Answer:
Mutation, Gene flow/Migration/Immigration of gene and Recombination
Explanation:
For any species there are majorly three sources of genetic variations –
a) Mutation – This leads to change in the genetic code with in the DNA of an organism. Sometimes mutation does not produce any effect on the organism. Mutation can produce both positive and negative impact. Its effect is observed in long run as its rate is slow.
b) Recombination – When an organism undergoes sex, his/her genes recombine with the genes of mating partner. The rate of recombination is faster than the rate of mutation
c) Gene flow /Migration/Immigration of gene – In this gene travel from one set of population to the other. The frequency of gene in the mixed population lies between the original population gene frequency and the migrated or donor population gene frequency
Based on research, microbes have been recently associated with the following four diseases that were once considered noninfectious:
- gastric ulcers
- multiple sclerosis
- cancer
- diabetes
<h3>What are microbes?</h3>
Microbes refers to microscopic organisms, that is organisms which can not be seen with the ordinary eye but with the aid of a microscope.
Microbes consists of the following organisms:
- bacteria
- fungi
- protozoa
- viruses
Some microbes are not harmful while many other microbes are harmful and are known to be the causative organisms for many diseases.
The diseases that are caused by microbes can be passed from one person to another and are known as infectious diseases.
However, recent research have linked microbes to some diseases such as gastric ulcer, multiple sclerosis, cancer, and diabetes which were once considered non-infectious.
Example are given below;
- gastric ulcer caused by <em>Helicobacter pylori</em>
- Multiple sclerosis caused by Epstein-Barr virus
- Cancer caused by human papilloma viruses, hepatitis B and C viruses
- Diabetes caused by E. coli and Candida spp.
In conclusion, microbes cause infectious diseases.
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Note that the complete question is given below as:
Based on research, microbes have been recently associated with which four of the following diseases that were once considered noninfectious?
muscular dystrophy
multiple scleriosis
diabetes
cystic fibrosis
gastric ulcer
cancer
gastric ulcers
multiple scleriosuis
cancer
diabetes
Answer:
The current answer is b) bacteria need for proper growth and cannot make themselves.
Explanation:
An essential nutrient is one which is required to the cell for the proper growth from the environment because it cannot be synthesized by the cell itself.
Some essential nutrients that bacteria require for their growth are carbon, nitrogen, water, iron, inorganic salts, and many other molecules.
These nutrients should be given from an easily available source to the bacteria for their proper growth because these nutrients are required to perform essential metabolic activities and can not be synthesized by bacteria on their own.
For a(n) repressible operon, transcription normally takes place, and it is turned off by a(n) active repressor.
<h3>What is repressible operon ?</h3>
An operon that is normally on but that can be turned off in the presence of a repressor molecule is referred to as repressible. The repressor binds to the operator in such a way that it prevents RNA polymerase from moving or attaching, which prevents transcription from starting.
<h3>What is active repressor?</h3>
A protein that prevents the expression of one or more genes is known as a repressor in the context of genomics. The repressor protein inhibits the synthesis of messenger RNA by attaching to the promoter region of the gene(s) (mRNA). The control of gene expression in cells requires repressor proteins.
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