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73 Cards in this Set

  • Front
  • Back
• SCIENCE
method of investigation, involving the mind (logic), body (senses)
o Body of knowledge
o Way of knowing (w/ a certain point of view) (assumption)
• EXPERIMENTAL METHOD
• MAKE OBSERVATIONS – measurable sensory experiences
• ASK QUESTIONS – about oberservations
• FORMULATE HYPOTHESIS (prediction) – (tentative answers) testable/consistent/predictive
• MAKE PREDICTIONS – based on hypothesis
• TEST HYPOTHESIS – conclusive/repeatable
• ANALYZE RESULTS (data) – tables/graphs/statistics
• DRAW CONCLUSIONS – accept/modify/reject hypotheses
• CONTRUCT THEORIES – well tested hypotheses
• EXPERIMENTAL METHOD IN USE
• MAKE OBSERVATIONS – some frog species have declined in certain areas around the world, especially in mountains.
• ASK QUESTIONS – why have these species declined in those areas and more so at high elevations?
• FORMULATE HYPOTHESES – scientists identified environmental factors that change with elevation, including UV-B radiations.
• Hypothesis: Declines in some frog species are due to increased exposure to UV-B radiation.
• MAKE PREDICTIONS – prediction: Reducing exposure of developing frogs to UV-B radiation should improve survival.
• TEST HYPOTHESIS – Response of tadpoles of two frog species from Australian mountains were tested. Littoria verreauxii had disappeared from high elevations; Crinia signiera had not. Scientists predicted l. verreauxii tadpoles would survive less well than C. signigera tadpoles when exposed to UV-B radiations typical of high elevations.
• ANALYZE RESULTS – L. Verreauxii survived less well in tanks exposed in UV-B radiation. Both species survived well in tanks with liters that blocked UV-B radiation.
• DRAW CONCLUSIONS - the experiments confirmed the hypothesis.
• COMPARITIVE METHOD
• MAKE OBSERVATIONS ABOUT SITUATION – measurable sensory experiences
• ASK QUESTIONS - about observations
• FORMULATE HYPOTHESES ABOUT SITUATION – tentative answers; testable/consistent/predictive
• PREDICT PATTERNS – based on hypotheses
• TEST HYPOTHESES – conclusive/repeatable
• OBSERVE PATTERNS – compare with predicted patterns
• ANALYZE RESULTS - tables/graphs/statistics
• DRAW CONCLUSIONS – accept/modify/reject/hypotheses
• CONSTRUCT THEORIES – well-tested hypotheses
• COMPARITIVE METHOD IN USE
• MAKE OBERSERVATIONS OF SITUATION – there are regional differences in the decline of populations of certain frog species.
• ASK QUESTIONS – why are these declines occurring in some regions and not in others?
• FORMULATE HYPOTHESIS ABOUT SITUATION - the frogs are sensitive to urban and agricultural air pollutants and affected adversely by them.
• PREDICT PATTERNS – Population declines should be greater in areas exposed to such pollutants than in unexposed areas.
• GATHER DATA ABOUT SITUATION – Scientists conducted a census of several amphibian species to determine whether there ere present of absent at hundreds of study sites across California.
• OBSERVE PATTERNS – One species, Rana aurora, was more likely to be absent from sites downwind of large urban and agricultural areas but present in sites upwind.
• MAKE COMPARISONS – Scientists compared the actual results with those predicted by the hypothesis.
• ANALYZE RESULTS – Rana aurora population declines had occurred where expected.
• DRAW CONCLUSIONS – the census data confirmed the hypothesis for Rana aurora.
• ATOMS
: the constituent of matter
• Contain: a central nucleus
• Protons & Neutrons
 Peripheral shells (energy levels)
• Electrons
• Matter: occupies space and has mass
• Element- distinctive kind of matter
• Atom: smallest unit of an element <~ contains only one kind of atom
• P - +1, 1 amu
• n- 0, 1 amu
• e - -1, 0.0005 amu
• PROPERTIES OF ATOMS
• Atomic number – protons – unique to each element
• Atomic mass – protons + neutrons – varies within each element
• Atomic Charge - +charges vs. – charges (what it attracts and repels) – positive, negative, or neutral.

