Origin of Life
Origin of Life BIOL 1014
Popular in Life: Continuity and Change
Popular in Biology
verified elite notetaker
This 4 page Class Notes was uploaded by Crystal Florman on Tuesday April 26, 2016. The Class Notes belongs to BIOL 1014 at University of Northern Iowa taught by Dr. Kurt Pontasch in Spring 2016. Since its upload, it has received 77 views. For similar materials see Life: Continuity and Change in Biology at University of Northern Iowa.
Reviews for Origin of Life
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 04/26/16
Exam 4 Notes- Topic 2 Origin of Life A. Introduction a. What is life how did it originate? B. Spontaneous Generation a. At the beginning of historical time no one doubted that life originated from nonliving material b. Spontaneous generation is the idea that living organisms came from nonliving material i. 1600’s some people began to believe in biogenesis c. Living organisms only came from other living organisms d. 1668- Redi- designed an experiment to disprove spontaneous generation i. He had 2 jars and put meat in both- covered one with gauze and left the other one open- flies land on the open one but not the closed one e. 1861- Pasteur- placed sugar solution in 2 beakers with swan necks- boiled them- cut off the swan neck from one beaker- the solution in the beaker without the swan neck fermented where the other one did not C. Modern Theory of the Origin of Life a. 1920’s- Oparin and Haldone- independently proposed the idea of spontaneous generation in a new form i. It took billions of years for life to arise from nonliving material ii. *it only can occur under conditions present very early in the Earth’s history 1. Early Earth a. Most scientists agree that the earth was formed about 4.5 billion years ago b. Large amounts of heat was generates as particles collected to form the earth c. Molten mass of particles cooked and became covered by a crust- which had a considerable amount of volcanic activity d. At this time, 4 billion years ago, the surface was very hot, there was no water, and probably no atmosphere e. Over millions of years the volcanos release water vapor, CO2, methane, ammonia, and Hydrogen f. *because there is no oxygen the atmosphere is called a reducing atmosphere g. Further cooling allowed the water vapor to turn to rain, run over the land, and form the oceans 2. Organic molecules a. *they were formed in the reducing atmosphere b. Molecules above provided all of the N C O and H necessary to form simple organic molecules c. Lightning, heat from volcanos, and sunlight supplied the energy necessary to drive reactions d. Once the simple organic molecules were formed in the atmosphere they were washed into the oceans by rain Exam 4 Notes- Topic 2 e. *in the oceans the organic molecules could have reacted with each other to form simple sugars, amino acids, and nucleic acids f. It was thought that it took 500 million years to form the “soup” in the oceans g. It is thought that these monomers served as the basic building blocks for more complex macromolecules- carbs, lipids, proteins, and nucleic acid h. 1953- Stanley Miller i. Experiment- tried to see if organic material could be formed from inorganic material ii. Set up a glass apparatus containing water, ammonia, methane, and hydrogen iii. Heated some parts and cooled others to simulate rain and added an electrical charge to simulate lightning iv. Able to synthesize amino acids and sugars i. How are Macromolecules formed? i. Dehydration synthesis- how? 1. A portion of the ocean became separated from the rest and began to evaporate, as that took place the organic molecules became more concentrated, as water disappeared completely- macromolecules could have been formed by dehydration synthesis 2. Simple organic molecules couel have concentrated by freezing- as the water froze they became more concentrated- as the water froze and became unavailable macromolecules could have formed by dehydration synthesis 3. Clay particles, which are electrically charged, could have attracted and concentrated the simple organic molecules- then dehydration reactions could have formed the macromolecules D. Coacervates and Protenoid Microspheres (PM) a. Oldest known fossils of living cells are about 3.5 billion years old b. There are 2 theories for the formation of prebiots i. Prebiot- nonliving structure that led to the first living cells 1. Operan theorized that a prebiot consisted of carbs, proteins, lipids, and nucleic acids that formed to make a coacervte a. Coacerate- consistes of organic molecules surrounded by a shell of water cells Exam 4 Notes- Topic 2 b. Can be made in the lab and have the following characteristics i. Tending to adsorb (things stick to it) and then incorporate substances from the surrounding environment ii. Orderly arrangement of macromolecules iii. They are able to grow as they incorporate other substances iv. Able to divide under some conditions 2. More recently the theory of PM gas been suggested by Sydney Fox as the original prebiot a. PM- droplet that form when hot mixtures of polypeptides are cooled b. Similar to cells in the following ways i. Shrink in a hypertonic solution and expand in a hypotonic solution ii. double layered outer “membrane” iii. contain protenoids that can work as enzymes 1. protenoid- branded chain of amino acids iv. use ATP as a source of energy to direct the form of polypeptides and nucleic acids v. can bud off and form new microspheres vi. tend to form clusters similar to bacteria c. the experiments by Miller and Fox can only happen in a reducing atmosphere d. now widely believed that the first living cells developed through spontaneous generation in the absence of oxygen E. Heterotrophs to Autotrophs a. *first primitive cells were probably heterotrophs- no oxygen- they were anaerobic i. Able to feed on the large amounts of organic molecules in the oceans ii. As they were used up- competition for food came into play iii. Thought over time that some of those heterotrophs developed metabolic pathways that allowed them to make their own food from sunlight (blue green algae) F. Oxidizing Atmosphere a. Once the autotrophs were present- an oxidizing atmosphere was formed- *2billion years ago b. Prevented further spontaneous generation c. Opened door for aerobic organisms G. Origin of Eukaryotic Cells a. All original cells were prokaryotes b. Thought that eukaryotic cells evolved from prokaryotic cells through endosymbiosis H. Continuity of Life a. All organisms from bacteria to humans have many things in common i. DNA is the universal genetic material Exam 4 Notes- Topic 2 ii. Proteins serve as both structural material and enzymes iii. ATP is the source of energy iv. All have the same “building blocks b. Very probable that all life evolved from a single origin
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'