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Primordial soup

2018-12-10T11:34:43Z

170061744:

The Primordial soup theory was first developed by Alexander Oparin in 1942, and theorises that [[Abiogenesis|abiogenesis]] did occur in a warm water body in primordial earth. He stated that the conditions present in this primordial earth could've given rise to early life forms, but that the earths atmosphere had changed so radically that it was impossible to conduct experiments.

Around the same time, J.B.S Haldane introduced his theory, which likened the primordial ocean to a chemical laboratory, containing [https://teaching.ncl.ac.uk/bms/wiki/index.php/Organic_molecules organic] and [[Inorganic molecules|inorganic molecules]]. As both these theories occured at the same time, with similarity in conclusion, the Primordial soup theory can also be named the Oparin-Haldane hypothesis<ref>Biology Wise, Finding The Origin of Life: The Primordial Soup Theory Explained.[Cited 10/12/2018] Available from: https://biologywise.com/primordial-soup-theory-explainedfckLR</ref>. 

This hypothesis gained momentum when the [[Miller-Urey experiment|Miller-Urey experiment]] managed to synthesize [[Amino-acids|amino acids]] from a chemical mixture, by simulating weather conditions that would occur in early primordial earth. However this experiment is now scrutinised for having an [[Methane|methane]] and [[Ammonia|ammonia]] rich atmosphere which is now thought to not have been present in primordial earth. The current understanding of the primordial earths atmosphere is now thought to be more inert, with it being [[Carbon|carbon]] and [[Nitrogen|nitrogen]] rich. In recent times, new research has shown that this atmosphere would still produce many amino acids, as the primordial soup would contain [[Iron|iron]] and carbonate materials, which neutralise [[Nitrates|nitrates]] (molecules that destory amino acids) and [[Acidity|acidity]] (in which amino acids dont form)<ref>Fox D. Primordial Soup's On: Scientists Repeat Evolution's Most Famous Experiment. Scientific American. 2007 March. [Cited 10/12/2018} Available from: https://www.scientificamerican.com/article/primordial-soup-urey-miller-evolution-experiment-repeated/</ref>.

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Primordial soup

2018-12-10T11:32:09Z

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Primordial soup

2018-12-10T11:31:36Z

170061744:

The Primordial soup theory was first developed by Alexander Oparin in 1942, and theorises that [[Abiogenesis|abiogenesis]] did occur in a warm water body in primordial earth. He stated that the conditions present in this primordial earth could've given rise to early life forms, but that the earths atmosphere had changed so radically that it was impossible to conduct experiments.

Around the same time, J.B.S Haldane introduced his theory, which likened the primordial ocean to a chemical laboratory, containing [https://teaching.ncl.ac.uk/bms/wiki/index.php/Organic_molecules organic] and [[Inorganic molecules|inorganic molecules]]. As both these theories occured at the same time, with similarity in conclusion, the Primordial soup theory can also be named the Oparin-Haldane hypothesis<ref>Biology Wise, Finding The Origin of Life: The Primordial Soup Theory Explained. Available from: https://biologywise.com/primordial-soup-theory-explainedfckLR [Cited 10/12/2018]</ref>. 

This hypothesis gained momentum when the [[Miller-Urey experiment|Miller-Urey experiment]] managed to synthesize [[Amino-acids|amino acids]] from a chemical mixture, by simulating weather conditions that would occur in early primordial earth. However this experiment is now scrutinised for having an [[Methane|methane]] and [[Ammonia|ammonia]] rich atmosphere which is now thought to not have been present in primordial earth. The current understanding of the primordial earths atmosphere is now thought to be more inert, with it being [[Carbon|carbon]] and [[Nitrogen|nitrogen]] rich. In recent times, new research has shown that this atmosphere would still produce many amino acids, as the primordial soup would contain [[Iron|iron]] and carbonate materials, which neutralise [[nitrates|nitrates]] (molecules that destory amino acids) and [[Acidity|acidity]] (in which amino acids dont form)<ref>Fox D. Primordial Soup's On: Scientists Repeat Evolution's Most Famous Experiment. Scientific American. 2007 March. [Cited 10/12/2018} Available from: https://www.scientificamerican.com/article/primordial-soup-urey-miller-evolution-experiment-repeated/</ref>.

