Which one of the following conditions though harmful in itself, is also a potential saviour from a mosquito borne infectious disease:
- Thalassaemia
- Sickle cell anaemia
- Pernicious anaemia
- Leukemia
The Correct Option is B
Solution and Explanation
Sickle cell anemia is a genetic disorder caused by a mutation in the hemoglobin gene. While it is a harmful condition in itself and can cause various health problems, individuals with sickle cell trait (heterozygous for the gene) are less susceptible to contracting malaria, a mosquito-borne infectious disease. This is because the sickled red blood cells are less favorable for the malaria parasite's growth and survival. Therefore, in regions where malaria is prevalent, having the sickle cell trait can provide some level of resistance to the disease, which is why it's considered a potential savior from malaria. However, it's essential to note that sickle cell anemia itself is a severe health condition with its own set of complications.
So, the correct option is (B): Sickle cell anaemia
Top Questions on Principles of Inheritance and Variation
Assertion (A): In dihybrid crosses involving sex-linked genes in \(\textit{Drosophila}\), generation of non-parental gene combinations are observed
Reason (R): Two genes present on different chromosomes show linkage and recombination in \(\textit{Drosophila.}\)- CBSE CLASS XII - 2025
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Questions Asked in NEET exam
- Given below are two statements:
Statement I: Fig fruit is a non-vegetarian fruit as it has enclosed fig wasps in it.
Statement II: Fig wasp and fig tree exhibit a mutual relationship as the fig wasp completes its life cycle in the fig fruit and the fig fruit gets pollinated by the fig wasp. Which of the following microbes is NOT involved in the preparation of household products?
A. \(\textit{Aspergillus niger}\)
B. \(\textit{Lactobacillus}\)
C. \(\textit{Trichoderma polysporum}\)
D. \(\textit{Saccharomyces cerevisiae}\)
E. \(\textit{Propionibacterium sharmanii}\)- NEET (UG) - 2025
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A sphere of radius R is cut from a larger solid sphere of radius 2R as shown in the figure. The ratio of the moment of inertia of the smaller sphere to that of the rest part of the sphere about the Y-axis is :
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Concepts Used:
Principles of Inheritance and Variation - Mutation
A Mutation is a change in the sequence of our DNA base pairs caused by numerous environmental stimuli such as UV light or mistakes during DNA replication. Germline mutations take place in the eggs and sperm and can be passed onto offspring, whereas somatic mutations take place in body cells and are not passed on.
Types of Mutations
There are three types of mutations, which are as follows:
Silent mutation
It refers to any change in DNA sequence that has no effect on the amino acid sequence in a protein or the functions that a protein performs. There is no phenotypic indication that a mutation has occurred.
Nonsense mutation
When there is a change in the sequence of base pairs due to a point mutation, that results in a stop codon. This leads to a protein that is either shortened or non-functional.
Missense mutation
A missense mutation occurs when a point mutation causes a change in the codon, which then codes for another amino acid.
The mutation is caused by the following factors:
Internal Causes
When DNA copies incorrectly, the majority of mutations occur. Evolution occurs as a result of all of these mutations. DNA makes a copy of itself during cell division. When a copy of DNA isn't flawless, it's called a mutation since it differs somewhat from the original DNA.
External Causes
When certain chemicals or radiations are used to break down DNA, it causes the DNA to break down. The thymine dimers are broken by UV radiation, resulting in altered DNA.