Bio lectures 1-5

There's no universally accepted definition of life. Discovery is constant and also limited to our planet, thus making a solid definition difficult

Life is a self-sustaining system capable of Darwinian Evolution (NASA exiobiology board, 1992)

1. Order within the cell (molecules, structures, and organelles are organized)
2. Energy production and use (ATP)
3. Reproduction (sexual or asexual)
4. Response to stimuli (has receptors)
5. Homeostasis (stable internal conditions)
6. Growth (increases in size, mass/cells)
7. Evolution (Darwin's theory)

Hypothermic (low)
Normothermic (normal)
Hyperthermic (high)

- Nucleic Acids (DNA, RNA) coated in protein
- Attaches to live cells, it loses the protein coat, hijacks the live cell and uses it as a catalyst to replicate its own genetic material and make more viral protein
- are NOT considered LIVING as they rely on living cells to stay alive (not self-sustaining)

Chunks of DNA; molecules carrying instructions to direct growth and development in a cell

- sterile + sealed flask of broth: no life
- sterile + open flask of broth: microorganisms life
⤷ proving all life originates from pre-existing living organisms.

- Organisms co-evolve with their environment (biotic-abiotic relationship)
⤷ the living create the nonliving and the nonliving sustain the living
*Ex.* organisms making oxygen, oxygen sustaining the organism + the rest of the ecosystem

- current atmosphere developed from a pooreducing atmosphere due to evolution of photosynthetic cells. More oxygen, more complex life forms.

1. the atmosphere of primitive earth was a reducing atmosphere: lacking oxygen while having high concentrations of ammonia, hydrogen, and methane— not supportive of life
2. organic molecules (amino acids, nucleotides, simple sugars) that formed the building blocks of life could have been formed by abiotic synthesis.
⤷ abiotic synthesis: organic molecules made from inorganic molecules

using a gaseous chamber replicating the conditions of primitive earth with reducing compounds + electricity for energy, it produced organic molecules.
- silica from glass may have been a catalyst
- macromolecules (key components of life) were not formed in the expirement

polymerization is the creation process of macromolecules (key components of life). this reaction needs a solid surface.

⤷ polymerization: small molecules link together to make macromolecules

- clay has been found in space: mars, **meteorites**, and comets.

Metabolism and Replication
1. Oparin’s Theory of Life (Metabolism First):Genes needed more molecules to accumulate. Spontaneous reactions occured in solution or clay, catalysed by inorganic ions or molecules. supported by the Droplet Theory (Primitive Evolvement of Life): Cells formed → enzymes were produced → genes were created
(oily liquid mixed with water produces “coacervate”, oil droplets suspended in water appear superficially to cells.)
2. Eigen and Orgel Theory (Genes first): information-carrying polymers emerged spontaneously from prebiotic organic molecules
reversed the order of the droplet theory: RNA → enzymes → cells

Generally accepted replication first, then metabolism (enzymes) from complex molecules.

chunks of DNA, which are molecules carrying instructions to direct growth and development in a cell

genetic intstructions for the development/function of living organisms

product of genes that perform trait-determining functions

information in DNA is copied into molecules of RNA… directs prodction of protein molecule

- converting organic molecules (such as sugar) into ATP (this process is called cell respiration), and in using that ATP, living cells produce Carbon Dioxide
- can work forward and reverse
- some organisms do a revers rxn to make energy as apposed to us; we use oxidative mode,