• ATOMS
• Chemical Symbols: represent elements and their atoms
• Elements present in bulk amount in living things ~> CHNOPS
• Elements present in small amounts in living things ~> Cl, Na, K, Fe, Mg
• The periodic table arranged elements in rows according to atomic number in columns according to similar properties.
• Ions that have lost electrons become positive (cations) - Na
• Ions that have gained electrons become negative (anions) – Cl
• Isotopes with the same atomic number but different atomic mass
• Radioisotopes: unstable and radioactive some used in medicine and research
• ATOMS
• Valence(outermost) shell determines chemical reactivity
• Reactive atom: which unfilled valence shell, is unstable, and interacts with other atoms (to fill valence shell0
• Inert Atoms: filled valence shell, stable, does not interact.
• Electrons in shells closer to the nucleus have less energy than those further from nucleus.
• CHEMICAL BONDS: LINKING ATOMS TOGETHER
• Molecular Weight: Sum of atomic mass in molecule or compound
• P=E
• Tritium – 31H
• Covalent Bond – Chemical bond in which two atoms share one or more electron pairs.
• Single Covalent – Share one electron pair
• Double Covalent – Share two electron pairs
• Triple Covalent- share three electron pairs
• Chemical Bond – force that stabilizes reactive atoms by linking them together
• Molecules – group of atoms linked by chemical bonds
• Compound – group of different atoms linked by chemical bonds
• Structural Formula: show #/ kinds/arrangement
• Empirical Formula: show #/kind of atom
• CHEMICAL BONDS LINKING ATOMS TOGETHER
• Nonpolar covalent: same kind of atoms (same electronegativity) share electron pairs equally.
• Polar Covalent: different kinds (different electronegativities) share electron pairs unequally
• Shared electrons move closer to nucleus that has greater electronegativity
• Electronegativity – attractive force nucleus exerts on electron
• Weak bond that may form within or between polar molecules
• Ionic bond- chemical.
• CHEMICAL BONDS
• Nonpolar Covalent
• Hydrophobic
• Do not interact with/dissolve in water
• Oil/wax
• Polar Covalent
• Hydrophilic
• Do interact with/dissolve in water
• Sugar-salt, bc water and these have little charges
• Nonpolar molecules interact with one another due to weak van der waals forces (weakest bond) – shifting electron distributions within them.
• CHEMICAL BONDS
• Ionic bond: chemical bond in which an atom of lower electronegativity transfers one or more electrons to an atom of higher electronegativity.
• Electron transfer creates two oppositely charged ions which then attract each other.
• Functional group: Charged group of covalently bonded atoms. (PO43-, SO43-, NH4+)
• WATER: STRUCTURES & PROPERTIES
• Chemical reaction: makes/breaks chemical bonds, releases/stores chemical energy
• Reactants -> products: a chemical reaction is written s a balanced equation energy same as energy on other side of atoms.
• -
• Water has unusual properties due to molecular shape, polarity, and hydrogen bonding.
• Cohesion ->capillary & surface tension (hydrogen bonds: hold water together)
• High heat capacity -> heat storage
• High heat of vaporization -> temperature moderation
• Freezing density -> lake insulation
• Slight reactivity ->universal solvent
• Solute dissolved in solvent ->solution
• ACIDS BASES AND PH SCALE
• Acids dissolved in water ionize release H+
• Strong acid dissolves completely example HCl, irreversible
• Weak acid dissolves incompletely example H2CO3, reversible
• Organic acids may have a carboxyl group (-COOH)
• -COOH -> -COO + H+
• ACIDS BASES AND PH SCALE
• Molecules vary in size, shape, structure, reactivity, solubility (ability to dissolve in water)
• Bases dissolved in water ionize accept H+
• Strong base: dissolves completely, ex. Na-OH, irreversible
• Weak Base: dissolves incompletely NH4-OH, reversible
• The hydroxyl ion (OH) then accepts H+ - H2O
• Organic bases may have an amino group (-NH2)
• -NH2 + H+ -> -NH3
• Buffer: a mixture of a weak acid and a weak base minimize ph change.
