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The Big Bang Model
Our universe, Galaxy and Earth came about because matter and energy was suddenly distributed outward from a single explosion point. 13-15 billion years ago
Evidence for the Big Bang Model
Universal expansion, Galaxies are still moving apart from one another; cyclical process.
The Early Earth
was composed of molten surface, lava, meteorites. Some molecules were also found like Carbon, Methane H2O. (no organic compounds)
Used to test whether compounds could have formed spontaneously on earth. Non- Organic templates to make Organic Templates
The Clay template Hypothesis
- -Amino acids were dissolved in sea water (positive charge)
- -Positively charged amino acids became attracted to negatively charged amino acids and stuck together,
- -Then radiated by the suns light energy, initiated bonding of amino acid into the very first peptide chain.
- (amino acid in water)
- Super heated mineral rich water getting expelled as steam
Origin of Membranes
- Phosphate head
- 2 fatty acid tails
Membrane bond enclosed sac of molecules that capture energy, concentrates material , engages in metabolism and replicates itself.
Thought that the earliest form of genetic material were RNA, because it functioned as the first molecule that stored genetic code and functioned like an enzyme
Evidence for RNA as first
- 1) rRNA Catalyze peptide bond formation
- 11) Ribozymes cut and splice RNA molecules during transcription
History of Life 1
Accumulation of organic molecules, like lipids, proteins and nucleic acids etc...
History of Life 2
The first cells made ATP by aerobic pathways
History of Life 3
Common ancestors of bacteria were, archeans and eukaryotes. (formation of 3 domains)
History of Life 4
photosynthesis evolved independently in some bacterial and archean groups
History of Life 5
Origin of endomembrane system, including nuclear envelope developed.
History of Life 6
History of Life 7
Later plants, fungi and animals evolved
Disease causing agent
Non- cellular infectious particles that cannot replicate on their own
Inside a virus
- -You can have a RNA or DNA (heritable material)
- -Protein Coat
- -Some have envelope, some do not, this correlates to their method of infecting
Viruses that infect bacteria or archeans. They have a complex structure. Their DNA is located in the "head", protected by a protein coat . They have Sheath and Fiber Tails
Are naked (non-enveloped) viruses that infect animals. Their protein coat has a distinctive protein spike @ each corner. (Some infections: Hepatitis, Polio, Common cold, Warts)
- Allows recognition. Manipulates, Transcripts and is translational. (Key and Lock)
- Many have RNA as an internal component
- (Some infections: Bronchitis, HIV, Rabies, Mumps)
How did Viruses Evolve? 1
Viruses are descendants of cells that were parasites inside other cells.
How did Viruses Evolve? 2
Parasites are genetic elements that escaped from cells.
How did Viruses Evolve? 3
Viruses represent a separate evolutionary branch.
Replication of Viruses with DNA
Replication of Viruses with DNA
- have 2 life cycles.
- I. Lytic Pathway
- II. Lysogenic Pathway
DNA and some enzymes will insert and manipulate the host immediately, to generate new copies. The virus will replicate, re-assemble and burst out of the cell. (Lysis)
The virus enters the host chromosome, and can sit inactive for an extended period of time. Then replicating and entering the lytic pathway. (only some viruses will take this pathway)
Circular Bacteria DNA
Replication of Viruses with RNA
- I. Often have outer compound, protein lipid projection called Keys
- II. Virus enters the cell and releases RNA into the nucleus, to do reverse TRANSCRIPTION, with reverse TRANSCRIPTASE (enzymes)
- III. Viral DNA will get integrated into the host cells.
Primary Diff, between Cells and Viruses
- I. Protein envelope
- II. Virus can't replicate alone, cells can.
- III. No organelles
- IV. Some viruses just have RNA; cells have RNA and DNA
- V. Viruses are incredibly small.
Similarities between Cells and Viruses
- I. Carry genetic Material
- II. Made out of proteins and lipids (organic molecules)
- Simplest forms of life
- - no nucleus
- -has great metabolic diversity
Prokaryotic Nutritional Modes
- 1. Photoautotrophic
- 2. Chemoautotrophic
- 3. Photoheterotrophic
- 4. Chemoheterotrophic
Use light energy to to build organic compounds from carbon dioxide and water
Get energy by removing electrons from inorganic molecules. They use this energy to build organic compounds from carbon dioxide and water. All are Prokaryotes
Prokaryotes that use light energy to obtain carbon by breaking down organic compounds in the environment
Get both carbon and energy by breaking down organic compounds. Some protist, and all are animals and fungi.
Prokaryotic Fission + Binary Fission
A parent cell replicates its single chromosome, and this DNA replica attaches to the plasma membrane adjacent to the parent molecule.(Asexual)
Involves transfer of plasmid between prokaryotic cells through use of sex pilis.(sexual)
Acquiring DNA by taking it up from the environment (Rat experiment with pneumonia strains )