Properties of Gas exchange surfaces Alveolus – Air sac in the lungs • Hundreds of thousands in lungs • Increase lungs SA SA:V ratio = Surface area Volume Diffusion 0.5 cm cube – 2mm cubed of non dyed agar 1cm cube – 5mm cubed of non dyed agar 2cm cube – 18mm cubed of non dyed agar DIFFUSION IS QUICKER WITH SMALLER SA’s Alveoli are so small. • Diffusion is fast - blood capillary nearby • Thin walls (alveoli and capillary) (one cell thick) • Numerous Alveoli – Increases SA of Lungs (Each alveolus is small for quick diffusion) • Lots of blood capillaries next to alveoli • LUNGS = EFFICIENT GAS EXCHANGE SA = rate of diffusion Difference in concentration gradient = Rate of diffusion Thickness of gas exchange surface = Rate of diffusion RATE OF DIFFUSION = SA * DIFFERENCE IN CONCENTRATION GRADIENT Thickness of gas exchange surface Protein Structure Proteins are made up of amino acids • Primary Structure • Secondary Structure • Tertiary Structure • Quaternary Structure Primary Structure – Chain of Amino Acids COOH – Carboxylic acid group NH2 – Amine Group Condensation – Loss of H20 (joining of acids) Hydrolysis – Gain of H20 (splitting of acid chain) Peptide bond formed in condensation reaction (p for protein) Each time an Amino Acid joins the chain there is a condensation reaction. 2 Amino Acids = Dipeptide bond More than 2 Amino Acids (long chain) = Polypeptide – (Primary Structure - Chain of Amino Acids) Secondary Structure Alpha Helix or Beta pleated sheet (Sheet or spring) Structures are held together with an H Bond H Bonds form between the C=0 of the Carboxylic acid group and the N-H of the amine group Alpha Helix – H bond happens between eve... ... middle of paper ... ...model • Another experiment involved the fusing of mouse and human cells • The proteins mixed proving the FMM right, because the proteins could not have mixed if there was no fluid in the membrane The more unsaturated phospholipids the more fluid The more unsaturated phospholipids containing unsaturated fatty acids in the membrane the more fluid it is. The “kinks” in the Hydro C tails of the unsaturated phospholipids prevent them from packing closer together, making more movement possible. Cholesterol reduces the fluidity, by preventing phospholipid movement Different types of protein are found within the membrane, each having specific functions. Some are enzymes others as carriers and channel proteins involved in transport of substances in and out of cells. Glycoprotein’s and glycolipids have important roles in cell to cell recognition and as receptors.
The primary structure is the sequence of amino acids that make up a polypeptide chain. 20 different amino acids are found in proteins. The exact order of the amino acids in a specific protein is the primary sequence for that protein. [IMAGE] [IMAGE]Protein secondary structure refers to regular, repeated patterns of folding of the protein backbone. The two most common folding patterns are the alpha helix and the beta sheet.
An enzyme is often known as biological catalysts. It acts a substance which speeds up the rate of a chemical reaction but remains unchanged through the process. It works by lowering the activation energy (the amount of energy required to initiate a chemical change) required for a reaction. Enzymes are proteins that are vital to the body because they act as effective catalysts and play an important role within body cells. Enzymes are proteins that are folded into a complex three-dimensional shape that contains an active site where the specific substrate binds structurally and chemically. There are four main protein structures: primary, secondary, tertiary, and quaternary. A primary structure consists of a linear strand of amino acids in a polypeptide chain. They are bonded to one another through covalent peptide bonds. Secondary structures are in coils and folds due to the hydrogen bonds present between hydrogen and oxygen atoms near the peptide bonds. Tertiary structures take a three-dimensional form due to the interaction between amino acids functional groups and disulfide bonds. ...
This occurs when special carrier proteins carry solutes dissolved in the water across the membrane by using active transport. When the concentration gradient can not allow travel from one side of the membrane to the other fast enough for the cell’s nutritional needs, then facilitated diffusion is used. The transport protein is specialized for the solute it is carrying, just as enzymes are specialized for their substrate. The transport protein can be
The researcher learned that the Rosetta stone is one of the most important artifacts of the Egyptians. It was written in three ancient scripts and is located at the British museum in London.
On a cellular level, Mrs. Jones’ cells are dehydrated due to osmotic pressure changes related to her high blood glucose. Cells dehydrate when poor cellular diffusion of glucose causes increased concentrations of glucose outside of the cell and lesser concentrations inside of the cell. Diffusion refers to the movement of particles from one gradient to another. In simple diffusion there is a stabilization of unequal of particles on either side of a permeable membrane through which the particles move freely to equalize the particles on both sides. The more complex facilitated diffusion is a passive transport of large particles from a high concentration of particles to a lower concentration of particles with the aid of a transport protein (Porth, 2011). The cellular membranes in our bodies are semipermeable allowing for smaller molecules to flow freely from the intracellular to extracellular space. The glucose molecule, however; is too large to diffuse through the cellul...
