NEET Previous Year Questions (2016-2024): Biological Classification | Biology Class 11 PDF Download

2024

Q1: Which one of the following is not a criterion for classification of fungi?     (NEET 2024)
(a)    Morphology of mycelium
(b)    Mode of nutrition
(c)    Mode of spore formation
(d)    Fruiting body
Ans: (b)

The classification of fungi is based on various criteria that broadly include morphology, genetics, and physiological features. Each of the provided options, except one, is a valid criterion for the classification of fungi:

• Morphology of mycelium: Fungi can have different types of mycelium, which refers to their vegetative structure. Fungi can be classified based on whether they have septate (with cross-walls) or coenocytic (without cross-walls) mycelium. This morphological characteristic is crucial for classification.
• Mode of spore formation: Spore formation in fungi is a key reproductive strategy and varies significantly among different groups. Spores can be produced sexually or asexually, and the structures involved in spore production are critical for classification. Fungi are often categorized based on whether they form spores inside a sac (ascospores) or on basidia (basidiospores), among others.
• Fruiting body: The presence and type of fruiting body (such as mushrooms, toadstools, puffballs, etc.) are used in fungi classification. These structures are involved in the production of spores and can be quite distinctive among different fungi groups.

However, the option that is not a criterion for the classification of fungi is:

Mode of nutrition: While fungi are heterotrophic (meaning they obtain their food by absorbing dissolved molecules, typically from decomposing material), this characteristic is generally true across all fungi. They can be saprophytic (decomposers), parasitic (feeding on living organisms), or mutualistic (engaging in mutually beneficial relationships). Despite these differences in their ecological roles or interactions, the mode of nutrition is not typically used as a primary criterion for formal taxonomic classification in fungi. It is more pertinent to ecological or functional groupings rather than taxonomic classification.

Therefore, the correct answer is Option B: Mode of nutrition.

Q2: Match List I with List II      (NEET 2024)

Choose the correct answer from the options given below:
(a) A-III, B-II, C-IV, D-I
(b) A-I, B-III, C-II, D-IV
(c) A-III, B-II, C-I, D-IV
(d) A-IV, B-III, C-II, D-I
Ans: (a)

Let's analyze the matching based on what each item in List I corresponds to in List II:

• Rhizopus is commonly known as black bread mold, which matches with "Bread mould." Therefore, Rhizopus corresponds to III.
• Ustilago is a type of smut fungus that affects grains, so it rightfully matches with "Smut fungus." Thus, Ustilago corresponds to II.
• Puccinia is well-known for causing rust in plants, indicating that it matches with "Rust fungus." This means Puccinia corresponds to IV.
• Agaricus is the genus that includes various mushrooms, such as the common button mushroom. This matches with "Mushroom," so Agaricus corresponds to I.

Given the matches:

A - Rhizopus corresponds to III, B - Ustilago corresponds to II, C - Puccinia corresponds to IV, D - Agaricus corresponds to I. Comparing these with the provided options:
Option A (A-III, B-II, C-IV, D-I) matches exactly with the analysis above.
Therefore, the correct answer is: Option A.

2022

Q1: Given below are two statements:       (NEET 2022 Phase 1)
Statement I: Mycoplasma can pass through less than 1 micron filter size.
Statement II : Mycoplasma are bacteria with cell wall.
In the light of the above statements, choose the most appropriate answer from the options given below: 
(a) Statement I is correct but Statement II is incorrect 
(b) Statement I is incorrect but Statement II is correct 
(c) Both Statement I and Statement II are correct 
(d) Both Statement I and Statement II are incorrect
Ans: (a)
Mycoplasma are the smallest cells and are only 0.3 μm in length. So it can pass through less than 1 μm filter size.
Mycoplasma lack cell wall.

Q3: Mad cow disease in cattle and Cr Jacob disease in humans are due to infection by ______.
(a) Prion
(b) Bacterium
(c) Virus
(d) Viroid      (NEET 2022 Phase 2)
Ans: (a)
Prions are abnormally folded proteins. They cause mad cow disease in cattle and Cr Jacob disease in humans.

2021

Q1: Which of the following statements is correct?       (NEET 2021)
(a) Organisms that depend on living plants are called saprophytes.
(b) Some of the organisms can fix atmospheric nitrogen in specialized cells called sheath cells. 
(c) The fusion of two cells is called Karyogamy.
(d) Fusion of protoplasms between two motile on non-motile gametes is called plasmogamy.
Ans: (d)

• In some blue-green algae specialised cells called heterocyst fixes atmospheric nitrogen into ammonia.
• Fusion of two nuclei is called Karyogamy.
• Organisms that depend on living plants are parasites, saprophytes grow on dead material.
• Fusion of protoplasts of two cells is called plasmogamy.

