This website uses cookies to ensure you have the best experience. Learn more

Biology The Movement Of Molecules

415 words - 2 pages

Every cell is surrounded by a plasma membrane. The cell membrane is selectively permeable- only certain substances can cross it freely. The structure of the membrane allows materials to move across it by 2 main means: active and passive transport. Password transport involves two processes: Diffusion and Osmosis. Passive transport allows some substances such gases and water to move into and out of the cell without using energy. Active transport includes processes such as "ion pumps", "exocytosis" and "phagocytosis". Molecules such as sucrose's are moved against their concentration gradient ...view middle of the document...

Cells use diffusion to take in things from their environment and rid themselves of waste. Diffusion takes place down a concentration gradient. Water, carbon dioxide and other small ions can diffuse freely through cell membranes. Concentration gradients occur in all organisms. Where they do, simple diffusion will transport things around. Nutrients being carried in blood for example will diffuse into those cells that need them. Diffusion is also vital for getting oxygen into cells and carbon dioxide out of them, for example, in humans. Facilitated diffusion occurs when substances move down the concentration gradient by "carrier proteins" in the cell membrane.Osmosis is also a type of passive transport involving the diffusion of water molecules across a selectively permeable membrane. Water will move by diffusion from an area where there is more of it to an area where there is a less of it. This results in the movement of water from a dilute (less concentrated) solution to a stronger (more concentrated) solution. It is the way water enters and leaves a cell. Osmosis is a special case of the diffusion of water. Osmosis occurs when water diffuses across a semi permeable membrane. Semi-permeable membranes will let small molecules pass through it easily, but will hold back larger molecules like sucrose's. It acts as if it has tiny holes in it, too small for the larger molecules to squeeze through.

Other Essays On Biology - The Movement of Molecules

A Comparative Study Of Greek And Celtic Pagan Religions, The Variations Between Them And Their Demise Through The Christian Movement

3023 words - 13 pages small Messianic movement in Galilee occurring from approximately 20 AD onwards. In the 1st Century AD, there wasn't an organised attempt to convert the British pagan beliefs to that of Christianities monotheism. Rather, it began with Roman traders and artisans spreading stories of Jesus along with stories of their Pagan deities. Originally it was a cult much the same as others in the era, pagan and non pagan alike however it demanded strict

How Did The Nineteenth Amendment Come To Be Part Of Our Constitution And Why Was It Significant? A History Of The Female Right's Movement And The Importance Of The 19th Amendment

1560 words - 7 pages , a right that men have possessed since the beginning of our nation.The beginning of the women's rights movement can be traced all the way back to 1848, where the first women's rights convention was held in Seneca Falls, NY. Under the guidance of feminist Elizabeth Cady Stanton, they produced the Declaration of Sentiments, which protested the political, social, and economic inferiority of women. Four years later, the women's rights activists gained

Cell Biology Notes

1308 words - 6 pages ; Simple diffusion: movement of molecules from areas of high concentration to areas of low concentrations in a free state. Osmosis of water involves this kind of diffusion through a selectively permeable membrane (plasma membrane)The Breakdown of materials in a cell.Cells can sometimes breakdown complex molecules into simple molecules which can then be rebuilt into what is required by the body with these new raw materials.Such as:Pinocytosis is

DNA

1661 words - 7 pages table to the right, showing it's movement from thenucleus to the cytoplasm. The tRNA molecules were then matched up with an amino acid. Once matched up,they were slid along the mRNA until their nucleotides matched.Conclusions:The most surprising discovery made was finding out that there are only four main bases needed in a DNA andRNA molecule. Also, each of these bases will only bond with one other base. It is important to realize howDNA greatly

Biology Notes On Cell Metabolism

437 words - 2 pages *Metabolism:Term used to describe chemical reactions in a cell.*Reactants:Chemicals that react with each other.*Products:Chemicals produced at the end of a chemical reaction.*Anabolic reaction:Reactions that involve the building up of complex molecules from simpler molecules. Enery is required. e.g photosynthesis*Catabolic reaction: Reactions where complex molecules are broken down into simpler molecules. These reactions realease energy.e.g

