The Structure of Eukaryotic Cells and Importance of Membranes (Term Paper Sample)

The structure of Eukaryotic Cells and Importance of Membranes.
Institution
Date
Introduction
The most basic unit of fully functional and replicable form of life is a cell. Cells are the most basic form of life. All living organism have numerous cells working together to sustain life. While most organisms are made of various cells, some organism are made of single cells. For instance, most species of bacteria and protozoa exists as a single cell even though they might be living as part multicellular organism. Unicellular organisms refer to an organisms with only one cell in their body while multicellular relates to an organism with many cells like fungi, animals, and plants.
The cells in a living organism can be categorized as either prokaryotic or eukaryotic. Prokaryotic cells are those cells without nucleus and membrane bound organelles. Eukaryotic cells on the other hand refer to cells with membrane-bound organelles. The scope of this assignment is to examine and describe the structure and functions of the organelles in a eukaryotic cell. It will distinguish between membranous and nonmembranous organelles and explain the significance of membrane structure and its function in the organization of living process within a cell.
The structure and functions of organelles
Eukaryotic cells are found in all plants, fungi, protists and animals. Some of the mentioned organism occur as a single cell while in other the cells work together in the body. Life in a eukaryotic cell starts at the nucleus and organelles. Eukaryotic cells are thus made or subunits known as organelles. An Organelle is therefore any membrane-limited structure found in the cytoplasm of eukaryotic cells. The organelles include nucleus, endoplasmic reticulum, Golgi body, vesicles, mitochondrion, chloroplast, lysosome, peroxisome, and vacuole. Other organelles without membrane are ribosomes and centriole. Other than the organelles, there is a system of interconnected protein filaments known as cytoskeleton which reinforce, organize and move cell structures. It is made up of the microtubule, microfilament, and intermediate filament which support and guide cell's lengthening mechanism in a particular direction (Starr, Evers, & Starr, 2010).
The nucleus
The nuclear of a cell serves the purpose of keeping the genetic composition of a cell away from the metabolic reaction which might damage it. The nuclear of a cell isolates and maintain the DNA away from the activities of the cytoplasm. Additionally, the nuclear controls the passage of molecules across its membrane. It is made up of the nuclear envelope, nucleoplasm, nucleus, chromatin and chromosome. The nuclear envelope also known as the nuclear membrane is made up of two lipid bilayers folded together to form one single layer. Thousand pores containing membrane protein are embedded on the lipid bilayers. The pores are a gateway for molecules to enter and exit the nuclear (Starr, Evers, & Starr, 2010).
Another structure of nucleus is the nucleolus which contains at least nucleoli. It is a protein dense area where subunit of ribosomes are produced and transferred into the cytoplasm through nuclear pores for active photosynthesis. The DNA is suspended in a viscous fluid known as nucleoplasm in the nuclear envelope. The DNA and proteins attached to it are known as chromosomes and together with associated proteins are called chromatin. Chromosomes carry the genetic information of a particular cell (Starr, & Starr, 2013). 
Mitochondria
The mitochondrion is an organelle that makes adenosine triphosphate chemical also known as ATP. ATP carries oxygen between reactions. Aerobic respiration occurs inside mitochondria which provide energy for cellular reactions. It is made up of two membranes highly folded to into outer and inner layers. During respiration, hydrogen ions build up in the outer compartment forcing ions across the inner membrane thus creating ATP.
Lysosome
The organelle lysosome acts as the waste disposal vessels of the cells. Lysosomes contain enzymes that break down molecules to either be eliminated or reused. When it malfunctions molecules builds up, and the cells deform leading to diseases like ganglioside among infants.
Chloroplasts
Also known as photosynthetic plastids (Starr, Evers, & Starr, 2010). The chloroplast is made up of stroma which contains enzymes and chloroplast’s DNA. Photosynthesis takes place in a highly folded membrane found in the stroma. The innermost membrane of chloroplast contains color green pigments known as chlorophyll. Pigments capture energy from the sun during photosynthesis, which is passed to other molecules for the formation of ATP. ATP is then used to build carbon dioxide and water inside stroma.
Endoplasmic reticulum
It makes the membrane surface in a eukaryotic cell. Manufacturing of lipids and most proteins takes place in the endoplasmic reticulum. There are two types one that specializes in the production of protein is known as the rough endoplasmic reticulum, and the soft endoplasmic reticulum specializes in the production of lipids (Starr, & Starr, 2013). 
Golgi apparatus
They are groups of flattened membrane-bound compartments that are attached next to the rough endoplasmic reticulum. Its primary purpose is to package protein into vesicles inside the cells before being released into the membrane (Starr, & Starr, 2013).  It is situated at the intersection of lysosomes and endocytic pathways. It contains glycosylation enzymes which assign sugar to proteins as the pass through the apparatus.
Vesicles
Organelle in the eukaryotic cells made up of the lipid bilayer. They act as the transport system for proteins and other cellular components. It occurs in two parts, lysosomes which are used to break down molecules and transport vesicles which move a particle from one point to another within the cells.
Vacuole and peroxisome
Vacuoles are storage sacks found in the cells. They store nutrients required by cells for survival. Other than food vacuoles also store waste materials excreted by cells. In plant cells, vacuoles play a fundamental role in controlling turgor pressure which dictates the rigidity of the cell. Peroxisome, on the other hand, is an organelle within the cytoplasm and has no DNA, it carries enzymes by which are used by other organelles to function (Starr, & Starr, 2013). 
Ribosome and centriole are organelles within the cell but those that do not have a membrane. Ribosomes' primary functions are to assemble polypeptide chains while centriole act as the anchor to the cytoskeleton.
Membranous and non-membranous organelles
A membranous organelle is surrounded by either a unit of the membrane or a double membrane while nonmembranous organelle is not surrounded by any membrane (Stubbs, & Suleyman, 2015). Nonmembranous organelles include ribosomes which occur freely in the cytoplasm and is attached to endoplasmic reticulum and mitochondria, chloroplast among others. Ribosomes assemble polypeptide chains which are used in the synthesis of protein.
Another non-membranous organelle is the cytoskeletal structure which is found in the cytoplasm, and its primary task is to anchor the organelles in the cytoplasm. Other than the two, centriole is also another nonmembranous organelle, cilia and flagella are also nonmembranous organelles. Membrane-bound ...