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Biology exam #2
Chapter 7 & 8
| Term | Definition |
|---|---|
| Cell Membrane | Separates ICF from ECF environment is semipermeable (selective ) which means that it allows certain substances across |
| Phospholipids | Make up the cell membrane calling it the phospholipid bi-layer -makes the membrane semipermiable b/c of fatty acid tails -are amphipathic molecules containing both hydrophilic and hydrophobic regions |
| Structure of a phospholipid | contains 1 glycerol +2 fatty acids + phosphate + polar head group |
| Substances that can cross the cell membrane | Lipid soluble substances like gases and cholesterol can easily pass through ex) estrogen non polar molecules ex) CO2 &O2 |
| Substances that CANNOT cross the cell membrane | ions cannot pass because of their charge carbohydrates cannot pass b/c they are to big and are not able to cross either w/ out protein channels Polar molecules |
| Other components of the cell membrane | consists of cholesterol & proteins that contribute to the membrane rigidity (stiffness) |
| Cholesterol in the cell membrane | adds support to the membrane by getting in through the openings in the lipid layers it helps add fluidity to the cell membrane when in different tempertures |
| Proteins in the cell membrane | there are 3 types - Integral transmembrane proteins -Lipid anchored proteins are made of single fatty acids in & out of the bilayer -Peripheral membrane proteins |
| Function of the proteins in the cell membrane | as receptors they are activated by ligands ex)epinephrine and act as (CAMs) cell adhesion molecules to anchor cells towards eachothers ECM |
| Fluid Mosaic Model | Says that the membrane fluid structure has various proteins embedded in it thus making tempertures affect the state of the cell membranes must be fluid & unsaturated than saturated in order to work |
| membrane transport | primary factor is is to create cell membrane permiability -the cell must be able to exchange materials in and out of the membrane |
| Trans membrane protein functions | 1) Transport as a channel or carrier protein 2) Receptor that detects chemical stimulas 3) cell adhesion Molecules (CAMs) help stick to other cells |
| Aquaporins | are water allowing protein channels through the membrane |
| Types of membrane transport | Passive transport or active transport |
| Passive transport | this transport does not require energy to move substances across it may or may not require a trans membrane protein -does require a concentration gradient of high to low ex) diffusion , facilitated diffusion |
| Active transport | Requires energy to move substances across the membrane -does not require a concentration gradient b/c it uses energy and trans membrane proteins to get across ex) sodium potassium pump ,pumps Na out of the cell & K into the cell like a revolving door |
| Diffusion | Focuses on the movement of solutes from a high concentartion to a low one until it reaches equilibrium |
| Concentration Gradient | Is the difference btwn 2 solute concentrations |
| Equilibrium | depends on concentration not volume |
| Diffusion for ions and lipids | b/c ions have a charge an ion channel is required for ions to move across the membrane lipids are able to diffuse though the membrane because the membrane is lipid soluble |
| Osmosis | is a special type of diffusion it requires a semi permeable membrane b/c it focuses on the movement of water in the direction of a high [solute] until equilibrium is reached -this is important in our cells b/c our cells are 99% made of water |
| Osmotic pressure | is exerted by a solution on a cell -is the ability of the ECF to cause a cell to gain or lose water from the cytosol/ICF b/c of the movement of water the cell can lyse, or rupture due to swelling |
| Tonicity | is the movement of water that creates pressure on the cell membrane there are 3 types 1) Isotonic solution 2) Hypotonic solution 3)Hypertonic solution |
| Isotonic Solution | this solution does not cause the cell to gain or lose water b/c the [solute] are equal in and out of the cell there is no net movement but the water is moving to both sides |
| Hypotonic solution | In this solution water is able to pass freely into the cell causing the cell to gain water and lyse -the ECF [solutes] is less than the ICF [solute] |
| Hypertonic solution | this solution has a higher [solute] outside the cell causing it to lose water (shrink/ shrivel) -the ECF [solute] is greater than the ICF [solute] |
| Carrier Mediated Transport | is the transport of ions and compounds across the cell membrane by trans membrane proteins (carrier/channel) may or may not require ATP 2 types 1)facilitated diffusion 2) active transport |
| Facilitated Diffusion | is a type of passive process requiring no energy -does require a carrier protein and a [gradient] example is glucose transporter carries glucose from a high [glucose] to a low [glucose] the mvment is limited depending on # of carrier proteins |
| Vesicular Transport | are tiny lipid packages used to transport molecules -these are derived from the cell membrane or Golgi apparatus 2 types of transport 1)Endocytosis 2)Exocytosis |
