The earliest forms of life on Earth were likely simple protocells consisting of fatty acid membranes enclosing genetic molecules like RNA. These protocells could grow and divide by incorporating new fatty acids and duplicating their genetic material with heat from nearby hot rocks. Over time, as RNA randomly mutated and some sequences gained the ability to self-replicate more efficiently, the earliest forms of evolution and metabolism began to emerge. Eventually, proteins were produced that proved more effective as catalysts than RNA, and DNA arose as the primary genetic material due to its stability, marking the transition from an 'RNA world' to a DNA-based biology as we know it today.

1. Life On Earth
• Every living cell interacts with molecular machinery, which copy
genetic molecules, transport nutrients or turn them into energy,
communicate different messages
• It is hard to visualise how a cell’s machines, which are mostly
protein-based enzymes, would have evolved from non living
matter to life
• In lab experiments the amino acids have successfully been
created from simple chemicals, But going from there to proteins
and enzymes is a complex matter

2. • A cell make protein form the information on DNA strand with the
help of different proteins (enzymes)
• Thus, explaining how life began entails a serious puzzle: because for
protein formation we need both DNA and protein. Then how protein
was first formed
• What if the first organisms did not require proteins at all? The puzzle
would be solved
• Recent experiments suggest it would have been possible for genetic
molecules to form spontaneously
• And because these molecules can curl up in different shapes and act
as basic catalysts, they may have become able to copy themselves—to
reproduce—without the need for proteins

3. • The earliest forms of life could have been simple membranes made of
fatty acid that enveloped water and these self-replicating genetic
molecules
• Just like DNA, The genetic material would encode the traits that each
generation handed down to the next
• Accidental mutations, appearing at random in the copying process,
would then force evolution, enabling these early cells to adapt to their
environment, and to form life
• The ultimate challenge is to construct an artificial organism that can
reproduce and evolve and help us understand how life on earth could
have started

4. Reg no: SP17-R02-012
Name: Qurat-ul-Hain

5. RNA to DNA
• One of the most complicated and interesting fact is origin of life
• RNA was discovered before DNA
• RNA is an unstable molecule
• Modern cells makes protein by first copying gene from DNA into RNA
• RNA is used as a blueprint to make proteins

6. RNA to DNA
• RNA versions of enzymes are called ribozymes
• Ribozymes serve as a pivotal role in modern cells
• RNA –protein machines translate RNA into proteins
• RNA does the catalytic work
• Each of our cells appaers to carry in its ribosomes fossil

7. NUCLEIC ACID Properties
• Genetic Molecules (DNA or RNA) are polymers made of building
blocks called nucleotides
• Nucletides have 3 components:
1. Sugar
2. Phosphate
3. Nucleobase
• Nucleobases are Adenine (A), Guanine (G), Cytocine (C), and
Thymine (T) and in RNA T is replaced by Uracil (U)
• A pairs with U or T
• G pairs with C

8. NUCLIC ACID Properties
• DNA is a twisted ladder and is double helix and are crucial for
copying the genetic information , when the cell is reproduce.
• RNA is single stranded and act as a messenger for the protein
synthesis

9. LIFE ON EARTH
JAWAD ALI KHAN

10. Got to start somewhere
• The phosphate and sugar molecules form the backbone of
each strand of DNA or RNA.
• Nucleobases can assemble spontaneously, in a series of steps,
from cyanide, acetylene and water.
• Sugars are also easy to assemble from simple starting mate-
rials. It has been known for well over 100 years that mixtures
of many types of sugar molecules can be obtained by warming
an alkaline solution of formaldehyde, which also would have
been available on the young planet.

11. • The problem, however, is how to obtain the “right” kind of
sugar—ribose, in the case of RNA—to make nucleotides.
Ribose, along with three closely related sugars, can form from
the reaction of two simpler sugars that contain two and three
carbon at-oms, respectively.
• Ribose’s ability to form in that way does not solve the problem
of how it became abundant on the early earth, however,
because it turns out that ribose is unstable and rapidly breaks
down in an even mildly alkaline solution.

12. • This observation has made many researchers conclude that the first genetic
molecules could not have contained ribose.
• The phosphate part of nucleotides presents another intriguing puzzle.
Phosphorus—the central element of the phosphate groupis abundant in the
earth’s crust but mostly in minerals that do not dissolve readily in water, where
life presumably originated. So it is not obvious how phosphates would have
gotten into the prebiotic mix.
• In 2005 Matthew Pasek and Dante Lauretta of the University of Arizona
discovered that the corrosion of schreibersite in water releases its phosphorus
component. This pathway seems promising because it releases phosphorus in a
form that is both much more soluble in water than phosphate and much more
reactive with organic (carbon-based) compounds.

13. Saba Naz
Sp17-R02-004

14. Some Assembly Required
• Given the outline of potential pathways leading to the nucleobases,
sugars and phosphate
• The next step would be to properly connect these components.
• Chemical bonding needed, energy must be supplied, by adding
energy-rich.

16. • 2-amino oxazole, which can be viewed as a fragment of a sugar
joined to a piece of a nucleobase.
• once the water evaporated, the 2-aminooxazole vaporized, only to
condense elsewhere in a purified form.
• It accumulate as a reservoir of material, ready for further chemical
reactions that would form a full sugar and nucleobase attached to
each other.

17. • These pathway does not generate the “correct” nucleotides.
• In some cases, the sugar and nucleobase are not joined in the
proper spatial arrangement.
• Intense solar UV rays hit shallow waters on the early earth, destroys
the “incorrect” nucleotides and leaves behind the “correct” ones.

