SOLAR SYSTEMSOLAR SYSTEM

LIFE-capacity for growth, metabolism, reproduction, LIFE-capacity for growth, metabolism, reproduction, reaction to stimulireaction to stimuli

SOLAR SYSTEM-Big Bang theory- one mass of matter SOLAR SYSTEM-Big Bang theory- one mass of matter blew apart 12-15 billion years agoblew apart 12-15 billion years ago

Smaller H and He atoms fused to form heavier elements- Smaller H and He atoms fused to form heavier elements- stars huge masses of interstellar gases; sun formed 6 stars huge masses of interstellar gases; sun formed 6 billion years agobillion years ago

Planets formed 4.6 billion years ago by the condensing Planets formed 4.6 billion years ago by the condensing of peripheral gases and matter around the sun.of peripheral gases and matter around the sun.

FORMATION OF EARTHFORMATION OF EARTH Earth formed about 4.6 billion years agoEarth formed about 4.6 billion years ago

Four layers of earth formed by the effect of heat from gravitation and Four layers of earth formed by the effect of heat from gravitation and radioactivity:radioactivity: Inner solid core- mostly of iron and nickelInner solid core- mostly of iron and nickel Outer molten core- of iron and sulfurOuter molten core- of iron and sulfur A plastic mantel – iron, magnesium, aluminum, silicon, oxygen silicate A plastic mantel – iron, magnesium, aluminum, silicon, oxygen silicate

compoundscompounds A thin crust which solidified 4.1 billion years agoA thin crust which solidified 4.1 billion years ago

The earth’s diameter is 12,742 KM (7,900 miles) compared with that of the The earth’s diameter is 12,742 KM (7,900 miles) compared with that of the sun –(1,391,000 KM) and an object on the sun’s surface would weigh 28 sun –(1,391,000 KM) and an object on the sun’s surface would weigh 28 times as much as it does on earth’s surface.times as much as it does on earth’s surface.

Atmosphere-Atmosphere- due to the earth size under a gravitational field due to the earth size under a gravitational field

Gases Gases in atmosphere- nitrogen, carbon dioxide, hydrogenin atmosphere- nitrogen, carbon dioxide, hydrogen

Water vaporWater vapor due to intense heat- in thick clouds; when cooled forms rain due to intense heat- in thick clouds; when cooled forms rain collected in rivers, lakes, oceans etc.collected in rivers, lakes, oceans etc.

ORIGIN OF LIFEORIGIN OF LIFE

CHEMICAL EVOLUTION – complexity of chemicals led to first cellsCHEMICAL EVOLUTION – complexity of chemicals led to first cells Oparin (1938) – postulated that reducing atmosphere coupled with Oparin (1938) – postulated that reducing atmosphere coupled with

free energy from volcano activity, lightening, radioactive minerals free energy from volcano activity, lightening, radioactive minerals and the sun (devoid of ozone layer) facilitated the formation of and the sun (devoid of ozone layer) facilitated the formation of organic molecules.organic molecules.

Miller (1953) – duplicated the early conditions in the lab by creating Miller (1953) – duplicated the early conditions in the lab by creating an artificial ‘atmosphere’ and ‘ocean’ and introducing hydrogen, an artificial ‘atmosphere’ and ‘ocean’ and introducing hydrogen, methane, ammonia, and water into the system with electric spark as methane, ammonia, and water into the system with electric spark as energy supply, to obtain after one week, the formation of amino energy supply, to obtain after one week, the formation of amino acids and small organic molecules.acids and small organic molecules.

Other scientists repeated their work, eventually producing amino Other scientists repeated their work, eventually producing amino acids, ATP, glucose and other sugars, lipids, and the bases which acids, ATP, glucose and other sugars, lipids, and the bases which form RNA and DNA, and adenine the key component of ATP and form RNA and DNA, and adenine the key component of ATP and NAD.NAD.

Over a long period of time the lack of oxidation and decay allowed Over a long period of time the lack of oxidation and decay allowed organic molecules to form a thick, warm organic “primordial soup”.organic molecules to form a thick, warm organic “primordial soup”.

PROTOCELLSPROTOCELLS

PROTOCELL – cell-like structure with a lipid-protein membrane PROTOCELL – cell-like structure with a lipid-protein membrane developed from developed from coacervatecoacervate droplets. droplets.

Coacervate droplets – are complex spherical units formed Coacervate droplets – are complex spherical units formed spontaneously when concentrated mixtures of macromolecules (like spontaneously when concentrated mixtures of macromolecules (like RNA, DNA, amino acids, phospholipids, clayRNA, DNA, amino acids, phospholipids, clay etc.) are held at the etc.) are held at the right temperature, ion composition, and pH. They absorb and right temperature, ion composition, and pH. They absorb and incorporate various substances from the surrounding solution.incorporate various substances from the surrounding solution.

A protocell could have contained only RNA to function as both A protocell could have contained only RNA to function as both genetic material and enzymes. First protocells were genetic material and enzymes. First protocells were heterotrophsheterotrophs using ATP as energy and carrying out a form of fermentation.using ATP as energy and carrying out a form of fermentation.

