Biology MCQ Quiz - Objective Question with Answer for Biology - Download Free PDF

The correct answer is 1 to 2 weeks.

Key Points

• Peels of vegetables and fruits, leftover food items, all these are called organic waste.
• Organic Waste -
  • Due to the very fast (one to two weeks) action of bacteria on such waste, it gets decomposed quickly and mixes in soil, water, and air.
  • It does not cause any kind of pollution.
  • Agricultural waste, crop plants, peels of fruits and vegetables, dry leaves and wood, feces, urine, etc. are organic waste.
  • Compost and biogas can be made from organic waste.

Additional Information

• ​Non-organic wastes -
  • Bacterial action on such waste is slow.
  • Some substances take hundreds of years to decompose, such as glass, plastic, polythene, etc.
  • These substances remain in the environment for a long time and produce toxic substances in the environment.

The correct answer is Sanctuary.

• The boundaries in biosphere reserves and national park are defined by legislation.
• Whereas the boundaries of wildlife sanctuaries are not demarcated by the authorities.

Wildlife Sanctuary:

• This is a conservation area dedicated to the conservation of a particular species.
• In wildlife sanctuaries, human activities such as grazing, cutting of trees, timber collection etc is allowed.
• The state governments are authorised to notify a forest area as a wildlife sanctuary.

National Parks:

• The conservation scope of national parks is wider than that of wildlife sanctuaries.
• The national parks aim to conserve biotic as well as abiotic components of a landscape.
• Human activities are not permitted in the core area of national parks but limited activities like tourism are allowed outside the core area.
• The state government can notify a wildlife sanctuary or other reserve forest as a national park under the Wildlife Protection Act 1972.

Biosphere Reserve:

• Biosphere reserves are the largest conservation areas and may comprise of more than one national parks and wildlife sanctuaries.
• The biosphere reserves are notified by the central government under UNESCO's Man and Biosphere (MAB) programme.
• A biosphere reserve has a Core Area, a Buffer Zone and a Transition Zone.
• Human activities are strictly prohibited in the core area, in buffer zone activities like tourism, research and grazing can be carried out.
• In the transition zone, human settlements are also allowed. 

The correct answer is 'Water vapor, carbon dioxide, methane, nitrous oxide, ozone'.

Key Points

Greenhouse Gases

• Greenhouse gases are responsible for the greenhouse effect.
• These gases absorb and emit energy within the thermal infrared range.
• The primary greenhouse gases include carbon dioxide, methane, ozone, and water vapors.
• While the secondary greenhouses are Sulfur dioxide as well as nitrous oxides.
• The vibrations of any gas molecule such as oxygen tend to be invisible to the electromagnetic field.
• It does not absorb infrared light, in other words, it is not infrared active.
• Hence, oxygen is not a greenhouse gas as it is transparent to infrared light.

The correct answer is All of the above.

Key Points

• Several factors can contribute to the spread of a wildfire, including wind, topography, and humidity. Wind can spread the fire by carrying embers and heat to new areas, while topography, such as hills or canyons, can create natural wind tunnels that accelerate the spread of the fire. Low humidity can cause vegetation to dry out, making it more combustible and easier to ignite.
• High atmospheric temperatures and dryness (low humidity) offer favorable circumstances for a fire to start.
• In a natural setting, such as a forest, grassland, brushland, or tundra, any uncontrolled and non-prescribed combustion or burning of plants that consume the available fuels and spreads as a result of environmental factors (such as wind, and topography) is known as a bushfire, vegetation fire, or wildfire.
• For a wildfire to start and spread, the following three factors must be true: a source of heat, fuel, and oxygen.

Additional Information 

Types of Forest Fire:

There are three basic types of wildfires:

• Crown fires burn trees up their entire length to the top. These are the most intense and dangerous wildland fires.
• Surface fires burn only surface litter and duff. These are the easiest fires to put out and cause the least damage to the forest.
• Ground fires (sometimes called underground or subsurface fires) occur in deep accumulations of humus, peat, and similar dead vegetation that become dry enough to burn. These fires move very slowly but can become difficult to fully put out, or suppress.

Environmental protection refers to the practice of safeguarding the natural environment and its resources from degradation, pollution, overexploitation, and other detrimental impacts caused by human activities.

Key Points

•  The goal is to ensure the sustainable use of natural resources, preserve biodiversity, and maintain the overall health and balance of ecosystems.
• Environmental protection involves adopting measures to minimize pollution, conserve energy, manage waste responsibly, protect endangered species, and promote sustainable practices in industries, agriculture, and daily life.
• It also emphasizes the importance of environmental awareness, education, and policies to address global challenges like climate change and loss of biodiversity.

The correct answer is Male gamete.

Key Points

• Sperm or spermatozoa is a gamete (sex cell) produced in the male reproductive system.
• It is a mobile cell with one goal - to fertilize a female egg.
• Each sperm contains the entire genome of the male that produced it.
• Combined with the female genome contained in the egg, a zygote is formed - a single pluripotent stem cell containing the fused male and female genomes.
• Sperm cells were first described in the late 17th century by Antonie van Leeuwenhoek.

