BIOLOGICAL CLASSIFICATION (3)

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Question 1

The cell walls of which kingdom are primarily composed of cellulose?

A) Monera

B) Fungi

C) Plantae

D) Animalia

Answer: C) Plantae
Explanation:
The cell walls of the Plantae kingdom are primarily composed of cellulose, which provides structural support and protection to plant cells.

Question 2

Which type of fungi are known for their role in bread and beer production?

A) Zygomycetes

B) Ascomycetes

C) Basidiomycetes

D) Deuteromycetes

Answer: B) Ascomycetes
Explanation:
Ascomycetes, also known as sac fungi, are a type of fungi that play a crucial role in bread and beer production. They include species like baker's yeast (Saccharomyces cerevisiae) and brewer's yeast, which are used in fermentation processes.

Question 3

Which of the following is a significant feature of cyanobacteria?

A) They are multicellular

B) They lack chlorophyll

C) They can perform photosynthesis

D) They do not have a cell wall

Answer: C) They can perform photosynthesis
Explanation:
Cyanobacteria are significant because they are capable of performing photosynthesis, just like plants. They contain the pigment chlorophyll a, which allows them to convert light energy into chemical energy. This feature makes them essential for the Earth's ecosystem, producing oxygen and serving as a food source for many organisms.

Question 4

Which of the following is a major group of protozoans characterized by their ability to move using pseudopodia?

A) Ciliated protozoans

B) Flagellated protozoans

C) Amoeboid protozoans

D) Sporozoans

Answer: C) Amoeboid protozoans
Explanation:
Amoeboid protozoans are a major group of protozoans characterized by their ability to move using pseudopodia, which are extensions of their cell membrane that allow them to engulf food particles and move about. Examples of amoeboid protozoans include Amoeba proteus and Chaos carolinensis.

Question 5

Which of the following processes occurs during the sexual reproduction of fungi?

A) Budding

B) Plasmogamy

C) Binary fission

D) Fragmentation

E) None of the above

Answer: B) Plasmogamy
Explanation:
Plasmogamy is the process of fusion of the cytoplasm of two fungal cells, which occurs during sexual reproduction. This process involves the union of two compatible haploid nuclei, leading to the formation of a diploid zygote. Plasmogamy is a critical step in the life cycle of many fungi, allowing for genetic recombination and diversity.

Question 6

In fungi, what is the term for the network of hyphae?

A) Mycelium

B) Sporangium

C) Fruiting body

D) Conidia

Answer: A) Mycelium
Explanation:
The mycelium is the vegetative part of a fungus, consisting of a network of branching hyphae. It is responsible for absorbing nutrients from the surrounding environment and is essential for the growth and development of the fungus.

Question 7

Which of the following is a significant feature of diatoms?

A) They are multicellular

B) They have indestructible silica cell walls

C) They lack chlorophyll

D) They are exclusively heterotrophic

Answer: B) They have indestructible silica cell walls
Explanation:
Diatoms are a type of algae that are characterized by their unique cell walls, which are made of silica (silicon dioxide) and are highly resistant to decay. This feature allows diatoms to preserve well in sedimentary rocks and makes them important indicators of past environmental conditions.

Question 8

In Whittaker's classification, which characteristic is NOT used for differentiating the kingdoms?

A) Mode of nutrition

B) Body organization

C) Habitat

D) Color of the organism

Answer: D) Color of the organism
Explanation:
Whittaker's classification system uses characteristics such as mode of nutrition, body organization, and cell structure to differentiate between kingdoms. Color is not a characteristic used in this system, as it can be variable within a kingdom and is not a reliable indicator of evolutionary relationships.

Question 9

What is the main role of heterocysts in cyanobacteria?

A) Photosynthesis

B) Energy storage

C) Spore production

D) Nitrogen fixation

Answer: D) Nitrogen fixation
Explanation:
Heterocysts are specialized cells found in certain cyanobacteria that are responsible for nitrogen fixation, the process of converting atmospheric nitrogen (N2) into a form that can be used by the cell. This process is essential for the survival of the cyanobacteria and other organisms that rely on them for nitrogen.

Question 10

Which of the following is a characteristic of dinoflagellates?

A) They lack chlorophyll

B) They have a rigid cell wall with cellulose plates

C) They are exclusively heterotrophic

D) They are found only in freshwater

Answer: B) They have a rigid cell wall with cellulose plates
Explanation:
Dinoflagellates are a type of protist characterized by their rigid cell wall, which is composed of cellulose plates. These plates provide protection and support to the cell, and are a distinctive feature of dinoflagellates.

Question 11

Which of the following is true about slime moulds?

A) They are exclusively aquatic

B) They can form a plasmodium

C) They lack a defined nucleus

D) They are autotrophic

Answer: B) They can form a plasmodium
Explanation:
Slime moulds are a type of organism that can form a plasmodium, a large, amoeba-like cell that can engulf and digest food particles. This stage of their life cycle allows them to feed and grow before eventually forming fruiting bodies and producing spores.

Question 12

Protozoans are primarily classified based on their:

A) Habitat

B) Mode of locomotion

C) Color

D) Size

Answer: B) Mode of locomotion
Explanation:
Protozoans are primarily classified based on their mode of locomotion, such as flagellates (using flagella), ciliates (using cilia), amoeboids (using pseudopodia), and sporozoans (using no locomotory organelles). This classification reflects their unique characteristics and adaptations for movement.

Question 13

The dikaryotic stage in fungi is characterized by:

A) Two nuclei per cell

B) A single nucleus

C) Asexual reproduction

D) Formation of spores

Answer: A) Two nuclei per cell
Explanation:
The dikaryotic stage in fungi is a unique phase where two nuclei, one from each parent, coexist in a single cell. This stage occurs after mating and before karyogamy (nuclear fusion), and is a critical step in the sexual reproduction of many fungi.

Question 14

Which of the following is a common example of a pathogenic bacterium?

A) Lactobacillus

B) Streptococcus

C) Nostoc

D) Saccharomyces

Answer: B) Streptococcus
Explanation:
Streptococcus is a genus of bacteria that includes several pathogenic species, such as Streptococcus pneumoniae and Streptococcus pyogenes, which can cause diseases like pneumonia, strep throat, and skin infections.

Question 15

Assertion: Archaebacteria are found in extreme habitats like hot springs and marshy areas. Reason: Archaebacteria have a different cell wall structure that helps them survive in extreme conditions.

A) Both assertion and reason are true, and the reason is the correct explanation for the assertion.

B) Both assertion and reason are true, but the reason is not the correct explanation for the assertion.

C) Assertion is true but reason is false.

D) Assertion is false but reason is true.

Answer: A) Both assertion and reason are true, and the reason is the correct explanation for the assertion.
Explanation:
Archaebacteria are indeed found in extreme habitats like hot springs and marshy areas, and their unique cell wall structure, which lacks peptidoglycan, helps them survive in these conditions. This structure provides resistance to extreme temperatures, high salinity, and low pH.

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