2Living things share some common characteristics: An organism is any individual living thing.Living things share some common characteristics:All are made of one or more cells.All need energy for metabolism.Metabolism: All of the chemical processes inan organism that build up or break down materials.All respond to their environment.Stimuli, or physical factors, include light, temperature, and touch.All have genetic material (DNA) that they pass on to offspring.
3Life depends on hydrogen bonds in water. Water is a polar molecule.Polar molecules have slightly charged regions.OH_+Atom: OxygenCharge: Slightly negativeHydrogen bondsform between slightly positive hydrogen atoms and slightly negative atoms. (oxygen)Atom: HydrogenCharge: Slightly positiveNonpolar molecules do not have charged regions.
4High Specific Heat: water resists changes in temp. Hydrogen bonds are responsible for important properties of water.High Specific Heat: water resists changes in temp.Provides stability of temperature for land masses surrounded by water & for the temperature of the human body, & makes it an effective cooling agent.Cohesion: water molecules stick to each other.Adhesion: water molecules stick to other things.Ice floats on water: one of the only solids to float on its liquid form – due to arrangement of water molecules due to charged regions.
5Many compounds dissolve in water. A solution is formed when one substance dissolves in another. A solution is a homogeneous mixture.Solvents dissolve other substances.Solutes dissolve in a solvent.solution
6Polar solvents dissolve polar solutes. “Like dissolves like.”Polar solvents dissolve polar solutes.Nonpolar solvents dissolve nonpolar solutes.Polar substances and nonpolar substances generally remain separate.Example: Oil (non-polar) and water (polar)
7pH<7=Acid (more H+)7=Neutral>7=Base (less H+)Maintaining homeostasis*Buffer: Helps to maintain pH.
8Speaking of homeostasis… Homeostasis refers to your body maintaining stable, constant internal conditions.This may include:Regulation of temperature (thermoregulation)Regulation of pHRegulation of oxygen delivery (for cellular respiration!)
9Carbon atoms have unique bonding properties. 1. Carbon forms covalent bonds (strong bonds) with up to four other atoms, including other carbon atoms 2. They can form large, complex molecules
10Carbon atoms have unique bonding properties – Slide 2 3. Carbon can form single, double, or triple bonds4. Carbon forms isomersIsomers are compounds that have the same chemical formula, but different structural formulasExample: C4H10Only carbon has these 4 characteristics
11Monomers are the individual subunits. Many carbon-based molecules are made of many small subunits bonded together.Monomers are the individual subunits.Polymers are made of many monomers.
12Carbohydrates Monomer monosaccharide Polymer disaccharide (dimer), polysaccharide ExamplesMonosaccharide: glucose, fructoseDisaccharide: sucrose (table sugar)Polysaccharide: starch & cellulose (cell wall in plants),glycogen (in animals)UniqueProvide a quick source of energy
13 glycerol & fatty acids; polar heads & fatty acid tails LipidsLIPIDSMonomer glycerol & fatty acids; polar heads & fatty acid tailsPolymer triglycerides; phospholipidsExamplesFats, oils, cholesterol, steroids, waxes, phospholipidsUniqueNonpolarBroken down to provide energyUsed to make steroid hormones (control stress, estrogen, testosterone)Phospholipids make up all cell membranes Fats and oils contain fatty acids bonded to glycerol
14Proteins Molecule Proteins Monomer Amino acid Polymer Polypeptide (protein) ExamplesEnzymes, hemoglobin (in blood), muscle movement, collagenUnique3D structure makes them active Peptide bonds hold amino acids togetherHave a side group (R) that makes each amino acid (and therefore protein) differentSometimes may contain sulfur
15Nucleic acids Molecule Nucleic acids Monomer Nucleotide (5-carbon sugar, phosphate group, & base)PolymerNucleic acid ExamplesDNA & RNA Unique - Order of the bases makes every living thing uniqueDNA stores genetic informationRNA builds proteins
16Chemical reactions release or absorb energy. Activation energy is the amount of energy that needs to be absorbed to start a chemical reaction
17A catalyst lowers activation energy. Catalysts are substances that speed up chemical reactionsDecrease activation energyIncrease reaction rate
18Enzymes are catalysts in living things. Enzymes allow chemical reactions to occur under tightly controlled conditions.Enzymes are catalysts in living things.Enzymes are needed for almost all processes.Most enzymes are proteins.
19Disruptions in homeostasis can prevent enzymes from functioning. Enzymes function best in a small range of conditions.Changes in temperature or pH can break hydrogen bonds.An enzyme’s function depends on its structure.
20An enzyme’s structure allows only certain reactants to bind to the enzyme. Substrates: reactants that bind to an enzymeActive site: area on the enzyme where substrates bind
21Exothermic reactions release more energy than they absorb. Excess energy is released by the reaction.Energy “exits” the reaction. (Exo = exit)
22Endothermic reactions absorb more energy than they release. Energy is absorbed by the reaction to make up the difference.Energy goes into the reaction. (Endo = “into”)
23The Cell Theory:All organisms are made of cells.All cells come from other cells.The cell is the basic unit of structure & function in living things.
24All cells share certain characteristics. Cells tend to be microscopic.All cells are enclosed by a membrane.All cells are filled with cytoplasm.All cells have ribosomes.