| Endocytosis | Begins in cell membrane by folding it inward and bringing in large quantities of substances 3 types of ways 1)receptor mediated endocytosis 2) pinocytosis 3) phagocytosis |
| Receptor mediated endocytosis | selective endocytosis/ a form of pinocytosis |
| Pinocytosis | not selective endocytosis/ cellular drinking |
| Phagocytosis | host defense/ cellular eating |
| Exocytosis | begins at the Golgi apparatus where it is stored -it is also known as protein secretion b/c the vesicles fuse w/ the membrane resulting in a release of proteins |
| selective permiability | allows some substances to move in the cell more easily than others by regulating transport |
| protein functions | 1) transport 2)enzymatic activity 3)receptor 4)joins 2 cells 5)attached to the ECM |
| carrier proteins | change their own shape while holding on to a substance during transport |
| ligands | are any molecule that binds specifically to a receptor site on another molecule |
| Energy in cells | is the ability to perform work, and cause change -is required to assemble and dissasemble compounds , transport & production of energy |
| 2 types of energy | Potential and kinetic energy |
| Kinetic energy | the energy of movement -heat which can often be lost -light which is energy movement of photon particles |
| potential energy | is stored energy that an object can contain -can power up a cell for example the process of cellular respiration the conversion of glucose to ATP |
| Cellular respiration equation | Glucose + O2 ---> 6 H2O + 6 CO2 + 32 ATP |
| ATP | is a type of energy or potential energy |
| chemical reactions | lead to the making (synthesis) or breaking (disassociation) of a covalent bond |
| enzymes | are proteins that catalyze /speed up chemical reactions that convert glucose into ATP in cells |
| What is thermodynamics | the study of energy transformation |
| 1st law of thermodynamics | when the total amnt of energy of a system is constant - the energy cannot be created or destroyed also known as the conservation of energy |
| 2nd law of thermodynamics | when energy conversions increase entropy / the disorder of the universe heat is a type of entropy b/c it is sometimes lost in the cell and becomes unusable |
| making and breaking | energy can be stored by making chemical bonds or released by breaking chemical bonds |
| Gibbs free energy | is a living systems energy that can do work when there is a change in temp. and pressure in the cell |
| Changes in gibbs free energy | energy to do work can be calculated by subtracting the final state from the initial state -or the products minus the reactants |
| Types of chemical reactions | 1) endergonic reaction 2) exergonic reactions these chemical reactions couple up in order for both of them to occur |
| Endergonic reactions | absorbs energy from the surroundings or by making stored energy the change is positive ex) ADP+p ---> ATP (non spontaneous ) |
| Exergonic reactions | breaks a covalent bond in order to release energy -the change is negative ex) ATP----> P+ ADP (spontaneous) |
| enzyme jobs | to act on substrates and form or break chemical bonds with/out requiring alot of ATP -they speed up metabolic reactions by lowering energy barriers |
| Enzyme temp. changes | -the enzyme works best at 37 degrees -they change shape and function if the temperature is not to their liking. - if it is to hot the enzyme will unfold and denature -if the temp is to low the enzyme will become inactive or slow down. |
| -ase... | 2 types of enzymes that break down & then form new things 1) DNase breakes down to DNA & nucleotides 2)Sucrase breakes down to sucrose & fructose |
| Factors that effect enzyme functions | 1) Co factors 2) Chelators 3) Temperture 4) pH 5) [Substrate] 6) Inhibitors |
| Co-factors | are cations that can help an enzyme maintain its shape & function ex) Ca2+, Mg 2+, Cu 2+ |
| Chelators | remove cations from a solution to inhibit enzyme function called EDTA & PTU EDTA removes {Ca2+, & Mg2+} PTU removes {Cu2+} |
| Temperture | body temp. is 37 degrees if it is increased to 100 or higher proteins unfold & denature if the temp decreases the enzyme works slower |
| Different pHs | ex) In the digestive tract - in the stomach the enzyme pepsin has a pH of 2 -in the small intestine the enzyme Tripsin breaks down proteins with a pH of 8 |
| Inhibitors | 1) CI competative inhibitor : are small molecules that compete w/ substrates for an enzymes active site 2) Non Competative inhibitor : are molecules that bind to a region away from active site changing its shape and function ex) amino acid isolucine |
| Allosteric regulators | control cell enzyme activity they are the relationship that a cell can have w/ another cell through a change in shape & activity |
| Switch for on & off in a cell | is caused by a product in a cell that can lead to feedback inhibition during diff. stages of the protein structure |
| Allosteric Inhibitor | binds to the regulatory site to keep enzymes in a stabilized in active form |
Created by:
Marlene0127
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