwan, Joyce. “Membrane Transport.” Rpi.edu. Web 20 February 2013. . Naveen. “Difference Between Intracellular and Extracellular Fluids.” Differencebetween.com. Web 20 February 2013. < http://www.differencebetween.com/difference-between-intracellular-and-vs-extracellular-fluids/>. NCBI. “Molecular Biology of the Cell.” Nih.gov. Web 20 February 2013. . RSC. “Nerves and hormones.” Rsc.org. Web 20 February 2013. < http://www.rsc.org/Education/Teachers/Resources/cfb/nerves.htm>. Weizmann Institute of Science. “The Sodium-potassium Pump.” weizmann.ac.il. Web 20 February 2013. < http://www.weizmann.ac.il/Biological_Chemistry/scientist/Karlish/steve_karlish.pdf>. Read More