Q.6 Match List I with List II

1. A-IV, B-III, C-I, D-II
2. A-III, B-IV, C-II, D-I
3. A-II, B-I, C-III, D-IV
4. A-I, B-II, C-IV, D-III

   The correct answer is A-III, B-IV, C-II, D-I.

   Matching Explanation

   Heterocyst (A) is a specialized nitrogen-fixing cell in blue-green algae (cyanobacteria) like Anabaena and Nostoc, featuring thick walls to exclude oxygen. Cap cells (B) are distinctive ring-like structures at the apical ends of cells in Oedogonium, formed during cell division in this filamentous green alga. Frustule (C) is the unique two-valved silica cell wall of diatoms (Bacillariophyceae). Aegagropilous forms (D), or ball-like masses, form in Cladophora due to hydrodynamic conditions, creating detached spherical aggregates.

   Option Analysis

   • A-IV, B-III, C-I, D-II: Incorrect; wrongly links heterocyst to Oedogonium and frustule to Cladophora.

   • A-III, B-IV, C-II, D-I: Correct; matches all precisely as detailed.

   • A-II, B-I, C-III, D-IV: Incorrect; confuses heterocyst with diatoms and cap cells with Cladophora.

   • A-I, B-II, C-IV, D-III: Incorrect; mismatches all terms.

   Heterocyst blue green algae, cap cells Oedogonium, frustule diatoms, and aegagropilous forms Cladophora are essential algal structures in phycology for exams. This match list evaluates knowledge of cyanobacterial nitrogen fixation, green algae division, and diatom walls.

   Heterocyst in Blue Green Algae

   Heterocysts are colorless, thick-walled cells in filamentous cyanobacteria (blue-green algae) like Nostoc, dedicated to N2 fixation via nitrogenase under anaerobic microenvironments. They differentiate from vegetative cells during nitrogen stress, pole-connected by microplasmodesmata.

   Cap Cells in Oedogonium

   Cap cells, or calyptras, form as gelatinous rings on apical cells of Oedogonium (Chlorophyceae) during division, marking each event and aiding identification. This unbranched filament thrives in freshwater, reproducing via zoospores or fragmentation.

   Frustule Structure in Diatoms

   The frustule is the ornate silica exoskeleton of diatoms, with epitheca and hypotheca valves overlapping like a petri dish, enabling auxospore expansion during reproduction. Pores facilitate nutrient exchange in these major phytoplankton.

   Aegagropilous Forms of Cladophora

   Aegagropilae are spherical, free-rolling balls from Cladophora filaments tangling in currents, seen in lakes (e.g., Lake Erie balls) and marine lagoons. They lack rhizoids, differing from attached upright forms.

   Exam Insights

   Ideal for GATE Biotechnology or Life Sciences, focusing on algal cell specialization and adaptations. Memorize: heterocysts (N-fixation), frustules (silica).