Heterotroph Heterotroph – an organism unable to synthesize organic – an organism unable to synthesize organic compounds from inorganic substances and therefore must take in compounds from inorganic substances and therefore must take in preformed organic compounds, e.g. animalspreformed organic compounds, e.g. animals

Autotroph Autotroph – an organism that make organic molecules from – an organism that make organic molecules from inorganic nutrients, e.g., plantsinorganic nutrients, e.g., plants

HISTORY OF LIFE - 1HISTORY OF LIFE - 1

PRECAMBRIAN encompasses 87% of geological time scale and PRECAMBRIAN encompasses 87% of geological time scale and based on this, life began from 570 million to 4.6 billion years ago.based on this, life began from 570 million to 4.6 billion years ago.

Early bacteria resembled archaea that live in hot springs today.Early bacteria resembled archaea that live in hot springs today. Archaeans Archaeans resemble bacteria but developed separately from resemble bacteria but developed separately from

common ancestor nearly 4 billion years ago. They thrive under common ancestor nearly 4 billion years ago. They thrive under extreme conditions and are labeled as ‘extremophiles’.extreme conditions and are labeled as ‘extremophiles’.

Bacteria and archaea are termed as PROKARYOTES –organisms Bacteria and archaea are termed as PROKARYOTES –organisms whose DNA is not enclosed in a nucleus of the cell.whose DNA is not enclosed in a nucleus of the cell.

EUKARYOTIC cells are aerobic and arose 2.1 billion years ago. EUKARYOTIC cells are aerobic and arose 2.1 billion years ago. They contain nuclei and organelles.They contain nuclei and organelles.

Plants appeared on land (mud flats) during the ‘Paleozoic’ period, Plants appeared on land (mud flats) during the ‘Paleozoic’ period, about 440 million years ago. They provided food for higher animals about 440 million years ago. They provided food for higher animals to evolve.to evolve.

HISTORY OF LIFE - 2HISTORY OF LIFE - 2

MESOZOIC PERIOD-ruled by dinosaurs; sub-divided into 3 categories.MESOZOIC PERIOD-ruled by dinosaurs; sub-divided into 3 categories. TriassicTriassic – 245-208 million years ago; appearance of ferns, gingkophytes, – 245-208 million years ago; appearance of ferns, gingkophytes,

cycads, coniferscycads, conifers Jurassic Jurassic – 208-146 million years ago (mya)- birds, dinosaurs– 208-146 million years ago (mya)- birds, dinosaurs CretaceousCretaceous – 146- 65 million years ago – angiosperms (flowering plants and – 146- 65 million years ago – angiosperms (flowering plants and

extinction of dinosaursextinction of dinosaurs CENOZOIC PERIOD – 66-24 million years ago – mammals and tropical CENOZOIC PERIOD – 66-24 million years ago – mammals and tropical

forests; forests; 24 mya – appearance of monkeys apes and humans; major climatic shift; 24 mya – appearance of monkeys apes and humans; major climatic shift;

grasslands replaced forestsgrasslands replaced forests 6-24 mya – grazing animals flourished; 2-6 mya - herbaceous flowering 6-24 mya – grazing animals flourished; 2-6 mya - herbaceous flowering

plants flourished and first plants flourished and first homonidshomonids ( intermediate between apes and ( intermediate between apes and people e. g. genus people e. g. genus AustralopithecusAustralopithecus ) appeared ) appeared

PLEISTOCENE EPOCH (0.01-2 mya)- ice age caused mammalian PLEISTOCENE EPOCH (0.01-2 mya)- ice age caused mammalian extinction; herbaceous plants spread and the RISE OF MODERN extinction; herbaceous plants spread and the RISE OF MODERN HUMANS.HUMANS.

PROKARYOTESPROKARYOTES

ProkaryotesProkaryotes are are single celledsingle celled micro-organismsmicro-organisms characterized by:characterized by:

i.i. the lack of a the lack of a membrane-boundmembrane-bound nucleusnucleus and and ii.ii. membrane bound membrane bound organellesorganelles. .

There are two There are two domainsdomains of prokaryote: of prokaryote: i.i. the Eubacteria/the Eubacteria/BacteriaBacteria ii.ii. the Archaebacteria/the Archaebacteria/ArchaeaArchaea

Cont…Cont…

Differences between bacteria and archaea:Differences between bacteria and archaea:

Eubacteria have Eubacteria have cell wallscell walls composed of composed of peptidoglycanpeptidoglycan, Archaebacteria , Archaebacteria have cell walls composed of various different substances. have cell walls composed of various different substances.

Eubacteria have Eubacteria have esterester-linked straight-chain membrane -linked straight-chain membrane lipidslipids (fatty (fatty acids). Archaebacteria have ether-linked branched-chain member lipids. acids). Archaebacteria have ether-linked branched-chain member lipids.

