General Biology MCQ

Answer: (2) 16500

Explanation: In humans, mitochondrial DNA spans about 16,500 DNA building blocks (base pairs)
-> It contains 37 genes, all of which are essential for normal mitochondrial function.

Answer: (4) 80

Explanation:
-> Amylopectin: water-soluble polysaccharide and highly branched polymer of α-glucose units found in plants.
-> It is one of the two components of starch, and another component is amylose.

Answer: (2) Mitochondria

Explanation: Mitochondria is the largest particulate component of the cytoplasm
-> About 15% to 20% of dry weight of the cell.

Answer: (1) (C₆H₁₀O₅)_n

Explanation: No explanation is needed.

Answer: (1) Epimers

Explanation:
-> Epimers are carbohydrates that vary in one position for the placement of the -OH group. Example: D-glucose and D-galactose.
-> Anomers: Cyclic stereoisomer, such as sugar, whose sole conformational difference involves the arrangement of atoms or groups in the aldehyde or ketone group.
-> Optical isomers: Compounds with the same number and kinds of atoms, and bonds but different spatial arrangements of the atoms. Two optical isomers are L and D isomers.

Answer: (1) Virus

Explanation: Viruses are non-living. Feeds on the host body and makes use of the enzyme machinery of the host for their replication.

Answer: (3) Mutarotation

Explanation: Mutarotation is defined as the change in the optical rotation because of the change in the equilibrium between two anomers when the corresponding stereocenters interconvert.

Answer: (4) IgE

Explanation: Allergic reactions can be grouped into two classes.
-> Immunoglobulin E (IgE): most common and best understood is mediated by a class of antibodies called immunoglobulin E (IgE)
-> Non-IgE mediated: symptoms to appear more slowly and reaction does not necessarily involve antibodies but instead, cell reactions of the immune system.
-> Diagnose for IgE-mediated allergy: blood test to identify allergen-specific IgE or a skin prick test which results in a local inflammatory reaction after administration of the trigger allergen.
Reference: Allergy by Immunology British Society

Answer: (4) HCP

Explanation: Hexagonal close-packed (hcp) has ABABABA (every other layer is the same) arrangement. In this arrangement, each sphere has twelve neighbors.

Answer: (4) Gluconeogenesis

Explanation:
-> Glycolysis: cytoplasmic pathway that breaks down glucose into two three-carbon compounds (pyruvic acid) and generates energy.
-> Gluconeogenesis: synthesis of glucose from nonsugar precursors, such as lactate, pyruvate, and the carbon skeleton of glucogenic amino acids.
-> Glycogenolysis: biochemical pathway in which glycogen breaks down into glucose-1-phosphate and glucose.
-> Saponification: formation of a metallic salt of a fatty acid; such a salt is called soap. In general, a base (for example, sodium hydroxide) reacts with free fatty acid to form glycerol and soap.

Answer: (1) Euchromatin

Explanation: During most of a cell’s life cycle, the chromosomes exist in an unraveled
a linear form that can be transcribed to code for proteins.

-> Region of chromosomes that are transcriptionally active is known as euchromatin.
● These chromosomes undergo normal chromosome condensation and decondensation
during the cell cycle.
● These regions account for most of the genome and lack repetitive DNA.

-> The transcriptionally inactive portions of chromosomes, such as centromeres, are
heterochromatin regions and remain condensed throughout the cell cycle.
● These chromosomes are generally not sequenced due to complex repeat patterns (repetitive DNA) that can be found at centromeres, much of the Y chromosome’s long arm, and the short arms of the acrocentric chromosomes.