BIOL 1108 1nd EditionExam # 1 Study Guide Lectures: 2 – 6Lecture 2 (August 22)Introduction to Prehistoric EarthLearning Objectives1. How does ‘abiogenesis’ differ from ‘biological evolution’? Despite their differences, how are the two concepts similar to one another?2. What was the major significance of the work of Stanley Miller? Jack Szostak? 3. What were some of the natural sources of biologically important molecules that were presenton the early Earth before the origin of life? Where did these biomolecules come from?In The News: Why were authorities handing out bottled water in Toledo, Ohio in early August of 2014? MicrocysTIS is the algae, MicrocysTIN is the toxin it produces- Microcystis is a cyanobacteria algae that produces a toxin MICROCYSTIN, which is contaminating the water supply in Toledo, Ohio via Lake Erie.- Warmer temperatures and waste dumped into the lake have provided microcystis with an ideal breeding ground to bloom.- Microcystin causes extreme liver damage- The problem with microcystin is the body does not know how to remove it.- Microcystin is very resilient to Ph changes and temperature fluctuations, as well as many enzymes in the bodyPREBIOTIC EARTH Abiogenesis: emergence of biotic life from abiotic resources- This lies in the grey area between biology and chemistryAbiogenesis formed spontaneously through millions of years of random molecule interactions (chemical evolution), and (biological) evolution occurs spontaneously through many years of spontaneous gene mutation.The earth’s crust floats upon a relatively fluid mantle - Mantle is constantly heated by radioactive decay from core- Convection currents from fluid mantle cause crust plates to shift (i.e. Pangea → modern continents)Primitive Earth’s Atmosphere80% H2O VAPOR10% CO210% INERT GASES (N2, CO, CH4)OXYGEN (O2) NOT PRESENT Present Earth’s Atmosphere77% NITROGEN (N2)21% OXYGEN (O2)1% WATER (H2O) VAPOR0.035% CARBON DIOXIDE (CO2)**BIGGEST CHANGE IS THE MAJOR REDUCTION OF CARBON DIOXIDEIn recent years, the carbon dioxide percentage has risen from 0.035% to 0.4%. This may seem like an insignificant elevation, but it has a large effect on the atmosphere - leads to global warming- Mostly anthropogenic (originates from human activity)- The increased levels cause CO2 dissolve in the oceans and lead to ocean acidification which would be bad for marine lifeEarth’s atmosphere developed from outgassing, in which gases are released from molten rock inthe mantle of the planet by volcanic activity (Comets and meteorites bring gases too).HOW DID LIFE FORM?Primitive chemicals had to have combined to form larger, more complex molecules.Primitive Earth’s chemicals had to form organic molecules- Molecules had to combine to form primitive cells (protocells)- Protocells had to evolve into true cellsEndosymbiosis: larger organism engulfing a smaller one“Life begets life.” Early scientists thought that life could spontaneously arise (like Jan Baptista van Helmont’s theory: Dirty clothing + wheat + 21 days = mice). Scientists like Francisco Redi (hedid the experiment with the meat and the flies and how maggots did not appear if the flies could not get to the meat) and Louis Pasteur (he did the experiment where he had two open flasks with a broth or something that would allow bacteria to grow and one was sterilized and curved so that no outside bacteria from the air could get in and the other wasn’t) proved that life couldn’t be spontaneous. Life had to come from other forms of life.- STANLEY MILLER EXPERIMENT: combined chemicals thought to have been present in prebiotic Earth to form “life.” (i.e. water, ammonia, carbon dioxide, etc.)- Successfully synthesized 9/20 critical amino acids required for life to exist.- JACK SZOSTAK: earlier forms of life had a simpler biochemistry than today’s organisms; life probably started in a puddle, not an ocean (what we normally think) because oceanic salt content would be so high it would destroy some precursor to membranes-hydrothermal vents= life’s oven/freezerHYDROTHERMAL VENTS: It is hypothesized that the extreme heat in underwater heat vents provided substantial energy to procure life from abiotic materials.- Demonstrated complex organic compounds such as methane, ethane, and butane- Can be produced via inorganic processesLecture 3 (August 25) Brief History and the Origin of LifeLearning Objectives1. Be able to explain the differences between the conventional “5 Properties” definition of livingthings and NASA’s definition of “life”.2. How does the concept of the “RNA World” solve some of the problems associated with the early stages in origin of life?3. What roles did symbiosis and lateral gene transfer (LGT) play in the early development of living systems?In The News Why did the Liberian police use wood and wire to seal 50,000 people inside the West Point slum in Monrovia?EBOLA - Closely related to Marburg virus- Filovirus - believed to be primarily transmitted from African fruit bats- Affects non-human primates also- Hemorrhagic fever  often results in organ failure (main cause of death- There is no PROVEN cure for Ebola yet, but a new treatment called ZMAPP has just been testedat Emory.- Also, does ZMAPP provide immunity for life?No one knows yet, the doctor who went back to Africa will test it out and see What happens 1. Ebola is engulfed by macrophages and monocytes but then replicates its single stranded RNA genome within the infected cells.2. Infected cells release cytokines which actually facilitate the entry of the virus into endothelial cells that line the blood vessels.3. Viral protein interferes with the production of some important components of the human immune system, like interferons.4. When the new viral particles burst the cell open, they cause detachment of the host cell fromits neighboring cell. This leads to loss of contact between the cells causing massive hemorrhage.RNA WORLDRNA molecule- Polypeptides associating with RNA could aid in replication- RNA can store information and can act as an enzyme.- Theoretical evolution of self-replicating RNA- Self-sustaining chemical reactions known as “hypercycles” result in complex products being formed provided there is an input of energyIt has self-catalytic ability, made from simpler role moleculesRNA may have be able to duplicate itself by curling up into itself and acting as a catalyst.