Transport Of Substances Across The Cell Membrane example essay topic

2) LEVEL 1 - Cells Are the basic unit of structure and function in living things. May serve a specific function within theorganismExamples- blood cells, nerve cells, bone cells, etc. tissue LEVEL 2 - Tissues Made up of cells that are similar in structure and function and which work together to perform a specificactivityExamples - blood, nervous, bone, etc. Humans have 4 basic tissues: connective, epithelial, muscle, and nerve. LEVEL 3 - Organs Made up of tissues that work together to perform a specific activity Examples - heart, brain, skin, etc. LEVEL 4 - Organ Systems Groups of two or more tissues that work together to perform a specific function for the organism. Examples - circulatory system, nervous system, skeletal system, etc.

LEVEL 5 - Organisms Entire living things that can carry out all basic life processes. Meaning they can take in materials, release energy from food, release wastes, grow, respond to the environment, and reproduce. Usually made up of organ systems, but an organism maybe made up of only one cell such as bacteria or protist. Examples - bacteria, amoeba, mushroom, sunflower, human 4) 1) Atom: The smallest unit of matter that retains the properties of an element. 2) Ion: An atom that has gained or lost electrons thus acquiring a charge. 3) Electro negativity: The attraction of an atom for the electrons of a covalent bond.

4) Hydrogen Bond: A type of weak chemical bond formed when the slightly positive hydrogen atom of a polar covalent bond in one molecule is attracted to the slightly negative atom a polar covalent bond in another molecule. 5) Hydrophilic: Having an affinity for water. 6) Cohesion: The binding together of like molecules, often by hydrogen bonds. 7) Capillary action: Physical effect caused by the interactions of a liquid with the walls of a thin tube. The capillary effect is a function of the ability of the liquid to wet a particular material. 8) Organic Compound: Contains carbon chemically bound to hydrogen.

Organic compounds often contain other elements (particularly O, N, halogens, or S). 9) Polar Covalent Compound: A type of covalent bond between atoms that differ in electro negativity. The shared electrons are pulled closer to the more electronegative atom, making it slightly negative and the other atom slightly positive. 10) Molecule: Two or more atoms held together by covalent bonds. 11) Isotope: One of several atomic forms of an element, each containing a different number of neutrons and thus differing in atomic mass. 12) Ionic bonding: A chemical bond resulting from the attraction between oppositely charged ions.

13) Nonpolar covalent bond: A type of covalent bond in which electrons are shared equally between two atoms of similar. 14) Hydrophobic: Having an aversion to water; tending to coalesce and form droplets in water. 15) Adhesion: The attraction between different kinds of molecules. 16) Monomer: The subunit that serves as the building block of a polymer. 17) Inorganic compound: Combination of two or more elements other than those used to form organic compounds. 18) Chemical bonding: An attraction between two atoms resulting from a sharing of outer-shell electrons or the presence of opposite charges on the atoms the bonded atoms gain complete outer electron shells.

19) Covalent bond: A type of strong chemical bond in which two atoms share on pair of valence electrons. 20) Solvent: The dissolving agent of a solution. Water is the most versatile solvent known. 21) Solute: A substance that is dissolved in a solution. 22) Heat Capacity: The amount of heat it takes to raise the temperature of one gram of a material one degree Celsius.

23) Surface Tension: A measure of how difficult it is to stretch or break the surface of a liquid. After has a high surface tension because of the hydrogen bonding of a surface molecule. 24) Polymer: Polymers are used with other chemical coagulants to aid in binding small suspended particles to form larger chemical flocs for easier removal from water. All poly electrolyte are polymers, but not all polymers are poly electrolyte. 25) Macromolecule: A giant molecule formed by the joining of smaller molecules, usually by a condensation reaction.

Polysaccharides, proteins, and nucleic acids are macromolecules Class: Lipid a. They consist of large biological molecules that doesn't include polymers. b. 10-20 carbon atoms long (A double bond connects the two, red Carbon atoms. Since Carbon forms four bonds, these Carbon atoms are only bonded to one Hydrogen each) c. -Triglycerides (true fats) -Phospholipids (similar to triglycerides) -Steroids (different) d.

Triglycerides - comprises of fats and oils, which are primarily energy storage molecules. Their energy is a little less available than that stored as glucose or starch or glycogen. If the chains contain no double or triple bonds then the fat is said to be saturated, since it can hold no more hydrogen's. Saturated triglycerides are solid at room temperature and a recalled fats. Triglycerides with one or more double bonds are said to be unsaturated because they have room for more hydrogen, if they are not saturated with hydrogen. If the chain has more than one unsaturated bond it is polyunsaturated.

Phospholipids - They are similar to the triglycerides in having a glycerol backbone and fatty acids. There are only two fatty acids however as one has been replaced by a negatively charged (hence polar) phosphate group. There is also some nitrogen involved. Phospholipids are very important in cell membranes. Their importance depends on this dual solubility in both fat and water. Steroids - are complex molecules that function in a variety of ways.

Energy storage is not an important function. They are sometimes structurally important, as in cell membranes, but many of them play a role in intercellular communication, as hormones. class: protein a. Every function of a living cell depends on proteins. Ex: # Motion and locomotion of cells and organisms depends on contractile protein (muscles). # The catalysis of all biochemical reactions is done by enzymes, which contain protein. # The structure of cells, and the extracellular matrix in which they are embedded, is largely made of protein.

