Origins Of Life

Question 1

What does the term ‘Abiogenesis’ refer to?

Answer 1

Life arose from non-living matter under early Earth’s reducing conditions

Abiogenesis suggests that life can originate from chemical processes in the absence of pre-existing life.

Question 2

What is the RNA World Hypothesis?

Answer 2

RNA molecules can act as catalysts and carry out reactions related to genetic information

This hypothesis posits that RNA was the first molecule capable of both genetic information storage and catalytic functions.

Question 3

What is the difference in stability between DNA and RNA?

Answer 3

DNA is more stable than RNA

DNA is double-stranded, which contributes to its stability compared to single-stranded RNA.

Question 4

Where did the first metabolic processes occur?

Answer 4

Deep sea alkaline vents

These environments provided unique conditions for early metabolic reactions.

Question 5

What role do iron-sulfur clusters play in early metabolism?

Answer 5

They were precursors to enzymes involved in energy metabolism

Iron-sulfur clusters are still present as cofactors for many modern enzymes.

Question 6

What is the significance of early phototrophs?

Answer 6

They used sunlight to produce energy, leading to oxygenic photosynthesis by Cyanobacteria

This process was crucial for the development of aerobic life.

Question 7

What was the Great Oxygenation Event?

Answer 7

Oxygen accumulation due to photosynthesis caused mass extinction of anaerobes

This event created an environment for the evolution of aerobic respiration and eukaryotes.

Question 8

Fill in the blank: The first metabolic processes occurred in _______.

Answer 8

deep sea alkaline vents

Question 9

True or False: DNA can be extracted as a single-stranded molecule.

Answer 9

False

DNA is typically found as a double-stranded molecule.

Question 10

What are ribozymes?

Answer 10

RNA molecules that act as catalysts

They play a role in biochemical reactions, similar to protein enzymes.

Question 11

What type of photosynthesis was developed by Cyanobacteria?

Answer 11

Oxygenic photosynthesis

This process produces oxygen as a byproduct.

Question 12

What are the earliest fossils known?

Answer 12

Stromatolites

Stromatolites are layered rock formations created by microorganisms that trap sediment.

Question 13

How old are the earliest fossils?

Answer 13

Approximately 3.5 billion years old

Question 14

What does radio carbon evidence suggest about early life?

Answer 14

Early life dates back to approximately 3.9 billion years

Question 15

What are the main components of all organisms?

Answer 15

• Nucleic acids
• Proteins
• Lipids

Question 16

What was the probable composition of the early atmosphere?

Answer 16

• High levels of H2
• CO2
• NH3
• CH4
• Absent O2

Question 17

What hypothesis suggests the early atmosphere was reducing?

Answer 17

Oparin-Haldane Hypothesis

Question 18

What molecules were present in the early atmosphere according to the Oparin-Haldane Hypothesis?

Answer 18

• H2
• CO2
• CH4
• NH3

Question 19

What type of atmosphere do we have today?

Answer 19

Oxidizing atmosphere with high O2 levels

Question 20

What did experiments simulating early atmosphere conditions demonstrate?

Answer 20

Formation of amino acids and organic molecules

Question 21

What role did clay play in the origins of life?

Answer 21

Acted as a catalytic surface for polymerization

Question 22

Fill in the blank: All organisms are composed of nucleic acids, proteins, lipids, and _______.

Answer 22

Carbohydrates

Question 23

True or False: The early atmosphere contained high levels of oxygen.

Answer 23

False

Question 24

What are protocells?

Answer 24

Early forms of cellular life that emerged from polymerization on mineral surfaces

Question 25

What does LUCA stand for?

Answer 25

Last Universal Common Ancestor

LUCA is theorized to be the most recent organism from which all life on Earth descends.

Question 26

What type of metabolism did LUCA utilize?

Answer 26

Anaerobic metabolism

Anaerobic metabolism occurs without oxygen.

Question 27

What were the primary elements involved in LUCA’s metabolism?

Answer 27

H2, C03, N2

These elements likely refer to various forms of carbon and nitrogen compounds, although Tz may need clarification.

Question 28

What is the significance of the information retrieval system in LUCA?

Answer 28

It relates to the transition from RNA to proteins

This transition is crucial for the development of complex cellular functions.

Question 29

What is the origin of eukaryotic evolution?

Answer 29

Originated via endosymbiosis

Endosymbiosis is a symbiotic relationship where one organism lives inside another.

Question 30

What did aerobic bacteria become during eukaryotic evolution?

Answer 30

Mitochondria

Mitochondria are the powerhouses of the cell, responsible for energy production.

Question 31

What did photosynthetic bacteria become during eukaryotic evolution?

Answer 31

Chloroplasts

Chloroplasts are responsible for photosynthesis in plant cells.

Question 32

What is the process through which aerobic bacteria contribute to energy production?

Answer 32

Endosymbiosis

This process allows for the integration of aerobic bacteria into eukaryotic cells, enhancing energy production.