A 2.1 Origin of Cells

When did the sun form?

4.6 billion years ago (gya)

3 characteristics of earths pre-biotic atmosphere and why they're there

- Traces of oxygen because it reacted with other elements.
-High methane concentrations due to intense volcanic activity and meteorite bombardment.
-High Carbon dioxide concentrations due to emissions from volcanos.

Why were temperatures higher on pre-biotic earth? 2 reasons.

-Due to higher co2 and methane emissions and they trap heat.
-Comet and asteroid impacts.

pH of pre-biotic oceans

5-11

Why didnt the ozone layer exist on pre-biotic earth?

-Due to lack of oxygen and more UV rays would've penetrated earths surface.

What does the increase of lightening on pre-biotic earth do?

-Trigger other chemical processes.

Where did carbon compounds form on pre-biotic earth?

Specialized environments like
-hot springs
-on land
-hydrothermal vents in ocean

How is aersol haze formed?

When carbon compounds formed in droplets of water in the atmosphere by bonding together.

What enormus changes happened to the conditions on earth as time went by?

-Organisms increased the concentration of oxygen from zero to 20%.
-Reduced co2 to low concentrations.
-Ozone layer formed meaning UV protection was formed.

Key difference between living and non living things?

Living things use energy to keep themselves in a highly ordered state.

Why do cells divide?

produce more cells

Celles being taken from the body and cultured is an example that they are

alive

Theory of Spontaneous Generation

Living organisms can be formed from non living matter

Is the theory of Spontaneous Generation true?

Girl no lol

How was the theory of spontaneous generation proved false?

Robert Remak studies cells in chickens and frogs and discovered that every cell is formed by division of a pre-existing cell.

4 Developments required for the origin of cells

-catalysis
-self-assembly
-compartmentalization
-self-replication of molecules

Define catalysis within the origin of cells

to give control over which chemical reactions occur

Define Self-assembly within the origin of cells

when carbon compounds such as amino acids must assemble to form polymers

Define Compartmentalization within the origin of cells

A membrane must develop to enclose cell contents

Define self replication of molecules

As a basis for inheritance and the persistence of successful variants

Aim of Miller-Urey experiment

To find the origin of carbon compounds/life and if organic molecules could've from inorganic compounds.

Procedure of Miller-Urey Experiment

Put together a model to simulate the water cycle and pre-biotic earth. Put water in a flask and boiled it to mimic evaporation. In another flask put water vapor with methane, hydrogen, and ammonia (which are simple gasses they thought were abundant on earth). Also added a condenser to cool the vapor and simulate rain falling back into ocean. Within the water vapor flask they also added sparks to simulate lightening.

Results of Miller-Urey Experiment

Water turned dark red and multiple carbon compounds were formed including 20 amino acids.
-Showed that carbons compounds could form on earth pre life.

What are vesicles?

Small droplets of fluid enclosed in a membrane.

Exosomes

extracellular vesicles

What is the membrane of vesicles composed of?

Phospholipids

2 Parts of phospholipids?

Polar Hydrophilic head- 2 Hydrophobic tails (attracted to non polar)

Molecule with hydrophobic and hydrophilic parts

Amphipathic

What are used as catalysts

enzymes

What are enzymes

Proteins composed of amino acids linked together

RNA is self... and can act....

-Self replicating
-Can act as a catalyst

Why do Viruses that use RNA as their genetic material have a high mutation rate?

The polymerase enzyme that copies the base sequence is a lot less accurate than the equivalent enzyme used to copy DNA.

How can a high mutation rate in viruses be an advantage?

Can help the virus evade the host's immune system.

How can RNA act as a catalyst?

Can form complex three dimensional structures that can undergo precise interactions with other molecules.

How is a polypeptide produced?

Amino acids bond together with peptide bonds.

How many codons are there are and what are the 3 jobs

-64 codons
-An amino acid
-A start signal
-A stop signal

covergent evolution

When similar structures evolve in organisms that don't have a recent common ancestor.

LUCA

last universal common ancestor

Fossils date back to

3.5-3 gya

How is a stromatolite formed?

Mats of cyanobacteria in shallow water trap sediments and secrete calicium carbonate, building rock over thousands of years.

Earliest cells existed before

3.42 gya

When did earth form

4.5-4.6 gya

Why is LUCA, luca?

Has a shared gene with all organisms.

What type of environment did LUCA live in? Where are these conditions found?

-Environment with high concentrations of hydrogen, co2, and iron.
-Conditions found around hydrothermal vents in ocean.

Hydrothermal Vents

cracks from which hot, water carrys reduced inorganic chemicals

Temp of hydrothermal vent

60-90 degrees

What 5 inorganic chemicals were in hydrothermal vents, and which at the highest concentration.

Hydrogen
Methane
Ammonia
Sulfides
Co2 (in highest quantity)