(Collagens) # The transport of materials in body fluids depends of proteins. b. The commonly occurring amino acids are of 20 different kinds which contain the same dipolar ion group H 3 N+. CH. COO-. They all have in common a central carbon atom to which are attached a hydrogen atom, an amino group (NH 2) and a carbonyl group (COOH). The central carbon atom is called the C alpha-atom and is a chi ral centre. c. d. primary structure (linear sequence of amino acids), secondary, tertiary (folding of a single polypeptide chain) and quaternary structure (involves the association of two or more polypeptide chains into a multi-subunit structure). e.

# The transport of materials in body fluids depends of proteins. # The receptors for hormones and other signaling molecules are proteins. # Proteins are an essential nutrient for heterotroph's. # The transcription factors that turn genes on and off to guide the differentiation of the cell and its later responsiveness to signals reaching it are proteins. # and many more - proteins are the physical basis of life. Class: protein a. purpose (s) of this class b. atoms that compromise it. monomer of a protein (name the compound) d. general structure of the monomer e. major groups: structural; storage; transport; defensive; regulatory f. examples and biological significance of each major group and subgroup (hint some common proteins are keratin, collagen antibodies, enzymes, hemoglobin, actin, myosin) 8. Compare and contrast prokaryotic and eukaryotic cells.

Give examples of each. Even though all cells share the same basic features such as a plasma membrane, , also ribosome's and chromosomes. However there is a huge difference between prokaryotic and eukaryotic cells. To start the eukaryotic cells are significantly bigger than the Prokaryotic cells. In prokaryotic cells DNA is found within the region called the where there is no membrane that separates the from the rest of the cell. Eukaryotic cells on the other hand have a true nucleus bounded by a membranous nuclear envelope.

9. Compare and contrast animal and plant cells. Animal cells have a variety of organelles which are bounded by membranes. The nucleus is the most prominent organelle in the cell. Unlike plant cells, animal cells contain lysosomes, centrioles and flagella (although flagella sometimes found in plant sperm). What plant cells do contain that animal cells do not is chloroplasts, central vacuole, , cell wall, and.

Plant cells have a process which happens within them called photosynthesis. 11) Diffusion: The tendency for molecules of any substance to spread out into available space. In its simplest form, diffusion is the transport of a material or chemical by molecular motion. If molecules of a chemical are present in an apparently motionless fluid, they will exhibit microscopic erratic motions due to being randomly struck by other molecules in the fluid.

Individual particles or molecules will follow paths sometimes known as 'random walks. ' Passive Transport: Diffusion of a substance across a biological membrane. A molecule or ion that crosses the membrane by moving down a concentration or electrochemical gradient and without expenditure of metabolic energy is said to be transported passively. Another name for this process is diffusion Osmosis: Passive transport of water which diffuses water from a less concentrated solution to a more concentrated solution.

Large quantities of water molecules constantly move across cell membranes by simple diffusion, but, in general, net movement of water into or out of cells is negligible. For example, it has been estimated that an amount of water equivalent to roughly 250 times the volume of the cell diffuses across the red blood cell membrane every second; the cell doesn't lose or gain water because equal amounts go in and out. Plasmolysis: This happens when a cell loses water to its surrounding and shrinks because of the being immersed in a hypertonic environment. Plasmolysis occurs when a plant cells membrane shrinks away from its cell wall. This phenomenon occurs when water is drawn out of the cell an into the extracellular (outside cell) fluid. The movement of water occurs across the membrane moving from an area of high water concentration to an area of lower water concentration outside the cell.

Facilitated Diffusion: Hydrophilic substances including water molecules which diffuse through membranes with the assistant. Glucose, sodium ions and chloride ions are just a few examples of molecules and ions that must efficiently get across the plasma membrane but to which the lipid bi layer of the membrane is virtually impermeable. Their transport must therefore be 'facilitated' by proteins that span the membrane and provide an alternative route or bypass. Facilitated diffusion is the name given this process. It is similar to simple diffusion in the sense that it does not require expenditure of metabolic energy and transport is again down an electrochemical gradient. Active Transport: Some transport proteins act as pumps moving substances across a membrane against their concentration gradients.

Energy for this work is supplied by ATP. Active transport involves the use of proteins that don't just passively facilitate the transport of substances across the cell membrane, but require the use of cellular energy (usually ATP) to actively pump substances into or out of the cell. The animation represents the action of a sodium-potassium pump found in the cell membrane of neurons. Dialysis: The artificial process of cleaning wastes from the blood when kidneys fail. The two major forms of dialysis are hemodialysis and peritoneal dialysis. Endocytosis: In, the cell engulfs some of its extra cellular fluid (ECF) including material dissolved or suspended in it.

A portion of the plasma membrane is invaginated and pinched off forming a membrane-bounded vesicle called an endo some. Exocytosis: Exocytosis is the reverse of. And that is just as well. In 30 minutes an active cell like a macrophage (right) can an amount of plasma membrane equal to its complete plasma membrane 12) The cell cycle is the life of a cell from its origin in the division of a parent cell until its own division into two. A cell must divide because to maintain a favorable Surface area to volume ratio.

The increase in the volume of the cell increases the requirements of the cell and this increases the need for greater membrane area. And through the cell membrane a cell receives food and oxygen and turns out waste materials. The volume of the cell increase more rapidly then the area of its membrane. So, as a cell grows, it's membrane in a course of time becomes insufficient to move the required amount of substances in and out.