Bio 111 Full Notes Bundle
Bio 111 Full Notes Bundle Bio 111 - Fundamentals of Biology II
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Bio 111 - Fundamentals of Biology II
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This 48 page Bundle was uploaded by Shelby Flippen on Monday September 5, 2016. The Bundle belongs to Bio 111 - Fundamentals of Biology II at Washington College taught by Dr. Reynolds in Spring 2016. Since its upload, it has received 5 views. For similar materials see Bio 111- General Biology in Biology at Washington College.
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Date Created: 09/05/16
Bio 111 – General Biology 1. Basic Terms - Matter- everything that takes up space and has mass - Element- building block of matter, stable (C, O, H, and N are the primary ones in the body) - Compound- substance containing two or more different elements - Atom- smallest unit of an element that retains the element’s physical and chemical properties a. Electron- Negative (-) b. Proton- Positive (+) c. Neutron- Neutral ( ) - Atomic Number- number of protons in an atom’s nucleus (the top number) - Atomic Mass- the approximate number of protons and neutrons (in Daltons), approximately the same as mass # - Isotopes- have a different number of protons than neutrons, unstable - Valence electrons- electrons in the outer shell, determine the chemical behavior of an atom - Inert- chemically unreactive because the outer shell is full (2,8) - Covalent bonds- sharing of valence electrons, very strong - Molecule- two or more atoms of different types joined together - Compounds- two or more atoms of different types joined together - Electronegativity- atom’s attraction for the electrons in a covalent bond (the greater the electronegativity, the stronger the pull of shared electrons) - Nonpolar, covalent bond- equal electronegativity, probably the same atoms (equal sharing) - Polar, covalent bond- one element is more electronegative (example: H O – un2qual sharing) - Ionic bonds- results from attraction of two elements because of the transfer of electrons (example: 1 Na valence electron Cl to complete its 8 shell), not as strong as a covalent bond - Ions a. Cation- Positive (+) b. Anion- Negative (-) - Polar molecule- when a molecule’s overall charge is unevenly distributed a. One that accepts the electron more negative (anion) b. One that gives the electron more positive (cation) Note: I highly recommend finding images of all of the terms and concepts because they will help you understand and memorize the content. Chapter 3: Water and Life Four emergent properties of water that contribute to Earth’s suitability as an environment for life: - Cohesive behavior - Ability to moderate temperature - Expansion upon freezing - Versatility as a solvent 1. Cohesive behavior Hydrogen bond- results when a hydrogen atom covalently bonded to one electronegative atom is attracted to another electronegative atom - Usually oxygen and nitrogen - Weak bond (weakest of three) Chemical reactions break and/or form bonds. - Reactants- starting materials - Products- ending materials (produced from the reactants by a reaction) Water is a polar molecule. - Polarity allows water to form hydrogen bonds with each other. Water interacts with ions - δ+ (delta plus- partial charge) hydrogen atoms interact with anions - δ- (delta minus- partial charge) oxygen atoms interact with cations Water has 3.4 hydrogen bonds while ice has 4 hydrogen bonds Cohesion- the linking together of like molecules, often by hydrogen bonds - Dependent on hydrogen bonds - Important for transport of water against gravity in plants Adhesion- water binds to all walls by hydrogen bonds Surface tension- tension liquid’s surface caused by the attraction of the particles in the surface layer 2. Expansion Capacity Hydrogen bonds in ice are more ordered, which makes ice less tense. - These bonds are more stable and spread out. 3. Moderation of Temperature Water absorbs heat from warmer air and releases stored heat into air. Heat and Temperature - Kinetic energy- energy of motion - Heat: measure of the total amount of kinetic energy due to molecule in Celsius (dependent upon volume) - Temperature: the intensity of the heat due to the average kinetic energy of the molecule in Celsius (independent of volume) Specific Heat- the amount of heat that must be absorbed or lost for 1g of that substance to change its temperature by one degree Celsius - High for water (due to hydrogen bonds) a. Heat is absorbed when hydrogen bonds break. b. Heat is released when hydrogen bonds break. - Important for regulation of temperature of