Biological Molecules & Biological Molecules & Origin of LifeOrigin of Life

Introduction to important molecules which comprise the structure and

function of all living organisms

• Universe formed 15 billion years ago (Big

Bang)

• Galaxies formed from stars, dust and gas

• Earth formed 4.6 billion years ago

• Suns energy stripped away 1st atmosphere

• 2nd atmosphere formed from volcanic outgassing

• Primitive atmosphere: CO2, water vapor, lesser

amts of CO, N2, H2, HCl, and traces of NH3 and

CH4 (3.5 bya)

• O2 came in 3.2-2 bya

• Autotrophic Organisms: photosynthesis

• Another environmental change

• Result in evolution

Life began~ 3.5 bya

Organic molecules (C H O N P S) swimming in shallow seas

Stage 1: Abiotic synthesis of organic molecules such as proteins, amino acids and nucleotides

Stage 2: joining of small molecules (monomers) into large molecules

Stage 3: origin of self-replicating molecules that eventually made inheritance possible

Stage 4: packaging these molecules into pre-cells, droplets of molecules with membranes that maintained an internal chemistry

Thomas Huxley- Search for origin of life

Wyville Thompson: HMS Challenger (1872-1876) found it was actually diatomacous ooze reacting with seawater and ethyl alcohol

Bathybias heckali- primordial ooze

• 0.5 billion years ago

• Atmosphere O2 to 1% current

• Compare to present: 78% N2, 21% O2, 0.04% CO2, + trace gasses

• Relatively small, most single cell

• Start of multicellularity

• Increase in cell complexity

Miller and Urey’s Experiment

ELECTRICITY!!!

Organic molecules like amino acids

Produced:• 20 amino acids• Several sugars• Lipids• Purine and pyrimidine bases

(found in DNA, RNA & ATP)

RNA worldRNA world The first genetic material was probably self-

replicating, catalytic RNA not DNA; In “RNA world”, RNA could have provided

the template on which DNA was assembled Once DNA appeared “RNA world” gave

way to “DNA world” The first organisms were not

photosynthetic; they were probably heterotrophic

Protobionts, collections of abiotically produced molecules surrounded by a membrane-like structures

Liposomes can form when lipids or other organic molecules are added to water.

- Have a bilayer- Can undergo osmosis- Can “reproduce”

Protocell (Protobiont)Protocell (Protobiont)

Fatty acid membrane with ribozymes inside

chemosynthetic bacteria (extremophiles)

Chemosynthesis:

02 + 4H2S + C02 CH20 + 4S +3H20

Stromatolites (bacteria & cyanobacteria)

Oldest fossils found in western Australia and southern Africa ~ 3.5 byo

Photosynthesis:

6H2O + 6CO2 + nutrients + light energy C6H12O6 + 6O2

Stromatolites from Shark’s Bay Australia

mostly cyano

Early prokaryotes may have arisen Early prokaryotes may have arisen near hydrothermal ventsnear hydrothermal vents

Hydrothermal vents are rich in sulphur and iron-containing compounds needed for ATP synthesis. Temperatures can reach 120oC.

Hot springs in Yellowstone National Hot springs in Yellowstone National Park – pigmented bacterial matsPark – pigmented bacterial mats

Categories:

Lipids

Proteins Nucleic Acids

Carbohydrates

Biological CompoundsBiological Compounds

Characteristics of Characteristics of Biological Molecules to Biological Molecules to ConsiderConsider

Monomer

• Subunits that serve as building blocks

• Connected by condensation reactions (dehydration) Polymers

• Covalent bonding occurs• Solubility in Water

Monomers and Monomers and PolymersPolymers

Monomer

Polymer

Dehydration Dehydration SynthesisSynthesis

Polymer

Monomers

H HO

H HO

H2O

C6H12O6 + C6H12O6 C12H22O11 + H2O

Dehydration Dehydration SynthesisSynthesis

H2O

Monomers

H HO

H2O

C12H22O11 + H2O C6H12O6 + C6H12O6

HydrolysisHydrolysis

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Characteristics of Characteristics of CarbohydratesCarbohydrates

Sugars, Starches & Others

Principle Elements: C, H, & O

From Photosynthesis

Monomers: Monosaccharides

Polymers: Polysaccharides

Water Soluble

• Energy Metabolism• Structural Components• Cell-to-Cell Contacts and Recognition• Elimination of wastes (fiber)

APT cell

Helper-T cell

Chemical FormulasC6H12O6

C6H12O6

From corn syrup

Chemical FormulasC5H10O5 C5H10O4

deoxyribose

MaltoseMaltose

SucroseSucrose

glucose + fructose

glucose + glucose

LactoseLactose

glucose + galactose

glycogen

Characteristics of Characteristics of LipidsLipids

• Oils, fats, waxes, phospholipids, steroids

• Principle Elements: C, H, & O

• Some With P & N

• Water Insoluble

Functions of LipidsFunctions of Lipids

• Energy Storage

• Protection & Cushioning of Body

Organs

• Structural Components of

Membranes

• Chemical Messengers (hormones)

