Protein Structure

Words: 1018
Pages: 5
Open Document
Proteins are reasonably large macromolecules comprised of one or more long amino acid chains. They are in every living organism and play a vital role in almost every biological process. They are involved in responding to stimuli, DNA replication, the transportation of molecules to another location, and they act as catalysts for metabolic reactions. In relation to protein structure it is much more complex than when we talk about the structure of smaller molecules because proteins have four different levels to their structure, these are primary, secondary, tertiary, and quaternary. There are twenty separate standard amino acids that cells use to construct protein. As their name suggests, amino acids contain an acidic carboxyl group and a basic …show more content…
Chains that have less than 50 amino acids in them are commonly known as peptides, while chains with more than 50 amino acids are referred to as polypeptides or proteins. A protein can comprised of one or several polypeptide molecules. The end of the sequence that has the free carboxyl group is known as the C-terminus and the end of the sequence with the free amino group is known as the N-terminus. The amino acids are all different based on their side chains which can give different structural, physical, and chemical properties to the protein. The amino acids all have one and three letter abbreviations given to them which are commonly used in science to simplify things. The amino acids can all be classed as either neutral, acidic, or basic depending on their side chain properties. Of all the twenty amino acids that are required to construct the proteins found in humans we are only able to synthesise ten of them in our bodies, the other ten are called essential amino acids meaning we must obtain these through our dietary intake. The sequence of amino acids determines the primary structure of the protein but the chemical and biological characteristics of the protein are highly dependent on the tertiary or three-dimensional …show more content…
There are two primary steps for the synthesis of proteins, these are transcription and translation. Protein synthesis starts off with transcription, the DNA code is transferred to messenger RNA in the nucleus of the cell. RNA polymerase creates a messenger RNA strand using the DNA as a template, this new messenger RNA moves through the nucleus to the cytoplasm. Messenger RNA associates with the ribosome subunits, and an enzyme in the cytoplasm activates its transfer RNA by attaching a specific amino acid to each transfer RNA. The first transfer RNA attaches to the P site of the ribosome and begins a sequence of building a protein using amino acids. The transfer RNA (or tRNA) carries an anticodon which is complementary to the codon on the messenger RNA (or mRNA) strand. For example, if the codon on the mRNA is AUG then the tRNA will have an anticodon UAC. Then the ribosome moves down the tRNA-mRNA complex. The first tRNA anticodon is now at the A site on the ribosome. A new tRNA complementary to the next anticodon in the sequence moves into the P site carrying the next amino acid, an enzyme in the ribosome catalyses the formation of a bond between the two amino acids now in the ribosome. Then the ribosome moves down the tRNA-mRNA complex again, the tRNA that was in the A site is now in the E site, and the tRNA that was in the P site is now in the A site. The
Show More

Related Documents: Protein Structure

Essay about How Does The Structure Of A Protein Dictate Its Function

How does the structure of a protein dictate its function? The primary structure of any protein is determined by the number and sequence of amino acids. Each sequence of amino acids is specific for each protein. The secondary structure of a protein is based on hydrogen bonding. The C=O and -NH group on neighbouring amino acids will form many hydrogen bonds due to an unequal distribution of electrons in the bonds. The bonds causes polypeptide chains to twist into a three dimensional shape such as…

Words 1181 - Pages 5

Censoring Huck Finn Essay

Cell membranes are very important structures to cells because they function as a barrier between the components of the cell and the outside environment. The cell membrane is not only responsible for creating a wall between inside and outside the cell, it must also act as a threshold through which select molecules can enter and exit the cell when necessary. The cell membrane is what defines the cell and keeps its components separate from outside cells or organisms. The cell membrane is composed of…

Words 1000 - Pages 4

Amino Acids Essay

Protein Structure “Proteins are polymers of amino acid covalently linked through peptide bonds into a chain. Within and outside cells, proteins serve a myriad of functions, including structural roles (cytoskeleton), as catalysts (enzymes), transporter to ferry ions and molecules across membranes, and hormones.” (http://www.vivo.colostate.edu/hbooks/genetics/biotech/basics/prostruct.html) Proteins are polymers of amino acids joined together by peptide bonds. There are 20 different…

Words 505 - Pages 3

bio nucleus ribosome Essay

single rounded structure and it contains the genetic material. It is surrounded by a membrane that protects it from the rest of the cell. It floats within the cytoplasm. The nucleus is the control center of the cell. It controls the activities of the cell by regulating the expression of the genes. You could also say it is like the "brain" of the cell. Ribosomes are made inside the nucleolus and then sent outside the nucleus to make proteins. When a cell needs to make proteins, it looks for…

Words 4629 - Pages 19

Protein and Polypeptide Chains Essay

epithelial cells is sticky because it has less water than normal, this is because of less salt & water transport caused by a faulty protein channel. PROTEIN STRUCTURE: Antibodies, enzymes and many hormones are all protein molecules. Proteins also have functions within a membrane. Proteins are composed of amino acids, there are 20 different amino acids that occur in proteins. All amino acids contain an amine group -NH, a carboxylic acid group -COOH, and a hydrogen -H attached to central carbon atom…

Words 580 - Pages 3

Essay on template 2 A

Protein Structure Alicia Stone 000262467 5/6/2015 A. Insert your original model of an essential amino acid that shows all atoms and bonds in both the backbone and the side chain. Click here to learn how to insert images into a Google Document. (Insert in-text citation here). 1 Characteristics of Leucine: Hydrophobic Oxygenation Insert your description of two characteristics (e.g., reactivity, hydrophobicity, how it affects the structure or functions…

Words 1141 - Pages 5

Bio Exam 1 Study Guide Essay

are shipped along protein fibers 4. elements of the cell’s internal skeleton grow and shrink. * Electron micrograph(higher resolution than Light microscope) * fact that it was easily stained with early dyes, giving a colorful appearance (chromo = color; Soma = body; colorful body) * Flagellum move 60 cell lengths per min * Cell mitochondria received their name because they looked like threads in early microscopes * Ribosome (made up of rna and proteins) are in cytosol and…

Words 777 - Pages 4

Essay on Biology Chapter 5

CHAPTER 5: MORE DETAILED All living things contain four main classes of large molecules know as carbohydrates, lipids, proteins, and nucleic acids. Polymer: a long molecule consisting of many similar and identical building blocks linked by covalent bonds. Monomers: building blocks that form polymers. In other to synthesis and break down these polymers two processes are required: Condensation/dehydration reaction: involves a removal of a water molecule to form a bond between two or more monomers…

Words 1305 - Pages 6

A&P 1 Study Guide Essay

Objective 1 Anatomy Describes the structures of the body, and physiology is the study of how those structures function. Gross Anatomy-(Macroscopic anatomy) examines large, visible structures. Microscopic anatomy-examines cells and molecules 1. Chemical Level-Examines atoms and how they combine to form the molecules of the human body (water, sugar, protein, DNA). Atoms are the smallest chemical units. 2. Cellular Level-Examines cells (the most basic structural and functional unit of…

Words 2080 - Pages 9

Essay about CH.8 Sanstokes

Chapter 6 – Protein: Amino Acids Describe how the chemical structure of proteins differs from the structures of carbohydrates and fats? -The nitrogen atoms give the name amino (nitrogen containing) to the structures of carbohydrates and fats. Explain the process used by the body to synthesize new proteins. -More than half of the amino acids are nonessential, meaning the body can synthesize them for itself. Proteins in foods usually deliver these amino acids, but it is not essential that they…

Words 685 - Pages 3