Top 100 Botany Questions - Telangana Board Botany

High-Yield Botany Concepts and Exam Questions

Nutrient Enrichment, Algal Blooms, and Eutrophication

Nutrient enrichment in water bodies leads to algal blooms, which cause oxygen deprivation in lower layers, resulting in fish death. This process is termed eutrophication, not biomagnification. Oxygen deprivation occurs due to excessive growth of algae in the upper water layer, blocking light and reducing oxygen supply.

• Eutrophication: Excess nutrients → algal bloom → oxygen depletion → fish death.
• Biomagnification: Not applicable in this context.

Enzymes: Nature, Function, and Exceptions

Enzymes are biological catalysts, mostly proteins, with a few exceptions. They accelerate metabolic…

High-Yield Botany Concepts and Exam Questions

Nutrient Enrichment, Algal Blooms, and Eutrophication

Nutrient enrichment in water bodies leads to algal blooms, which cause oxygen deprivation in lower layers, resulting in fish death. This process is termed eutrophication, not biomagnification. Oxygen deprivation occurs due to excessive growth of algae in the upper water layer, blocking light and reducing oxygen supply.

• Eutrophication: Excess nutrients → algal bloom → oxygen depletion → fish death.
• Biomagnification: Not applicable in this context.

Enzymes: Nature, Function, and Exceptions

Enzymes are biological catalysts, mostly proteins, with a few exceptions. They accelerate metabolic conversions and are essential for various biochemical reactions. Most enzymes are proteins, except for some RNA-based enzymes called ribozymes.

• Enzyme nature: Mostly proteins; few exceptions (ribozymes).
• Function: Catalyze metabolic reactions.
• Ribozyme: RNA enzyme, e.g., 23S rRNA.

Genetic Principles: Pleiotropy, Test Cross, and Somaclonal Variation

A single gene producing multiple effects is called pleiotropy. Test cross is used to determine the genotype of a dominant phenotype by crossing it with a homozygous recessive parent. Somaclonal variation refers to genetic variation among plants regenerated from tissue culture, not sexual reproduction.

• Pleiotropy: One gene, multiple phenotypic effects (e.g., phenylketonuria).
• Test cross: Determines genotype of dominant phenotype.
• Somaclonal variation: Variation among tissue culture-derived plants.

Seed Structure: Perisperm, Pericarp, Endosperm, and Aleurone Layer

Persistent nucellus in seeds is called perisperm. The pericarp is the fruit wall, differentiated into epicarp, mesocarp, and endocarp in fleshy fruits. Endosperm forms after double fertilization and provides nutrition. The aleurone layer separates endosperm from embryo.

• Perisperm: Persistent nucellus.
• Pericarp: Fruit wall (epicarp, mesocarp, endocarp).
• Endosperm: Formed after double fertilization.
• Aleurone layer: Differentiating layer between endosperm and embryo.

Lac Operon: Gene Functions and Repressor Coding

In the lac operon, the I gene codes for the repressor RNA, which regulates the operon. Other genes code for β-galactosidase, permease, and transacetylase.

• I gene: Codes for repressor RNA.
• Z, Y, A genes: Code for β-galactosidase, permease, transacetylase.

Calvin Cycle: Regeneration of RuBP and ATP Requirement

Regeneration of RuBP in the Calvin cycle requires ATP. For six RuBP molecules, six ATP are needed. The process involves carboxylation, reduction, and regeneration steps.

• RuBP regeneration: 6 ATP required for 6 RuBP molecules.
• Key steps: Carboxylation (CO₂ + RuBP), reduction (G3P formation), regeneration (G3P → RuBP).

Cell in Hypertonic Solution: Plasmolysis

When a cell is placed in a hypertonic solution, water moves out due to higher water potential inside the cell, causing the cell to shrink (plasmolysis).

• Hypertonic solution: Cell loses water, shrinks.

Photorespiration: Effect on Photosynthetic Efficiency

Photorespiration decreases photosynthetic efficiency as it consumes ATP and releases CO₂ without sugar synthesis. The process forms phosphoglycolate, which is wasteful.

• Photorespiration: Decreases efficiency, releases CO₂, consumes ATP.

Alcoholic Fermentation: Ethanol Inhibition

Alcoholic fermentation stops beyond a certain ethanol concentration because ethanol inhibits enzyme activity, not due to oxygen limitation or substrate exhaustion.