• PROPERTIES OF MOLECULES
• Isomers: same molecule different structure
• Structural isomers: molecules with same chemical formula, but atoms linked in different ways
• Optical isomers: molecules with same chemical formula but atoms linked as mirror images.
• Isomers have different chemical properties.
• PROTEINS: polymers of amino acids
• Atoms: CHON
• Structural Units: Amino Acids
• Linkages: Peptide (covalent bond between amino acids)
• Functions: Structural, Enzymatic
• Special Features: Four Structural Levels
• Examples: Hemoglobin, Insulin
• -
• Polymers: large molecules composed of monomer chains
• Monomers: small molecules w/ similar chemical structures linked to form polymers.
• Mer=piece
• Monomer-shapes/chemical properties determine polymer function
• Molecular weight > 1000
• Dehydration (condensation) synthesis – removes h20, stores energy, constructive.
• Polymerization-putting monomers together to make polymers
• Depolymerization – taking a polymer apart into its monomers
• Hydrolysis: add h20 to break apart, release energy, destructive.


• #22
• PROTEINS POLYMERS OF AMINO ACIDS
• Primary structure: polypeptide chain – determined by #, kind, sequence of amino acids
• Secondary Structure: polypeptide chain
o Alpha helix – twisted chain
o Beta pleated sheet
• Tertiary structure
o Fold the helix
o Determined by Nitrogen group interactions
• Quaternary structure- polypeptides determined by subunit interactions
• Renaturation – usually impossible
• Disulfide bonds and H bonds between amino acids to hold form
• denatured- not in natural shape causes pH, salinity, temp, redox conditions
• Denaturation – disrupts secondary/tertiary structure destroys function
• Peptide-linkages- form between amino acids
• Amino groups joins carboxyl groups to produce
o Dipeptides – 2 linked amino acids
o Tripeptides- 3 linked amino acids
o Polypeptides – many linked amino acids
• Proteins- very long peptides
• CARBOHYDRATES: Sugars and sugar polymers
• Atoms: CHO
• Structural Units: Monosaccharides
• Linkages: Glycosidic
• Functions: Structural; immediate energy
• Special Features: Skeletons for other molecules
• Examples: Glucose (monosaccharide)
 Sucrose (disaccharide)
 Starch (polysaccharide)
• CARBOHYDRATES
• Monosaccharide
• Disaccharides – two monosaccharide
• Oligosaccharides- few monosaccharide
• Polysaccharides- many monosaccharides.
• Sugars can be modified by adding functional groups.
• LIPIDS
• Atoms: CHO
• Structural Units: Glycerol; Fatty acids
• Linkages: Ester
• Functions Structural; Stored Energy
• Special Features: insoluble in water
• Examples: Phospholipids; fats
• LIPIDS
• Unsaturated – C-C & C=C bonds, flexible, bent in plant oils, liquid @ room temperature -> food processors remove (=) to make more like animal fat - > saturated w/ hydrogen’s: C-C bonds only rigid/straight in animal fats, make fats solid @ room temperature.
• -
• Bonds=covalent
• Nucleotides are composed of three components
• Nitrogen-containing base – the nitrogenous bases fall into two categories
o Base
 Pyrimidines have 1 ring (C,T,U)
 Pyrines have two rings (A,G)
o Ribose or deoxyribose = nucleoside + phosphate = nucleotide
• Pentose sugar (ribose or deoxyribose)
• Phosphate groups
• NUCLEIC ACIDS
• Atoms: CHONP
• Structural Units: Nucleotides
• Linkages: Phoshpdiester
• Functions: Information Storage/Transfers
• Special Features: Replicate
• Examples: DNA/RNA
• -
• DNA-RNA contain a serried of phosphate groups and pentose that for the backbone of structure
• -in RNA, bases are attached to ribose, the bases A, G, C, and U
• -in DNA, bases are attached to deoxyribose, the bases are A, G, C, and T; contains deoxyribose sugar
• -RNA: single stranded; DNA- double stranded
• -The numbering of ribose carbons is the bases for identifying the 5’ &3’ end of DNA&RNA strands
• -Strands are anti-parallel
• Stands are complementary- C, G- A, T
• THE CELL
• Cell theory – cells are fundamental units of life, all organisms composed of cells, all cells from preexisting cells.
