A2.1 Flashcards
What were the conditions of early life on Earth?
Ammonia and methane in the atmosphere (no ozone layer due to no oxygen), Volcanoes, single global ocean
When was life thought to have originated on Earth?
Between 3.5 and 3.9 billion years ago.
The conditions on early Earth included electrical storms and
____ temperatures.
high (202 F, 100C)
Asteroid and comet collisions, along with volcanic eruptions resulted in high levels of ______ and _______ gas in the atmosphere.
ammonia, methane
Why was there more solar radiation present on the early Earth?
Lack of a sufficiently strong electromagnetic shield around the Earth. (no ozone layer)
Which of these molecules is considered to be a complex carbon compound?
protein
Explain why cells are the smallest units of self-sustaining life.
Cells are the smallest unit of self-sustaining life because they contain all the components necessary to carry out all eight processes of life at some point in their life cycle {Metabolism, Response to stimuli, Homeostasis, Movement, growth, reproduction, excretion, nutrition}
MR HM GREN
Metabolism, Response to stimuli, Homeostasis, Movement, growth, reproduction, excretion, nutrition
-Simple organic molecules such as amino acids and ___________ chains were formed.
-Chemical reactions were accelerated in the process of _________.
-Larger organic molecules including RNA and __________ were assembled from smaller molecules.
-Some of these molecules, including RNA were able to _________.
-Formation of a membrane-bound compartment (the cell surface membrane) allowed the internal chemistry of the cell to become ______ from that outside the compartment.
hydrocarbon, catalysis, phospholipids, self replicate, different
What was the Miller-Urey experiment?
It was designed to show early life on Earth. Miller and Urey set up a closed system. The system contained:
-water, which simulated the ocean
-a gas inlet with which to add the reducing gases methane, ammonia and hydrogen
-electrical sparks to simulate the electrical storms present on prebiotic Earth.
Miller and Urey’s investigation is still at the core of most origins of life theories today because it showed that ______ compounds can be formed from __________ precursor molecules.
organic, inorganic
Which of these gases did Miller and Urey include in their simulation of the early atmosphere?
I. oxygen
II. ammonia
III. methane
IV. hydrogen
II, III, IV
The ‘RNA first’ hypothesis posits that RNA was the first molecule of life, acting as both the
______ material, and as a catalyst for the chemical reactions occurring in a cell.
genetic
Where do scientists predict that LUCA evolved and existed?
hydrothermal vents
(Scientists examine phylogenetic and fossil evidence to infer that LUCA existed in hydrothermal vents, fissures in the ocean floor through which water, heated from the Earth’s core, and rich in mineral flows.)
- Simple _______ molecules such as amino acids were formed
- Chemical reactions were accelerated in the process of ________.
- Larger organic molecules such as ________ and RNA were assembled from smaller molecules
- Some molecules, including RNA were able to ____________.
- Formation of a ________________ compartment.
organic, catalysis, protein, self-replicate, membrane-bound