• Ethanol inhibition: Stops fermentation by inhibiting enzymes.

Biological Classification: Monera, Protista, Fungi

Blue-green algae belong to Monera, Euglena and Amoeba to Protista, and yeast to Fungi.

• Monera: Blue-green algae.
• Protista: Euglena, Amoeba.
• Fungi: Yeast.

DNA Replication: Okazaki Fragments and Ligase

During DNA replication, Okazaki fragments are joined by the enzyme ligase, known as molecular glue.

• Ligase: Joins Okazaki fragments.

Recombinant DNA Technology: Large-Scale Production

The last step in recombinant DNA technology is culturing in bioreactors for large-scale production of the gene or product of interest.

• Bioreactor culturing: Large-scale gene/product production.

Plant Cell Wall: Cellulose and Rigidity

Plant cell walls are made of cellulose, providing rigidity and mechanical strength. The assertion and reason are correct but not a direct explanation.

• Cellulose: Provides rigidity and strength.

Half-Leaf Experiment: Essentiality of CO₂ for Photosynthesis

In the half-leaf experiment, one part of the leaf is exposed to sunlight, the other to potassium hydroxide (absorbs CO₂). The part without CO₂ shows negative starch test, indicating CO₂ is essential for photosynthesis.

• CO₂ essential: Confirmed by half-leaf experiment.

Industrial Microbes: Products

• Aspergillus: Produces citric acid.
• Penicillium: Produces penicillin.
• Clostridium butylicum: Produces butyric acid.
• Saccharomyces: Produces ethanol.

Gymnosperms: Naked Seed Plants

Gymnosperms are called naked seed plants because their ovules are not enclosed by any ovary wall.

• Naked seeds: Ovules not enclosed.

Methanogens and Biogas

Methanogens are anaerobic bacteria. Biogas contains methane and CO₂. Sludge from digesters is used as fertilizer. Oxygen is not essential for methanogenesis.

• Methanogens: Anaerobic.
• Biogas: Methane, CO₂.

Sucrose Transfer: Sieve Tube and Sink

After sucrose transfer from sieve tube elements to sink, osmotic pressure in the sieve tube decreases due to solute movement.

• Osmotic pressure: Decreases in sieve tube after transfer.

Bryophytes, Ferns, and Gymnosperms: Key Features

• Moss protonema: Haploid, starting stage of gametophyte.
• Sorus in ferns: Cluster of sporangia.
• Gymnosperms: No double fertilization.
• Cycas: Motile sperms.

Glycolysis: Sequence of Steps

Glycolysis involves conversion of glucose to glucose-6-phosphate, then to fructose-6-phosphate, fructose-1,6-bisphosphate, phosphoglyceraldehyde, and finally bisphosphoglyceric acid.

• Sequence: Glucose → G6P → F6P → F1,6BP → PGAL → BPG.

Enzyme Types and Green Algae Experiment

Most enzymes are proteins. The first action spectrum of photosynthesis was plotted using prism and green algae (Cladophora) by Engelmann.

• Engelmann experiment: Action spectrum using prism.

Nitrogen Fixation and Element Deficiency

Biological nitrogen fixation converts atmospheric N₂ to NH₃ by microbes (e.g., Rhizobium). Nitrogen deficiency causes chlorosis in older leaves; calcium deficiency in younger leaves.

• Nitrogen fixation: N₂ → NH₃.
• Chlorosis: Nitrogen (older leaves), calcium (younger leaves).

Hydrarch Succession: Pioneer Species

In hydrarch succession, pioneer species are lichens and bryophytes.

• Pioneer species: Lichens, bryophytes.

Growth Types: Arithmetic and Geometric

Arithmetic growth is exemplified by root elongation and shows a linear curve. Geometric growth follows $w_1 = w e^{rt}$ and shows a sigmoid curve.

• Arithmetic growth: Linear, root elongation.
• Geometric growth: Sigmoid, exponential.

Bulk Flow and Energy Requirement

Bulk flow (mass flow) hypothesis requires energy for active transport from low to high concentration, especially at the sink during phloem translocation.

• Active transport: Energy required for low to high concentration.

Monocots and Endosperm

In many monocots, endosperm is retained in mature seeds and food is absorbed only during germination.

• Monocots: Endosperm retained.