'''References:'''

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Primordial soup

2018-12-10T11:18:45Z

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Connective tissue

2018-12-10T11:11:33Z

170061744: linked tendons to its page

Connective tissue is any supporting tissue in which cells are embedded in an [[Extra-cellular matrix|extra-cellular matrix]] (a network of [[Polysaccharides|polysaccharides]] and proteins- particularly [[Collagen|collagen]])<ref>Alberts, Johnson, Lewis, Raff, Roberts, Walter (2008). Molecular Biology of the Cell. 5th ed. New York: Garland Science Taylor and Francis Group. G9.</ref>. It often lies between different tissues, connecting, supporting, binding to or separating them depending on specific location and function in a multi-cellular [[Organism|organism]].

Connective tissue can take many different structures; when calcified they become very hard like teeth or bone, then can form rope like structures with high mechanical strength forming [[Tendons|tendons]], they are also responsible for the colourless gel of the [[Cornea|cornea]] in the [[Eye|eye]]<ref>Alberts, Johnson, Lewis, Raff, Roberts, Walter (2008). Molecular Biology of the Cell. 5th ed. New York: Garland Science Taylor and Francis Group. p1178</ref>.

Connective tissue is a structure in which cells adhere, to each other and to the extracellular matrix. This is necessary in multi-cellular organisms to provide mechanical strength but also to allow interaction, behaviour coordination, and regulation of [[Gene expression|gene expression]]<ref>Alberts, Johnson, Lewis, Raff, Roberts, Walter (2008). Molecular Biology of the Cell. 5th ed. New York: Garland Science Taylor and Francis Group. p1131</ref>.

Connective tissue is made up of cells surrounded by large amounts of extracellular matrix which is predominantly secreted by [[Fibroblasts|fibroblasts]]. Connective tissue is rich in extracellular matrix and cells are sparsely dispersed within it. The extracellular matrix in these connective tissues influences survival, development, migration, rapid reproduction of cells, their shape, and function<ref>Alberts, Johnson, Lewis, Raff, Roberts, Walter (2008). Molecular Biology of the Cell. 5th ed. New York: Garland Science Taylor and Francis Group. p1178</ref>.

An example of a specialised connective tissue is collagen.

=== References ===

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Primordial soup

2018-12-10T11:09:28Z

170061744:

The Primordial soup theory was first developed by Alexander Oparin in 1942, and theorises that [[abiogenesis|abiogenesis]] did occur in a warm water body in primordial earth. He stated that the conditions present in this primordial earth could've given rise to early life forms, but that the earths atmosphere had changed so radically that it was impossible to conduct experiments.

Around the same time, J.B.S Haldane introduced his theory, which likened the primordial ocean to a chemical laboratory, containing [https://teaching.ncl.ac.uk/bms/wiki/index.php/Organic_molecules organic] and [[Inorganic molecules|inorganic molecules]]. As both these theories occured at the same time, with similarity in conclusion, the Primordial soup theory can also be named the Oparin-Haldane hypothesis<ref>Biology Wise, Finding The Origin of Life: The Primordial Soup Theory Explained. Available from: https://biologywise.com/primordial-soup-theory-explainedfckLR [Cited 10/12/2018]</ref>. 

'''References:'''

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Primordial soup

2018-12-10T11:07:46Z

170061744:

The Primordial soup theory was first developed by Alexander Oparin in 1942, and theorises that abiogenesis did occur in a warm water body in primordial earth. He stated that the conditions present in this primordial earth could've given rise to early life forms, but that the earths atmosphere had changed so radically that it was impossible to conduct experiments.

Around the same time, J.B.S Haldane introduced his theory, which likened the primordial ocean to a chemical laboratory, containing [https://teaching.ncl.ac.uk/bms/wiki/index.php/Organic_molecules organic] and [[Inorganic molecules|inorganic molecules]]. As both these theories occured at the same time, with similarity in conclusion, the Primordial soup theory can also be named the Oparin-Haldane hypothesis<ref>Biology Wise, Finding The Origin of Life: The Primordial Soup Theory Explained. Available from: https://biologywise.com/primordial-soup-theory-explainedfckLR [Cited 10/12/2018]</ref>. 