Additional Information

• Isogamete:
  • Isogamete is a gamete that is similar in shape, size, and behavior to another gamete with which it can produce a zygote.
  • They are also known as homogametes.
• Female gamete:
  • Female gametes are produced in the ovary. It is called an egg or egg.
  • Each month, the female produces one egg during her menstrual cycle.
• Gamete:
  • A gamete is a haploid cell that fuses with another haploid cell during fertilization in sexually reproducing organisms.
  • Gametes are reproductive cells of an organism, also known as sex cells.

Concept:

• Thermoregulation is the mechanism by which some animals like mammals maintain their core body temperature irrespective of the changing environmental temperature.
• Based on whether an animal can maintain their body temperature or not they are divided into two: Homeotherm and Poikilotherms.

1. Homeotherm: An animal that can maintain constant internal body temperature. Birds and mammals are homeotherms.
2. Poikilotherm: An animal that cannot maintain a constant internal body temperature. The internal temperature in these animals varies generally with the varying environmental temperatures. Amphibians and reptiles are poikilotherms.

Explanation:

• Frogs are poikilotherms i.e. they cannot maintain a constant body temperature.
• Their body temperature fluctuates with that of the environment.
• During winters, the frog's body temperature becomes too low. As a result of which all the body activities of the frog get ceased and it becomes sluggish.
• Similarly during summers, due to high temperatures again the body's activities cease and the animal becomes sluggish.
• To avoid such harsh environmental conditions, frogs undergo special adaptations that enable them to survive in unfavorable conditions.
• Hibernation and Aestivation are the two adaptations taken up by the frog to avoid unfavorable conditions.

HIBERNATION:

• Hibernation is also known as winter sleep.
• During winters, frogs dig deep down into damp earth at the bottom of the ponds and rest there.
• During hibernation, lung breathing is stopped in the frog.
• The skin continues breathing which suffices the oxygen requirement of the frog during hibernation.

AESTIVATION:

• Aestivation is also known as summer sleep.
• Just like in hibernation, during aestivation too frogs burrow themselves into the damp earth.
• On the arrival of the rainy season, the animal resumes its normal body activities.

So from the above-given information, the correct answer is option 4 (Skin only).

Additional Information

•  Ectotherm: Ectotherms rely on the external environment to regulate their body temperature. These are also called cold-blooded animals. Poikilotherms are regarded as ectotherms.
• Endotherm: Endotherms are animals that maintain their own body temperature through metabolic activities. These are also called warm-blooded animals. Homeotherms are regarded as endotherms.

The correct answer is autotrophic nutrition.Key Points

• Autotrophic nutrition is the mode of nutrition in which organisms make their food themselves from simple substances.
• The process of autotrophic nutrition involves the use of light energy (in photosynthesis) or chemical energy (in chemosynthesis) to produce organic compounds.
• Autotrophs are organisms that carry out autotrophic nutrition, such as plants, algae, and some bacteria.

Additional Information

• Heterotrophic nutrition is the mode of nutrition in which organisms obtain their food by consuming other organisms or organic matter.
• Saprotrophic nutrition is a type of heterotrophic nutrition in which organisms obtain their food by decomposing dead organic matter.
• Phototrophic nutrition is a subcategory of autotrophic nutrition, in which organisms use light energy to produce their own food.

The correct answer is i - b, ii - c, iii - d, iv - a.

Key Points

The trophic levels represent the hierarchical levels in an ecological food chain, indicating the position of organisms based on their feeding relationships. Here's the explanation for the correct match:

• First trophic level - phytoplankton:
  • The first trophic level typically consists of primary producers that convert sunlight into energy through photosynthesis.
  • Phytoplankton are microscopic plants that form the base of aquatic food chains.
• Second trophic level - zooplankton:
  • The second trophic level comprises primary consumers that feed on the primary producers.
  • Zooplankton, which includes tiny animals, consume phytoplankton, placing them at the second trophic level.
• Third trophic level - fishes:
  • The third trophic level involves secondary consumers that feed on primary consumers.
  • In aquatic ecosystems, fishes are often positioned at the third trophic level as they consume zooplankton or other smaller organisms.
• Fourth trophic level - human:
  • The fourth trophic level represents tertiary consumers, which are higher-order predators.
  • Humans, being omnivores or carnivores, are often placed at the fourth trophic level in food chains when they consume animals from lower trophic levels.​ 

The correct answer is a - iv, b - iii, c - ii, d - i.