places near water. Evaporation- transformation of water from liquid to gas - Heat of vaporization: quantity of heat a liquid must absorb for 1g to be converted to gas. - Evaporative cooling- the cooling of a surface due to liquid evaporation temperature stabilization 4. Universal Solvent of Life Solutions: - Solution- a homogenous mixture of two or more substances - Solvent- dissolving agent of a solution - Solute- substance that is dissolved - Aqueous solution- one in which water is the solvent Water loves polar, charged molecules because these molecules can dissolve in water - Many biological molecules are polar. - Water forms hydrogen bonds with polar groups. - Water dissolves glucose (sugar) by surrounding it with a hydration shell. a. First- polar b. Next- water-water water-glucose (for example) Hydrophilic- affinity for water, water-loving (polar, or ionic/charged) Hydrophobic- repels water, hates/has a phobia of water (nonpolar, uncharged) A water molecule can lose a hydrogen ion (H+) to another - Hydronium ion (H O+3 - Hydroxide ion (OH-) - Ionization 5. Acids and Bases Acids- dissociate in water and release hydrogen ions - Strong acids give away all H+ ions Bases- take up hydrogen ions or release hydroxide ions (OH-), take H+ pH- the negative logarithm of H+ concentration - 7 is neutral - 0-6 = acidic - 8-14 = basic - 10 times more concentrated as you move from one # to another # - Body pH= 7.4 6. Buffers Buffers- take up excess H+ or OH- and maintain homeostasis - They consist of weak acid and conjugate base (more common) or weak base and conjugate acid (less common). - pH in our body needs to be maintained. Examples: - Phosphate system: H PO (interaction) H + HPO 2 4 4 a. Extracellular fluids and cytoplasmic compartments - Bicarbonate system: CO + H O2 H2CO H+HCO2 3 3- a. Blood, lungs, kidneys Chapter 4: Carbon and the Molecular Diversity of Life 1. Carbon Carbon has 4 electrons (needs 4 for outer shell) and has single or double bonds. Carbon enters the biosphere through the action of plants. Plants use solar energy to transform atmospheric CO int2 the molecules of life. These molecules are taken in by plant-eating animals. Carbon is unparalleled in its ability form large, complex, and varied molecules. - This allows for the diversity of organisms that have evolved. a. Proteins, DNA, carbs, etc. are made of carbon - Most organic compounds have both H and C atoms. a. Different species are distinguished by variations in their organic molecules. - Hydrogen, oxygen, Nitrogen, sulfur, ad phosphorus (SHNOP- for memorization: think liquor) are common ingredients in these compounds. Organic chemistry- the branch of chemistry that specifies in the study of Carbon compounds/organic compounds. - In the early 1800s, Jons Jakob Barzelins made the distinction between organic and inorganic compounds. a. Organic = living/biological, Nonorganic = nonliving - Vitalism, the belief in a life force outside the jurisdiction of physical and chemical laws Mechanism: physical and chemical laws govern all natural phenomena (life). - Most organic compounds have both H and C atoms. 2. Carbon Atoms They can form diverse molecules by bonding with four other atoms. (Different species are distinguished by variations in their organic molecules.) Electron bonding (how cute) - Carbon has 6 electrons (4 valence electrons that want 4 more). - In organic compounds, carbon usually forms single or double covalent bonds. - Each carbon atom acts as an intersection point from which a molecule can branch off in as many as 4 directions. a. 109.5 degree angle where Carbon has 4 single bonds Carbon Compatibility - Molecules are 3 dimensional and the shape often determines its function. - Frequent bond partners: H (hydrogen), O (oxygen), and N (nitrogen) --- (the COHNs) a. Each line represents a pair of shared electrons (remember, they need to have 2 or 8 in their outer shells) b. H (1 in outer shell)- needs 1, O (6), N (5), C (4) c. CO l2cks hydrogen and is often considered inorganic Hydrocarbons- organic molecules consisting of only carbon and hydrogen - Major components of petroleum - Not present in most living organisms - Many of a cell’s organic molecules have regions consisting only of C and H (fat tails of phospholipids) - Hydrophobic and nonpolar - Can undergo reactions that release a relatively large amount of energy (fat, gas) Isomers- compounds that have the same number of atoms of the same elements, but with different structures and thus, different properties - The subtle difference in shape between isomers can dramatically affect the biological activities of organic molecules. - Structural