Astrobiology: Origin of Life and RNA World Lecture Notes

These flashcards cover key concepts from the astrobiology lecture focused on the origin of life and the RNA World hypothesis.

Definition of Life

An entity that can reproduce and evolve through natural selection, specifically carbon-based, water-dependent, and uses DNA for evolution.

Origin of Life Timing

Life began on Earth between 3.5 and 4.25 billion years ago, according to fossil evidence.

Tree of Life

A diagram that shows the evolutionary relationships among various biological species based on similarities and differences in their DNA sequences.

Deep-sea Vents Hypothesis

Suggests life originated underwater at deep-sea vents providing chemical energy and protection from harmful radiation.

Sources of Organic Molecules

Four proposed sources are sunlight-driven reactions, reactions at deep-sea vents, extraterrestrial delivery, and heat/pressure from impacts.

RNA World Hypothesis

Proposes that RNA, being simpler than DNA, was the original self-replicating molecule prior to the evolution of DNA.

Pre-cells

Microscopic enclosures that can form spontaneously and serve as primitive membranes to concentrate reactants and facilitate reproduction.

Four-Step Molecular Evolution

A proposed sequence of events illustrating the evolution from RNA to early life involving self-replication, protein formation, and pre-cell division.

Amino Acids Role

They attach to RNA and form small proteins, which may act as enzymes to accelerate RNA replication.

Importance of Clay Minerals

They can help promote the assembly of RNA strands by concentrating organic molecules.

Definition of Life

An entity that can reproduce and evolve through natural selection, specifically carbon-based, water-dependent, and uses DNA for evolution.

Origin of Life Timing

Life began on Earth between 3.5 and 4.25 billion years ago, according to fossil evidence.

Tree of Life

A diagram that shows the evolutionary relationships among various biological species based on similarities and differences in their DNA sequences.

Deep-sea Vents Hypothesis

Suggests life originated underwater at deep-sea vents providing chemical energy and protection from harmful radiation.

Sources of Organic Molecules

Four proposed sources are sunlight-driven reactions, reactions at deep-sea vents, extraterrestrial delivery, and heat/pressure from impacts.

RNA World Hypothesis

Proposes that RNA, being simpler than DNA, was the original self-replicating molecule prior to the evolution of DNA.

Pre-cells

Microscopic enclosures that can form spontaneously and serve as primitive membranes to concentrate reactants and facilitate reproduction.

Four-Step Molecular Evolution

A proposed sequence of events illustrating the evolution from RNA to early life involving self-replication, protein formation, and pre-cell division.

Amino Acids Role

They attach to RNA and form small proteins, which may act as enzymes to accelerate RNA replication.

Importance of Clay Minerals

They can help promote the assembly of RNA strands by concentrating organic molecules.

What unique properties of RNA make it central to the RNA World Hypothesis?

RNA can store genetic information (like DNA) and catalyze biochemical reactions (like proteins/enzymes), allowing for self-replication and enzymatic functions in early life.

Describe the chemical environment of deep-sea vents that supports the origin of life.

Deep-sea vents release hydrogen-rich fluids and other reduced inorganic compounds, providing chemical energy for chemosynthesis in the absence of sunlight, along with metal catalysts.

What is the very first step in the 'Four-Step Molecular Evolution' theory of life's origin?

The first step is the abiotic synthesis of simple organic monomers (e.g., nucleic acids, amino acids) from inorganic molecules under primitive Earth conditions.

How do pre-cells contribute to the formation of early life?

Pre-cells provide a confined environment, concentrating organic molecules and replicating genetic material, which increases the efficiency of reactions fundamental for early life forms.

Definition of Life

An entity that can reproduce and evolve through natural selection, specifically carbon-based, water-dependent, and uses DNA for evolution.

Origin of Life Timing

Life began on Earth between 3.5 and 4.25 billion years ago, according to fossil evidence.

Tree of Life

A diagram that shows the evolutionary relationships among various biological species based on similarities and differences in their DNA sequences.

Deep-sea Vents Hypothesis

Suggests life originated underwater at deep-sea vents providing chemical energy and protection from harmful radiation.

Sources of Organic Molecules

Four proposed sources are sunlight-driven reactions, reactions at deep-sea vents, extraterrestrial delivery, and heat/pressure from impacts.

RNA World Hypothesis

Proposes that RNA, being simpler than DNA, was the original self-replicating molecule prior to the evolution of DNA.

Pre-cells

Microscopic enclosures that can form spontaneously and serve as primitive membranes to concentrate reactants and facilitate reproduction.

Four-Step Molecular Evolution

A proposed sequence of events illustrating the evolution from RNA to early life involving self-replication, protein formation, and pre-cell division.

Amino Acids Role

They attach to RNA and form small proteins, which may act as enzymes to accelerate RNA replication.

Importance of Clay Minerals

They can help promote the assembly of RNA strands by concentrating organic molecules.

What unique properties of RNA make it central to the RNA World Hypothesis?

