Science Homework Help

After you have posted your initial post, read and respond to at least three classmates. Your response should state what you liked about your classmate’s post, validate the post by sharing a personal experience or relevant course information, continue your classmate’s post by expanding the information presented, explain how the post helped you understand relevant topics, or even ask questions that can be answered by the original poster or another student. Note: You will not see your classmates’ posts until you post to the discussion.

Your response postings must be a minimum of 250 words. 

Post 1:

The Nucleus is the largest organelle in the cell that contains genetic material and contains all of the information required to reconstruct the organism. Excluding red blood cells, the Nucleus is present in every cell of the human body. The Nucleus is composed of the Nuclear envelope, Nuclear lamina, Chromosomes, Nucleolus, and Nucleoplasm. (See structure below). The nuclear envelope surrounds the nucleus, separating it from the cell’s cytoplasm (double membrane). The nuclear envelope separates the nucleoplasm from the cytoplasm. The nuclear envelope is broken down into two membranes: the outer and inner membranes. The outer and inner nuclear membranes remain separated by a space known as peri nuclear space, outer nuclear membrane often remains rough due to the presence of ribosomes on its surface. The inner nuclear membrane contains no ribosomes and sometimes it also remains associated with the chromatin. 

These components work together to accomplish all of it’s functions. One of the major functions to the Nucleus is storing and replicating deoxyribonucleic acid, commonly known as DNA. The Nucleus also produces ribosomes, regulates the transcription of the mRNA to protein, stores DNA, RNA, and ribosomes, controls cell growth and cell division, and controls the protein and enzyme synthesis. 

Recent studies have shown that the mutations in the nuclear envelope proteins, such as lamins or emerin, were the identifiable cause of some human diseases. One of these diseases is Emery-Dreifuss Muscular Dystrophy (EDMD). EDMD is a condition that primarily affects muscles used for movement (skeletal muscles) and the heart (cardiac muscle). Over time, the disease restricts the joints and weakens muscles, while most affected individuals develop heart problems by adulthood. Mutations in several genes, including EMD, FHL1, and LMNA, can cause Emery-Dreifuss muscular dystrophy. Another disease stemming from genetic mutation of the nucleus is Hutchinson-Gilford Progeria Syndrome (HGPS). Hutchinson-Gilford progeria syndrome is a genetic condition characterized by the dramatic, rapid appearance of aging beginning in childhood. Mutations in the LMNA gene cause Hutchinson-Gilford progeria syndrome. Mutations that cause Hutchinson-Gilford progeria syndrome result in the production of an abnormal version of the lamin A protein. The altered protein makes the nuclear envelope unstable and progressively damages the nucleus, making cells more likely to die prematurely. Lastly is a disease called Familial Partial Lipodystrophy (FPLD). FPLD is a rare condition characterized by an abnormal distribution of fatty (adipose) tissue. Familial partial lipodystrophy can be caused by mutations in several genes. Type 2 results from mutations in the LMNA gene. The other, less common forms of the disorder are caused by mutations in different genes. In some people with familial partial lipodystrophy, no gene mutations have been found. Researchers are looking for additional genetic changes that can cause this disorder.

References

“Familial Partial Lipodystrophy: Medlineplus Genetics.” MedlinePlus, U.S. National Library of Medicine, 18 Aug. 2020, https://medlineplus.gov/genetics/condition/familial-partial-lipodystrophy/.

“Hutchinson-Gilford Progeria Syndrome: Medlineplus Genetics.” MedlinePlus, U.S. National Library of Medicine, 18 Aug. 2020, https://medlineplus.gov/genetics/condition/hutchinson-gilford-progeria-syndrome/#causes.

Marieb, Elaine Nicpon, and Katja Hoehn. Human Anatomy & Physiology. Pearson Education Limited, 2019. 

Shaziya Allarakha, MD. “What Are the 3 Functions of the Nucleus?” MedicineNet, MedicineNet, 12 Feb. 2021, https://www.medicinenet.com/what_are_the_3_functions_of_the_nucleus/article.htm.