isomers- differ in their covalent arrangement of their atoms a. The number of possible isomers increases greatly as carbon structures increase in size. b. Structural isomers may also differ in the location of double bonds. - Cis or trans isomers- carbons have covalent bonds to the same atoms, but the atoms differ in their spatial arrangement, due to the inflexibility of double bonds a. Single bonds allow the atoms they join to rotate freely about the bond axis without changing the compound. - Enantiomers- isomers that are mirror images of each other and that differ in shape due to the presence of an asymmetric carbon. a. Asymmetric carbon- one that is attached to 4 different atoms or group of atoms. - Usually only 1 isomer is biologically active because only that form can bind to specific molecules in an organism. 3. Chemical Groups A few chemical groups are key to the functionality of biological molecules. - The distinctive properties of an organic molecule depend not only on the arrangement of its carbon skeleton, but also on the chemical groups attached to it. a. They may participate in chemical reactions or contribute to function indirectly by their effects on molecular shape. b. The number and arrangement of the groups help make each molecule unique. Different chemical groups contribute to function by affecting the molecules shape OR by being directly involved in chemical reactions. Functional groups- affect molecular function by being directly involved in chemical reactions. 7 chemical groups- most important in biological processes are: - Hydroxyl, Carbonyl, Carboxyl, Amino, Sulfhydryl, Phosphate, and Methyl groups (C-CHAMPS or Carbon champs for memorization) - All but Methyl can act as functional groups. a. They are hydrophilic and can increase the solubility of organic compounds in water. b. Methyl group is non-reactive and often serves as a recognition tag on biological molecules. 7 Chemical Groups Formula Name Hydroxyl- -OH Alcohols (not OH ion), polar Carbonyl -C= O (double bond with O) Aldehydes (single bonds: R (O double covalent bond) and H) Ketones (H and H) - Carboxyl -C = O O Carboxylic Acids (double bond with O, single - OH with OH- hydroxide) (non-ionized) (w/O ionized) Makes it more acidic and neg Amino -N- H Amines (N bonded to H) - H Sulfhydryl -S- H Thiols (sulfur bonded to H) Cysteine 2- Phosphate OPOS Organic Phosphates (P single bonded to O, double bonded to O, two single bonds to OH) Methyl CH 3 Methylated (one carbon with bonded to 3 H) Carboxyl Amino Hydroxyl Carbonyl (aldehyde) 4. ATP (adenosine triphosphate) An important source of energy for cellular processes (composed of Adenosine + a string of 3 phosphate groups) - 1 phosphate may be split off as a result of a reaction with water (ATP becomes adenosine diphosphate or ADP) a. This reaction releases energy that can be used by the cell (primary energy transferring molecule in the cell). Ch. 5: Large Biological Molecules 1. Organic Molecules The main ones: - Carbohydrates, Proteins, Nucleic Acids = macromolecules - Lipids Macromolecules- joined by covalent bonds, made by monomers (through dehydration) - We can break them down to get energy (hydrolysis). Monomer- smaller molecules that serve as building blocks of a polymer Polymer- long molecule consisting of many similar or identical building blocks, linked by covalent bonds - Example: C-C-C-C-C-C Diversity of polymers - Each cell has thousands of different kinds of macromolecules. - Macromolecules vary among cells of an organism, within a species, and between species. - An immense variety of polymers can be built from a small set of monomers. Making and breaking biological polymers - Dehydration- highly regulated removal of a water molecule- builds a new bond, takes energy and removes H O, b2ilding polymers from monomers - Hydrolysis- opposite of dehydration, releases energy from breaking apart polymers, adds H O2 2. Carbohydrates Basics: - Functions as long and short term energy - Simple: 3 – 7 carbon atoms (in length) Types - Monosaccharides a. Aldoses or ketoses (aldoses=aldehydes, ketoses=ketones) b. Trioses (C P3),oses (C ), 3exoses (C 6) c. Simple 3-7 Carbon molecules - Disaccharide: 2 monosaccharides a. Glucosidal linkage- link between two monomers - Polysaccharides: many glucose units (complex) a. Starches: form of stored glucose in plants b. Glycogen: form of stored glucose in animals, humans c. Cellulose: found in plant cell walls (insoluble fibers) Cellulose - Major component of the walls of plant cells - Different from starch because of the glucose ring structures a. A (below the plane), B (above) glucose ring