• -Control system: information processing; in all cells
 nucleus (ei)
 nucleolus (-li)
 chromosomes
 ribosomes
• Endomembrane system – materials conversion
• Endoplasmic reticulum (ER)
• Golgi Apparatus
• Vacuaoles
• Lysosomes – in plants only
• Cytoskeleton system- support movement
• Microtubules- in all cells
• Immediate filaments- in all cells
• Microfilaments all cells
• Centrioles-in animals
• Flagellum-in animals
• Cilium-in animals
• Cell wall – in plants only
• Metabolic system- energy transformation
• Mitochondrion-in all cells
• Chloroplasts – in plant cells.
• -
• PLASMA MEMBRANE
• Structure: lipid/protein cell boundary
• Functions: cellular integrity
• Transport interface
• Molecular organizer
• Organelles: bodies within cell having: unique structures
 Specific functions
• NUCLEUS
• Structure: nucleoplasm (interior fluid of nucleus) with lamina (meshwork) nuclear envelope (double membrane) with ports
• Functions: cell control
• NUCLEOLUS
• Structure: RNA-protein region inside nucleus
• Functions: Ribosome synthesis – make proteins.
• CHROMOSOMES
• Structure: DNA/protein threads inside nucleus
• Functions: Information storage
• CHROMATIN-mass of indistinguishable chromosomes
• RIBOSOMES
• Structure: large & small RNA/protein subunits in cytoplasm & on ER
• Functions: protein synthesis

• ENDOPLASMIC RETICULUM – a network of membrane inside the fluid
• Structure: Interconnected membranes in cytoplasm
• Functions
• Rough (RER):
 Protein
 Segregation/modification/transport
• Smooth (SER)
 Protein modification
 Glycogen hydrolysis
 Lipid synthesis
• GOLGI APPARATUS
• Structure: flattened membranous
• Cisternae & vesicles
• Cis/medial/trans regions
• Functions: proteins
• Storage/modification/packaging
• Cell wall (plants) polysaccharide synthesis
• LYSOSOMES
• Structure: membranous sacs
• Functions: Digestion
• -
• The Golgi chemically modifies proteins in its lumen and targets them to correct address
• VACUOLES
• Structure: membranous sacs
• Function: food/waste/pigment
 Storage
 Support
 Turgor in plants
• MITOCHONDRIA
• Structure: outer smooth membrane
• Inner wrinkled membrane: cristae
• Internal space – matrix
• Functions: respiration
• CHLOROPLASTS
• Structure: outer smooth membrane
• Inner wrinkled membrane (thylakoids)
• Internal space (stroma)
• Functions: Photosynthesis
• CHROMOPLASTS
• Contain red/orange/yellow pigments
• Leucoplasts: store starch/oils
• MICROTUBLES
• Structure: hollow cylinders or tubulin subunits
• Functions: support tracts (for organelle movement)
• INTERMEDIATE in size FILIMENTS
• Structure: tough fibers of keratin subunits
• Functions: suppose (Resist tension)
• Found only in multicellular organisms
• MICROFILIMENTS
• Structure: filaments/bundles/networks of actin subunits
• Functions: support contract for cell/organelle movement
• -
• Long thin fibers of cytoskeleton play three roles:
• Maintain cell shape & support
• Provide cell movement
• Help move things within the cell
• CENTRIOLES
• Structure: paired 9+0 microtubular triplets
• Functions: form spindle during cell division (attach to chromosomes to keep them in order while separating
• FLAGELLA
• Structure: long & few 9+2 microtubular doublets
• Functions: move cell with whip-like undulations
• CILIA
• Structure: Short & numerous 9+2 microtubular doublets
• Functions: Move cell with oar-like strokes
• CELL WALL
• Structure: rigid cellulose surface covering
• Functions: support, protection
• FLUID-MOSAIC MODEL OF CELL MEMBRANE
• Proteins float in phospholipids bilayer
• Integral proteins: have hydrophobic regions can penetrate bilayer
• Peripheral proteins: Lack hydrophobic regions cannot penetrate bilayer
• CELL RECOGNITION AND ADHESION
• Allows cells to form tissue-specific and species-specific aggregations
• TIGHT JUNCTIONS
• Membrane-protein mesh
• Brings epithelial cells together
• Prevents substances moving through intercellular space
• Restricts membrane protein. Phospholipids movement from one cell region to another
• DESMOSOMES
• Membrane-plaque (flat structure) anchor intracellular adhesion proteins and cytoplasmic intermediate filaments
• Bind epithelial cells together
• Strengthen cells
• Allow substances to move through intercellular space.
