Eukaryotic cells rely on the ubiquitination of proteins for the proper control of their internal processes. Adding multiple ubiquitin groups aids in the breakdown of proteins, whereas adding only one ubiquitin serves regulatory roles other than degradation. The enzymatic activity of two protease classes frees ubiquitin groups from associated proteins: Ubiquitin specific proteases (USP) and Ubiquitin C-terminal hydrolases (UCH). USPs are strongly involved in eukaryotic cellular functions and are found in copious amounts. Certain protein ligases attach ubiquitin to proteins, which degrades them and interferes with normal cellular functions.
The nuclear envelope is attached to a network of membrane-enclosed tubules that extends throughout the cell called the endoplasmic reticulum. The nuclear envelope is perforated by many holes, called nuclear pores, that permit the movement of selected molecules between the nucleus and the rest of the cell, while blocking the passage of other molecules. The nucleus contains the nucleolus, which manufactures the organelle known as the ribosome, or the protein producing organism. Genetic information in the form of deoxyribonucleic acid(DNA) is stored in threadlike, tangled structures called chromatin within the nucleus. During the process of cell division known as mitosis, in which the nucleus divides, the chromatin condense into several distinct structures called chromosomes.
Cells transport proteins to different parts of the body, they transport waste product, Provide energy in form of ATP, protects our body by making sure that blood is not exposed to germs. Cell are also composed of nucleus which contains the DNA used for reproduction and protein formation. The normal red blood cells are round in shape to increase the surface area for oxygen transportation whereas sickle cell anemia cells are sickle shaped and stiff. This makes the cells unable to carry oxygen because the surface area is reduced in size. Furthermore, when the cells becomes sickle they only last for a couple of days and die.
Cytoplasm helps move stuff around in the cell and also dissolves cellular waste. The rough endoplasmic reticulum makes membranes and fluid-like protiens. The smooth endoplasmic reticulum has many jobs such as carbohydrate and lipid synthesis. Next is the golgi complex, which is responsible for making, storing, and sending certain cellular products. Lysosomes have the job of breaking down cellular macromolecules.
Introduction In eukaryotes, the nascent mRNA needs to be processed and transported to the cytoplasm for translation to occur. The processing steps includes 5’ capping, 3’ polyadenylation and RNA splicing. RNA splicing is an essential posttranscriptional modification which increases protein diversity and regulates the development and growth of cells. The splicing events include the removal of introns from the precursor mRNA and occur at the spliceosome. Splicing factors (SFs) are proteins involved in the splicing event and can regulate alternative splice site by the binding to specific cis-acting sequence elements and promote or disrupt spliceosome assembly.
It has an interesting feature, the mitochondria has a double membrane where the internal membrane is folded up and this where the cell respiration takes place. Also mitochondria have own DNA and its own set of ribosomes. (Clamp, 2000, pg. 92) Another important organelle is a Golgi apparatus; it is a collection of membranes and vesicles. The Golgi body is an organelle with a number of functions, including the synthesis of glycoproteins; the secretion of enzymes and hormones; and the
Protein Synthesis DNA – is the molecule that carries the genetic information in all cellular forms of life and some viruses. It belongs to a class of molecules called nucleic acids, which are polynucleotides. Each nucleotide consists of three components. • A nitrogenous base: cytosine, guanine, adenine or thymine. • A deoxyribose sugar • A phosphate molecule The back bone of the polynucleotide is a chain of sugar and phosphate molecules.
On the other hand RNA (ribonucleic acid) contains nucleotides having sugar ribose and is usually single stranded. RNA contains the bases guanine, cytosine, adenine, and uracil. Some of the components of RNA that allows it to function are have the components of ribosomes (rRNA), transporting amino acids (tRNA), and translating the message of the DNA code (mRNA) (Freeman). The first step in converting or copying genetic information is by the process called transcription. Transcription occurs in the nucleus of the eukaryotic cell and begins when the sigma is binded to the promoter of the start of the gene (Freeman).
The polypeptide folds and bonds with other polypeptides, and functions as a complete structure of a protein. In conclusion, DNA contains “blueprints” which are used to create cells. It provides instructions to the cell. Depending on the cells environment the genes could be switched on or to off. Since it’s the cause of the production of enzymes.
Changing one amino acid in the polypeptide sequence can destroy this shape and make the protein function improperly if not at all. A very important function that proteins can serve are to act as catalysts. Enzymes are organic catalysts ma... ... middle of paper ... ... cells their shape and as well as parts of the linkages that stick cells together into tissues and organs. So, the sequence of amino acids in all proteins is genetically determined by the sequence of nucleotides in cellular DNA. So basically Proteins are basic constituents in all living organisms.