25There are two cell types: Eukaryotic cellsHave a nucleusHave membrane-bound organellesProkaryotic cellsDo not have a nucleus (still have DNA)Do not have membrane-bound organelles
26Review Eukaryotes Prokaryotes Have nucleus (DNA) Have membrane-bound organellesLarger size because of organellesMore complexUnicellular or multicellularNo nucleus (still have DNA)No membrane-bound organellesSmaller size because of lack of organellesLess complexUnicellular
27Organelles and Functions See attached list!!!How does the rough ER work with the Golgi?Rough ER packages the proteins its ribosomes synthesize (including membrane and secretory proteins) in vesicles to ship to the Golgi Apparatus/Body for further processing, sorting and packaging.
28Cell membranes are composed of two phospholipid layers. The cell membrane has two major functionsForms a boundary between inside and outside of the cellControls passage of materials in & out of cell
29Phospholipid Bilayer Forms a double layer surrounding a cell Head is polar (attracted to water) and forms hydrogen bonds with waterTails are nonpolar(repelled by water)
30Passive transport does not require energy (ATP) input from a cell. Molecules can move across the cell membrane through passive transport.Two types of passive transport:Diffusion: movement of molecules from high to low concentrationOsmosis: diffusion of water
31Diffusion and osmosis are types of passive transport (NO ENERGY) Molecules diffuse down a concentration gradient.High to low concentration
32Cell Membrane Dialysis Tubing – Diffusion Lab WHY? Starch stays in bag – too big. Iodine goes through bag - small
33How do different solutions affect cells? There are 3 types of solutions:Isotonic: solution has the same concentration of solutes as the cell.Water moves in and out evenlyCell size stays constant
34How do different solutions affect cells? There are 3 types of solutions:Hypertonic: solution has more solutes than a cellMore water exits the cell than entersCell shrivels or dies
35How do different solutions affect cells? There are 3 types of solutions:Hypotonic: solution has fewer solutes than a cellMore water enters the cell than exitsCell expands or bursts
36Some molecules can only diffuse through transport proteins Some molecules cannot easily diffuse across the membraneEx: glucose (needed by cell to make energy)Facilitated diffusion is diffusion through transport proteinsDOES NOT USE ENERGYVideo
373.5 Active Transport, Endocytosis, & Exocytosis Key Concept:Cells use energy (ATP) to transport materials that cannot diffuse across a membrane.
38Active TransportDrives molecules across a membrane from lower to higher concentrationGoes against the concentration gradient
39TYPES OF ACTIVE TRANSPORT Endocytosis: Brings materials into cell (Endo=into)Exocytosis: Releases materials out of cell (Exo=Exit)
40Sodium-Potassium Pump Uses a membrane protein to pump three Na+ (sodium ions) across the membrane in exchange for two K+ (potassium ions)ATP (energy) is needed to make the protein change its shape so that Na+ and K+ can move through it and cross the membraneHelps the heart contract, helps regulate blood pressure, allows neurons to respond to stimuli and send signals
414.1 How do living things get ATP? ATP is the energy carrier in living things – it is usable energy for the cell.ATP stands for Adenosine triphosphate.Living things get ATP from breaking down carbon based molecules. (carbohydrates & lipids)Starch moleculeGlucose molecule
434.2 & 4.3 PhotosynthesisThe process of photosynthesis captures energy from sunlight and converts it into sugar (glucose).This process happens in organisms called autotrophs or producers. (Need to make their own food)This process takes place in and organelle called the chloroplast.The chloroplast has a green pigment in it called chlorophyll that is responsible for capturing the light energy.
44So how does photosynthesis work? The first stage of photosynthesis is called the Light Dependent Stage.Light is captured by the chlorophyll in the thylakoid.
45So how does photosynthesis work? The second stage of photosynthesis is called the Light Independent Stage/ Calvin Cycle/ Dark Cycle.This process takes place in the stroma.
46The chemical formula for photosynthesis 6CO2 + 6H2O + light C6H12O O2(reactants) (products)Carbon dioxide plus water plus lightyieldsGlucose and oxygen
47Purpose of Cellular Respiration To make ATP from the energy stored in glucoseGlucose comes from an organism doing photosynthesis themselves or from eating foods containing glucoseRemember: the purpose of photosynthesis was just to get glucose
48GlycolysisTakes place in cytoplasm (eukaryotes and prokaryotes do this step since all cells have cytoplasm)Splits one glucose molecule into two pyruvate moleculesCosts the cell 2 ATP molecules to do this4 ATP molecules are produced (only gain 2 ATP)This portion of CR does NOT require oxygen (anaerobic)
49Kreb’s Cycle (Citric Acid Cycle) Takes place in matrix of mitochondria (only in eukaryotes)2 pyruvate (made during glycolysis) enter the mitochondrionEach pyruvate is broken down to create 1 ATPTotal products of Kreb’s cycle (because of 2 pyruvates):2 ATP
50Electron Transport Chain (ETC) Takes place in inner membrane of mitochondria (cristae)Folded to create more surface area for reactions to produce more ATP in a small spaceOxygen and hydrogen ions combine to form water (released as a waste product)32 ATP are made
51ATP from Cellular Respiration 4 from Glycolysis (uses up 2, so really only gain 2 ATP)2 ATP from Kreb’s cycle32 ATP from ETCGAIN 36 ATP from one glucose molecule
52Equation for Cellular Respiration C6H12O6 + 6O CO2 + 6H2O + 36ATPLike the reverse of photosynthesisEnergy transfers:Photo: LightCPE CR: CPECPE
53What happens when there’s no/not enough oxygen or there are no mitochondria? Answer: FermentationTwo Kinds:Lactic Acid FermentationAlcoholic FermentationAllows glycolysis to continue making ATP without oxygen