Eubacteria and Archaebacteria have differences in their Eubacteria and Archaebacteria have differences in their DNA replicationDNA replication and and transcriptiontranscription systems that suggest independent elaboration in these systems that suggest independent elaboration in these two groups two groups

Eubacteria usually use Eubacteria usually use N-N-formylmethionineformylmethionine as the initial as the initial amino acidamino acid of a of a proteinprotein, while Archaebacteria use plain , while Archaebacteria use plain methioninemethionine. .

The The translationtranslation apparatus of Eubacteria is inhibited by such antibiotics apparatus of Eubacteria is inhibited by such antibiotics as as chloramphenicolchloramphenicol, cycloheximide, tetracycline, streptomycin, and , cycloheximide, tetracycline, streptomycin, and kanamycin, while the translation apparatus of Archaebacteria is not. kanamycin, while the translation apparatus of Archaebacteria is not.

The translational apparatus of Archaebactera is inhibited by diphtheria The translational apparatus of Archaebactera is inhibited by diphtheria toxin, while the translational apparatus of Eubacteria is not. toxin, while the translational apparatus of Eubacteria is not.

PROKARYOTEPROKARYOTE

CELL BIOLOGYCELL BIOLOGY

A)A) Cell = fundamental unit of biology, building block of all organisms Cell = fundamental unit of biology, building block of all organisms B)B) Organisms range from unicellular to multicellular Organisms range from unicellular to multicellular

1)1) Unicellular: 1 cell = 1 organism Unicellular: 1 cell = 1 organism 2)2) Multicellular: 1036 cells = 1 organism, different cells for different Multicellular: 1036 cells = 1 organism, different cells for different

functions, exhibit division of labor functions, exhibit division of labor C)C) Diversity of cells Diversity of cells

1) Different types of unicellular organisms (Paramecium &1) Different types of unicellular organisms (Paramecium &Amoeba) Amoeba) 2) Different types of cells in multicellular organisms 2) Different types of cells in multicellular organisms

(muscle, skeletal, immune, lungs, epithelium, etc...) (muscle, skeletal, immune, lungs, epithelium, etc...) D) Classification of cells D) Classification of cells

1) Two major groups - 1) Two major groups - ProkaryotesProkaryotes and and EukaryotesEukaryotes 2) Differences: Prokaryotes - smaller size, simple structure 2) Differences: Prokaryotes - smaller size, simple structure

(no (no membrane bound organelles, no nucleus, DNA in a single membrane bound organelles, no nucleus, DNA in a single strand), primitive (old group of organisms, nearest relatives strand), primitive (old group of organisms, nearest relatives

of of first living organisms) first living organisms)

EUKARYOTESEUKARYOTES

Cells having a membrane-bound nucleus, Cells having a membrane-bound nucleus, membrane-bound organelles and membrane-bound organelles and chromosomeschromosomes

Includes all other cells from other origins Includes all other cells from other origins

EUKARYOTESEUKARYOTES

CELL STRUCTURES EUKARYOTESCELL STRUCTURES EUKARYOTES

ORGANELLESORGANELLES

DNA-associated with chromosomes, chromatin, nucleolus, ATP-ase; DNA-associated with chromosomes, chromatin, nucleolus, ATP-ase; synthesizes RNA and ribosomessynthesizes RNA and ribosomes

RIBOSOMES-protein synthesisRIBOSOMES-protein synthesis ER-protein transport (rough ER); regulates Ca levels; breaks down toxic ER-protein transport (rough ER); regulates Ca levels; breaks down toxic

substances (smooth ER)substances (smooth ER) GOLGI APPARATUS- process and packages substances produced by the GOLGI APPARATUS- process and packages substances produced by the

cellcell LYSOSOMES- digests old molecules and foreign substancesLYSOSOMES- digests old molecules and foreign substances CYTOSKELETON (microfilaments/tubules) contributes to support, CYTOSKELETON (microfilaments/tubules) contributes to support,

movement and division of cellmovement and division of cell CILIA- propels cell CILIA- propels cell MITOCHONDRION- transfers energy from ATPMITOCHONDRION- transfers energy from ATP Vacuole- (in plants) stores enzymes and waste productsVacuole- (in plants) stores enzymes and waste products Plastids- (in plants) stores pigmentsPlastids- (in plants) stores pigments

Function Eukaryotes Prokaryotes

Isolation

(plants and)

cell wall (plants)phospholipid bilayer

cell membrane with proteins

same but minor chemical differences

Support cytoskeleton none

Energy (production)

chloroplasts (plants)

mitochondrion (Krebs cycle) chlorophyll but no covering

none (fermentation)

Energy (digestion) lysosomes (aging??) None

Protein Synthesis animals Rough ER ribosomes only

Fat Synthesis Smooth ER none

Refine Chemical and Storage

Golgi apparatus none

Movementcilia and flagella

psuedopod movementflagella (different)

Reproduction and Control DNA

DNA on chromosomes inside nucleus

DNA in single strand, DNA floating freely, no nucleus