RNA can store genetic information (like DNA) and catalyze biochemical reactions (like proteins/enzymes), allowing for self-replication and enzymatic functions in early life.

Describe the chemical environment of deep-sea vents that supports the origin of life.

Deep-sea vents release hydrogen-rich fluids and other reduced inorganic compounds, providing chemical energy for chemosynthesis in the absence of sunlight, along with metal catalysts.

What is the very first step in the 'Four-Step Molecular Evolution' theory of life's origin?

The first step is the abiotic synthesis of simple organic monomers (e.g., nucleic acids, amino acids) from inorganic molecules under primitive Earth conditions.

How do pre-cells contribute to the formation of early life?

Pre-cells provide a confined environment, concentrating organic molecules and replicating genetic material, which increases the efficiency of reactions fundamental for early life forms.

What did the Miller-Urey experiment demonstrate?

It demonstrated that various organic molecules essential for life (like amino acids) could be formed spontaneously from inorganic components under primitive Earth conditions.

What is the Panspermia hypothesis?

The hypothesis that life's building blocks or even primitive life forms originated elsewhere in the universe and were transported to Earth, possibly via meteorites or comets.

How could early membranes or pre-cells have formed spontaneously?

Early membranes could have formed through the self-assembly of lipid-like molecules into vesicles in water, creating enclosed compartments necessary for concentrating organic reactants.

Definition of Life

An entity that can reproduce and evolve through natural selection, specifically carbon-based, water-dependent, and uses DNA for evolution.

Origin of Life Timing

Life began on Earth between 3.5 and 4.25 billion years ago, according to fossil evidence.

Tree of Life

A diagram that shows the evolutionary relationships among various biological species based on similarities and differences in their DNA sequences.

Deep-sea Vents Hypothesis

Suggests life originated underwater at deep-sea vents providing chemical energy and protection from harmful radiation.

Sources of Organic Molecules

Four proposed sources are sunlight-driven reactions, reactions at deep-sea vents, extraterrestrial delivery, and heat/pressure from impacts.

RNA World Hypothesis

Proposes that RNA, being simpler than DNA, was the original self-replicating molecule prior to the evolution of DNA.

Pre-cells

Microscopic enclosures that can form spontaneously and serve as primitive membranes to concentrate reactants and facilitate reproduction.

Four-Step Molecular Evolution

A proposed sequence of events illustrating the evolution from RNA to early life involving self-replication, protein formation, and pre-cell division.

Amino Acids Role

They attach to RNA and form small proteins, which may act as enzymes to accelerate RNA replication.

Importance of Clay Minerals

They can help promote the assembly of RNA strands by concentrating organic molecules.

What unique properties of RNA make it central to the RNA World Hypothesis?

RNA can store genetic information (like DNA) and catalyze biochemical reactions (like proteins/enzymes), allowing for self-replication and enzymatic functions in early life.

Describe the chemical environment of deep-sea vents that supports the origin of life.

Deep-sea vents release hydrogen-rich fluids and other reduced inorganic compounds, providing chemical energy for chemosynthesis in the absence of sunlight, along with metal catalysts.

What is the very first step in the 'Four-Step Molecular Evolution' theory of life's origin?

The first step is the abiotic synthesis of simple organic monomers (e.g., nucleic acids, amino acids) from inorganic molecules under primitive Earth conditions.

How do pre-cells contribute to the formation of early life?

Pre-cells provide a confined environment, concentrating organic molecules and replicating genetic material, which increases the efficiency of reactions fundamental for early life forms.

What did the Miller-Urey experiment demonstrate?

It demonstrated that various organic molecules essential for life (like amino acids) could be formed spontaneously from inorganic components under primitive Earth conditions.

What is the Panspermia hypothesis?

The hypothesis that life's building blocks or even primitive life forms originated elsewhere in the universe and were transported to Earth, possibly via meteorites or comets.

How could early membranes or pre-cells have formed spontaneously?

Early membranes could have formed through the self-assembly of lipid-like molecules into vesicles in water, creating enclosed compartments necessary for concentrating organic reactants.

What is Abiogenesis?

The natural process by which life arose from non-living matter, such as simple organic compounds, often considered the beginning of life's evolution on Earth.

What is the Primordial Soup theory?

A hypothesis proposing that early Earth's oceans contained a 'soup' of organic molecules formed from atmospheric gases and energy, from which the first life arose.

What are Ribozymes?

RNA molecules that possess catalytic activity, meaning they can act as enzymes to facilitate biochemical reactions, a key component of the RNA World Hypothesis.

What was the composition of Earth's early atmosphere relevant to abiogenesis?

Believed to be a reducing atmosphere, rich in gases like methane (CH4), ammonia (NH3), water vapor (H2O), and hydrogen (H2), facilitating the formation of organic molecules.

What is Chemosynthesis?

A process used by some organisms to produce food (organic molecules) by using chemical energy from the oxidation of inorganic substances, rather than light energy.