“The plasma membrane is the edge of life, the boundary that separates the living cell from its nonliving surroundings. The plasma membrane is a remarkable film, so thin that you would have to stack 8,000 of these membranes to equal the thickness of the page you are reading. Yet the plasma membrane can regulate the traffic of chemicals into and out of the cell. The key to how a membrane works is its structure” (Simon, 02/2012, p. 60).
The cell plasma membrane, a bilayer structure composed mainly of phospholipids, is characterized by its fluidity. Membrane fluidity, as well as being affected by lipid and protein composition and temperature (Purdy et al. 2005), is regulated by its cholesterol concentration (Harby 2001, McLaurin 2002). Cholesterol is a special type of lipid, known as a steroid, formed by a polar OH headgroup and a single hydrocarbon tail (Wikipedia 2005, Diwan 2005). Like its fellow membrane lipids, cholesterol arranges itself in the same direction; its polar head is lined up with the polar headgroups of the phospholipid molecules (Spurger 2002). The stiffening and decreasing permeability of the bilayer that results from including cholesterol occurs due to its placement; the short, rigid molecules fit neatly into the gaps between phospholipids left due to the bends in their hydrocarbon tails (Alberts et al. 2004). Increased fluidity of the bilayer is a result of these bends or kinks affecting how closely the phospholipids can pack together (Alberts et al. 2004). Consequently, adding cholesterol molecules into the gaps between them disrupts the close packing of the phospholipids, resulting in the decreased membrane fluidity (Yehuda et al. 2002).
The Rosetta Stone was found in a small delta village called Rashid which is known to Europeans as Rosetta. The stone is a black slab that is now called granodiorite. The stone is over a meter high, 28cm thick and weighs over three-quarters of a ton. On the face of the stone there are three scripts engraved onto it: Greek, demotic and hieroglyphs. Interestingly enough, upon translation the three scripts are found to say the same thing but with slight variations. Napoleon’s army originally found the stone but surrendered it to the British once being defeated at the Battle of the Nile by Admiral Nelson in 1801. The stone being taken during war does not give the British the right to keep it. The stone should be returned to Egypt due to simple ethical reasoning. If Britain were to hand the stone over to Egypt, this would not be the first time war spoils have been returned to their rightful owner. Agreements have been made
One could very well conclude that the Egyptians of the northern kingdom were critical thinkers in order to discover this intricate technique that forever left a lasting impact on mankind and his ability to pass on knowledge for future generations. We would later discover just how much the papyrus plant was important to later Egyptian creations during the unification, such as the creation of the Mdw-Ntr (Hieroglyphic) writing system—imagine having a writing system with nothing practical in everyday life to write on. Although stones were carved into, the papyrus plant would have made it easier for scribes to pass on more information at a time.
plasma membranes, meaning animals and plants contain lipids. In this paper I will display and
Iversen, Erik. The Myth of Egypt and Its Hierolyphs In European Tradition. Princeton, New Jersey: Princeton Univeristy Press, 1993.
Arguably one of the most important discoveries made regarding the historical and cultural study of ancient Egypt is the translation of the writing form known as hieroglyphics. This language, lost for thousands of years, formed a tantalizing challenge to a young Jean François who committed his life to its translation. Scholars such as Sylvestre de Sacy had attempted to translate the Rosetta Stone before Champollion, but after painstaking and unfruitful work, they abandoned it (Giblin 32). Champollion’s breakthrough with hieroglyphics on the Rosetta Stone opened up new possibilities to study and understand ancient Egypt like never before, and modern Egyptology was born.
Protein is the basis for all life on Earth. Without it, nothing would survive. It is important for growth and development (Eltz & Zieve, 2013, p. 1). It can be defined as any of a class of nitrogenous organic compounds that consists of long amino acid chains that are essential to any living organism. Protein is mainly used to construct, maintain, and fix body tissues.
"Within a single subunit [polypeptide chain], contiguous portions of the polypeptide chain frequently fold into compact, local semi-independent units called domains." - Richardson, 1981
...ill form a string, and the tRNA molecules will be released into the cell. When this string of amino acids is completed, it is called a protein. Some proteins provide structure in living things (such as the protein in muscle tissue), while others can promote certain chemical reactions in cells (such as the breakdown of pectin in tomato cell walls).