Zwerger, Monika, et al. “Nuclear Mechanics in Disease.” Annual Review of Biomedical Engineering, U.S. National Library of Medicine, 15 Aug. 2011, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC46004… @

Post 2:

The center of each cell contains a nucleus, which makes up about 10 percent of the cell’s volume.  The nucleus is a large and oval-shaped structure attached by a double membrane called the nuclear envelope (Hoehn, 2019). The nuclear envelope has two layers that stay divided from each other by a space known as the perinuclear space.  The nuclear envelope also divides the inner contents of the nucleus from the rest of the cell. Located on the inside of the nucleus are nucleoli, which compile RNA and synthesize ribosomal subunits (Hoehn, 2019).  It also contains the genetic material of the cell, DNA, which form chromatin.  Throughout the inside of the nucleus, is a substance called the nucleoplasm. The nucleoplasm contains many proteins, which help maintain the shape and structure of the nucleus. This halts the nucleus’ structure. 

The nucleus regulates the activity of the cell to provide life and reproduce.  It is also responsible for regulating the synthesis of protein by sending mRNA to ribosomes of the cell as a template for protein production.  The nucleus holds encoded instructions for the synthesis of proteins in a helical molecule called DNA. By containing the genetic information of the cell in the form of DNA, the nucleus controls cell growth and multiplication.  This is also where DNA does the replication process.

If the nucleus was removed from a cell, then the cell would die after time.  The proteins and the mRNAs that are existing in the cytoplasm would be sufficient to keep the cell alive for quite some time (Chakraborty, 2017).  Without the nucleus there would be no way that replication could occur within the cell.  There would be no way for the cell to divide and eventually the cell would die (Chakraborty, 2017).  Without the nucleus there would be no way to for new mRNA leading to the reduction in protein synthesis in the cytoplasm, and just like not be able to divide the cell would soon die.

When organelles malfunctions this can lead to many problems or diseases within the human body.  When the nucleus malfunctions this can lead to a change from genes normal position will cause them to malfunction leading to heart failure, vascular disease and muscle wasting (Organizations, 2013).  With the lack of two proteins known as Lamin A and B, the heterochromatin will fall into the nuclear center.  This disturbs gene expression and alters skeletal muscle development, resulting in muscle failure.  A genetic variation can change the way a particular organ performs.   

References

Chakraborty, A. (2017, 07 30). What will happen to cell if the nucleus is removed? Retrieved from Quora: https://www.quora.com/What-will-happen-to-the-cell…

Hoehn, E. N. (2019). Human Anatomy & Physiology. Pearson.

Organizations, R. (2013, 02 08). Science News. Retrieved from Science Daily: https://www.sciencedaily.com/releases/2013/02/1302… 

Post 3:

The Organelle that I picked Is the plasma Membrane. The Plasma membrane is made up of a Bilayer of Phospholipids, one side being hydrophobic: making the fatty acid tails face inward toward each other.  Throughout the lipid bilayer, there are cholesterol molecules. The primary element of the plasma membranes is lipids, proteins, and carbohydrates groups that are attached to some of the lipids and proteins.   Attached to the proteins and lipids on the outward-facing surfaces of the membranes there are carbohydrates. The attachment of carbohydrates adds complexity to the cell and also helps other cells identify the cell’s function. The main function of the plasma membrane is to protect the cell from its surroundings. The plasma membrane is complex in the fact that it is selectively permeable to ions and natural molecules and controls the movement of materials in and out of the cells in addition to being selectively permeable but the cell membrane also regulates how much of a substance comes into the cell. The cell membrane keeps Toxic substances out of the cell it contains receptors that channel allow specific molecules, ions, nutrients, wastes, and metabolic products.  The Cell membrane help with molecule transport moving substance across the membrane. The Plasma membrane creates complex proteins to help in the transmission of signals. The proteins created can be receptors, which act as receivers of extracellular input and as activators of intracellular processes, or marks that also help with the identification of cells. The Plasma membrane mediates the cellular and extracellular activities to pass between organelles. If the cell membrane is not functioning properly there is a release of cellular components including cells organelles and cytoplasm in the external environment leading to the death or the destruction of cells.  If there is cell death or damage this disrupts the start of cell electrolytes, which can cause apoptosis and Ribosome damage. Without the Cell membrane, the layer of protection cells has been removed or limited causing the organelles within to get easily damaged due to toxins, bacterial toxins, and parasites.  If a cell does not have a membrane a cell will die because there is no protection from the external environment. The Cell membrane is the most essential portion for the protection it is the first line of defense and it is what allows for cells to receive the necessary tools to function and carry out the essential processes. Some of the disease that can be acquired with out a cell membrane are receptor type disease such as  type II familial hypercholesterolemia,  and Graves disease. But all organelles are very fascinating.