Major Types of LipidsMajor Types of Lipids

• Triglycerides (neutral fats)• Phospholipids• Sterols• Waxes

TriglyceridesTriglycerides

GlycerolGlycerol

Fatty AcidsFatty Acids

• Saturated with H+

• Most animal fats are saturated, ex. butter• Solid at room temp

• Has one or more double bonds between carbons• Most vegetable fats• Liquid at room temp

Hydrophilic head

Hydrophobic tails

phosphorous

carbon

hydrogen

oxygen

Nonpolar hydrophobic tails (fatty acids) exposed to oil

Polar hydrophilic heads exposed to water

Phospholipid Phospholipid BilayerBilayer

Outside of Cell

Inside of Cell

SteroidsSteroids

cholesterol

Bacon grease

• Cholesterol: <200 mg/dl• Triglycerides: blood fats, 30-175

mg/dl• HDL: Good cholesterol, > 35 mg/dl• LDL: Bad Cholesterol, <100 mg/dl• Chol/HDL ratio: < 4.5 indicates

heart disease

Your Cholesterol LevelYour Cholesterol Level

Lowering Your Cholesterol LevelLowering Your Cholesterol Level

• Eat healthy

• Exercise

• Lose wt.

• Quit smoking

• 1 glass of wine or beer

• Medications (Lipitor)

• Principle Elements: C, H, O, & N

• Monomers: Amino Acids

• Polymers: Polypeptides or Proteins

• Generally Water Soluble

Characteristics of ProteinsCharacteristics of Proteins

Characteristics of ProteinsCharacteristics of Proteins

Functional Groups of Amino Acids

• Carboxylic Acid (-COOH)

• Amine (-NH2)

• R-Groups (variable - 20 different kinds)

Functions of ProteinsFunctions of Proteins

• Enzymes

• Structural Proteins

• Chemical Messengers

• Hormones

• Antibodies

Levels of Protein Structure

Primary structure

Secondary structure

Tertiary structure

Quarternary structure

Primary structure: Linear sequence of amino acids

Levels of Protein Structure

Alpha helix

H-Bonds

Secondary structure:

Beta Pleated sheet

NH3 Leu Cys Val Asp Phe COO

Levels of Protein Structure

Tertiary: 3D configuration Weak bonds between side chains

Quartenary: Two or more polypeptides e.g. Hemoglobin (Hb)

Amino Acid StructureAmino Acid Structure

Some Amino AcidsSome Amino Acids

Formation of Peptide BondsFormation of Peptide Bonds

Peptide bond

Dipeptide Water

AA1 AA2

Formation of a Formation of a PolypeptidePolypeptide

Formation of a Formation of a PolypeptidePolypeptide

Two Different PolypeptidesTwo Different Polypeptides

GLY SER ALA TYR ILE GLNLEUMET

GLY SERASP GLUILE GLN HISASN

Characteristics of Nucleic AcidsCharacteristics of Nucleic Acids

Principle Elements: C, H, O, N, & PPrinciple Elements: C, H, O, N, & P

Monomers: NucleotidesMonomers: Nucleotides

Polymers: Nucleic AcidsPolymers: Nucleic Acids

Generally Water SolubleGenerally Water Soluble

Characteristics of Nucleic Characteristics of Nucleic AcidsAcids

Nucleotide Components: Ribose (5-C) Sugar

Phosphate

Nitrogenous Base

Functions of Nucleic AcidsFunctions of Nucleic Acids

• Genetic Instruction Set (DNA)

• Protein Synthesis (DNA & RNA)

• Energy Metabolism (ATP)

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PolynucleotidesPolynucleotides= Nucleic Acids= Nucleic Acids

Double-Double-Stranded DNAStranded DNA

DNAPolymers made up of individual

nucleotidesNucleotides contain

• Phosphate group• Five carbon sugar• Ring shaped nitrogen base

DNA contains information for almost all cell activities

ATPATP

Role of ATP in Energy Role of ATP in Energy MetabolismMetabolism

ATP ATP ADP + ADP + PPii + Energy + Energy

Role of ATP in Energy MetabolismRole of ATP in Energy Metabolism

InquiryInquiry1. How old is the Earth?2. What was the 1st organism to

have appeared 3.5 bya?3. How did it eat?4. When did oxygen 1st appear in

the atmosphere?5. How was it produced?6. What did Miller & Urey’s study

conclude?

INQUIRY1. Describe the difference

between saturated and unsaturated fats.

2. Where are phospholipids found?

3. Cholesterol is the base molecule for what type of lipids?

4. Name a polysaccharide used to store energy.

5. Name the currency molecule for all the cells activities.