Life Flashcards
1
Q
List 8 characteristics of living things
A
1) Chemical Uniqueness
2) Reproduction
3) Metabolism
4) Environmental interaction
5) Movement
6) Development
7) Possession of genetic program
8) complex and hierarchical organization
2
Q
What is Life?
A
- Not a simple definition
- History of life on earth => extensive and ongoing change
- Answer based on the common history of life on earth
Universal properties since life began (replication)
Properties of living things today (DNA)
3
Q
Earth’s History
A
- The earth formed approx. 4.6 billion years ago
- Early earth had no atmosphere, soil, ocean
- Life is thought to have formed approx. 4. billion years ago
4
Q
What’s the Oparin-Haldane Hypothesis
A
- Alexander Oparin and J.B.S. Haldane
- Primordial soup theory
- Organic compounds characteristic of life formed slowly over time from simple molecules present in the prebiotic environment
- Early atmosphere consisted of simple compounds (water vapour, hydrogen gas, ammonia, carbon dioxide, methane, limited free oxygen)
- With an energy source, these compounds came together to form more complex organic molecules
5
Q
What is the Miller-Urey Experiment (1953)
A
- Stanley Miller and Harold Urey
- Circulated a mixture of; water, hydrogen, methane and ammonia
- Energy source: electrical spark
- Results: In a week, 15% of the carbon in the mixture was converted to organic compounds such as: amino acids, urea, fatty acids
6
Q
What are the origins of life?
A
- Next stage formation of polymers
- Probably within the semipermeable amphiphilic membranes
- Why?
In aqueous solution, polymers would tend to be hydrolysed
Semipermeable membranes could provide protection - Simple inorganic molecules formed and began to accumulate in the early oceans. Over time:
simple organic molecules
complex organic molecules
cells
7
Q
What is amphiphilic?
A
One part soluble in water (polar), another part insoluble in water (non-polar)