Respiratory Quotient (RQ)

RQ is less than one when the substrate is protein. RQ formula: volume of CO₂ evolved / volume of O₂ consumed.

• RQ < 1: Protein substrate.
• Formula: $RQ = \frac{\text{CO}_2 \text{ evolved}}{\text{O}_2 \text{ consumed}}$

DNA Replication: Semi-Conservative Method

DNA replication is semi-conservative, conserving half of the genetic material in the parental strand.

• Semi-conservative: Parental strand conserved.

Water Movement in Tall Plants

Transpiration pull is responsible for the ascent of sap in tall plants (up to 100 feet).

• Transpiration pull: Main force for water movement.

Punnett Square: Genetic Probability

Punnett square is used to indicate possible unions of gametes during fertilization and calculate offspring genotype probabilities.

• Punnett square: Genetic probability calculation.

Chargaff's Rule: DNA Base Percentages

In double-stranded DNA, percentage of adenine equals thymine, and guanine equals cytosine. If adenine is 20%, guanine is 30%.

• Chargaff's rule: A = T, G = C.

Meristematic and Permanent Cells: Differentiation

Meristematic cells lose their capacity to divide when becoming permanent. Permanent cells can regain division capacity through dedifferentiation.

• Dedifferentiation: Permanent → meristematic.
• Differentiation: Meristematic → permanent.

Stop Codons and Universal Codon

Stop codons: UAA, UAG, UGA. AUG is the universal start codon coding for methionine.

• Stop codons: UAA, UAG, UGA.
• Start codon: AUG (methionine).

Chromosomal Theory of Inheritance

Chromosomal theory of inheritance was proposed by Sutton and Boveri, stating that chromosomes behave like genes during meiosis.

• Chromosomal theory: Chromosome behavior parallels gene behavior.

Amphibolic Nature of Respiration

Respiration is amphibolic, involving both catabolic and anabolic reactions. Intermediates like acetyl-CoA and pyruvic acid are used in synthesis and breakdown.

• Amphibolic: Both catabolic and anabolic.

Animal and Plant Storage Polysaccharides

Glycogen is the storage polysaccharide in animal cells; starch in plants.

• Glycogen: Animal storage.
• Starch: Plant storage.

RNA Stability Compared to DNA

RNA is less stable than DNA due to the presence of a free hydroxyl group at the second carbon, making it more reactive.

• RNA stability: Less than DNA (free OH group).

Plasmid: Extra Chromosomal DNA in Bacteria

Plasmid is the extra chromosomal, self-replicating, usually circular DNA found in bacterial cells.

• Plasmid: Extra chromosomal DNA.

Enzyme Kinetics: Effect of Inhibitors

Non-competitive inhibitors affect $V_{max}$ but not $K_m$. Competitive inhibitors are structurally similar to substrate.

• Non-competitive inhibitor: Affects $V_{max}$, not $K_m$.
• Competitive inhibitor: Structurally similar to substrate.

Alleles: Definition and Examples

Alleles are alternative forms of genes coding for contrasting traits, e.g., tall and dwarf forms of a gene.

• Alleles: Alternative gene forms.

Glycolysis: Partial Oxidation of Glucose

In glycolysis, glucose is partially oxidized to pyruvic acid.

• Partial oxidation: Glucose → pyruvic acid.

Vegetative Propagation: Clones and Variation

Vegetative propagation involves mitotic division, results in clones, and does not exhibit somaclonal variation.

• Vegetative propagation: Clones, no somaclonal variation.

Peptide Bond Formation in Proteins

Peptide bond links two amino acids in a protein, formed by elimination of water between carboxyl and amino groups.

• Peptide bond: Links amino acids, water eliminated.

ATP Consumption in Glycolysis

ATP is consumed in the conversion of glucose to glucose-6-phosphate and fructose-6-phosphate to fructose-1,6-bisphosphate.

• ATP consumption: First and third steps of glycolysis.

Essential Elements and Beneficiary Elements

Essential elements include nitrogen, potassium, sulfur, magnesium, calcium, iron, zinc, manganese, chloride, nickel, boron, molybdenum. Silicon is a beneficiary element, not essential.

• Essential elements: Listed above.
• Beneficiary element: Silicon.

Enzyme Activity and pH

Enzyme activity shows a bell-shaped curve with respect to pH due to changes in ionization state.

• Bell-shaped curve: Enzyme activity vs. pH.

