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Chemically, what is a peptide linkage?
The NCERT text clearly states, 'Chemically, peptide linkage is an amide formed between –COOH group and –NH2 group.' (Biomolecules_chemistry, page 292).
If a protein undergoes a change in its primary structure, what is the consequence?
The NCERT text explains, 'Any change in this primary structure i.e., the sequence of amino acids creates a different protein.' (Biomolecules_chemistry, page 293).
Which of the following bonds is NOT directly involved in establishing the primary structure of a protein?
The primary structure is defined by the sequence of amino acids linked by peptide (amide) bonds, which are covalent. Ester bonds are not involved in linking amino acids in the primary structure.
Which of the following techniques is NOT primarily used for the early diagnosis of diseases when pathogen concentration is very low?
The context states that Recombinant DNA technology, PCR, and ELISA are some techniques that serve the purpose of early diagnosis. However, recombinant DNA technology itself is a broader technique for gene manipulation, while PCR and ELISA are specifically employed for detecting low concentrations of pathogens or specific gene mutations for early diagnosis. Autoradiography is a detection method after probe hybridization, which is a part of molecular diagnosis for mutated genes as described in the context.
PCR is routinely used for which of the following applications?
The NCERT text explicitly states: 'PCR is now routinely used to detect HIV in suspected AIDS patients. It is being used to detect mutations in genes in suspected cancer patients too. It is a powerful technique to identify many other genetic disorders.'
In the context of detecting mutated genes, a radioactive probe is used. What characteristic of the probe is crucial for its detection using autoradiography?
The context mentions: 'A single stranded DNA or RNA, tagged with a radioactive molecule (probe) is allowed to hybridise to its complementary DNA in a clone of cells followed by detection using autoradiography.' The radioactivity is essential for detection via autoradiography.
What is the basis of detection in ELISA?
The NCERT text clearly states: 'ELISA is based on the principle of antigen-antibody interaction. Infection by pathogen can be detected by the presence of antigens (proteins, glycoproteins, etc.) or by detecting the antibodies synthesised against the pathogen.'
Why would a clone having a mutated gene NOT appear on a photographic film when using a radioactive probe and autoradiography for detection?
The NCERT text explains: 'The clone having the mutated gene will hence not appear on the photographic film, because the probe will not have complementarity with the mutated gene.'
The three main steps in each cycle of Polymerase Chain Reaction (PCR) are:
Figure 9.6 and its caption in the 'BIOTECHNOLOGY - PRINCIPLES AND PROCESSES' chapter explicitly state: 'Polymerase chain reaction (PCR) : Each cycle has three steps: (i) Denaturation; (ii) Primer annealing; and (iii) Extension of primers'.
Which of the following is an advantage of using PCR for disease diagnosis?
The context highlights: 'However, very low concentration of a bacteria or virus (at a time when the symptoms of the disease are not yet visible) can be detected by amplification of their nucleic acid by PCR.'
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