Prepare for NEET Biology Biomolecules with MCQs & PYQs on NEET.GUIDE. Get free practice, previous year questions, and expert explanations of carbohydrates, proteins, and more.
A novel protein was discovered containing a unique amino acid with a side chain composed of a selenol group (-SeH). Compared to a cysteine residue (-SH) in a similar protein, this selenol-containing amino acid would MOST likely exhibit which property?
Increased reactivity towards oxidizing agents
Decreased reactivity towards oxidizing agents
Identical reactivity towards oxidizing agents
Formation of stronger disulfide bonds
Which amino acid substitution in a protein is MOST likely to disrupt a beta-sheet structure due to steric hindrance?
Glycine to Valine
Alanine to Glycine
Valine to Isoleucine
Serine to Threonine
A novel virus is discovered with a single-stranded nucleic acid genome. Treatment with RNase H significantly reduces its infectivity, while DNase I has no effect. Further analysis reveals the presence of short RNA fragments complementary to the genome. What can be most confidently inferred about the viral genome?
It is a single-stranded RNA virus that replicates through a DNA intermediate.
It is a single-stranded DNA virus that replicates through an RNA intermediate.
It is a single-stranded RNA virus that replicates through a double-stranded RNA intermediate.
It is a double-stranded RNA virus.
A researcher isolates a nucleic acid sample and finds it contains 22% adenine. Which of the following is the MOST LIKELY composition of the sample?
22% thymine, 28% guanine, 28% cytosine
28% thymine, 22% guanine, 22% cytosine
22% uracil, 28% guanine, 28% cytosine
Equal amounts of all four bases
A mutation in a tRNA molecule alters its anticodon sequence from 3'-AUC-5' to 3'-AUA-5'. Assuming the wobble hypothesis applies, which of the following changes in protein synthesis is MOST likely to occur?
Protein synthesis will be terminated prematurely.
A different amino acid will be incorporated at the corresponding codon.
The mutant tRNA might recognize a different codon but still incorporate the same amino acid.
The mutation will have no effect on protein synthesis.
An enzyme exhibiting positive cooperativity shows a sigmoidal kinetic curve. Which statement is FALSE regarding this type of enzyme?
The binding of the first substrate molecule decreases the enzyme's affinity for subsequent substrate molecules.
The enzyme likely has multiple subunits.
The Hill coefficient is greater than 1.
The enzyme's activity is more sensitive to substrate concentration changes compared to enzymes with Michaelis-Menten kinetics.
Two molecules of a monosaccharide, , undergo a dehydration reaction to form a disaccharide. What is the general formula of the resulting disaccharide?
If the formula for maltose is and it is formed by the dehydration reaction of two glucose molecules, what is the formula of glucose?
Lipid are found in acid insoluble fraction during the analysis of chemical composition of tissues. Given the reason
It has very high molecular weight
It is polymer
It has low molecular weight
On grinding, the biomembranes are broken into pieces and form insoluble vesicles
