12th Class Botany Quiz

1. What is systematics?
A: The study of different kinds of organisms,their diversities and relationships among them is called systematics.

2. Which is the largest botanical garden in the world? Name a few well known botanical gardens in India.
A: Largest botanical garden in the world – (Royal) Botanical garden or Kew botanical garden – England.
? Botanical gardens in India: Indian Botanical garden – Howrah, National Botanical Research Institute – Lucknow.

3. Define the terms couplet and lead in taxonomic key.
A: A pair of contrasting characters in a key is called a couplet.
? Each statement in the key is called a lead.

4. What is the basic unit of classification? Define it.
A: Species is the basic unit of classification.
? Species is a group of individual organisms with fundamental similarities.

5. What is the nature of cell-walls in diatoms?
A: The cell wall in diatoms is made up of two overlapping halves called epitheca and hypotheca which give the appearance of a
soapbox. It is made up of hard and indestructible silica.

6. How are viroids different from viruses?
A: Viroids differ from viruses in lacking a protein coat. Ex: Potato spindle tuber viroid. Viroid contains only nucleic acid (RNA) whereas
virus contains nucleic acid and protein coat.

7. State two economically important uses of heterotrophic bacteria.
A: Heterotrophic bacteria are used in production of antibiotics.
? Rhizobium is used in fixing atmospheric nitrogen in agricultural lands.
? Lactobacillus is used in making curd from milk.

8. Plants are autotrophic. Name some plants which are partially heterotrophic.
A: Partially heterotrophic plants
? Bladder wort (Utricularia)
? Venus fly trap (Dionea)

9. Name two diseases caused by Mycoplasmas.
A: Witches broom in plants.
? Pleuropneumonia in cattle.
? Mycoplasmal urethritis in humans.

10. Name the books written by Parasara and mention the important aspects discussed in those books.
A: i) Krishi Parasaram – Deals with agriculture and weeds.
ii) Vrikshayurveda – Deals with different types of forests, external and internal characters of plants (medicinal plants).

11. Who are herbalists? What are the books written by them?
A: The botanists who identified and described medicinal plants during 16th and 17th centuries were called herbalists.
? Herbals.

12. What was the contribution of Carolus Von Linnaeus for the development of plant taxonomy?
A: Carolus Von Linnaeus proposed the sexual system of classification and popularised the Binomial Nomenclature system.

13. Why is Mendel considered as father of genetics?
A: As Mendel introduced the laws of inheritance he is considered as the father of genetics.

14. Who discovered the cell and what was the book written by him?
A: Robert Hooke.
? Micrographia.

15. What is palaeo botany? What is its use?
A: Palaeo botany is the study of fossil plants. It helps in understanding the course of evolution in plants.

16. Which group of plants is called vascular cryptogams? Name the branch of Botany which deals with them?
A: Pteridophyta.
? Pteridology.

17. Differentiate between syngamy and triple fusion.
A: Syngamy is the fusion of first male gamete with the female egg cell to form a diploid zygote.
? Triple fusion is the fusion of second male gamete with diploid secondary nucleus to form a triploid primary endosperm nucleus.

18. Name the stored food materials found in Phaeophyceae and Rhodophyceae.
A: Phaeophyceae – stored food is laminarin or mannitol.
? Rhodophyceae – stored food is Floridian starch.

19. Name the integumented megasporangium found in Gymnosperms. How many female gametophytes are generally formed inside the megasporangium?
A: Ovule – Integumented megasporangium.
? One female gametophyte.

20. Mention the fern characters found in Cycas.
A: Circinate vernation of young leaves.
? Presence of ramenta.
? Presence of archegonia.
? Multiciliate male gametes.

21. Give two examples for unicellular, colonial and filamentous algae.
A: Chlamydomonas – unicellular alga
? Volvox – colonial alga
? Spirogyra and Ulothrix – filamentous alga

22. Differentiate fibrous roots from adventitious roots.
A: The roots that arise from the base of the stem from the region of radicle are called fibrous roots.
? The roots that arise from parts of the plant other than the radicle are called adventitious roots.
Ex: Banyan

23. What is meant by pulvinous leaf base? In members of which angiospermic family do you find them?
A: The swollen leaf base is called pulvinous leaf base.
? It is found in Fabaceae (Leguminous plants).