2020

Q1: Which of the following is correct about viroids?       (NEET 2020)
(a) They have DNA with protein coat.
(b) They have free DNA without protein coat.
(c) They have RNA with protein coat.
(d) They have free RNA without protein coat.
Ans: (d)
Viroids have free RNA without protein coat. Viroid, an infectious particle smaller than any of the known viruses, an agent of certain plant diseases. The particle consists only of an extremely small circular RNA (ribonucleic acid) molecule, lacking the protein coat of a virus.

2019

Q1: Which of the following statements is incorrect?       (NEET 2019)
(a) Prions consist of abnormally folded proteins.
(b) Viroids lack a protein coat.
(c) Viruses are obligate parasites.
(d) Infective constituent in viruses is the protein coat.
Ans: (d)

• Virus : Viruses are obligate parasites. In addition to proteins, viruses also contain genetic material that could be either RNA or DNA. No virus contains both RNA and DNA. A virus is a nucleoprotein and the genetic material is infectious.
• Viroids: It lacks the protein coat that is found in viruses and hence, the name viroid.
• Prions: In modern medicine, certain infectious neurological diseases were found to be transmitted by an agent consisted of abnormally folded protein.

Q2: Which of the following statements is incorrect?       (NEET 2019)
(a) Yeasts have filamentous bodies with Iong thread-like hyphae.
(b) Morels and truffles are edible delicacies.
(c) Claviceps is a source of many alkaloid and LSD.
(d) Conidia are produced exogenously and ascospores endogenously.
Ans: (a)
Yeasts are not filamentous, they are usually oval in shape. They are not having hyphal structure.

2018

Q1: Which among the following is not a prokaryote?       (NEET 2018)
(a) Saccharomyces
(b) Mycobacterium 
(c) Nostoc
(d) Oscillatoria
Ans: (a)

• Saccharomyces are commonly known as sac fungi. All fungi are eukaryotes.
• Prokaryotes include bacteria (Mycobacterium), cyanobacteria (Nostoc and Oscillatoria), mycoplasma and archaebacteria.Also all bacteria are prokarypte.

Q2: Select the wrong statement.       (NEET 2018)
(a) Cell wall is present in members of fungi and plantae.
(b) Mushrooms belong to basidiomycetes. 
(c) Pseudopodia are locomotory and feeding structures in sporozoans.
(d) Mitochondria are the powerhouse of the cell in all kingdoms except monera.
Ans: (c)

• Cell wall is present in the member of Fungi (made up of chitin) and Plantae (made up of cellulose).
• Pseudopadia are locomotory and feeding structures in Amoeboid Protozoans.
• Mitochondria and other membrane bound cell organelles are absent in prokaryote (Monera). Mushroom, rust and smut fungus belongs to the class basidiomycetes.

Q3: After karyogamy followed by meiosis, spores are produced exogenously in ______.  (NEET 2018)
(a) Neurospora
(b) Alternaria
(c) Agaricus
(d) Saccharomyces
Ans: (c)
Karyogamy and meiosis takes place in the basidium producing four basidiospores. The basidiospores are exogenously produced on the basidium. The basidia are arranged in fruiting bodies called basidiocarps. Some common members are agaricus (mushroom).

Q4: Oxygen is not produced during photosynthesis by ______.       (NEET 2018)
(a) Green sulphur bacteria
(b) Nostoc
(c) Cycas 
(d) Chara
Ans: (a)
Green sulphur bacteria do not use H₂O as source of proton, therefore they do not evolve O₂.

Q5: Which of the following organisms are known as chief producers in the oceans?      (NEET 2018)
(a) Dinoflagellates
(b) Diatoms
(c) Cyanobacteria
(d) Euglenoids
Ans: (b)
Diatoms are the most common form of phytoplankton in the ocean. They have the pigment chlorophyll which helps in photosynthesis. Since they are the primary producers of the aquatic chain and the marine ecosystem depends on them. They are called chief producers in the oceans.

Q6: Ciliates differ from all other protozoans in:       (NEET 2018)
(a) Using flagella for locomotion.
(b) Having a contractile vacuole for removing excess water.
(c) Using pseudopodia for capturing prey.
(d) Having two types of nuclei.
Ans: (d)
Ciliates differs from other protozoans in having two types of nuclei. e.g., Paramoecium have two types of nuclei i.e. macronucleus & micronucleus.

2017

Q1: DNA replication in bacteria occurs:       (NEET 2017)
(a) Within nucleolus
(b) Prior to fission
(c) Just before transcription
(d) During the S phase
Ans: (b)
In bacteria DNA replication occurs in cytoplasm prior to fission. Prokaryotes due to their primitive nature do not show well marked S-phase.

