Origins of cells - formation of carbon compounds Flashcards
What conditions on early Earth were believed to have been instrumental in the origin of biological compounds?
Higher atmospheric temperatures and higher levels of carbon dioxide and methane
These conditions made life possible by allowing the formation of biological compounds.
What are methane and carbon dioxide classified as in the context of early Earth’s atmosphere?
Powerful greenhouse gases
They trap infrared radiation and increase surface temperatures.
What is the greenhouse effect?
The trapping of infrared radiation by greenhouse gases, preventing it from escaping into space
This effect leads to increased surface temperatures.
What was the impact of the lack of free oxygen in the early Earth’s atmosphere?
Prevented ozone from forming
Ozone (O3) protects life by absorbing damaging UV radiation.
What harmful effect does UV radiation have on living organisms?
Causes DNA damage and increases the rate of mutations
This can be detrimental to living organisms.
What hypothesis did Alexander Oparin and JBS Haldane propose regarding the origin of biological molecules?
The ‘primordial soup’ hypothesis
They suggested that organic molecules formed from chemical processes in early Earth’s conditions.
What organic molecules are considered the building blocks of early cells?
Amino acids, simple sugars, nucleotides, and fatty acids
These molecules could have formed from energy added to early atmospheric gases.
What was the purpose of the Miller-Urey experiment?
To recreate the conditions thought to have existed on Earth prior to life
This experiment aimed to simulate early Earth’s atmosphere.
What gases did Miller and Urey mix to recreate the early atmosphere in their experiment?
Methane, hydrogen, and ammonia
These gases were part of the simulated primordial soup.
What energy source did Miller and Urey use in their experiment?
Electrical discharges
This method was used to simulate lightning, one of the energy sources on early Earth.
What did Miller and Urey find after analyzing the condensed mixture from their experiment?
Traces of simple organic molecules, including amino acids
This finding supported the idea that organic molecules could form under early Earth conditions.
True or False: It is now believed that methane was in high supply in the atmosphere of early Earth during the Miller-Urey experiment.
False
Current understanding suggests that methane may have been in low supply.
What contradiction arises from the presence of water in the early environment according to Miller and Urey’s findings?
Amino acids tend to remain as monomers rather than forming proteins
This raises doubts about the formation of complex molecules in a watery environment.
What was one limitation of the Miller-Urey experiment regarding nucleotides?
Miller and Urey were unable to generate nucleotides
Nucleotides have since been chemically synthesized using different approaches.