Bio Lab Report

660 words - 3 pages Lab Report: Diffusion and OsmosisIntroduction:Atoms and molecules are constantly in motion. This kinetic energy causes the molecules to bump into each other and move in different directions. This motion is diffusion. Diffusion is the random movement of molecules from an area of higher concentration to an area of lower concentration. This will occur until the two areas reach a dynamic equilibrium.Osmosis is a special kind of diffusion in which

Dialysis Tube Lab

710 words - 3 pages Osmosis & Diffusion Lab - Dialysis TubingBackgroundThe movement of molecules through a cell membrane is termed osmosis or diffusion. Such movement is principally possible because nutritive molecules are smaller than membrane micropores. If the molecules are too large, no molecular transfer, or diffusion occur.Thus, some membranes may transmit selectively and are termed semi-permeable membranes. In the following experiment, cellophane

DNA STRUCTURE AND REPLICATION

351 words - 2 pages DNA is usually a double-helix and has two strands running in opposite directions. Each chain is made of subunits called nucleotides.Each strand has a backbone made up of deoxy-ribose sugar molecules (5 sugars) linked together by phosphate groups.Each sugar molecule is covalently linked to one of four possible bases, Adenine, Guanine, Cytosine and Thymine. A and G are larger molecules (called purines) and C and T are smaller molecules (called

The Lifestory Of A Cadherin

1234 words - 5 pages extracellular matrix through integrins that link intracellularly to actin filaments. In this way, muscle cells,for example, attach to their tendons at the myotendinous junction. Likewise,when cultured fibroblasts migrate on an artificial substratum coated withextracellular matrix molecules, they also grip the substratum at focaladhesions, where bundles of actin filaments terminate. At all such adhesions,the extracellular domains of transmembrane

What is the Feminist Divide?

283 words - 2 pages feminine power through their biology. They think women should embrace their differences from men and find strength in our anatomical differences. The ability to give birth is a power men lack and women should celebrate. Some of cultural feminist ideas were so extreme they often alienated women who considered themselves to be cultural feminist. One example is the Separatist Movement during the 60s. Some cultural feminist also thought that by

Structure and properties of Biological membranes

453 words - 2 pages ½Give an account of the structure and properties of Biological membranes. Include details of the modifications of membrane structure found in different specialised cells and organelles½The Fluid Mosaic model was codified by Singer and Nicolson in 1972. It describes the structure and properties of the cell membrane very simply. Every membrane consists of a Phospholipid bilayer. This is simply two layers of phospholipid molecules

Similar Papers

Study Notes On The Structure And Function Of Various Groups Of Molecules Including Proteins, Carbohydrates, And Lipids (Fats)

751 words - 4 pages between nonpolar side chains-Determined by disulfide bonds between sulfur atoms on the amino acids with sulfhydryl groups on their side chains-Determined by weak van der Waals interactions-Quaternary Structure is the overall protein structure that results from the aggregation of two or more polypeptide chains into one macromolecule-Some molecules important to organism's that are proteins are: keratin, collagen, silk, hemoglobin, and enzymes-Structural

Women Of The Nazi Movement Essay

2535 words - 11 pages Women of the Nazi Movement There were many groups of people affected by the Nazi movement, but women were in fact a very important group that is often left out. Women played a momentous role in the Nazi movement. Unlike other groups, they acknowledged their role in the movement and realized that Nazi Germany was a male leading public division in terms of establishing policies and making decisions or taking leadership, because for the most part

Bob Dylan And The Protest Movement Of The 1960's

2442 words - 10 pages this. The first baby boomers were now teenagers and they seemed alienated from the conservative world of their parents. The Civil Rights movement was well underway and the Cold War seemed to be without end. A far away place called Vietnam was starting to impose itself on the consciousness of a nation and a generation. A thread of popular music evolved that was dramatically different from the contemporary music scene of three chord guitar songs

This Essay Discusses The Fair Trade Coffee Movement And The Advantages Of Fair Trade Coffee Over Regular Coffee

1076 words - 5 pages The Fair Trade Certified coffee movement exists today to ensure that the small sizecoffee producers, who make up the majority of the world's coffee production, receive afair price for their coffee. Mass producers of coffee are able to grow their products at acheaper expense, often with lower quality, and as a result, they can sell their coffee for acheaper price. The problem with this is that the smaller producers must lower theircoffee prices