strucutres - Starch: 1-4 linkage of “a” glucose monomers - Cellulose: 104 linkage of “B” glucose monomers Starch - Has a spiral shape Cellulose - Has a straight shape, rigid - Hydrogen bonds form from between cellulose chains 3. Lipids Lipids function well as energy storage molecules, insulation, heat source Hydrophobic - Fats and oils, Phospholipids, Steroids Lipids are composed of hydrocarbons - Fats: animal origin and solid at room temperature (butter) - Oils: plant origin and liquid at room temperature Triglyceride - Glycerol and 3 fatty acids Saturated fatty acid- a structure with hydrogen - No double bonds between carbon atoms on chain - As many hydrogen atoms as possible bounded to C skeleton - Most animal fats Unsaturated fatty acid- has one or more double bonds - One fewer H atom on each double-bonded carbon Trans fats - Snack foods, fried food (very bad!) - Rearranged double bonds Phospholipids - Contains 2 fatty acids and a phosphate group attached to glycerol - Carries a charge - 2 Tails - Charged, polar head (Ph.) - Nonpolar tail (lipid), lipophilic - Amphoteric- has polar and nonpolar regions Steroids - Composed of fused carbon rings - Functional groups define characteristics - Exs/ Cholesterol, testosterone, estrogen 4. Proteins Very important in structure and function of all cells (structure determines function) Proteins can function as - Support and collagen - Enzymes: alcohol dehydrogenase - Transport: hemoglobin - Movement: actin and myosin - Cell communication: insulin - Defense: antibodies Amino Acids: building blocks of proteins - 20 essential amino acids - Chira Carbon- that has 4 different things attached to it - NH =3amino group - COOH = acid group - R group = R Non-polar Amino Acids - Glycine, Alanine, Valine, Leucine, Isoleucine, Methionine, Phenylalanine, Tryptophan, Proline Non-polar Amino Acids - Serine, Threonine, Cysteine, Tyrosine, Asparagine, Glutamine Electrically-Charged Amino Acids - Aspartic acid, glutamic acid - Lysine, Arginine Amino Acid Polymers - Amino acids linked by peptide bonds - A polypeptide is a polymer of amino aids - Each polypeptide has a unique linear sequence of amino aids Polypeptide- string of amino acids joined by a peptide bond (not a protein) - Nonpolar: methyl (CH 3) - Polar charged: Hydroxyl (R- CH -OH2, Sulfhydryl (R – CH – SH), C2rbonyl (R – C =O and = CH 3) Protein activities result from structure - A functional protein is one or more polypeptides twisted, folded, and coiled into a unique shape. - Proteins “fold” as they form - Proteins can bind to a. Polypeptide- No function b. Protein- function Protein shape is determined by all 4 levels of structure. Protein structure alterations - Change in primary structure can affect a protein’s structure and function a. Ex. Sickle Cell Disease Levels of protein structure a. Primary: the amino acid sequence of the peptide chain b. Secondary: consists of folds and coils in the polypeptide chain – use just hydrogen bonds A helix, B sheet c. Tertiary: 3-dimensional structure of a single protein molecule, determined by interactions among various side chains (R groups) d. Quaternary: several 3 dimensional structures (complex of several protein molecules or polypeptide chains) Primary structure (peptide, non-functional) - Amino acid sequence (not the shape of the protein) - Amino terminus- the “start” or of a protein “N” terminus - Carboxyl Terminus- the “end” if a protein “C” terminus Secondary Structure - Coils and golds resulting from hydrogen bonds between repeating constituents of the polypeptide backbone - Typical secondary structures are a oil called an “a helix” and a folded structure called a “B pleated sheet” - Hydrogen Bonds - R groups are NOT involved - Non-functional Tertiary Structure - Functional - Determined by interaction between R groups rather than interactions between back bone constituents - R group interactions may use hydrogen bonds, ionic bonds, Vander Waals interactions, and covalent bonds Quaternary Structure - 3D structure of a multi-subunit protein - Many functional proteins are made of multiple polypeptide chains (subunits) - R groups bond What determines protein structure? - Physical and chemical conditions a. pH, salt concentration, temperature - Denaturation- loss of a protein’s native structure; results in biological inactivity - Renaturation- protein refolding Ch. 6: The Cell Atom molecule cell tissue organ organ system organism Cell theory- a cell is the basic unit of life (and they look quite different!) Importance of Cells - All organisms are made out of cells. - A cell is the basic unit of structure and function. - All cells are