Given below are two statements :
In the light of the above statements, choose the most appropriate answer from the options given below :
Both Statement I and Statement II are correct
Both Statement I and Statement II are incorrect
Statement I is correct but Statement II is incorrect
Statement I is incorrect but Statement II is correct
Both Statement I and Statement II are correct.
Statement I: Phenylketonuria (PKU) is an example of Pleiotropy. Pleiotropy refers to a single gene influencing multiple phenotypic traits. In the case of PKU, a mutation in the gene responsible for producing the enzyme phenylalanine hydroxylase (PAH) leads to various phenotypic effects beyond the inability to metabolize phenylalanine.
Statement II: Affected individuals lack an enzyme that converts phenylalanine into tyrosine. This statement accurately describes the underlying cause of PKU. Due to the absence or dysfunction of phenylalanine hydroxylase, individuals with PKU cannot convert phenylalanine into tyrosine, leading to an accumulation of phenylalanine in the body.
Therefore, both Statement I and Statement II are correct.
The sequence of nitrogenous bases in a segment of a coding strand of DNA is
5' – AATGCTAGGCAC – 3'. Choose the option that shows the correct sequence of nitrogenous bases in the mRNA transcribed by the DNA.
1. Perform a cross between two sickle cell carriers. What ratio is obtained between carrier, disease free and diseased individuals in F1 progeny? Name the nitrogenous base substituted, in the haemoglobin molecule in this disease.
2. Explain the difference in inheritance pattern of flower colour in garden pea plant and snap-dragon plant with the help of monohybrid crosses.
OR,
Explain with the help of well-labelled diagrams how lac operon operates in E. coli :
1. In presence of an inducer.
2. In absence of an inducer.
Study the pedigree chart given below, showing the inheritance pattern of blood group in a family:
Answer the following questions:
(a) Give the possible genotypes of individual 1 and 2.
(b) Which antigen or antigens will be present on the plasma membranes of the R.B.Cs of individuals ‘5’ and ‘8’?
The prisoners in the concentration camps in World War-II had lost faith in the future. Being in the camp, I felt disgusted with the state of affairs and I forced my thoughts to turn to another subject. ”Suddenly, I saw myself standing on the platform of a well-lit, warm and pleasant lecture room. In front of me, the attentive audience were seated in comfortable upholstered seats. I saw myself giving a lecture on hope, optimism, and resilience under difficult circumstances.” Suddenly, all that oppressed me stopped giving me pain and distress. This practice was so impactful that I could succeed in rising above the situation and the sufferings of the moment.”
Just as individuals compare themselves with others in terms of similarities and differences with respect to what they have and what others have, individuals also compare the group they belong to with groups of which they are not a member. It has been found that groups are more likely to take extreme decisions than individuals alone. Suppose there is an employee who has been caught taking a bribe or engaging in some other unethical act. His/her colleagues are asked to decide what punishment he/she should be given. They may let him/her go scot-free or decide to terminate his/her services instead of imposing a punishment which may commensurate with the unethical act he/she had engaged in. Whatever the initial position in the group, this position becomes much stronger as a result of discussions and interaction in the group.
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.
There are three types of mutations, which are as follows:
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.
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.
A missense mutation occurs when a point mutation causes a change in the codon, which then codes for another amino acid.
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.
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.