• GAP JUNCTIONS
• Protein channels (connections) span intercellular space
• Allow molecules/electric signals to move through intercellular space
• Facilitate cell communication
• PLASMODESMATA – in plants cells
• ER- lined tubes (desmotubles) span cell walls
• Allow small molecules/ions to move across cell walls
• Facilitate cell communication
• PROCESS OF MEMBRANE TRANSPORT
• Biological membranes are selectively permeable (some substance can cross/other substances cannot cross
• Factors affecting passage:
 Size-small particles cross with ease large particle cross with difficulty
 Charge- uncharged/nonpolar particles cross with ease charge/polar particles cross with difficulty
 Phospholipids have a slightly negative charge
• DIFFUSION
• Random movement of particles
• NET DIFFUSION: diffusion down a concentration gradient until uniform particle distribution (or equivalent) results
• Factors affecting rate: temperature, particle size, charge, concentration
• Solutes distribute themselves by diffusion uniformity and independently of each other
• OSMOSIS
• Diffusion of H20 across a selectively-permeable membrane
• Net osmosis: osmosis draw a concentration gradient until uniform particle distribution or equivalent results
• -
• Isotonic solution- same [solute] concentration as another solution
• Hypotonic solution- lower [solute] concentration than another solution
• Hypertonic solution – higher [solute] concentration than another solution
• FACILITATED DIFFUSION
• Diffusion across a selectively-permeable membrane with help of specific proteins [hi->lo]
• Channel proteins- aid passage of polar (have charges and might get stuck in the negative permeable membrane) molecules/ions by forming pores
• Carrier proteins – aid passage of polar molecules by binding/releasing them; carrier molecules/ ions to other side
• Diffusion rates increases then plateaus because the cell runs out of transporters
• ACTIVE TRANSPORT
• Movement of substances up a concentration gradient across a selectively permeable membrane with the help of specific proteins
• VESICULAR TRANSPORT – a small vacuole
• Bulk movement of materials I vesicles into/out of cell without passing through membrane
• ENDOCYTOSIS- membrane invaginates to engulf materials
• Phagocytosis- intake solids
• Pinocytosis-intake liquids
• EXOCYTOSIS- membrane evaginates to secrete materials
• ENERGY AND ELECTRONS FROM GLUCOSE
• Glucose is the most common energy molecule. When oxidized (combined with oxygen) it breaks down releasing energy
• Complete chemical breakdown of glucose
• C6H1206 ->602->6C02 + 6H20 + energy
• Change in G = -686 kcal/mole
• COMBUSTIVE OXIDATION- releases energy in a single burst
• METABOLIC OXIDATION – releases energy in several steps –about half is stored in ATP
• Three metabolic processes breakdown glucose:
• Glycolysis
• Cellular respiration
• Fermentation
• GLYCOLYSIS- ring form in body, hexose
• Incomplete oxidation
• Anaerobic (does not require O2)
• Converts glucose to 2 pyruvate molecules
• Stores captured energy in 2 ATP molecules (net)
• Begins glucose metabolism in all cells
• CELLULAR RESPIRATION
• Complete oxidation of molecules
• Aerobic (requires o2)
• Converts pyruvate to CO2 and H20
• Stores captured energy in 34 ATP molecules (net)
• FERMENTATION
• Incomplete oxidation
• Anaerobic (does not require o2)
• Converts pyruvate from glycolysis into lactic acid or ethanol + CO2
• Stores captured energy in 2 ATP molecules (net)
• OXIDIZING AGENT
• Accepts electrons/hydrogen atoms from another substance. It is reduced
• REDUCING AGENT
• Donates/electrons/hydrogen atoms to another substance. It is oxidized.
