CLASS ELEVEN BIOLOGY CHAPTER 2 BIOLOGICAL CLASSIFICATION QUESTIONNAIRE PART 2

 

CLASS ELEVEN BIOLOGY CHAPTER 2

BIOLOGICAL CLASSIFICATION

QUESTIONNAIRE FOR TESTS AND REVISION 

PART 2 

It can be used as reference material for competitive exams also.

1)     Under which kingdom are all single-celled eukaryotes placed?

A: All single-celled eukaryotes are placed under Protista.

2)     How can the classification of a photosynthetic protistan vary among biologists?

A: What may be considered ‘a photosynthetic protistan’ to one biologist may be considered ‘a plant’ to another.

3)     Which groups are included under Protista?

A:  Chrysophytes, Dinoflagellates, Euglenoids, Slime moulds, and Protozoans are grouped under Protista.

4)     What is the primary habitat of protists?

A: Protists are primarily aquatic.

5)     What is a key characteristic of protistan cells?

A: Protistan cells contain a well-defined nucleus and other membrane-bound organelles because they are eukaryotes.

6)     Do some protists have locomotory structures, and if so, what are they?

A: Yes, some protists have flagella or cilia.

7)     How do protists reproduce?

A: Protists reproduce both asexually and sexually.

8)     What processes are involved in the sexual reproduction of protists?

A: The sexual reproduction of protists involves cell fusion and zygote formation.

9)     Which organisms are included in this group?

A: This group includes diatoms and golden algae (desmids).

10) Where are diatoms and golden algae found?

A: They are found in freshwater as well as in marine environments.

11) How do diatoms and golden algae exist in water?

A: They are microscopic and float passively in water currents, existing as plankton.

12) What is the primary mode of nutrition for most diatoms and golden algae?

A: Most of them are photosynthetic.

13) Describe the cell walls of diatoms.

A: The cell walls of diatoms form two thin overlapping shells that fit together like a soapbox, and they are embedded with silica, making them indestructible.

14) What is 'diatomaceous earth'?

A: 'Diatomaceous earth' refers to the large amount of indestructible cell wall deposits left behind by diatoms over billions of years.

15) What are some uses of diatomaceous earth?

A: Diatomaceous earth is used in polishing, filtration of oils, and syrups due to its gritty nature.

16) What role do diatoms play in the ocean ecosystem?

A: Diatoms are the chief 'producers' in the oceans, contributing significantly to the marine food web through photosynthesis.

17) What is the primary habitat of dinoflagellates organisms?

A: These organisms are mostly marine.

18) What is their primary mode of nutrition?

A: They are photosynthetic.

19) How do these organisms appear in terms of color?

A: They appear yellow, green, brown, blue, or red depending on the main pigments present in their cells.

20) What is the composition of their cell wall?

A: The cell wall has stiff cellulose plates on the outer surface.

21)  How many flagella do most of these organisms have, and where are they located?

 A: Most of these organisms have two flagella; one lies longitudinally and the other transversely in a furrow between the wall plates.

22) What phenomenon is caused by the rapid multiplication of red dinoflagellates like Gonyaulax?

A: The rapid multiplication of red dinoflagellates can make the sea appear red, a phenomenon known as red tides.

23) What is an example of a red dinoflagellate?

A: Gonyaulax is an example of a red dinoflagellate.

24) What effect do the toxins released by large numbers of red dinoflagellates have on other marine animals?

A: The toxins released by large numbers of red dinoflagellates may kill other marine animals such as fishes.

25) What type of environment do euglenoids primarily inhabit?

A.    Euglenoids are primarily found in fresh water environments, often in stagnant water.

26) How is the cell structure of euglenoids different from typical organisms?

A.    Instead of a cell wall, euglenoids have a protein-rich layer called a pellicle, which provides flexibility to their bodies.

27) Describe the flagella of euglenoids.

A.    Euglenoids possess two flagella: one short and one long. These flagella help in movement and navigation through their aquatic habitats.

28) How do euglenoids obtain energy?

A.    Euglenoids are photosynthetic in the presence of sunlight, utilizing chlorophyll and other pigments to convert light energy into chemical energy (photosynthesis).

29)  What happens to euglenoids in the absence of sunlight?

A.    When deprived of sunlight, euglenoids behave like heterotrophs, preying on smaller organisms for nutrition.

30) What is unique about the pigments of euglenoids?

A.    The pigments of euglenoids are identical to those found in higher plants, which allows them to effectively absorb sunlight for photosynthesis.

31) Can you give an example of a euglenoid organism?

A.    An example of a euglenoid organism is Euglena, which exhibits the characteristics mentioned above, including the presence of a pellicle, two flagella, and photosynthetic capabilities.

