Practice MCQ Questions and answers on Biology-GK

Answer: Option D

Algae, Amoeba and Paramaecium all are single celled organism.

Answer: Option A

Chlamydomonas is widely distributed in freshwater or damp soil. It is generally found in a habitat rich in ammonium salt.

Answer: Option D

The biological parameters, which included cell width, cell length, number of chloroplast spirals, and number of pyrenoids, ranged from 40 to 90 μm, 85 to 263 μm, 5.5 to 16 spiral, and 50 to 240 pyrenoids, respectively.

Answer: Option D

Penicillium and Agaricus are fungi while Volvox is an alga. All three are eukaryotes thus have a membrane bound nucleus. Nostoc is a cyanobacterium, i.e., prokaryote, so it lacks true nucleus, thus nuclear membrane is absent.

Answer: Option C

Microscopic organism which passively float on the surface of water is called Zooplanktons and Phytoplanktons.

Answer: Option D

Mycoplasma are a mollicute genus of bacteria that lack a cell wall around their cell membranes. Mycoplasma species are the smallest bacterial cells yet discovered, can survive without oxygen, and come in various shapes.

Answer: Option C

The ability to fix atmospheric nitrogen is found in the blue-green algae.

Answer: Option C

The number of chloroplasts in a cell of Spirogyra is 1-14.

Answer: Option D

The correct answer is option D. Spirogyra.

'Pond silk' is the common name given to Spirogyra, a filamentous green algae commonly found in freshwater habitats such as ponds, lakes, and slow-moving streams. Spirogyra is known for its long, thread-like filaments that appear silky and slimy.

Spongilla (option A) refers to a freshwater sponge, not 'pond silk'.
Chlorella (option B) is a genus of single-celled green algae that is not typically referred to as 'pond silk'.
Selaginella (option C) is a genus of spikemosses, which are vascular plants and not related to algae.

Therefore, the correct answer is option D. Spirogyra, as it matches the description of 'pond silk'.

Answer: Option C

The correct answer is option C. Smut.

Potato blight is a plant disease that affects potato plants. It is caused by a specific type of fungus called Phytophthora infestans. This fungus is responsible for the devastating disease known as potato blight or late blight.

Potato blight is a highly destructive disease that primarily affects the leaves, stems, and tubers of potato plants. It can cause significant damage to potato crops, leading to reduced yields and economic losses for farmers.

The disease spreads rapidly under favorable environmental conditions, such as high humidity and moderate temperatures. The fungus produces spores that can be carried by wind, water, or infected plant material, allowing it to spread from plant to plant and even between fields.

Symptoms of potato blight include dark, water-soaked lesions on the leaves, which can quickly turn into brown or black patches. Infected stems may also develop lesions, leading to withering and dieback of the foliage. Tubers can be affected as well, showing signs of rotting and decay.

To manage potato blight, farmers often employ a combination of preventive and control measures. These can include planting resistant potato varieties, practicing crop rotation, applying fungicides, and timely removal and destruction of infected plant material.

It is not caused by Penicillium (option A), which is a genus of fungi known for producing antibiotics, nor is it caused by Meningitis (option B), which is an inflammation of the protective membranes covering the brain and spinal cord. Additionally, it is not caused by Ringworm (option D), which is a fungal infection of the skin, hair, or nails.

In conclusion, the correct answer is option C. Smut, as potato blight is caused by the fungus Phytophthora infestans, not by Penicillium, Meningitis, or Ringworm.