the Cell Energy To move or rearrange matter Kinetic energy Motion Light Heat Potential Energy Location or Structure Chemical Energy potential energy of molecules Thermodynamics Energy transformations The System and The Surroundings ID: 567189
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Slide1
Workings of
the CellSlide2
Energy
To move or rearrange matter
Kinetic energyMotionLightHeatPotential EnergyLocation or StructureChemical Energy – potential energy of moleculesSlide3
Thermodynamics
Energy transformations – The System and The Surroundings
Open or ClosedFirst Law: Conservation of EnergySecond Law: EntropySlide4
Energy in Chemical Reactions
Potential energy
diferenceEndergonic ReactionsPhotosynthesisExergonic ReactionsCombustionRespirationCellular Metabolism
Energy CouplingSlide5
Adenosine Triphosphate
Stacked charge (-)
ATP to ADPCompressed SpringChemical: endergonic phosphorylationMechanical: phosphorylation of motor proteinsTransport: phosphorylation of membrane proteinsATP is recycledSlide6
Enzymes
Activation Energy
Heat and reaction ratesEnzymes and reaction ratesSlide7
Enzymes have specific tasks
Substrate
Active siteBonding and Induced FitEnzyme remains unchangedSlide8
Enzyme shape and function
Enzymes are required for most metabolic processes
Most enzymes are proteins (some RNA)TemperatureSalinity and pHCofactors – ions of copper, zinc, etc.Coenzymes – organic cofactors, vitaminsOften necessary to enzyme function
Examples: enzymes in human vs. bacteria and
stomach vs. duodenumSlide9
Enzyme Inhibitors
Poisons and Toxins bond covalently (irreversible)
Reversible inhibitors bond with HydrogenCompetitive inhibitor: binds to active siteHow can we overcome?Noncompetitive inhibitor: Changes enzyme shape/functionRegulating metabolismFeedback inhibition: products inhibit enzymesSlide10
Enzymes in membranes
The assembly line – substrate to enzyme to products = substrate for the next enzyme
Many organelles use this assembly line approachSelective permeability at cell borderSlide11
Phospholipids
Phosphate group and two fatty acids
Similar structure to fatsPolar and nonpolarSlide12
A Mosaic
Many different proteins embedded
Fluid drift - Double bonds in fatty acid tailsSkeletal linkagesProtein functionsGlycoprotein and glycolipid fingerprintsSlide13
Passive Transport
Diffusion
Concentration GradientPassive TransportNonpolar moleculesIons and transport proteinsSlide14
Facilitated Diffusion
Protein transport provides window
No energy required – concentration gradientProtein is specific to substanceSugars, amino acids, ions, etc.Aquaporins – water passageSlide15Slide16
Water Balance
Tonicity – to lose or gain water
Isotonic – same solute concentrationRed blood cellsMarine animalsHypotonic – Low extracellular solute concentrationHypertonic – High extracellular solute concentration
Osmoregulation – kidneys and cell wallsSlide17
Exo- and Endo-
cytosis
Macromolecules passing through the membraneExocytosis – releaseEndocytosis – intake PhagocytosisPinocytosisSlide18
Metric
1 x 10
6 - Mega (M) - uncommon1 x 103 - Kilo (K)Base unit1 x 10-3 - Milli
(m)
1 x 10
-6
- Micro (
μ
)
1 x 10
-9
- Nano (n)
1 x 10
-12
- Pico (p)