1.Demonstrate the scientific method at work by describing how Louis Pasteur cast
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Question
1.Demonstrate the scientific method at work by describing how Louis Pasteur cast doubt on the idea of spontaneous generation.
2.Describe a theory as defined in scientific study and provide an example.
3.The protein synthesis pathway—DNA: mRNA: protein—is a very important concept in biology. Within this framework: a. What is the information-bearing "building blocks" of DNA, and where is DNA located in the cell? b. What does the "m" in mRNA stand for, and what is the function of mRNA?
4.Define homeostasis and explain how it enables the body to adapt to changes in its environment.
Explanation / Answer
1 - Spontaneous generation theory by Louis Pasteur :
Louis Pasteur's Fermation expriments,
He find that skin is natural source of yeast which main souce of fermation in wine, he expriment on grape juiec which was made by sterile grape but that juice is never fermated.
Luis Pasteur cast doubt on this Idea :
Punchet stated that air everywhere, end of reults was spontaneous generation of living oraganism was observed in liquid, and after he claimed that he has evidance of spontaneous generation.
For evidance of against spontaneous generation, Francesco Redi and Spallanzani's experiments that air contaminated broths with bacteria.
After that Pasteur repeated that experiments, but Pouchet reported a different result using a different broth.
2 - Spontaneous theory disproving by Louis Pasteur :
Pasteur performed several experiments,
- Boiled liquid in a flask and let hot air enter the flask,then closed the flask, and no organisms grew in it.
- Opened flasks containing boiled liquid, dust entered the flasks, causing organisms to grow in some of them.
- Used swan neck flasks containing a fermentable liquid, allowed to air enter the flask via a long curving tube that made dust particles stick.
Results of above expriments :
- Nothing grew in the broths unless the flasks were tilted, making the liquid touch the contaminated walls of the neck.
- This showed that the living organisms that grew in such broths came from outside, on dust, rather than spontaneously generating within the liquid or from the action of pure air.
Conclusion by Louis Pasteur :
Never will the doctrine of spontaneous generation recover from the mortal blow of this simple experiment.
There is no known circumstance in which it can be confirmed that microscopic beings came into the world without germs, without parents similar to themselves.
Finally Pasteur get disproving theory of spontaneous generation and he got Nobel prize.
3 - Protein synthesis Pathway :
a - Building bolck of DNA :
Nucleotide is Building block of DNA,
Nucleotide made up with 5 - carbon sugars, a nitrogenous base and one phosphate.
The nitrogenous base - adenine (A), cytosine (C), guanine (G) and thymine (T).
DNA Location in cell :
Mainly DNA located in cell nucleus but can also be found in Mitochondria.
b - mRNA
m in mRNA is messanger RNA.
Function :
mRNA is in cells relays instructions from the DNA inside the cell nucleus to ribosomes.
4 - Homeostasis :
Homeostasis - Stable stage of oraganism and its internal enviroment, Regulation of stable condition.
Stable stage mintainace by many regulatory mechnasims.
Mainy tree interdependant component for varible being regulated :
- A receptor - Sensing component that monitor and responsed to change in enviroments e.g., thermoreceptor and mechano receptor.
- A control phase - respiratory and renin angiotensin system
- A effector - target acted on and to bring about to change back to the normal stage.
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