• During breakdown of glucose:
• Oxygen is oxidizing agent (is reduced)
• Glucose is reducing agent (is oxidized)
• Redox reactions
• Oxidation = loss of e-, H+, & energy
• Reduction = gain of e-, H+, and energy
• Whenever material is oxidized another is reduced
• Oil Rig: Oxidation is loss, reduction is gain.
• OXIDIZING AGENT- brings about oxidation
• Accepts electrons/hydrogen atoms from another substance. It is reduced
• REDUCING AGENT
• Donates electrons/hydrogen atoms to another substance. It is oxidized.
• During the breakdown of glucose
• Oxygen is oxidizing agent (is reduced)
• Glucose is reducing agent (is oxidized)
• ENERGY AND ELECTRONS FROM GLUCOSE
• Coenzyme NAD is a redox intermediate during metabolism
• NAD+ is oxidized form.
• NAD + H+ is reduced form.
• Reduction reaction endergonic:
• NAD+ +2H + ENERGY -> NADH + H+
• Oxidation reaction exergonic
• NADH + H+ ½ O2 - > NAD+ +H20 +ENERGY
• GLYCOLYSIS
• Energy – transformation in cells occur in interconnected metabolic pathways
• When O2 is present:
• Glycolysis, cellular respiration, pyruvate oxidation, citric acid cycle, respiratory chain (electron transport chain)
• When o2 absent:
o Glycolysis and Fermentation
• Inside Mitochondrion on Cristae:
• Pyruvate oxidation
• Respiratory Chain
• In matrix
• Citric Acid Cycle
• Outside Mitochondrion:
• Glycolysis
• Fermentation
• -
• Energy- Investing reactions – use ATP
• Glucose destabilized by phophorylation (With 2 ATP’S) – step 1 & 3
• Resulting molecule splits into 2 3-carbon molecules: DAP + G3P <- (2 molecules of G3P for every glucose) – step 4
• DAP converted to G3P- step 5
• ENERY HARVESTING REACTIONS – produce ATP
• Two G3Ps phosphorylated (with inorganic phosphates and oxidized (gains H+, e-, energy) by NAD+s – step 6
• Succeeding molecules dephosphorylated to produce 4 ATPs (substrate-level phosphorylation) – step 7 & 10
• Two 3-carbon pyruvates formed – step 10
• 1 GLUCOSE NETS:
• 2 ATP
• 2 NADH + H+
• 2 PYRUVATE
• PYRUVATE OXIDATION – in matrix
• Each pyruvate is oxidized (Take away H+, e-, energy) by NAD+ and splits into acetate +CO2
• Each acetate +coenzyme A -> Acetyl CoA (some energy stored temporarily)

• KREBS CYCLE-CITRIC ACID CYCLE – in matrix
• Each acetyl CoA enters Citric Acid Cycle
• Succeeding molecules oxidized, dephosphorylated, & rearranged
• Each turn of cycle (2) generates- will turn twice for each glucose molecule
 3NADH + H+
 1 FADH2
 1 ATP
 2 CO2
• 6-CO2, H20 left over from glucose
• ELECTRON TRANSPORT CHAIN-RESPIRATORY CHAIN –last step
• Glucose energy is lost because of 2nd law of thermodynamics
• It is to react by adding phosphate (2) from ATP
• Oxidizing lose- energy, electrons, hydrogen
• Put into NAD wagons (2)
• Remove phosphate and make ATP (happens twice for each = 4 ATP) dephosphorylation
• Which makes pyruvate, which we oxidize – pyruvate oxidation
• Pyruvate oxidized in citric acid cycle
• -
• Electrons flow from NADH + H+ and FADH2 to oxygen through a series of carriers on inner membrane (cristae)
• 02 +4H+ + 4e- -> 2 H20
• RESPIRATORY CHAIN
• Sub-level phosphorylation – ADP -> ATP, energy from redox
• Cellular Respiration
• Made 40 ATP – used 2 during glycolysis
• 38 ATP – 2 in pyruvate oxidation = 36 ATP
• Chemiosmosis
• The resulting redox reactions (1st step) actively transport (2nd step) H+ (protons) across membrane (inner membrane of cristae) from matrix to intermembrane space.
