Attributes of LifeAttributes of Life16 and 21 November16 and 21 November

Introduction to lifeIntroduction to life Themes/characteristics of living Themes/characteristics of living

organismsorganisms Structural and functional Structural and functional

characterscharacters

IntroductionIntroduction

What defines life?What defines life? ________________________________ ________________________________ ________________________________

ThemesThemes

Hierarchy theory and emergent propertiesHierarchy theory and emergent properties Structure: “it is the cell”Structure: “it is the cell” Continuity of life: function of “information”Continuity of life: function of “information” Openness of biological systemsOpenness of biological systems Regulatory capacity of living systemsRegulatory capacity of living systems Capacity to reproduceCapacity to reproduce Capacity to acquire, utilize, and store energyCapacity to acquire, utilize, and store energy Diversity and similarity of living systemsDiversity and similarity of living systems

Hierarchical Nature of Hierarchical Nature of Living SystemsLiving Systems

CommunityCommunity PopulationPopulation

OrganismOrganism OrganOrgan TissueTissue CellCell OrganellesOrganelles

MacromoleculesMacromolecules

AtomsAtoms

InfrastructureInfrastructure

Cell: Structure and Cell: Structure and FunctionFunction

Organism’s basic unit of structure and Organism’s basic unit of structure and functionfunction Lowest level of structure capable of Lowest level of structure capable of

performing life’s activities (e.g., irritability, performing life’s activities (e.g., irritability, reproduce, grow, develop, etc.)reproduce, grow, develop, etc.)

Most common basic structure of all living Most common basic structure of all living organisms organisms

Cell TheoryCell Theory Ubiquitous nature of cellsUbiquitous nature of cells All cells come from previous cellsAll cells come from previous cells

General Cell StructuresGeneral Cell Structures

Continuity of Life and Continuity of Life and InformationInformation

Order in any system originates from Order in any system originates from instructions serving as a template for instructions serving as a template for organization (e.g., Constitution, Bill of organization (e.g., Constitution, Bill of Rights)Rights)

In living systems, instructions codified in In living systems, instructions codified in the DNAthe DNA

Instructions/inheritance based on the Instructions/inheritance based on the precise, sequential order of nucleotides precise, sequential order of nucleotides (ATCG)(ATCG) Example: RAT versus TAR versus ARTExample: RAT versus TAR versus ART

Open SystemsOpen Systems All living organisms are open systems, living organisms are open systems,

allowing organisms to interact with their allowing organisms to interact with their environmentenvironment Processing stimuliProcessing stimuli Responding to stimuliResponding to stimuli

““Open” versus a “closed” systemOpen” versus a “closed” system ExamplesExamples

Orientation of leaves to sunOrientation of leaves to sun EyesEyes Microbes and single cell organisms (e.g., Microbes and single cell organisms (e.g.,

amoeba)amoeba)

Examples of Open Systems

26-580Figure 26.41

Eye

Sun-Tracking Plants

Regulatory SystemsRegulatory Systems Interplay of organisms with the Interplay of organisms with the

environment requires a well balanced environment requires a well balanced regulatory systemregulatory system

Outcome: Outcome: homeostasishomeostasis Set point, effectors, control centers and Set point, effectors, control centers and

sensorssensors Analogy: thermostat for heat controlAnalogy: thermostat for heat control ExamplesExamples

Enzymes in cells (lab exercise this week)Enzymes in cells (lab exercise this week) Thermostatic control of body temperatureThermostatic control of body temperature pH of the cellpH of the cell

Regulatory Systems: Regulatory Systems: CyberneticsCybernetics

Feedbacks (+ and -), homeostasis and Feedbacks (+ and -), homeostasis and cyberneticscybernetics

Control Center/Sensor

Set Point Effector

PositiveFeedback

NegativeFeedback

Universality of Universality of ReproductionReproduction

Reproduction: regenerative Reproduction: regenerative process of making new process of making new organisms (not necessarily organisms (not necessarily copies)copies)

MethodsMethods Sexual Sexual Asexual (microbes; cell Asexual (microbes; cell

division/mitosis)division/mitosis) Ancillary but important function: Ancillary but important function:

creating new variantscreating new variants ExamplesExamples

SiblingsSiblings Geranium plantsGeranium plants Dolly (the sheep)Dolly (the sheep)

Energy UtilizationEnergy Utilization Three related activities: acquisition, Three related activities: acquisition,

utilization, and storageutilization, and storage Energy AcquisitionEnergy Acquisition

