Necrosis, hypo plastic and hyperplastic symptoms of plant diseases, mechanism of infection Disease control-a brief knowledge, with emphasis on chemical and biological control. Necrotic symptoms in plants refer to: (a) Stunted growth (b) Abnormal cell division (c) Death of plant tissues (d) Chlorophyll loss Answer: (c) Explanation: Necrosis involves cell/tissue death (e.g., leaf spots, blights). Hypoplasia causes underdevelopment; hyperplasia causes overgrowth. Hypoplastic symptoms include: (a) Galls (b) Witches’ broom (c) Chlorosis (d) Tumors Answer: (c) Explanation: Hypoplastic symptoms involve reduced growth or development. Chlorosis (yellowing due to chlorophyll loss) is…

Which algal group exhibits the most complex thallus organization? (a) Chlorophyceae (b) Phaeophyceae (c) Rhodophyceae (d) Cyanophyceae Answer: (b) Phaeophyceae Explanation: Brown algae (Phaeophyceae) show the highest structural complexity, with differentiated parts such as holdfast (attachment), stipe (stem-like), and blade (leaf-like). Agar, a phycocolloid, is derived from: (a) Green algae (b) Brown algae (c) Red algae (d) Diatoms Answer: (c) Red algae Explanation: Agar is a gelatinous substance obtained from red algae, mainly Gelidium and Gracilaria. It is widely used in microbiology and food industries. Diatomite (Kieselguhr) is commercially important…

Divisions of ecology, ecological factors, ecological units   Which division of ecology focuses on individual organisms and their interactions with the environment? (a) Synecology (b) Autecology (c) Genecology (d) Applied Ecology Answer: (b) Autecology Explanation: Autecology studies an individual organism or species in relation to its environment. It focuses on adaptations, niche, and survival. The term “ecosystem” was coined by: (a) Ernst Haeckel (b) Arthur Tansley (c) Eugene Odum (d) Charles Darwin Answer: (b) Arthur Tansley Explanation: Arthur Tansley introduced the term “ecosystem” in 1935 to describe the system formed…

Plant Tissue: Definition, Classification, Distribution and Functions including Mechanical tissues.   Which tissue is responsible for the secondary growth in dicot stems? (a) Apical meristem (b) Intercalary meristem (c) Lateral meristem (d) Parenchyma Answer: (c) Lateral meristem Explanation: The lateral meristem includes vascular cambium and cork cambium, which are responsible for increasing the thickness (girth) of dicot stems. This secondary growth is crucial for structural support in woody plants. Collenchyma provides mechanical support primarily to: (a) Roots (b) Young stems and petioles (c) Woody stems (d) Leaves only Answer: (b)…

Prokaryotes and Eukaryotes: Characteristics, and differences with reference to their Nuclear and cell wall compositions.   Which of the following is a key difference between prokaryotic and eukaryotic nuclei? Prokaryotes have a nuclear membrane; eukaryotes do not. Eukaryotes have a nucleoid; prokaryotes have a true nucleus. Prokaryotic DNA is circular and lacks histones; eukaryotic DNA is linear with histones. Eukaryotes lack chromatin; prokaryotes have condensed chromatin. Answer: C Explanation: Prokaryotes have circular, histonefree DNA in a nucleoid, while eukaryotes have linear DNA bound to histones in a membranebound nucleus.  …