'''References:'''

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Primordial soup

2018-12-10T11:07:15Z

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Primordial soup

2018-12-10T11:06:54Z

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Primordial soup

2018-12-10T11:05:14Z

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Primordial soup

2018-12-10T11:04:43Z

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Primordial soup

2018-12-10T11:04:21Z

170061744: Created page with " The Primordial soup theory was first developed by Alexander Oparin in 1942, and theorises that abiogenesis did occur in a warm water body in primordial earth. He stated tha..."

The Primordial soup theory was first developed by Alexander Oparin in 1942, and theorises that abiogenesis did occur in a warm water body in primordial earth. He stated that the conditions present in this primordial earth could've given rise to early life forms, but that the earths atmosphere had changed so radically that it was impossible to conduct experiments.

Around the same time, J.B.S Haldane introduced his theory, which likened the primordial ocean to a chemical laboratory, containing [https://teaching.ncl.ac.uk/bms/wiki/index.php/Organic_molecules organic] and [[inorganic molecules|inorganic molecules]]. As both these theories occured at the same time, with similarity in conclusion, the Primordial soup theory can also be named the Oparin-Haldane hypothesis<ref name="1">Biology Wise, Finding The Origin of Life: The Primordial Soup Theory Explained. Available from: https://biologywise.com/primordial-soup-theory-explained
[Cited 10/12/2018]</ref>.

Refractory Period

2018-12-10T10:36:31Z

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Refractory periods are a short phase in time following an [[Action potential|action potential]] where another action potential cannot be generated. There are two types of refractory periods:

#The absolute refractory period is a period where it is completely impossible for another action potential to be activated, regardless of the size of the trigger ([[Stimulus|stimulus]]). This is because the [[Sodium channels|sodium channels]] are inactivated and remain that way until [[Hyperpolarisation|hyperpolarisation]] occurs. In the [[Cardiovascular system|cardiovascular]] mechanism, this refractory period is sometimes called effective refractory period (ERP)<ref>CV Pharmacology. Effective Refractory Period. Cvpharmacology.com. 2017 [cited 1 December 2017]. Available from: http://www.cvpharmacology.com/antiarrhy/ERP</ref>.
#The relative refractory period is the period that occurs during the undershoot phase; where an action potential can be activated but only if the trigger (stimulus) is large enough. This is because some of the [[Voltage gated sodium channels|sodium channels]] have been reactivated and have recovered but it is a difficult process due to the counter-acting [[Potassium|potassium]] flow as some potassium ion channels are still open<ref>Wayne M. Becker, Lewis J. Kleinsmith, Jeff Hardin. (2006) The World of the Cell, 6th edition, San Francisco: Benjamin Cummings</ref>.

A fibre first enters the absolute refractory period directly after an action potential has been fired, then the relative refractory period. The absolute refractory period of a human muscle fibre is typically between 2.2 and 4.6 ms<ref>Brian R. MacIntosh, Phillip F. Gardiner, Alan J. McComas, Skeletal Muscle: Form and Function, Second Edition, Champaign, Ill. ; Leeds : Human Kinetics, 2006, December 2017</ref>.

The refractory period causes 3 things to occur:

*The brain will be able to perceive [[Nerve impulse|nerve impulses]] as separated events since there is a time lag between them.
*The number of generated impulses or repetitive firing rate of a [[Neuron|neuron]] will be limited in a given period of time<ref>Bruce, A, Et al. Molecular biology of the cell. (6th ed.). New York: Garland Science, Taylor and Francis Group, LLC, an informa business; 2015. P622-623</ref>.
*The nerve impulses will only travel in one direction. This is because, as the [[Action potential|action potential]] is moving forwards along axons, the [[Resting potential|resting potential]] will be re-established behind it. However, not until this happens can a new [[Action potential|action potential]] occur.

=== References ===

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