The Molecules of Life - Overview. The Molecules of Life. The Molecules of Life. The Molecules of Life

The Molecules of Life

The Molecules of Life - - Overview Overview

The Molecules of Life The Molecules of Life The Importance of Carbon The Importance of Carbon Organic Polymers / Monomers Organic Polymers / Monomers Functions of Organic Molecules Functions of Organic Molecules Origin of Organic Molecules Origin of Organic Molecules

The Molecules of Life The Molecules of Life

Water is the universal medium Water is the universal medium for life

for life

But life is made up mostly of But life is made up mostly of compounds based on the compounds based on the element carbon element carbon – – organic organic molecules

molecules

Carbon enters the biosphere Carbon enters the biosphere via autotrophic organisms via autotrophic organisms – – convert CO

convert CO

in the atmosphere in the atmosphere into molecules of life

into molecules of life

The Molecules of Life The Molecules of Life

Carbon forms large, complex and diverse molecules

Carbon forms large, complex and diverse molecules

Protein, DNA, carbohydrates, etc. are all carbon

Protein, DNA, carbohydrates, etc. are all carbon- -based based

Carbon

Carbon – – backbone of life! backbone of life!

Carbon cycle Carbon cycle Organic chemistry Organic chemistry study of carbon study of carbon compounds compounds Basis of organic Basis of organic molecules molecules Reminder

Reminder – – molecules molecules are 3D!

are 3D!

The Importance of Carbon The Importance of Carbon

Chemistry Review in Chapter 3 Chemistry Review in Chapter 3 Forms covalent bonds:

Forms covalent bonds:

tetravalence tetravalence

The Importance of Carbon The Importance of Carbon

Form ~ Function

Form ~ Function

The Importance of Carbon The Importance of Carbon

Carbon forms a variety Carbon forms a variety of covalent bonds of covalent bonds… … single, double, & triple single, double, & triple

It also combines with a It also combines with a number of other elements number of other elements such as H, O, N, S, and P such as H, O, N, S, and P

The Importance of Carbon The Importance of Carbon

Versatility: infinite number of molecules Versatility: infinite number of molecules Carbon

Carbon – –carbon bonds: can produce carbon bonds: can produce long chains e.g. hydrocarbons long chains e.g. hydrocarbons

Organic Polymers Organic Polymers

Small organic molecules

Small organic molecules

Organic Polymers Organic Polymers

Four types of organic macromolecules are Four types of organic macromolecules are extremely important to life:

extremely important to life:

Carbohydrates Carbohydrates Proteins Proteins Lipids Lipids Nucleic acids Nucleic acids

Again

Again… … each of these polymers is made up of each of these polymers is made up of smaller, repeating subunits

smaller, repeating subunits

Organic Macromolecules & Their Organic Macromolecules & Their

Subunits (Monomers) Subunits (Monomers)

Carbohydrates Carbohydrates Proteins Proteins Lipids (Fats) Lipids (Fats) Nucleic Acids Nucleic Acids

Simple Sugars Simple Sugars Amino Acids Amino Acids

Glycerol & Fatty Acids Glycerol & Fatty Acids Nucleotides

Nucleotides

Form of Carbohydrates Form of Carbohydrates

Monosaccharides

Monosaccharides = sugar (glucose) = sugar (glucose) What is a sugar?

What is a sugar?

Form Form length length

carbonyl group

carbonyl group

hydroxyl group

hydroxyl group

Functions of Carbohydrates Functions of Carbohydrates

Carbohydrates

Fuel molecules (e.g. C

H

O

- glucose for cellular respiration)

Medium to Long term energy storage (starch, glycogen) Structural molecules (e.g. cellulose in cell walls)

Lipids Lipids

Fats: glycerol and fatty acids Fats: glycerol and fatty acids

Hydrophobic Hydrophobic

Lipids Lipids

No polymers. Composed of groups of

No polymers. Composed of groups of

Lipids: Form Lipids: Form

Fat =

Fat = glycerol + 3 FAs glycerol + 3 FAs

Phospholipids = Phospholipids =

glycerol + 2

glycerol + 2 FAs FAs + phosphate group + phosphate group

Steroids =

Steroids = Carbon skeleton Carbon skeleton consisting of four fused rings consisting of four fused rings

Functions of Lipids Functions of Lipids

Lipids

Long term storage of energy (e.g.

fats)

Structural molecules (e.g.

phospholipids in cell membranes) Hormones

Proteins Proteins

>50% of dry mass of most cells

>50% of dry mass of most cells Functions

Functions

Speed up reactions Speed up reactions Structural functions Structural functions Storage