Adventitious Roots

Adventitious roots arise from any part other than the radicle, e.g., base of the stem.

• Adventitious roots: Not from radicle.

Secondary Sewage Treatment

Secondary sewage treatment removes pathogens using biological treatment, resulting in water safe for release.

• Outcome: Pathogen removal, water release.

Cyclic and Non-Cyclic Photophosphorylation

Cyclic photophosphorylation does not produce NADPH or release oxygen; only generates ATP.

• Cyclic: ATP only, no NADPH, no O₂.

Light Reaction Steps

Light reaction includes light absorption, water splitting, and ATP formation.

• Steps: Light absorption, water splitting, ATP formation.

Micropropagation and Totipotency

Micropropagation produces genetically identical plants based on cellular totipotency.

• Micropropagation: Identical plants, totipotency.

Marsilea: Heterosporous Fern

Marsilea is a heterosporous fern; others like Adiantum, Lycopodium, and Selaginella are not.

• Marsilea: Heterosporous.

Plant Hormones: Functions

Auxins control xylem differentiation, gibberellins promote bolting, abscisic acid induces dormancy.

• Auxins: Xylem differentiation.
• Gibberellins: Bolting.
• Abscisic acid: Dormancy.

Bt Toxin Activation

Bt toxin becomes active in insect gut due to alkaline pH.

• Activation: Alkaline pH in insect gut.

RNA Interference: Nematode Protection

RNA interference protects plants from nematode infestation by silencing specific mRNA with complementary RNA.

• RNAi: Silences nematode mRNA.

Incomplete Dominance: Phenotypic Ratio

Incomplete dominance shows a phenotypic ratio of 1:2:1 (red:pink:white).

• Ratio: 1:2:1 for incomplete dominance.

Phyllotaxy in China Rose

China rose (Hibiscus) exhibits alternate phyllotaxy, with one leaf per node.

• Phyllotaxy: Alternate in Hibiscus.

Essentiality Criteria and Silicon

Silicon violates essentiality criteria but enhances plant growth; it is a beneficiary element.

• Silicon: Beneficiary, not essential.

Porins in Facilitated Diffusion

Porins, which are proteins, affect the rate of facilitated diffusion across cell membranes.

• Porins: Protein channels for facilitated diffusion.

Growth Curve Phases

Growth curve phases: lag (slow growth), exponential (rapid growth), stationary (nutrient limitation).

• Phases: Lag, exponential, stationary.

Insulin Production Challenge

The main challenge in recombinant insulin production was proper assembly of A and B peptides.

• Challenge: Assembly of A and B peptides.

Synapsis in Meiosis

Synapsis between homologous chromosomes occurs during the zygotene stage of meiosis.

• Synapsis: Zygotene stage.

Biofortification: Nutrient Enhancement

Biofortification enhances nutrient content in crops, e.g., protein in wheat, iron in rice, vitamin A in maize, β-carotene in golden rice.

• Biofortification: Protein (wheat), iron (rice), vitamin A (maize), β-carotene (golden rice).

Diffusion: Living and Non-Living Systems

Diffusion does not require a living system; occurs in both living and non-living environments.

• Diffusion: Not limited to living systems.

Reducing Sugars

Maltose is a reducing sugar; sucrose, cellulose, and starch are not.

• Reducing sugar: Maltose.

Immasculation in Laboratory Experiments

Immasculation is essential in bisexual, self-compatible flowers to prevent self-pollination.

• Immasculation: Prevents self-pollination in bisexual, self-compatible flowers.

Biological Names: Italics and Latin Origin

Biological names are printed in italics to distinguish them from English words and indicate Latin origin.

• Italics: Biological names.

Restriction Enzymes: Palindromic Sequences

Restriction enzymes recognize palindromic DNA sequences, not random sequences.

• Palindromic sequences: Recognized by restriction enzymes.

Chemiosmotic Hypothesis: Requirements

Chemiosmotic hypothesis requires protein gradient, intact thylakoid membrane, and ATP synthase enzyme; carbon dioxide fixation is not required.

• Requirements: Protein gradient, intact membrane, ATP synthase.

Pioneer Community in Xerarch Succession

In xerarch succession, bryophytes are the pioneer community.

• Pioneer: Bryophytes.

Microorganism Responsible for Curd Formation

Lactobacillus is responsible for curd formation.

• Lactobacillus: Curd formation.

Word Count: 1197