Biology questions for NDA & competitive exams with answers

Study the following Biology questions for NDA and increase your knowledge

Which plant disease is commonly referred to as ring disease?
A. Citrus Canker
B. Black arm of cotton
C. Wilt of Potato
D. None of the above

Ans. C

Explanation: Wilt of Potato is a bacterial plant disease. It gets its alternate name ‘ring disease’ because it forms a brown ring in the xylem tissue.
Which plant disease manifests as large yellow spots appearing on the leaves?
A. Bacterial Blight
B. Bacterial Spot
C. Aphids
D. Botrytis

Ans. A

Explanation: Bacterial Blight disease is characterized by large yellow spots on leaves that later develop into brown patches.
The bunchy top disease in banana plants is caused by:
A. Bacteria
B. Fungus
C. Virus
D. None of the above

Ans. C

Explanation: Bunchy top disease in banana plants is caused by a virus. This disease results in dwarfed plants with clustered leaves.
Which plant disease creates dark to light brown rotting around wounded plant tissues?
A. Gray Mold
B. Citrus Canker
C. Spider Mites
D. None of the above

Ans. A

Explanation: Gray Mold, scientifically known as Botrytis, primarily affects plants through their injured or decaying parts, particularly targeting leaves and flower petals.

( Biology questions for NDA )

Which plant disease characteristically shows white mildew formation on the leaf undersides?

A. Cylindrocladium
B. Angular leaf Spot
C. Downy Mildew
D. Black arm of Cotton

Ans. C

Explanation: Downy Mildew is a plant disease that develops during extended periods of moisture. Its distinctive feature is the appearance of white mildew specifically on the underside of plant leaves. ( Biology questions for NDA )

Which bacteria is responsible for causing bacterial blight in Rice plants?

A. Pseudomonas bacteria
B. Xanthomonas citri bacteria
C. Xanthomonas oryzae bacteria
D. None of the above

Ans. C

Explanation: Bacterial blight in Rice plants is caused by Xanthomonas oryzae bacteria. The disease manifests by blocking the plant’s vascular bundles due to bacterial proliferation.

Which plant disease results in chlorophyll destruction and leaf shrinkage?

A. Mosaic disease of tobacco
B. Citrus Canker
C. Tundu disease of wheat
D. Rhizoctonia

Ans. A

Explanation: In Mosaic disease of tobacco, the leaves undergo significant shrinkage and reduction in size. The disease also causes destruction of the leaf chlorophyll, severely impacting plant health.

Which plant disease affects leaves, branches, and fruits simultaneously?

A. Spider Mites
B. Mealybugs
C. Aphids
D. Citrus Canker

Ans. D

Explanation: Citrus Canker, which originated in China, is characterized by its comprehensive impact on the plant, affecting leaves, branches, and fruits simultaneously.

Which plant disease is characterized by fine webbing on leaf undersides?

A. Spider Mites
B. Anthracnose
C. Mealybugs
D. Rhizoctonia

Ans. A

Explanation: Spider Mites infestation is distinctly identified by the presence of fine webbing formations on the undersides of plant leaves.

Which plant disease manifests as stem rot at soil level with brown to red lesions?

A. Rhizoctonia
B. Angular leaf Spot
C. Bacterial Blight
D. Bacterial Spot

Ans. A

Explanation: Rhizoctonia disease is characterized by stem rot occurring at the soil line, displaying distinctive brown to red lesions.

(Biology questions for NDA)

This comprehensive overview has covered various plant diseases, their causative organisms, and characteristic symptoms.

Who made the groundbreaking discovery of cells in 1665?

a) Robert Hook
b) Robert Crook
c) David Thomson
d) Marie Francois

Ans. a)

Explanation: In 1665, Robert Hooke made the groundbreaking discovery of cells. This pivotal finding laid the foundation for numerous modern scientific breakthroughs and continues to influence contemporary research.

Which cellular organelle functions as the primary packaging center for molecules destined for distribution throughout the cell?

a) Mitochondria

b) Plastids

c) Golgi apparatus

d) Vacuole

Ans. c)

Explanation: The Golgi apparatus, also referred to as the Golgi complex or Golgi body, functions as the cell’s primary packaging center for molecular distribution. This essential organelle is situated in the cytoplasm, positioned adjacent to the endoplasmic reticulum and in close proximity to the cell’s nucleus.

What forms the outermost boundary of a cell?

a) Plasma membrane

b) Cytoplasm

c) Nuclear membrane

d) None of the above

Ans. a)

Explanation: The plasma membrane, also known as the cell membrane, constitutes the cell’s outermost boundary. This universal cellular component separates the cell’s internal environment from its exterior surroundings. In plant and bacterial cells, a cell wall is attached to the external surface of the plasma membrane.

( Biology questions for NDA )

What is the process by which cells internalize materials through their plasma membrane?

a) Egestion

b) Diffusion

c) Osmosis

d) Endocytosis

Ans. d)

Explanation: Endocytosis is the cellular process where materials are internalized by the cell through its plasma membrane. This mechanism involves the active transport of molecules into the cell by enveloping them within the membrane structure. ( Biology questions for NDA )

Which statement is incorrect regarding cellular organelles?

a) They are found in all Eukaryotic cells.

b) They are found in multicellular organisms.

c) They coordinate to produce the cell.

d) They are small sized and mostly internal.

Ans. b)

Explanation: Cellular organelles are present in all Eukaryotic cells, working in coordination to maintain cellular functions. These microscopic structures are predominantly internal and compact in size. An organelle is a specialized cellular component that performs specific functions, such as mitochondria, ribosomes, or endoplasmic reticulum. It’s important to note that organelles in single-celled organisms serve the same purpose as organs do in multicellular organisms.

What is the process where water molecules move from a higher concentration region to a lower concentration region through a semi-permeable membrane?

a) Diffusion

b) Osmosis

c) Both a) and b)

d) Neither a) nor b)

Ans. b)

Explanation: Osmosis describes the movement of water molecules from a region of higher concentration to a region of lower concentration through a semi-permeable membrane.

Which organism possesses a single chromosome and reproduces through processes like fission or budding?

a) Eukaryotes

b) Prokaryotes

c) Bacteria

d) Primitive organism

Ans. b)

Explanation: Prokaryotes are characterized by having a single chromosome and reproduce through processes like fission or budding. Binary fission is the primary method of cell division in prokaryotes. During this process, the prokaryotic chromosome, which consists of a single DNA molecule, first duplicates itself and then attaches each copy to different regions of the cell membrane.

( Biology questions for NDA )

Which cellular process involves the fusion of vesicle membrane with plasma membrane to release contents into the external environment?

a) Exocytosis

b) Endocytosis

c) Osmosis

d) Diffusion

Ans. a)

Explanation: Exocytosis is a cellular transport mechanism where vesicle membranes merge with the plasma membrane to release their internal contents into the extracellular environment.

Which substance fills the cell interior and has a gel-like consistency?

a) Cytoplasm

b) Ectoplasm

c) Nucleoplasm

d) None of the above

Ans. a)

Explanation: Cytoplasm is the gel-like material that fills the cell’s interior and houses various cellular organelles. This dense solution is contained within the cell membrane and is essential for cellular function.

Which category do Blue-green Algae belong to?

a) Prokaryotes

b) Eukaryotes

c) Both a) and b)

d) Neither a) nor b)

Ans. a)

Explanation: Blue-green Algae, also known as Cyanobacteria, are classified as Prokaryotes since they lack membrane-bound organelles and a true nucleus.

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