Lecture 1 Flashcards
Traditional definition of life
Cell based systems
More inclusive definition of life
Sustained chemical systems capable of evolution
Cell
Cyto-; generally defined as the smallest unit of life. Generally have a membrane defined boundary, a water based interior, and genetic material.
Darwinian evolution
Organisms/systems can create new copies which resemble them
Proposed steps for the beginning of life on Earth
- Conditions allowed for the synthesis of small organic compounds
- Macromolecules form
- Protocell formation
- Self-replicating molecules
Four major types of organic macromolecules
Nucleic acids, proteins, lipids, and carbohydrates
Polymer
Large molecule made of the same or similar molecules in a chain
Proposed origins of organic molecule synthesis
- Reducing atmosphere
- Extraterrestrial origin
- Deep sea vents
Miller-Urey Experiment
*1953
*water vapors and gases theorized to be on earth’s surface were held together and electricity added. After having run for a week a sample was collected and amino acids were found.
Events that can cause a change (mutation) in DNA
*Imperfect Replication
*Sorting
*Maintenance
*Exchange (genetic recombination)
Transformation (genetic recombination)
After the death of a cell, some genetic material is released into a liquid environment, and a bacteria picks up the genetic material and incorporates it into itself.
Transduction (genetic recombination)
A virus inserts genetic information into a cell
Bacterial conjugation
Bacteria form a temporary connection to exchange genetic material
Are viruses living organisms?
The traditional definition of life says no because a virus is not a cell based system, but the more inclusive definition says yes because a virus is a chemical system capable of replicating itself
Proposed environmental conditions that allowed for formation of early life
*Bombardment of Earth (extraterrestrial origin)
*Cooling temperatures
*Low oxygen atmosphere