Q2: Viroids differ from viruses in having:       (NEET 2017)
(a) DNA molecules without protein coat
(b) RNA molecules with protein coat
(c) RNA molecules without protein coat
(d) DNA molecules with protein coat
Ans: (c)
Viroids are free RNA particles that lack protein coat. They are infectious agents smaller than viruses.

Q3: Which of the following components provides a sticky character to the bacterial cell?        (NEET 2017)
(a) Nuclear membrane
(b) Plasma membrane
(c) Glycocalyx
(d) Cell wall
Ans: (c)
Glycocalyx is the outermost mucilage layer of the cell envelope which consists of non-cellulosic polysaccharides with or without proteins. It gives sticky character to the cell.

Q4: Which of the following are found in extreme saline conditions?       (NEET 2017)
(a) Eubacteria
(b) Cyanobacteria
(c) Mycobacteria
(d) Archaebacteria
Ans: (d)
Halophiles, a type of archaebacteria, usually occur in extreme saline conditions like salt pans, salt beds and salt marshes

Q5: Which among the following are the smallest living cells, known without a definite cell wall, pathogenic to plants as well as animals and can survive without oxygen?       (NEET 2017)
(a) Pseudomonas
(b) Mycoplasma
(c) Nostoc 
(d) Bacillus
Ans: (b)
Mycoplasmas are smallest, prokaryotes lacking cell wall and are pleomorphic in nature. These are pathogenic to both plants and animals.

2016

Q2: Methanogens belong to ______.       (NEET 2016 Phase 2)
(a) Eubacteria
(b) Archaebacteria
(c) Dinoflagellates
(d) Slime moulds
Ans: (b)

• Methanogens belong to archaebacteria. They include methane producing genera such as Methanobacillus and Methanothrix.
• Methanogens are obligate anaerobes found in oxygen-deficient environments, such as marshes, swamps, sludge (formed during sewage treatment) and the digestive systems of ruminants. Mostly they obtain their energy by reducing carbon dioxide and oxidising hydrogen, with the production of methane

Q3: Select the wrong statement.       (NEET 2016 Phase 2)
(a) The walls of diatoms are easily destructible.
(b) ‘Diatomaceous earth’ is formed by the cell walls of diatoms.
(c) Diatoms are chief producers in the oceans.
(d) Diatoms are microscopic and float passively in water.
Ans: (a)
Diatoms are marine or freshwater unicellular organisms which have cell walls (frustules) composed of pectin impregnated with silica and consisting of two halves, one overlapping the other. The siliceous frustules of diatoms do not decay easily.

Q4: One of the major components of the cell wall of most fungi is:       (NEET 2016 Phase 1)
(a) Cellulose
(b) Hemicellulose
(c) Chitin
(d) Peptidoglycan
Ans: (c)
Fungal cell wall contains chitin or fungal cellulose along with other polysaccharides, proteins, lipids and a number of other substances

Q5: Which of the following statements is wrong for viroids?       (NEET 2016 Phase 1)
(a) They cause infections.
(b) Their RNA is of high molecular weight.
(c) They lack a protein coat.
(d) They are smaller than viruses.
Ans: (b)

• Viroids, the smallest known pathogens, are naked, circular, single-stranded RNA molecules that do not encode protein but autonomously replicate when introduced into host plants.
• Viroids only infect plants; some cause economically important diseases of crop plants, while others appear to be benign.

Q6: Which one of the following statements is wrong?       (NEET 2016 Phase 1)
(a) Eubacteria are also called false bacteria.
(b) Phycomycetes are also called algal fungi.
(c) Cyanobacteria are also called blue-green algae.
(d) Golden algae are also called desmids.
Ans: (a)
Eubacteria are also called true bacteria

Q7: The primitive prokaryotes responsible for the production of biogas from the dung of ruminant animals include the ______.       (NEET 2016 Phase 1)
(a) Methanogens
(b) Eubacteria
(c) Halophiles
(d) Thermoacidophiles
Ans: (a)
Methanogens are microorganisms that produce methane as a metabolic byproduct in anoxic conditions. They are obligate anaerobic ancient and primitive bacteria. They are involved in methanogenesis

Q8: Chrysophytes, Euglenoids, Dinoflagellates and Slime moulds are included in the Kingdom ______.       (NEET 2016 Phase 1)
(a) Fungi
(b) Animalia
(c) Monera
(d) Protista
Ans: (d)
All unicellular eukaryotic organism like diatoms, desmids (chrysophytes), euglenoids, dinoflagellates and slime mould are included in Protista