related ot one another. Eukaryotic: Us! Plants, fungi (complex), protists Prokaryotic: Bacteria (Arche) – simple - Possibly first ells to evolve Common features of prokaryotic and eukaryotic cells - Plasma membrane (surrounding part of a cell) – phospholipids - Cytosol (semifluid substance) - DNA - Ribosomes (make proteins) Differences between Prokaryotic and Eukaryotic Cells Prokaryotic Eukaryotic - Smaller size - Larger size - No nucleus, DNA is in an - Has a nucleus unbound region called the nucleoid - No membrane-bound - Has membrane-bound organelles organelles Origin of the Eukaryotic Cell 1. Cell gains a nucleus by the plasma membrane invaginating and surrounding the DNA with a double membrane. 2. Cell gains an endomembrane system by proliferation of membrane. 3. Cell gains proto-mitochondrian. Plasma Membrane - “Semi permeable” - Separates the internal contents of the cell from the outside environment - Functions as a selective barrier a. Oxygen and nutrients in, waste out - Integrity important for survival Nucleus - “control center” of the cell - Contains 95% of DNA (5 in Mitochondria) - Separated from cytoplasm by a porous nuclear envelope - Site of DNA replication and transcription - Contains ribosomes – use information from DNA to make proteins (DNA - (transcription in nucleus) RNA (Translation outside of nucleus) protein - DNA and proteins in the nucleus form genetic material called chromatin. - Chromatin condenses to form discrete chromosomes. - Nucleolus is located within the nucleus and is the site of ribosomal RNA (rRNA) synthesis. Ribosomes - Composed of ribosomal RNA and protein - Carries out protein synthesis a. In the cytosol (free ribosomes)- smoother b. On the outside of the endoplasmic reticulum or the nuclear envelope (bound ribosomes) – more rough c. Can have more than 1 Endomembrane System (nucleus) - Components a. Nuclear Envelope b. Endoplasmic Reticulum c. Golgi Apparatus d. Lysosomes e. Vacuoles f. Plasma Membrane - Accounts for more than ½ of the total membrane in many eukaryotic cells - Continuous with the nuclear envelope - Two distinct regions a. Smooth ER: lack ribosomes b. Rough ER: ribosomes studding its surface Endoplasmic Reticulum Smooth ER Functions Rough ER Functions - Synthesizes lipids - Secretes glycoproteins - Metabolizes carbohydrates - Distributes transport vesicles - Detoxifies poisons (alcohol) - Membrane factory of the cell - Stores calcium Golgi Apparatus - Modifies products of the ER - Manufactures certain macromolecules - Sorts and packages materials into transport vesicles - Cis and trans sides a. Cis face- “receiving” side b. Trans face- “shipping” side Lysosome - Digestive compartments – extremely acidic - Lysosomal enzymes hydrolyze proteins, fats, polysaccharides, and nucleic acids - Phagocytosis: forms a food vacuole; fuses with lysosome for digestion - Autophagy: use of enzymes to recycle the cell’s own organelles and macromolecules Vacuoles - Common in plants and fungi (not animals) - Diverse a. Food vacuoles: formed by phagocytosis b. Contractive vacuoles: freshwater protists; pump water out of cells c. Central vacuoles: mature plant cells; hold organic compounds and water Powerhouses of cells - Mitochondria: nearly all Eukaryotic cells a. Glucose ATP (cellular respiration) - Chloroplasts: plants and algae; chlorophyll a. Solar energy chemical energy (photosynthesis) Peroxisomes - Produce hydrogen peroxide and converts it to water - Oxygen is used to break down different types of molecules - Single-membrane - Has Enzymes that can break down fats Cytoskeleton - Maintains cell shape - Anchors and or moves organelles in the cell - May regulate biochemical activities - Composed of 3 fibers a. Microtubules: thickest b. Microfilament: thinnest c. Intermediate Filaments - Microfilaments a. Help support cell shape b. Bundles of microfilaments make up the cone of microvilli of intestinal ells c. Involved in cellular mobility (myosin: thick and actin: thin) d. Very important in muscle cells - Microtubules a. Maintain all shape b. Cell mobility: cilia and flagella c. Movement of organelles d. Separate chromosomes during cell division centromeres - Intermediate Filaments a. Help support cell shape and fix organelles in plae b. They are more permanent cytoskeleton fixtures than the 2 other classes. Cilia and Flagella - Important for movement - Made of microtubules - Powered by ATP - Genetic Disorders a. Trachae- Cilia, Sperm- Flagella Extracellular Components - Most cells synthesize and secrete materials that are external to the plasma membrane a. Cell walls of plants b. Extracellular matrix (ECM) of animal cells