32) How does the pellicle contribute to the survival of euglenoids?

A.    The pellicle provides flexibility to the body of euglenoids, allowing them to adapt to changing environmental conditions and move efficiently through water.

33) What role do euglenoids play in their ecosystem?

A.    Euglenoids play a significant role as primary producers in aquatic ecosystems, contributing to the food web by providing food for other organisms and influencing nutrient cycles.

34) How do euglenoids respond to changes in light availability?

A.    Euglenoids adjust their metabolic processes based on light availability; in the presence of sunlight, they perform photosynthesis, while in darkness, they switch to heterotrophic mode to obtain energy.

35) What is the ecological role of slime molds?

A.    Slime molds are saprophytic protists that contribute to the decomposition of organic material, such as decaying twigs and leaves.

36) Describe the movement of the body of slime molds.

A.    The body of slime molds moves along decaying twigs and leaves by engulfing organic material.

37) What is a plasmodium in the context of slime molds?

A.    Under suitable conditions, slime molds form an aggregation called a plasmodium, which is a multinucleate mass of cytoplasm that can grow and spread over several feet.

38) What happens during unfavourable conditions for slime molds?

A.    During unfavourable conditions, the plasmodium of slime molds differentiates and forms fruiting bodies bearing spores at their tips.

39) What are the characteristics of the spores of slime molds?

A.    The spores of slime molds possess true walls and are extremely resistant, capable of surviving for many years, even under adverse conditions.

40) How are the spores of slime molds dispersed?

A.    The spores of slime molds are dispersed by air currents, facilitating their spread to new environments.

41) Can you explain the life cycle of slime molds?

A.    Slime molds start as spores that germinate under suitable conditions to form a plasmodium. The plasmodium grows and spreads, and during unfavourable conditions, it forms fruiting bodies with spores. These spores, equipped with true walls, are dispersed by air currents, where they can germinate again under favourable conditions.

42) What adaptations do slime molds exhibit for survival?

A.    Slime molds exhibit adaptations such as spore formation with true walls and resistance to adverse conditions, allowing them to survive for extended periods.

43) How do slime molds contribute to nutrient cycling in ecosystems?

A.    Slime molds play a crucial role in nutrient cycling by breaking down organic material and releasing nutrients back into the environment, which can then be used by other organisms.

44) Are slime molds more closely related to plants or animals?

A.    Slime molds are protists and are more closely related to other protists than to plants or animals, despite their diverse and unique life cycle characteristics.

45) What are protozoans, and how do they obtain nutrients?

A.    Protozoans are heterotrophic organisms that obtain nutrients by living as predators or parasites, feeding on other organisms.

46) How are protozoans related to animals?

A.    Protozoans are considered primitive relatives of animals due to their heterotrophic nature and similar cellular organization.

47) What are the four major groups of protozoans?

A.    The four major groups of protozoans are amoeboid protozoans, flagellated protozoans, ciliated protozoans, and sporozoans.

48) Describe the characteristics of amoeboid protozoans.

A.    Amoeboid protozoans live in freshwater, seawater, or moist soil. They move and capture prey by extending pseudopodia (false feet), as seen in Amoeba. Marine forms may have silica shells on their surface, and some like Entamoeba are parasitic.

49) Provide an example of a disease caused by a flagellated protozoan.

A.    Flagellated protozoans may be free-living or parasitic. Parasitic forms such as Trypanosoma cause diseases like sleeping sickness. 

50) What distinguishes ciliated protozoans from other protozoan groups?

A.    Ciliated protozoans are aquatic organisms characterized by thousands of cilia, which enable active movement. They possess a gullet that opens to the cell surface, and the coordinated movement of cilia directs food-laden water into this gullet. Example: Paramecium.

51) How do sporozoans differ from other protozoans in terms of their life cycle?

A.    Sporozoans include organisms with an infectious spore-like stage in their life cycle. They are diverse, and notable examples include Plasmodium, which causes malaria—a disease with significant effects on human populations.

52) What role do cilia play in the life of ciliated protozoans?

A.    Cilia in ciliated protozoans facilitate locomotion and food capture. Their coordinated beating creates currents that sweep food particles into the oral groove leading to the gullet. 

53) How do amoeboid protozoans adapt to their environments? 

A.    Amoeboid protozoans adapt to various habitats such as freshwater, seawater, or moist soil by altering their shape and movement using pseudopodia, which aids in prey capture and environmental navigation. 

54) Why are sporozoans like Plasmodium considered significant in human health? 

A.    Sporozoans like Plasmodium are significant because they cause diseases like malaria, which have a profound impact on human health and global populations.