• An electrochemical gradient (proton-motive force) results
• Store ATP
• ATP synthase (3rd step) allows H+ to diffuse back across membrane through proton channels and synthesizes ATP (oxidative phosphorylation) – ADP -> ATP, H+ go back through and combine with CO2
• Every 2 e- flowing along chain from NADH + H+ -> 3 ATP
• Every 2 e- flowing along chain from FADH2 -> 2 ATP
• LACTIC ACID FERMENTATION
• NADH + H+ reduces pyruvate (from glycolysis) to lactate
• NAD+ replenished for continued glycolysis and ATP production
• Occurs in certain bacteria and oxygen-starved muscles.

• ALCOHOLIC FERMENTATION
• CO2 removed from pyruvate (from glycolysis)
• Acetaldehyde forms
• NADH + H+ reduces - H+, e-, energy give it to acetaldehyde to form ethanol
• NAD+ replenished for continued glycolysis and ATP production
• Occurs in certain yeasts
• ONE GLUCOSE
• In glycolysis pyruvate oxidation and citric acid cycle
 40 ATP (gross)
 -2 ATP to activate glucose in glycolysis
 -2 ATP to shuttle NADH + H+ across inner membrane in glycolysis
• In fermentation
 2 ATP (net)
 End products still contain much energy
• RELATIONSHIPS BETWEEN METABOLIC PATHWAYS
• Glucose metabolism is central to other metabolic pathways
• Catabolic interconverstions: macrmolecules hydrolyzed into metabolic intermediates
• Anabolic interconversions: Metabolic intermediates synthesized into macromolecules
• Cells maintain metabolic homeostasis by regulating enzymes of catabolism and anabolism
• The metabolic pool (levels of biochemicals) in remarkably constant
• PHOTOSYNTHESIS
• Plants obtain CO2, H20, and NH4 (for nucleic acids) from environment and ATP from glycolysis/ cellular respiration or fermentation
• 6CO2+12H20 - > C6H12O6 + 6O2 + 6H20 – photosynthesis reaction
• THER INTERACTIONS OF LIGHT AND PIGMENTS
• Photosynthesis occurs in two sets of chemical reactions: light and CO2 fixation reactions (Calvin Benson cycle)
• Light is a part of electromagnetic spectrum. It manifests as photons (units of light) or waves
• Wave energy inversely proportional to wavelength (color)
• Wavelengths (colors of light) measured in nanometers (nm)
• INTERACTIONS OF LIGHT AND PIGMENTS
• Photons can be biologically active when sufficiently energetic and absorbed by molecules.
• In photon-molecule interactions, photons may be scattered (bounce off), transmitted (pass through) or absorbed
• A pigment absorbs certain wavelength of light, and is raised from ground state to excited state
• Electrons jump to higher energy levels
• An absorption spectrum plots light absorption as functions of wavelength
• An action spectrum plots biological activity of function of wavelength
• Chlorophyll pigments – absorb blue and red wavelengths
• Accessing pigments – absorb intervening wavelengths
• INTERACTIONS OF LIGHT AND PIGMENTS
• Antenna system – set of pigments packed on thylakoid membranes
• Reaction Center – are of antenna system where pigments transform (absorbed light energy to usable chemical (electron) energy
• An excited pigment may release the energy (fluoresce) or pass it along to reaction center
• Excited – energy moving from lower to higher energy levels
• Energized electrons jump from excited chlorophylls (chlorophyll alpha in plants) in reaction center and enter redox reactions (electron acceptor)
• Light reactions in thylakoid membrane
• LIGHT REACTIONS
• Photosystem 1 (P700nm)
 Antenna system whose reaction center best absorbs light of wavelength 700nm and donates electrons to an electron transport chain, replacing them with electrons from photosystem II
• Photosystem II – P680nm
 Antenna system whose reaction center best absorbs light of wavelength 680nm and donates electrons to an electron transport chain, replacing them with electrons from H20
• LIGHT REACTIONS
• Electrons released from photosystem flow through electron transport chain on thylakoid membranes
• Non-cyclic transport -> ATP +NADPH+ H+ 02 using water and photosystems I and II.