Plant Cell Walls - Distinguishes plant cells from animal cells - Protect, maintains shape, prevents excessive uptake of water - Prokaryotes, fungi, and some protists have it - Made of cellulose - Composed of multiple layers a. Primary: thin and flexible b. Middle lamellae: thin layer between primary walls of adjacent cells c. Secondary cell wall: (in some cells) added between the plasma membrane and the primary cell wall d. Plasmodesmata: channels between adjacent plant cells Extracellular matrix (ECM) of animal cells - Composed of glycoproteins such as collagen, proteoglycans, and fibronectin - Proteins bind to receptor proteins in the plasma membrane called interims - Composed of cellulose fibers embedded in other polysaccharides and proteins - Important for a. Support, adhesion, movement, regulation Intercellular junctions - Facilitate contact between neighboring cells, tissues, organs, and organ systems in animal cells - Plant cells (plasmodesmata) - Types: a. Tight junctions: membrane of neighboring cells are pressed together, preventing leakage of extracellular fluid (epithelial cells in intestine) b. Desmosomes- “anchoring junctions” fasten together into strong sheets c. Gap junctions- “communicating junctions” provide cytoplasmic channels between adjacent cells Ch. 7: Membrane Structure and Function 1. Characteristics Provides compartmentalization Amphipathic- has a hydrophilic and hydrophobic region Made of phospholipids, proteins, and arbs Fluid Mosaic Model - Cells all look different different components - Supported by freeze fracture methods - Specialized method that splits membrane along middle of the phospholipid bilayer (double membrane) 2. Fluidity of Membranes Phospholipids in a plasma membrane can move with the bilayer Most of the lipids, and some proteins, drift laterally Rarely does a molecule flip-flop traversly across the membrane NOT rigid Lateral movement: fast, occurs a lot Vertical movement: slow, rare, enzymes (across hydrophobic region) - Flippose, floppases, scrambase enzymes Fluidity of membranes temp, lipid composition, and cholesterol can alter fluidity - As temperature cools, membranes switch from fluid to solid a. The temperature at which a membrane solidifies depends on the types of liquids b. Membranes rich in unsaturated fatty acids are more fluid than those rich in saturated fatty acids c. Membranes must be fluid to work properly - Cholesterol a. The steroid cholesterol has different effects on membrane fluidity at different temperatures temp buffer b. At warm temps, cholesterol restrains movement of phospholipids c. At cool temps, it maintains fluidity by preventing tight packing Membrane Proteins - Peripheral proteins: proteins that are bound to the surface of the membrane - Integral proteins: proteins that penetrate the hydrophobic core a. Proteins that span the membrane are called transmembrane proteins (nonpolar) - Major functions a. Transport b. Enzymatic activity c. Signal transduction (communicating) d. Cell-cell recognition e. Attachment to the cytoplasm and ECM 3. Membrane Binding and Penetration Binding on the extracellular surface of the plasma membrane aids in recognition - Carbohydrates: glycolipids, glycoproteins - Vary from species to species, cell type to cell type, and within a species (Ex. Blood type) Distinct inside and outside regions - Differ in lipid composition - Asymmetric - Determined with being synthesized by ER and Golgi Permeability of the lipid bilayer - Hydrophobic (nonpolar) molecules, such as CO and O2can dis2,lve in the lipid bilayer and pass through the membrane rapidly. - Polar molecules, such as sugars, do not cross the membrane easily Transport proteins - Transport proteins- allow the passage of hydrophilic substances across the membrane - Channel proteins- tunnels that allow certain substances to pass through the membrane a. Usually no energy b. Aquaporins: water c. Fast transport - Carrier Proteins- hold onto “substances” and change shape as a means to transport through membrane a. Glucose transporters b. Has to be a conformational change In this CASSE- Conformational change, Active or passive, Saturation or not, Speed, Energy or not Channel Carrier - Fast - Slower - No conformational change - Conformational change - No saturation - Saturation can occur - No energy - Energy - Passive (usually) - ACTIVE transport 4. Types of Transport Transport Mechanisms - Passive transport: no energy required a. Simple diffusion b. Facilitated diffusion c. Osmosis - Active transport: energy required Passive diffusion: simple (osmosis and facilitates, no energy) - Higher concentration lower concentration - Influenced by: a. Concentration b. Lipid solubility c. Ionization (membrane potential) d. Molecular size e. Temperature f. Permeability Passive diffusion: osmosis - Movement of water from an area of high water low water - Diffusion of water - Solute: substance dissolved into a solution (sugar for ex) - Hypertonic: low water, high solute (cell shrinkage) - Hypotonic: low solute, high water (cell swelling) - Hyper: more, Hypo= less, Tonic= water Water balance of cells with walls - Cell walls help maintain water balance - A plant cell in a hypotonic solution swells until the walls opposes uptake; the cell is now turgid (firm) - If a plant cell and it surroundings are isotonic, there is no net movement of water into the cells; the cell becomes flaccid (limp) Passive Diffusion: facilitated - Utilizes transport proteins - Higher concentration lower concentration Active transport - Movement against concentration gradient a. Low high - Utilizes carrier proteins - ATP ADP Maintaining membrane potentials - Membrane potential- the voltage different across a membrane - Voltage is created by differences in distribution of positive and negative ions - Two combined forces, called the electrochemical gradient- drive the diffusion of ions across a membrane a. Chemical force- ion concentration b. Electrical force- effect of the membrane potential on the ion’s movement - Electrogenic pump generates voltage across a membrane - NaK pump is the major electrogenic pump in animals cells - The proton pump is the major electrogenic pump in plants, fungi, and bacteria Exocytosis – “export” - Requires energy - Used for longer molecules - Transport vesicles migrate to the membrane, fuse with it, release their contents Endocytosis- “import” - Requires energy - Used for longer molecules - 3 different types a. Phagocytosis: cellular eating b. Pinocytosis: cellular drinking c. Receptor mediated endocytosis- SPECIFIC Ch. 8: An Introduction to Metabolism Metabolism- complete set of cellular chemical reactions 1. Types of Reactions Catabolic reactions: release energy, break things down, spontaneous, -delta G a. Ex/ cellular respiration b. Exergonic decrease Anabolic reactions: requires energy input, building, not spontaneous, +delta G, stores energy a. Endergonic increase 2. Energy Energy- the capacity to do work, to move against opposing forces - Metabolism converts energy from one form to another Forms of energy - Kinetic energy- energy associated with relative motion of objects a. Heat or thermal energy is the movement of atoms or molecules - Potential energy- possessed due to location or structure a. Chemical potential energy- arrangement and connections of atoms (bonds) Ex. glucose/ gas 3. Energy Rules First Law of Thermodynamics- energy can be transferred and transformed, but can’t be created or destroyed Second Law of Thermodynamics- energy transformation makes the universe more disordered - Entropy- measure of disorder Life is a struggle against disorder Living organisms organize things - Organization requires energy - Entropy always increases 4. Reactions Reactions alter bonds - Reactants - Products Spontaneous reactions: occur without the addition of energy Free energy (G): energy available to do work Change in free energy (∆ G) = G G final –initial - - ∆ G = spontaneous - + ∆ G = not spontaneous 5. Types of Reactions Exergonic Reaction: -∆G, spontaneous, releases energy Endergonic Reaction, +∆G, not spontaneous Life is not at equilibrium because disequilibrium is required for life. 6. ATP Powers the Cell ATP: Adenosine Triphosphate- is a common energy curreny - Mechanical work (ex. Raising your hand) - Transport (active transport) - Chemical work (cellular respiration) ATP Hydrolysis - Releases energy - One mole of ATP ADP + P releasis 7.3 kcal of energy - (ATP in large doses ADP) 7. Enzymes Enzymes: an organic catalyst - Transition state- high energy phase of a reaction - Chemical bonds are stressed - Enzymes lower the activation energy The active site - Binding/active site: enzyme region that binds the substrate (reactant) - Induced fit: enzymes often change shape to improve substrate binding a. Enzymes unchanged after use Feedback - Metabolic pathway products are often allosteric regulators - Negative feedback: (less active, slow down or stop enzymatic activity), opposite direction - Positive feedback: more active, speed up enzymatic activity, same direction - Allosteric site: binds something other than substrate, negative feedback - Active site: positive feedback ATP Coupling Reaction: produce more energy favorable reactions
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