Unifying Characteristics of Life

Unifying Characteristics of LifeOrder the smallest unit of life is the cellMetabolismResponsivenessperceive and react to their environmentDevelopmentHereditygenes are passed from parent to offspringEvolutionpopulations change over time as they adapt

Fig 1.32. Molecule :

4. Cell :The simplestentity that has allthe properties of life

3. Organelle :

Biological Organization 1.Atom:smallest unit of an element that still retains the elements properties

7. Organ System:A group of bodyparts that carries out a particularfunction in an organism

6. Organ :5. Tissue :A group ofsimilar cells that carriesout a particular func-tion in an organism

8. Organism: individual composed of many coordinated organ systems9. Population:10. Community:

11. Ecosystem:12. Biosphere: Those regions of the earths waters, crust and atmosphere in which organisms can exist.The global ecosystem

The cell is the simplest structure that can perform all activities required for life

Cells and Their DNAThere are two major types of cells1.2.

All cells use DNA as the chemical material of genesGenes:

The diversity of known life includes 1.7 million speciesEstimates of the total diversity range from 5 million to over 30 million speciesThe Diversity of Life

EUKARYOTESUniversal AncestorBacteriaArchaea: Bacteria adapted to extreme environmentsProtistsPlantsAnimalsFungiPROKARYOTESThe Unity and Diversity of Life

The three domains of life are:The Three Domains of LifeBacteria Archaea Eukarya

Domain BacteriaDomain ArchaeaDomain EukaryaKingdom ProtistaKingdom PlantaeKingdom FungiKingdom AnimaliaFig 1.9

Underlying the diversity of life is a striking unity, especially at the lower levels of structureUnity in the Diversity of Life

Evolution accounts for this combination of unity and diversity

The history of life is a saga of a restless Earth billions of years oldEVOLUTION: BIOLOGYS UNIFYING THEMEFossils document this historyFig 1.10

Life evolvesEach species is one twig of a branching tree of life extending back in timeAncestral bearFig 1.11

Darwins book developed two main points1. Descent with modification2. Natural selection

Darwin was struck by the diversity of animals on the Galpagos IslandsNatural SelectionHe thought of origin of new species and adaptation to the environment the as closely related processes

MediumgroundfinchCactusgroundfinchSmalltree finchMediumtree finchWoodpeckerfinchLargegroundfinchSmallgroundfinchLarge cactusground finchVegetarianfinchLargetree finchMangrovefinchGreenwarblerfinchGraywarblerfinchSharp-beakedground finchSeed-eatersCactus-flower -eatersBud-eaterInsect-eatersGround finchesTree finchesWarbler finchesCommon ancestor fromSouth American mainlandDescent with modificationFig 1.13

Fact 1:

Fact 2:

Conclusion: Unequal reproductive successDarwins ConclusionDarwin synthesized the concept of natural selection from two observations:

Fig 1.14: Natural Selection

The Evolution of DiversityDifferent species have different traits. These arise from:Mutations heritable changes in DNA. Mutations are adaptive if they change the organisms ability to get food, mate, etc.Evolution

Natural selection - adaptive traits tend to increase over time. It is the mechanism of evolution

Darwins publication of The Origin of Species fueled an explosion in biological research

Evolution is one of biologys best demonstrated, most comprehensive, and longest lasting theoriesEvolution is the unifying theme of biology

Organisms and all other things in the universe consist of matterMatter is anything that occupies space and has massBASIC CHEMISTRY

Atomic numberElement symbolMass numberPeriodic table of the elements

25 Elements are essential to lifeC, H, O, N: 96% of the weight of the human bodyFig 2.3

Atom:Fig. 2.02(a) Hydrogen atom(b) Carbon atom(c) Oxygen atomProtonNeutronElectronAtomic nucleusFirstshellSecondshell

The subatomic particles of an atomAtomic StructureProtonNeutronElectronNucleus -Consists of neutrons and protons

Electrons

The number of electrons in the outermost shellChemical Properties of Atoms

ElectronFirstelectron shell:can hold2 electronsOutermostelectron shell:can hold8 electronsCarbon (C)Atomic number = 6Nitrogen (N)Atomic number = 7Oxygen (O)Atomic number = 8Hydrogen (H)Atomic number = 1Fig 2.7

Chemical reactions:

2 types of molecular bonding:Ionic BondsCovalent bondsChemical Bonding and Molecules

When an atom loses or gains electrons, it becomes electrically charged = ionIonic bondsIonic BondsSodium atom Chlorine atomComplete outer shellsNaClSodium chloride (NaCl)Fig 2.8

(a) Hydrogen atom (H)(c) Sodium atom (Na)(b) Hydrogen ion (H+)(d) Sodium ion (Na+)1 electron1 protonNo electrical charge11 electrons11 protonsNo electrical chargeNo electron1 proton10 electrons11 protonsAtoms: electrically neutralIons: Electrically charged

Covalent BondsFig 2.9

Covalent bonding in waterFull shell with 8 electronsSlightly negativeHydrogen atoms with unfilled shellsFull shells with 2 electrons each+Slightly positive+Covalent bond(shared pairof electrons)Oxygen atom with unfilled shellWater molecule (H2O)

The polarity of water results in..()Hydrogenbond()()()()()()()The Structure of WaterFig 2.10

1. Water as the Solvent of LifeIon in solutionSalt crystalFig 2.16

Dissolving of Sodium Chloride, NaCl, in WaterSaltWaterElectricalattractionWatermolecules(H2O)HydrogenbondsEdge of onesalt crystalIonic bondWater molecules dissolve NaCl,breaking ionic bond

Cohesion =Microscopic tubes

What are plants made of?

The Four Most Important Organic Biological CompoundsCarbohydratesLipidsProteinsNucleic Acids

C:H:O ratio is 1:2:1 (CH20)nSimple sugars:Structural units, used to make larger, storage compounds:Starch

Glycogen

Cellulose 1) Carbohydrates

Fig 3.13

Glucose Fructose Formation of a Disaccharide

C12H22O11

GlucoseFructoseH2O (water)SucroseA portion of a polysaccharide Monosaccharides

C6H12O6

(Simple sugars)

2. LipidsNon-polar, hydrophobic (dont dissolve in water)(CH)nCOOHFunctions:

A) Fats

Triglycerides most abundant lipids in body, abundant energy!

Fig. 3.15

B) Phospholipids

3) ProteinsFig. 3.20

Fig 3.21

Proteins continued

Primary structureFig 3.22

Fig 3.24

4) Nucleic AcidsDNA & RNA

Monomers of NucleotidesFig 3.26

Fig 3.27 The nitrogenous bases of DNA

RNA contains: ribose instead of deoxyribose, and uracil instead of thymineFig 3.29

Fig 3.28: The structure of DNA

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