Storage Transport Transport

Cellular communications

Proteins Proteins

Monomers

Monomers Polymers Polymers Amino Acids

Amino Acids Polypeptides Polypeptides Proteins

Proteins 1+polypeptides 1+polypeptides

Functions of Proteins Functions of Proteins

Proteins Proteins

Catalysts (enzymes) Catalysts (enzymes) Structural molecules (

Structural molecules (e.g. e.g. membranes, collagen, membranes, collagen, keratin)

keratin)

Proteins

Proteins - - Enzymes Enzymes

Catalytic

Catalytic

Nucleic Acids Nucleic Acids

Two major groups Two major groups

DNA

DNA - - provides directions for its own replication provides directions for its own replication and directs RNA

and directs RNA RNA

RNA - - carries the genetic information to the carries the genetic information to the Ribosome where it can be make into a protein Ribosome where it can be make into a protein

Monomers

Monomers Polymers Polymers Nucleotides

Nucleotides Polynucleotides Polynucleotides (Nucleic (Nucleic Acid)

Acid)

Functions of Nucleic Acids Functions of Nucleic Acids

Nucleic Acids Nucleic Acids

Store and transmit hereditary information Store and transmit hereditary information DNA controls production of proteins DNA controls production of proteins

Functions of Organic Molecules Functions of Organic Molecules - -

Review Review

They function chemically They function chemically

e.g

e.g. fuel, fuel storage, catalyze reactions . fuel, fuel storage, catalyze reactions

They have a structural function They have a structural function

e.g

e.g. cellulose in cell walls, phospholipids in cell membranes, . cellulose in cell walls, phospholipids in cell membranes, collagen (protein), protein structure in membranes collagen (protein), protein structure in membranes

Nucleic acids store and transmit hereditary Nucleic acids store and transmit hereditary information

information

The Molecules of Life The Molecules of Life Where it all Began Where it all Began

Oparin and

Oparin and Haldane Haldane s Hypothesis s Hypothesis - - Organic Organic molecules were synthesized from inorganic molecules in the molecules were synthesized from inorganic molecules in the conditions of the primitive earth (reducing environment) conditions of the primitive earth (reducing environment) These conditions do not exit today

These conditions do not exit today

Testing Hypotheses Testing Hypotheses

Before we get into

Before we get into Oparin Oparin & Haldane & Haldane’ ’s s hypothesis, lets talk about what an hypothesis hypothesis, lets talk about what an hypothesis actually is

actually is… …

A tentative (Not yet fully supported) explanation for some A tentative (Not yet fully supported) explanation for some observed phenomenon

observed phenomenon

It is a possible answer to a question that arises from It is a possible answer to a question that arises from observing

observing

We test it through experimentation or through analysis of We test it through experimentation or through analysis of available information/data

available information/data

The Molecules of Life The Molecules of Life Where it all Began Where it all Began

Oparin

Oparin (Russian) & Haldane (Russian) & Haldane (British) (British)

Miller

Miller- -Urey Urey s Experiment (1953) s Experiment (1953)

Tested Oparin and Tested Oparin and Haldane

Haldane’ ’s s hypothesis hypothesis (Figure 26.2 in Campbell) (Figure 26.2 in Campbell) Recreated conditions of Recreated conditions of early earth

early earth’ ’s atmosphere as s atmosphere as scientist thought to exist scientist thought to exist then (water, hydrogen, then (water, hydrogen, methane, ammonia) methane, ammonia) Source of energy: electrical Source of energy: electrical spark

spark

Modern Experiments Modern Experiments

Scientists now believe that hydrogen, ammonia Scientists now believe that hydrogen, ammonia

& methane were not overly abundant in early

& methane were not overly abundant in early atmosphere

atmosphere

Experiments have been performed using a Experiments have been performed using a variety of gasses and energy sources variety of gasses and energy sources Produced all 20 amino acids, some simple Produced all 20 amino acids, some simple sugars, lipids, and components of DNA sugars, lipids, and components of DNA Strong supporting evidence for the emergence Strong supporting evidence for the emergence of “ of “life life” ”

Other Hypotheses Other Hypotheses

More evidence emerging More evidence emerging which points to small which points to small

“

“pockets pockets” ” of the of the atmosphere which atmosphere which contained the molecules contained the molecules required

required

Volcanoes & underwater

Volcanoes & underwater

volcanoes or vents are

volcanoes or vents are

likely places of synthesis

likely places of synthesis – –