FYUG Odd Semester Exam, 2023 BOTANY (Phycology and Mycology) Paper: BOTDSC-102T

Subject Botany Paper Code BOTDSC-102T
Semester 1st Semester (FYUG) Full Marks 70
Time 3 Hours Pass Marks 28

Instructions: The figures in the margin indicate full marks. [span_7](start_span)Answer ten questions from Section-A (two from each Unit) and five questions from Section-B (one from each Unit).[span_7](end_span)

SECTION-A (Short Answers)

Answer any ten questions (2 marks each).

UNIT-I

1. Point out the pigments found in algae.[2]

Algae contain a variety of photosynthetic pigments categorized into three main groups: Chlorophylls (a, b, c, d, e), Carotenoids (carotenes and xanthophylls), and Phycobilins (phycoerythrin and phycocyanin). Chlorophyll-a is universal to all oxygenic algae.

2. Write briefly on the role of algae in agriculture.[2]

Algae play a crucial role in enhancing soil fertility. Blue-green algae (Cyanobacteria) like Nostoc and Anabaena fix atmospheric nitrogen, acting as biofertilizers. They also improve soil texture and provide growth-promoting substances like hormones.

3. Write the contributions of M.O.P. Iyengar.[2]

Mandayam Osuri Parthasarathy Iyengar is known as the "Father of Indian Phycology." His significant contributions include extensive research on Indian Algae, the discovery of several new taxa like Fritschiella tuberosa, and his work on the morphology and reproduction of various green algae.

UNIT-II

4. Write a short note on the morphology of Chara.[2]

Chara, often called "Stonewort," has a complex thallus divided into an underground rhizoidal system and an upright branched main axis. The main axis consists of nodes and internodes, with whorls of limited growth (primary branches) arising from the nodes.

5. Write a short note on the reserve food materials of Phaeophyta and Rhodophyta.[2]

  • Phaeophyta (Brown Algae): The primary reserve food materials are Laminarin (a polysaccharide) and Mannitol (a sugar alcohol).
  • Rhodophyta (Red Algae): The primary reserve food material is Floridean starch, which is structurally similar to amylopectin and glycogen.

6. What are unilocular and plurilocular sporangia?[2]

  • Unilocular sporangia: Single-celled structures where meiosis occurs, producing haploid zoospores.
  • Plurilocular sporangia: Multicellular structures where mitosis occurs, producing diploid zoospores in the sporophytic phase.

UNIT-III

7. Write two differences between plants and animals.[2]

Feature Plants Animals
Nutrition Autotrophic (Photosynthesis) Heterotrophic (Ingestion)
Cell Wall Present (composed of Cellulose) Absent

8. Write a short note on lichen.[2]

Lichens are composite organisms resulting from a symbiotic association between a fungus (mycobiont) and an alga or cyanobacterium (phycobiont). The fungus provides structure and moisture, while the alga provides nutrition through photosynthesis.

9. What do you mean by holocarpic and eucarpic thallus?[2]

  • Holocarpic: The entire vegetative thallus is converted into a reproductive structure.
  • Eucarpic: Only a part of the thallus is used for reproduction, while the rest remains vegetative.

UNIT-IV

10. Write a short note on heterothallism.[2]

Heterothallism is a condition in fungi where sexual reproduction occurs between two genetically different mycelia (compatible mating types). It was first discovered by A.F. Blakeslee in Mucor.

11. Write briefly on parasexuality.[2]

Parasexuality is a process in fungi where genetic recombination occurs without a standard sexual cycle (meiosis and syngamy). It involves plasmogamy, karyogamy, and haploidization within the vegetative mycelium.

12. Distinguish between uredospores and teleutospores.[2]

  • Uredospores: Binucleate, thin-walled, stalked spores that function as repeating spores to spread infection in the same season.
  • Teleutospores: Thick-walled, two-celled, black spores that serve as resting spores to survive winter.

UNIT-V

13. Mention two roles of fungi in biotechnology.[2]

  1. Production of antibiotics (e.g., Penicillin from Penicillium chrysogenum).
  2. Production of recombinant proteins and vaccines (e.g., using Saccharomyces cerevisiae).

14. Name two mycoproteins and their role.[2]

Mycoproteins like Quorn (derived from Fusarium venenatum) are high-protein, low-fat meat substitutes. They play a role in addressing global food security and providing vegetarian protein sources.

15. Name two fungi used for making organic acids.[2]

  1. Aspergillus niger (used for Citric acid production).
  2. Rhizopus oryzae (used for Lactic acid production).

SECTION-B (Long Answers)

Answer five questions, selecting one from each Unit (10 marks each).

UNIT-I

16. Describe Fritsch's system of classification of Algae. Mention the significant contributions of G. M. Smith.[8+2=10]

Fritsch's System of Classification (1935, 1945):
F.E. Fritsch classified algae into 11 classes based on pigmentation, types of flagella, and reserve food materials.

  • Chlorophyceae: Green algae; Chl a and b; starch reserve.
  • Xanthophyceae: Yellow-green algae; lack chlorophyll b; oil reserve.
  • Chrysophyceae: Golden-brown algae.
  • Bacillariophyceae: Diatoms; silica cell walls.
  • Cryptophyceae: Small biflagellate algae.
  • Dinophyceae: Dinoflagellates; two flagella in grooves.
  • Chloromonadineae: Very small group.
  • Euglenineae: Naked, flagellated forms.
  • Phaeophyceae: Brown algae; Fucoxanthin pigment; Laminarin reserve.
  • Rhodophyceae: Red algae; Phycoerythrin pigment; Floridean starch reserve.
  • Myxophyceae (Cyanophyceae): Blue-green algae; prokaryotic; Phycocyanin pigment.

