Question 1

Q1: Discuss how classification systems have undergone several changes over a period of time?

Accepted Answer

Classification systems for living organisms have evolved significantly over time as our understanding of biology has deepened. The changes reflect a shift from simple, practical classifications to more complex systems based on scientific criteria and evolutionary relationships. 1.  Earliest Attempts...

Question 2

Q10: What are the characteristic features of Euglenoids?

Accepted Answer

Euglenoids are a group of unicellular protists with the following characteristic features: 1.  Habitat: They are primarily found in freshwater, particularly in stagnant water bodies. 2.  Cell Wall: They lack a rigid cell wall. Instead, they have a flexible, protein-rich outer layer called a pellicle...

Question 3

Q11: Give a brief account of viruses with respect to their structure and nature of genetic material. Also name four common viral diseases.

Accepted Answer

Structure of Viruses: Viruses are non-cellular, infectious agents that can only replicate inside the living cells of other organisms. They have an inert, crystalline structure outside a host cell. A virus particle consists of two main components: 1.  Genetic Material: The core of the virus contains...

Question 4

Q12: Organise a discussion in your class on the topic - Are viruses living or nonliving?

Accepted Answer

Viruses are fascinating entities that exist on the borderline between living and non-living things. A discussion on this topic would involve arguments for both perspectives. Arguments for Viruses being Non-living: 1.  Acellular Structure: They lack a cellular structure, which is the basic unit of al...

Question 5

Q2: State two economically important uses of: (a) heterotrophic bacteria (b) archaebacteria

Accepted Answer

(a) Two economically important uses of heterotrophic bacteria are: 1.  Curd Production: Bacteria like Lactobacillus are used to convert milk into curd, which is a major dairy product consumed worldwide. 2.  Antibiotic Production: Many antibiotics, which are crucial for treating bacterial diseases, a...

Question 6

Q3: What is the nature of cell-walls in diatoms?

Accepted Answer

The cell walls of diatoms are unique and characteristic of the group. They are composed of the following features: 1.  Composition: The walls are embedded with silica, which makes them hard, rigid, and indestructible. 2.  Structure: The cell wall consists of two thin, overlapping shells that fit tog...

Question 7

Q4: Find out what do the terms 'algal bloom' and 'red-tides' signify.

Accepted Answer

Algal Bloom: The term 'algal bloom' refers to a rapid and excessive growth of algae, particularly cyanobacteria (blue-green algae), in a water body. These blooms often occur in polluted water bodies rich in nutrients like nitrogen and phosphorus. They can form a thick layer on the water surface, whi...

Question 8

Q5: How are viroids different from viruses?

Accepted Answer

Viroids and viruses are both infectious agents, but they differ in several key aspects: | Feature             | Viruses                                                              | Viroids                                                              |  |---------------------|----------------------...

Question 9

Q6: Describe briefly the four major groups of Protozoa.

Accepted Answer

Protozoans are heterotrophic, single-celled eukaryotes, considered to be primitive relatives of animals. They are classified into four major groups based on their locomotory structures: 1.  Amoeboid Protozoans:        Habitat: Live in freshwater, seawater, or moist soil.        Locomotion: They move...

Question 10

Q7: Plants are autotrophic. Can you think of some plants that are partially heterotrophic?

Accepted Answer

Yes, while the vast majority of plants are autotrophic (producing their own food through photosynthesis), some plants are partially heterotrophic. They supplement their nutrition by obtaining nutrients from other sources. These can be categorized as: 1.  Insectivorous Plants: These plants grow in nu...

Question 11

Q8: What do the terms phycobiont and mycobiont signify?

Accepted Answer

The terms phycobiont and mycobiont refer to the two components of a lichen, which is a symbiotic association between algae and fungi.    Phycobiont: This is the algal component of the lichen. The phycobiont is autotrophic, meaning it performs photosynthesis and prepares food for both itself and its...

Question 12

Q9: Give a comparative account of the classes of Kingdom Fungi under the following: (i) mode of nutrition (ii) mode of reproduction

Accepted Answer

Here is a comparative account of the four classes of Kingdom Fungi: | Class           | (i) Mode of Nutrition                                                 | (ii) Mode of Reproduction...

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