Energy capture (autotrophs; heterotrophs)Energy capture (autotrophs; heterotrophs) Energy utilizationEnergy utilization

Laws of Thermodynamics (1Laws of Thermodynamics (1stst and 2 and 2ndnd laws) laws) ATPATP (adenosine triphosphate) and (adenosine triphosphate) and ADPADP

(adenosine diphosphate(adenosine diphosphate Energy storageEnergy storage

Chemical bonds (C-C covalent bonds)Chemical bonds (C-C covalent bonds) Starch, glycogen and lipidsStarch, glycogen and lipids

Energy UtilizationEnergy Utilization

Catabolism Biosynthesis/Anabolism

ADP

ATP

Two Sides of a Coin: Two Sides of a Coin: Diversity and SimilarityDiversity and Similarity

DiversityDiversity is a hallmark of living systems is a hallmark of living systems 1.5 M known species of plants, animals and 1.5 M known species of plants, animals and

microbesmicrobes 100 M+ thought to exist100 M+ thought to exist

SimilaritySimilarity is a hallmark of living systems is a hallmark of living systems Striking similarity at the molecular level (DNA): Striking similarity at the molecular level (DNA):

kinship to worms, squirrels, birds and pigs (you kinship to worms, squirrels, birds and pigs (you DNA is ~90% pig)DNA is ~90% pig)

ExamplesExamples BiochemistryBiochemistry Structure and morphologyStructure and morphology DNADNA

DNA phylogeny lab (December)DNA phylogeny lab (December)

What is Life? “Nuts and What is Life? “Nuts and Bolts”Bolts”

Introduction to lifeIntroduction to life Themes/characteristics of all Themes/characteristics of all

living organismsliving organisms Cardinal structural and Cardinal structural and

functional charactersfunctional characters

Structural and Functional Structural and Functional CharactersCharacters

Cells as the physical infrastructureCells as the physical infrastructure Biological catalysis: enzymesBiological catalysis: enzymes Cell membranesCell membranes Water as the medium of lifeWater as the medium of life Polymers (C-based polymers)Polymers (C-based polymers) Compartmentation Compartmentation viavia organelles organelles Major types of cellsMajor types of cells

Cells as the Physical Cells as the Physical InfrastructureInfrastructure

Cell theoryCell theory All organisms composed of cellsAll organisms composed of cells Cells as smallest unit of organization exhibiting Cells as smallest unit of organization exhibiting

characteristics of lifecharacteristics of life StructureStructure

Cell Membrane

Nucleus

Cytoplasm

General Features of a General Features of a CellCell

Size correlated with functionSize correlated with function Upper limit: 0.00001 m (1 x 10Upper limit: 0.00001 m (1 x 10-5-5 m) m) Relationship of volume to distanceRelationship of volume to distance Anything over 1 x 10Anything over 1 x 10-5-5 m is nonfunctional m is nonfunctional

Efficacy of transport/diffusionEfficacy of transport/diffusion

Diffusion

23-479Figure 23.5

1 . 10-5 m

EnzymesEnzymes IntroductionIntroduction

Reactions are very slow (not sufficient to Reactions are very slow (not sufficient to sustain life)sustain life)

Mechanisms to accelerate specific Mechanisms to accelerate specific reactions reactions preferentiallypreferentially

Accelerants = Catalysts = EnzymesAccelerants = Catalysts = Enzymes Proteins (relate to information brokers)Proteins (relate to information brokers) Change rate of reactionsChange rate of reactions High degree of specificityHigh degree of specificity RegeneratedRegenerated

Energy Needed

ReactantsProducts

“Hill”

Base case for Base case for reactions to occurreactions to occur Reactants Reactants Products Products

Energy analysis Energy analysis (thermodynamics)(thermodynamics) Energy to cause Energy to cause

reaction to occur reaction to occur (over the “hill”)(over the “hill”)

Enzymes: How They Enzymes: How They WorkWork

How Enzymes WorkHow Enzymes Work Efficacy of enzymes: “Hill” Efficacy of enzymes: “Hill”

heightheight MechanismMechanism

Lower the height of the “hill”Lower the height of the “hill” Selectivity/specificitySelectivity/specificity

Protein 3-D structure (1, 2, 3, and Protein 3-D structure (1, 2, 3, and 4 protein conformation)4 protein conformation)

ConclusionConclusion Absence of enzyme: minutes to Absence of enzyme: minutes to

hours to days to yearshours to days to years Presence of enzyme: 1,000 - Presence of enzyme: 1,000 -

