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.
Which of the following lipid modifications is NOT typically found in integral membrane proteins?
Palmitoylation
Myristoylation
Prenylation
Glycosylphosphatidylinositol (GPI) anchor
Chitin, a structural polysaccharide found in the exoskeleton of arthropods, differs significantly from cellulose in terms of its monomeric unit. This difference primarily stems from:
The presence of an N-acetyl group at C-2 of the monomer
The type of glycosidic linkage between monomers
The degree of polymerization (chain length)
The three-dimensional arrangement of the polymer chains
Inulin, a storage polysaccharide found in some plants, differs from starch in several key aspects. Which of the following statements accurately describes a major difference between inulin and starch?
Inulin is a branched polymer, while starch is strictly linear.
Inulin is primarily found in animals, while starch is found in plants.
Inulin forms a helical structure, while starch forms a sheet-like structure.
Inulin is composed of fructose units linked by ฮฒ(2โ1) glycosidic bonds, while starch primarily consists of glucose units linked by ฮฑ(1โ4) and ฮฑ(1โ6) bonds.
The structural polysaccharide peptidoglycan, a key component of bacterial cell walls, possesses a unique feature that distinguishes it from other polysaccharides. This feature is:
The presence of ฮฑ(1โ6) glycosidic linkages.
The exclusive use of glucose as its monomeric unit.
The presence of short peptide chains cross-linking the polysaccharide chains.
Its ability to form triple helices.
In a metabolic pathway, enzyme A catalyzes the conversion of substrate X to intermediate Y. Enzyme B then catalyzes the conversion of Y to product Z. If a mutation in enzyme B renders it completely inactive, which of the following is MOST likely to occur?
Increased production of substrate X.
Accumulation of intermediate Y and depletion of product Z.
No change in the concentrations of X, Y, or Z.
Increased activity of enzyme A to compensate for the loss of enzyme B.
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.
A molecule is found to contain multiple hydroxyl groups and a ketone functional group. To which class of biomolecules does it most likely belong?
Lipids
Proteins
Nucleic Acids
Carbohydrates