24. Define venation. How do dicots differ from monocots with respect to venation?
A: The arrangement of veins and veinlets in the lamina of the leaf is called venation. In dicots it is reticulate venation and in monocots it is parallel venation.

25. How is a pinnately compound leaf different from a palmately compound leaf? Explain with one example each.
A: In a pinnately compound leaf the leaflets are arranged on either sides of the common axis called rachis.
Ex:Neem

? In a palmately compound leaf the leaflets are attached to the tip of the petiole (like the fingers of the palm, hence the name)
Ex: Bombax

1. What is meant by identification and nomenclature? How is a key helpful in the identification and classification of an organism?
A: Identification means to determine whether a collected organism is entirely new or already known.
? Nomenclature means providing a scientific name to an identified organism.
? A taxonomic key is based on contrasting characters in pairs (couplet).
? It refers to a choice between two opposite options out of which one is accepted and the other rejected. Thus plants or animals may be classified using keys based on similarities and differences. Each taxonomic category requires separate taxonomic keys.

• Ex: Couplet in a key: Reticulate venation – Parallel venation Flower pentamerous – Trimerous Tap root – Fibrous root Two cotyledons in seed – One cotyledon in seed

? By comparing the characters of a plant with the above options one can classify a plant into dicotyledonae / monocotyledonae.

2. Define a taxon. Give some examples of taxa at different heirarchial levels.
A: Any unit (or category) of classification which represents a rank in a taxonomic system is called a taxon.
? In botany the taxa at heirarchial levels are:
a. Kingdom
Ex:  Plant kingdom
b. Division
Ex:  Spermatophyta
c. Class
Ex: : Dicotyledonae
d. Order
Ex: Sapindales
e. Family
Ex:  Anacardiaceae
f. Genus
Ex: : Mangifera
g. Species
Ex:  indica

3. What are taxonomical aids? Give the importance of herbaria and museums.
A: Taxonomic aids are the means and devices used in the study of classification and identification of organisms. Ex: Herbaria and Museums.
? Herbaria: A herbarium is a store house of collected plant specimens that are dried, pressed and preserved on sheets for quick reference in taxonomical studies.
? Museums: Biological museums have a collection of preserved plants and animal specimens for study and reference.

4. Explain binomial nomenclature.
A: Binomial nomenclature is the system of naming an organism with two components.

• ? It was first proposed by Caspar Bauhin and later popularised by Carolus Linnaeus.
• ? The biological names are written in italics or underlined when handwritten or printed.
• ? The first word is the genus or generic name which starts with a capital letter.
• ? The second word is the species or specific epithet which starts with a small letter.
• ? Name of the author may be written after the species.

Ex:  Mangifera indica is the biological or botanical name of mango. Mangifera is the generic name and indica is the specific epithet.

Q: Define root modification. Explain how root is modified to perform different functions.
A: Any change in the shape and structure of a root to perform special functions other than absorption and conduction of water and minerals is called a root modification. Roots are variously modified in different plants according to their needs in different environmental conditions.
? Storage roots: Some roots store water and food and swell up called storage roots.

• Ex: Taproots of carrot, turnip Adventitious roots of sweet potato Fibrous roots of Asparagus

? Prop roots or pillar roots: These roots hang down from the stems and support theplant.

• Ex: : Banyan

? Stilt roots: These roots come out of the lower nodes of the stem and support the plant. Ex: Maize and sugarcane.
? Pneumatophores: These roots come out of the ground and help to get more oxygen for respiration in mangrove plants.

• Ex: : Rhizophora

? Velamen roots: These roots are found in some epiphytes and help in absorption of moisture from the atmosphere.

• Ex: Vanda

? Haustorial roots: These roots are found in parasitic plants and help to absorb water, minerals and / or Food from the host plants.

• Ex: : Cuscuta, Rafflesia, (both food and water with minerals) Viscum and Striga (only water and minerals).

? Nodular roots: These roots contain Rhizobium bacteria and help in nitrogen fixation in members of Fabaceae.

• Ex: : Arachis (groundnut).

? Photosynthetic roots: These roots are chlorophyllous and perform photosynthesis.

• Ex: : Taeniophyllum.

Q: What are aggregate fruits? Give two examples.
A: The fruits that develop from an apocarpous gynoecium of a single flower are called aggregate fruits.
Ex: Custard apple (Annona squamosal)

• ? Mulberry (Morus alba) 
• ? Polyalthia