10,000 reactions 10,000 reactions per secondper second Increase in rate > 10Increase in rate > 1066 orders of orders of

magnitudemagnitude

Membranes: StructureMembranes: Structure Membranes: complex polymer, Membranes: complex polymer,

with principal monomer (lipid) with principal monomer (lipid) being a fatty acid + glycerol being a fatty acid + glycerol (i.e., phospholipids)(i.e., phospholipids)

Lipid bilayer at the molecular Lipid bilayer at the molecular levellevel

Phosphate/ Glycerol (Hydrophilic)

Fatty Acid (Hydrophobic)

Membranes: StructureMembranes: Structure Lipid bilayer: “fluid membrane” with Lipid bilayer: “fluid membrane” with

floating chunks of proteins and floating chunks of proteins and carbohydrates (i.e., icebergs)carbohydrates (i.e., icebergs)

Lipid Bilayer

Protein Chunk

Proteins in Lipid BilayerProteins in Lipid Bilayer

Membranes: FunctionsMembranes: Functions

Example of hierarchy theory and Example of hierarchy theory and emergent propertiesemergent properties

Selective permeabilitySelective permeability Signaling: cell-to-cell communicationSignaling: cell-to-cell communication

Transport through Transport through Membrane: Selective Membrane: Selective

PermeabilityPermeability

Signaling in/on Signaling in/on MembranesMembranes

Cystic fibrosis Vaccinations Allergies

Water: Medium for Water: Medium for MetabolismMetabolism

Liquid medium for metabolism and its Liquid medium for metabolism and its importanceimportance

Role of water (HRole of water (H22O)O) Physical properties (e.g., polarity, phases)Physical properties (e.g., polarity, phases) Chemical properties (e.g., pH, solution)Chemical properties (e.g., pH, solution)

Exquisite and unique properties of HExquisite and unique properties of H22OO

Biological Biological MacromoleculesMacromolecules

Define polymer…..Define polymer….. Major biomacromolecules of carbonMajor biomacromolecules of carbon

Carbohydrates (monomer is ______)Carbohydrates (monomer is ______) Lipids (monomer is _______ + _______)Lipids (monomer is _______ + _______) Proteins (monomer is ____________)Proteins (monomer is ____________) Nucleic acids (monomer is __________)Nucleic acids (monomer is __________)

““Information brokers”, particularly for Information brokers”, particularly for nucleic acidsnucleic acids Analogy to an alphabetAnalogy to an alphabet

General Cell StructuresGeneral Cell Structures

Principle of Principle of CompartmentationCompartmentation

Cells are compartmentalizedCells are compartmentalized Elaborate and organized infrastructureElaborate and organized infrastructure Analogy to a dormAnalogy to a dorm

Corridors as endoplasmic reticulumCorridors as endoplasmic reticulum Rooms as organellesRooms as organelles

Consequence of not being Consequence of not being compartmentalizedcompartmentalized

Compartmentation

23-494Figure 23.22

Cell TypesCell Types ProkaryotesProkaryotes

No typical nucleusNo typical nucleus No mitochondria, chloroplasts, No mitochondria, chloroplasts,

Golgi, or endoplasmic reticulumGolgi, or endoplasmic reticulum DNA, enzymes, metabolize, etc.DNA, enzymes, metabolize, etc. Example: bacteriaExample: bacteria

EukaryotesEukaryotes True nucleus and all the True nucleus and all the

organellesorganelles Plant eukaryotesPlant eukaryotes

Chloroplast for Chloroplast for photosynthesis and cell wallphotosynthesis and cell wall

Animal eukaryotesAnimal eukaryotes

OmissionsOmissions Cell cycle (pp. 478-482)Cell cycle (pp. 478-482) Controlled methods transport (pp. Controlled methods transport (pp.

464-465)464-465) Non-membraneous organelles (pp. Non-membraneous organelles (pp.

474-475)474-475) Nuclear component (p. 475)Nuclear component (p. 475)

When you contract a fever, your When you contract a fever, your body temperature is elevated. body temperature is elevated.

Is fever and inadvertent Is fever and inadvertent consequence of the infection or is it consequence of the infection or is it an example of homeostasis?an example of homeostasis?

Each of you has been vaccinated for Each of you has been vaccinated for multiple childhood diseases. You may multiple childhood diseases. You may or may not have taken a flu vaccine.or may not have taken a flu vaccine.

Explain how membrane and Explain how membrane and information attributes of living systems information attributes of living systems underpin the efficacy of vaccinations.underpin the efficacy of vaccinations.