• Cyclic electron transport -> ATP using photosystem I
• CHEMIOSMOSIS
• Redox energy released in cyclic and non cyclic electron flow actively transports H+ (protons) across thylakolid membrane from stroma to thylakoid (intermembrane) space
• An electrochemical gradient (proton-motor forces) results
• ATP synthase allows H+ to diffuse back across membrane through proton channels and synthesize ATP – phosphorylation
• Energy 2 e- flowing along chain from photosystems -> 1 ATP
• ATP synthase couples fermentation of ATP
• CALVIN-BENSON CYCLE- in stroma
• CO2 fixation – attach CO2 to a molecule by the enzyme rubisco
• Reduction and production of G3 ( using ATP and NADHPH + H+) from light reactions on thylakoids
• Regeneration of RuBP using ATP
• CALVIN-BENSON CYCLE- through holes in stromata
• As CO2 molecules enter Calvin-Benson cycle, rubisco (enzyme) fixes each to RuBP (ribose 1, 5-biphosphate)
• Succeeding molecules reduced, phosphorylated, & rearranged
• -
• Each turn:
• Uses 2 NAPH + H+
 3 ATP
• Generates 2 G3P (glyceraldehydes 3-phophate)
• ENERGY AND ENERGY CONVERSIONS
• First law of thermodynamics – during energy transformations energy quantity (amount) is unchanged
• ENERGY INPUT = ENERGY OUTPUT
• Second law of thermodynamics – during energy transformations, energy quality (usefulness) is decreased
• USED ENERGY = USELESS ENERGY
• ENERGY AND ENERGY CONVERSIONS
• Entropy- tendency toward disorder due lack of useable energy. Ex. A road, a messy kid room.
• CLOSED SYSTEM- thermos bottle, no system-environment energy exchange
 Entropic (disorder overwhelms system) change stops
• OPEN SYSTEM –living cell, system-environment energy exchange
 Negentropic (system resists disorder) change continues.
• ENERGY AND ENERGY CONVERSIONS
• Free energy (G) - useable energy (Can do work) in a chemical reaction
• Entropy (S) – unusable energy (cannot do work) in a chemical
• Enthalpy (H) – total energy (usable & unusable) in a chemical reaction
• Absolute Temp (T) – Temperature scale based on absolute 0 (-273.15 degrees Celsius)
• Change in G = Change in H – Tchange in S
• ENERGY AND ENERGY CONVERSIONS
• Endergonic (nonspontaneous) reaction
 Change in G > 0(net free energy input) = positive
 Dehydration Syntehsis
• Exergonic (spontaneous) reaction
 Change in G <0 (net free energy output)
• ENZYMES: BIOLOGICAL CATALYSTS
• Energy barrier: thermodynamic resistance to reaction
• Activation Energy (Ea) – energy needed to overcome energy barrier
• Transition state- unstable intermediate condition following activation
• ENZYMES: BIOLOGICAL CATALYSTS
• Cofactors – inorganic/ bind temporarily to enzyme
• Coenzymes – organic/bind temporarily to enzyme
• Prosthetic group- organic/ bind permanently to enzyme
• Catalyst- lowers energy barrier speeds up chemical reaction does not change equilibrium point/change in G not altered by reaction
• Enzyme- protein catalyst combines with specific substrate
• Substrate binds specifically to active site or enzyme (lock and key)
• Enzyme changes shape (induced fit)
• Reaction occurs product released enzyme unaltered.