Contributions of G. M. Smith:
G.M. Smith is renowned for his classification system (1938, 1955) which separated algae into divisions. His monumental work "Marine Algae of the Monterey Peninsula" and "Fresh-water Algae of the United States" standardized phycological study.

UNIT-II

18. With necessary sketches, describe the thallus structure and asexual reproduction of Chlamydomonas.[10]

Chlamydomonas is a microscopic, unicellular, motile green alga.

Thallus Structure:

  • Cell Shape: Usually oval, spherical, or pyriform.
  • Cell Wall: Composed of glycoprotein (not cellulose in many species).
  • Flagella: Two equal, anteriorly placed whiplash flagella.
  • Chloroplast: Distinct cup-shaped chloroplast containing a single pyrenoid (for starch synthesis).
  • Eyespot (Stigma): A pigment spot at the anterior end used for light perception.

Asexual Reproduction:
Occurs primarily through the formation of zoospores under favorable conditions:

  1. The parent cell loses its flagella and the protoplast withdraws from the cell wall.
  2. The protoplast undergoes longitudinal division (usually 2, 4, or 8 times) to form daughter protoplasts.
  3. Each daughter protoplast develops its own cell wall and two flagella, becoming a zoospore.
  4. The parent cell wall ruptures or gelatinizes to release the new individuals.

UNIT-III

21. What are mycorrhizae? Describe the various types and significance of mycorrhizal association.[2+4+4=10]

Definition: Mycorrhiza is a symbiotic association between a fungus and the roots of a higher plant.

Types of Mycorrhizae:

  • Ectomycorrhizae: The fungus forms a mantle/sheath around the root surface and penetrates between cells of the cortex (Hartig net) but does not enter the cells. Common in trees like Pine and Oak.
  • Endomycorrhizae: The fungus penetrates inside the cortical cells. The most common type is VAM (Vesicular Arbuscular Mycorrhiza), which forms storage vesicles and branched arbuscules within the root cells.
  • Ectendomycorrhizae: Shows features of both types (mantle formation and intracellular penetration).

Significance:

  1. Nutrient Uptake: Greatly increases the absorption of Phosphorus, Nitrogen, and other minerals.
  2. Drought Resistance: Enhances the plant's ability to withstand water stress.
  3. Pathogen Protection: Provides a physical and chemical barrier against root pathogens.
  4. Growth Stimulation: Secretes growth hormones that aid plant development.

UNIT-IV

22. Give the general characteristic, life cycle and classification of black stem rust of wheat caused by Puccinia.[10]

Classification:
Kingdom: Fungi | Phylum: Basidiomycota | Class: Pucciniomycetes | Genus: Puccinia | Species: graminis tritici

General Characteristics:
Puccinia graminis is an obligate parasite and heteroecious (requires two hosts: Wheat as primary host and Barberry as alternate host). It produces five different types of spores.

Life Cycle (5 Spore Stages):

  1. Uredial Stage (Stage II): Occurs on Wheat. Uredospores are produced, spreading the infection rapidly (repeating stage).
  2. Telial Stage (Stage III): Occurs on Wheat at the end of the season. Teleutospores (thick-walled, 2-celled) are formed for survival.
  3. Basidial Stage (Stage IV): Teleutospores germinate to form Basidiospores.
  4. Pycnidial Stage (Stage 0): Occurs on Barberry leaves. Basidiospores infect Barberry and form Pycnidiospores (spermogonia).
  5. Aecial Stage (Stage I): Occurs on Barberry. Aeciospores are formed which go back to infect the Wheat crop.

UNIT-V

24. Discuss the application of fungi in food industry. Add a note on Fermentation.[6+4=10]

Applications of Fungi in Food Industry:

  • Baking: Saccharomyces cerevisiae (Baker's yeast) is used to leaven bread through CO2 production.
  • Cheese Production: Species like Penicillium roqueforti and P. camemberti are used for ripening and flavoring specific cheeses.
  • Direct Consumption: Edible mushrooms (e.g., Agaricus bisporus) are a rich source of nutrients.
  • Fermented Foods: Fungi are used in making Soy sauce, Tempeh, and Miso.

Note on Fermentation:
Fermentation is an anaerobic metabolic process where fungi (like yeast) convert sugars into ethyl alcohol and carbon dioxide.

C6H12O6 → 2C2H5OH + 2CO2 + Energy
In the food industry, this is exploited for both the ethanol (Brewing industry) and the carbon dioxide (Baking industry).

Exam Focus Enhancements

Exam Tips

  • For Botany papers, always draw neat diagrams even where not explicitly asked.
  • Use specific scientific names and underline them (e.g., Puccinia graminis).

Important Formulas/Concepts

  • Photosynthesis: 6CO2 + 6H2O → C6H12O6 + 6O2
  • Algae Pigments: Chl-a + Phycobilins (Rhodophyceae) / Fucoxanthin (Phaeophyceae).

Common Mistakes

  • Confusing Uredospores (repeating) with Teleutospores (resting).
  • Mixing up reserve food materials between Phaeophyta and Rhodophyta.

Answer Presentation Strategy

Start long answers with a formal classification block. Use bullet points for characteristics and numbered lists for life cycle stages to improve readability for the examiner.