18. • The end result is a remarkably clean route to the C and U
nucleotides
• Of course, we still need a route to G and A, so challenges
remain

19. Neelam

20. POLYMERIZATION
• Final step in the formarion of RNA molecule is
polymerization;the sugar of one nucleotide forms chemical
bonds with phosphate of the next,so that nucleotides string
themselves in a chain.
• By adding chemicals to a solution of chemically reactive
versions researchers have been able to produce short RNA
chains of 2 to 40 nucleotides.

21. • In the late 1950,JAM FERRIS and his coworkers showed that
clay minerals enhance the process ,it will produce chains of up
to 50 nucleotides.
• WATER Had little chances of combining into long strands to
store genetic information.
• Mlecular adhesion forces brought them close together

22. • it once had to carry on hereditary processes on its own. It now
seems certain that RNA was the first molecule of heredity, so it
evolved all the essential methods for storing and expressing
genetic information before DNA came onto the scene.
However, single-stranded RNA is rather unstable and is easily
damaged by enzymes. By essentially doubling the existing RNA
molecule, and using deoxyribose sugar instead of ribose, DNA
evolved as a much more stable form to pass genetic
information with accuracy.

23. saima

24. SOME WARM, LITTLE VIAL(2)
production of ribozymes by Alonsons and Ricardo:
• they started it with trillion of random RNA sequences and
selected those RNA sequences with efficient catalytic
properties
• Tracey and Gerald of the Scripps Research Institute also
evolved two ribozymes,which could copy short RNA sequences
but required RNA preexisting pieces.

25. • Alonson and Ricardo searched alternative chemical ways of
copying genetic molecules without using catalysts.
• In this experiment they use DNA template mix it with solution
containing nucleotide then allow it to polymerize to form a
double strand.

26. • Changes were made in sugar component-----made the
polymerization much efficient
• This new polymer behaved like classic RNA despite of changes
made in sugar component

28. Origin of life on Earth
Boundary issues
Mahnoor
SP17-RO2-009

29. • How molecules interacted to assemble into first cell
like structures or “Protocells”
• Modern cellular membranes lipid bilayer
• Membrane functions
• Keep components physically together
• Barrier to uncontrolled passage of molecules
• Sophisticated proteins act as gatekeepers
• Construction and repair of membrane

30. • Probably made of simpler molecules-
fatty acids
• Membranes could assemble
spontaneously from fatty acids
• Molecules as large as nucleotides could
slip easily across membrane
• A simple experiment to show how
protocells copy genetic information
Primitive Membranes

32. LET THERE BE DIVISION
By
Kainat fiyaz(SP17-R02-00)
Kifayat ullah(sp17-R02-003)

33. LET THERE BE DIVISION
• For protocells to start reproducing, they need to be able to
grow, duplicate their genetic contents and divide into
equivalent “daughter” cells.
• A protocell (or protobiont) is a self-organized, endogenously
ordered, spherical collection of lipids proposed as a
stepping-stone to the origin of life.

34. Growth of Primitive vesicles
• Experiments
1. Pier Luigi Luisi 1990s
 Added fresh fatty acids to the water surrounding such vesicles (Protocell).
 The membranes incorporated the fatty acids and grew in surface area.
 As water and dissolved substances slowly entered the interior, the cell’s volume also increased.

35. 2. Irene Chen:
 Involved competition between protocells.
 Model protocells filled with RNA became swollen due to osmotic effect.
 The membrane thus came under tension, and this tension drove growth, because adding
new molecules relaxes the tension on the membrane, lowering the energy of the system.
 In fact, swollen vesicles grew by stealing fatty acids from relaxed neighbouring vesicles,
which shrank.

36. Formation Of Protocells And Replication
• Membranes and genetic polymers self-assemble
• The two components can be brought together
– If the membranes form around preexisting polymers.
– These sacs of water and RNA will also grow, absorb new molecules,
compete for nutrients, and divide.
• But to become alive, they would also need to reproduce and
evolve.
• In particular, they need to separate their RNA double strands so
each single strand can act as a template for a new double strand
that can be handed down to a daughter cell.

38. • This process needs energy from some source.
• There could be pools of cold water, perhaps partly covered
by ice but kept liquid by hot rocks.
• Protocells in the water would be exposed to
– A burst of heat as they passed near the hot rocks,
– Instantly cool down again as the heated water mixed with the bulk
of the cold water.
• The sudden heating would cause a double he-lix to separate
into single strands.
• Once back in the cool region, new double strands copies of
the original one could form as the single strands acted as
templates.

39. Evolution
• As soon as the environment forced protocells to start reproducing,
evolution kicked in.
• RNA sequences mutated randomly, becoming ribozymes
– That speed up the copying of RNA
– Began to copy RNA without external help.

41. Metabolism
• Could have arisen gradually,
– Synthesize nutrients internally
from simpler and more abundant
starting materials.

42. Proteins Appear
• Ribozyme begin to translate
sequence of RNA (genes) into
chains of amino acids (proteins).
• Proteins later prove to be more
efficient catalysts and able to
carry out a variety of tasks.
• Proteins take on a wide range of
tasks within the cell. Protein-
based catalysts, or enzymes,
• Gradually replace most
ribozymes.

43. The Birth Of DNA
• Enzymes begin to make
DNA.
• Due to its superior stability,
DNA becomes the primary
genetic molecule.
• RNA’s act as a bridge
between DNA and proteins.
• At that point, The RNA world
became the DNA world, and
life as we know it began.

44. Bacterial world
Organisms resembling modern
bacteria adapt to living virtually
everywhere on earth and rule
unopposed for billions of years,
until some of them begin to
evolve into more complex
organisms.