Key Points

• Blue-green Algae (Cyanobacteria)
  • Blue-green algae are actually bacteria and are also known as Cyanobacteria.
  • They are photosynthetic organisms and can live in a wide variety of environments, including freshwater, seawater, damp soil, or rocks.
  • Cyanobacteria are known for their significant contribution to the Earth's oxygen atmosphere.
  • They can exist as single cells or can form colonies.
• Red Algae (Rhodophyta)
  • Red algae, often called Rhodophyta, have been identified as one of the oldest groups of eukaryotic algae.
  • They are mostly found in the warmer waters of the ocean.
  • Red algae are of great economic value because of their use in the production of agar and carrageenan, substances used as thickening agents in various food products.
  • Their red colour is due to the pigment, phycoerythrin.
• Green Algae (Chlamydomonas)
  • Green algae are a diverse group of algae from which plants evolved. Chlamydomonas is a genus of unicellular green algae.
  • Chlamydomonas species are widely distributed worldwide and are found in soil and freshwater.
  • They have two flagella that allow them to move.
  • They are known for their green colour due to the presence of chlorophyll.
• Brown Algae (Sargassum)
  • Brown algae are the most complex type of algae; many are seaweeds.
  • Sargassum is a brown algae, known for forming massive floating forests in the ocean.
  • It is primarily marine and is found in warm-temperate and tropical oceans.
  • They provide important ecological functions such as providing habitats for a wide variety of marine species.
  • The brown colour is due to the presence of a pigment called fucoxanthin, which masks the green colour of chlorophyll.

Concept: 

• Fruit refers to a mature or ripened ovary, developed after fertilization.
• The fruit consists of a wall or pericarp and seeds.
• When the pericarp is thick and fleshy, it is differentiated into the outer epicarp, the middle mesocarp, and the inner endocarp. 

Explanation:

• Fruit is said to be false fruit when the fruit is formed from the other parts of the flower as well as the ovary like the receptacle (base), the perianth, thalamus, inflorescence, or calyx.

• Examples of such fruits are strawberries, pineapple, mulberry, apples, pears, etc.

• The given figure is of a false fruit.

• False fruit develops from other floral parts and the thalamus along with the development of the ovary wall.

• Therefore, the correct answer is option 4.

Additional Information If the fruit is formed without fertilization of the ovary, it is called a parthenocarpic fruit.

The correct answer is Collar cells.

 Key Points

• The body of sponges (poriferans) has several minute pores called ostia through which the water enters into the central cavity, spongocoel.
• The flagellated cells called choanocytes (collar cells) line the spongocoel.
• These cells generate a flow of water and the water current helps in food gathering, respiratory exchange and removal of waste.
• The water finally goes out of the body through a large pore called osculum. (Plural: oscula).
• The body wall of the sponge is composed of two layers: outer pinacoderm and inner choanoderm. In between these two layers, mesenchyme is present with various mesenchymal cells.

Additional Information

• Somatic cells make up the connective tissue, skin, blood, bones and internal organs.
• White blood cells are made in the bone marrow. They are stored in your blood and lymph tissues.
• These sex cells are also called reproductive cells or gametes. Sperm cells are produced in men's testicles and egg cells are produced in women's ovaries

The correct answer is Rhodophyceae.Key Points

• Red algae:-
  • It is a type of marine algae that are predominantly red in color due to the presence of pigments such as phycoerythrins and phycocyanins.
  • They are found in both tropical and temperate waters and play an important role in marine ecosystems as primary producers and as a food source for herbivorous marine animals.
  • Some species of red algae are also used by humans for various purposes such as food, medicine, and cosmetics.
  • Red algae are known for their ability to survive in extreme environments such as deep-sea hydrothermal vents and polar regions.

Additional Information

• Chlorophyceae:
  • This is a class of green algae that are mostly freshwater species and are commonly found in ponds, lakes, and streams.
• Liverwort:
  • This is a type of non-vascular plant that grows in damp habitats such as forests, bogs, and riverbanks.
  • They are commonly found in temperate and tropical regions and play an important role in soil formation and nutrient cycling.
• Phaeophyceae:
  • This is a class of brown algae that are predominantly marine and are commonly found in temperate and cold waters.
  • They are important primary producers in coastal ecosystems and are also used by humans for food and other purposes.

The correct answer is i - b, ii - a, iii - c, iv - d

Key Points

• The cell physically expands, duplicates organelles, and creates the molecular building blocks it will require in subsequent stages during G1phase, also known as the first gap phase.
• The cell creates a full copy of the DNA in its nucleus during the S phase. Moreover, it makes duplicates of the centrosome, a structure that organises microtubules. During M phase, the centrosomes aid in the separation of DNA.
• The second gap phase, also known as the G2 phase, is a time of increased cell growth, protein and organelle production, and content reorganisation in preparation for mitosis.
• The cell's nuclear DNA condenses into its visible chromosomes during mitosis and is separated by the mitotic spindle, a specialised microtubule-based structure.

Additional Information

•  Stages of the cell cycle
  • ​A cell must grow, replicate its genetic material (DNA), and physically split into two daughter cells before it may divide.
  • The cell cycle is a structured, predictable series of actions that cells take to complete these goals.
  • Because the two daughter cells can restart the entire process from the beginning after each cycle, the cell cycle is a cycle rather than a linear pathway.

The correct answer is Ground tissue.

• The term cortex refers to the outermost layer of a structure.
• In the brain, the cortex most often refers to the cerebral cortex, although the cerebellum also has an outer layer called the cerebellar cortex.
• The three types of ground tissue: parenchyma, collenchyma, and sclerenchyma.
  • A function included photosynthesis, storage, regeneration, support, and protection.

Important Points

Additional Information