विस्तृत व्याख्या:

Peroxisomes (परॉक्सिसोम):

• Peroxisomes are single-membrane bound microbodies found in both plant and animal cells.
• They contain oxidative enzymes such as catalase, urate oxidase, and D-amino acid oxidase.
• Their primary metabolic functions include the $\beta$-oxidation of very long-chain fatty acids (वसा का ऑक्सीकरण), metabolism of amino acids (अमीनो अम्ल) and polyamines, and the breakdown of toxic hydrogen peroxide ($\text{H}_2\text{O}_2$) into water and oxygen.
• In plants, specialized peroxisomes called glyoxysomes convert stored fats into carbohydrates (via the glyoxylate cycle) during seed germination, and leaf peroxisomes are involved in photorespiration ($C_2$ cycle) alongside chloroplasts and mitochondria.

विस्तृत व्याख्या:

Carbohydrates as Cellular Energy Storage (कार्बोहाइड्रेट):

• Carbohydrates (such as glucose, glycogen in animals, and starch in plants) serve as the primary and most readily accessible source of stored chemical energy to fuel cellular work and metabolic activities.
• Glucose undergoes glycolysis, the citric acid cycle, and oxidative phosphorylation to generate cellular energy in the form of ATP.
• While lipids store higher energy per gram, carbohydrates are the immediate and principal energy storage molecules utilized for the majority of routine cellular work.

Correct Answer: Option 3 (Carbohydrate).

विस्तृत व्याख्या:

Eukaryotic Cell Cycle Phases (यूकेरियोटिक कोशिका चक्र की प्रावस्थाएं):

• The cell cycle comprises Interphase ($G_1$, S, $G_2$) and the M phase (Mitosis/Meiosis).
• $G_1$ Phase (Gap 1): This is the first growth phase post-mitosis. Cells actively synthesize proteins, enzymes, RNA, and duplicate organelles to prepare for DNA replication. In a typical 24-hour human cell cycle, $G_1$ occupies approximately 10–12 hours, making it the single longest phase of the cell cycle.
• S Phase: Synthesis phase where DNA replication occurs (~6–8 hours).
• $G_2$ Phase: Pre-mitotic preparation (~3–4 hours).
• M Phase: Mitosis and cytokinesis (~1 hour).

विस्तृत व्याख्या:

Chi-Square Test (काई-वर्ग परीक्षण - $\chi^2$):

• Developed by Karl Pearson in 1900, the chi-square statistic tests the 'goodness of fit' between observed frequencies ($O$) and expected frequencies ($E$) based on a specific genetic hypothesis (e.g., Mendelian segregation ratios 3:1, 9:3:3:1).
• The formula is expressed mathematically as:

where $O$ = Observed value, and $E$ = Expected value.

• F-test compares two population variances (ratio of two variances: $S_1^2 / S_2^2$).
• t-test compares the means of two groups.

Correct Answer: Option 2 (Chi-square statistic).

विस्तृत व्याख्या:

Size of Human Proteome vs. Genome (मानव प्रोटिओम की विविधता):

• The human genome contains approximately 20,000 to 25,000 protein-coding genes, which is surprisingly comparable to much simpler organisms like C. elegans or Arabidopsis.
• However, the human proteome consists of several hundred thousand distinct proteins.
• The principal biological mechanisms responsible for this vast proteomic diversity are:

• Alternative Splicing (वैकल्पिक स्प्लिसिंग): A single pre-mRNA transcript can be spliced in multiple different ways by combining different exons, producing diverse mRNA transcripts and distinct polypeptide isoforms from a single gene.
• Post-Translational Modifications (PTMs): Phosphorylation, glycosylation, ubiquitination, and proteolytic cleavage further diversify functional proteins.
  • Therefore, an individual gene can encode many distinct polypeptides.