Biology

141. Phloem tissues are mostly responsible for transport of

Phloem tissues are mostly responsible for transport of

[amp_mcq option1=”water” option2=”oxygen” option3=”minerals” option4=”food” correct=”option4″]

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The correct answer is D) food.
Plant vascular tissues consist of xylem and phloem. Xylem is primarily responsible for the transport of water and dissolved minerals from the roots to the rest of the plant. Phloem is primarily responsible for the transport of organic nutrients, mainly sugars (food) produced during photosynthesis in the leaves, to other parts of the plant where they are needed for growth or storage.
The transport of food in the phloem is called translocation and can occur in multiple directions (upwards, downwards, or sideways) depending on the source (where food is produced) and sink (where food is needed) areas. Oxygen is primarily exchanged through stomata on the leaves and lenticels on stems, not transported systemically through vascular tissue in this manner.

142. Buds produced in the notches along the leaf margin of Bryophyllum fall

Buds produced in the notches along the leaf margin of Bryophyllum fall on soil and develop into new plants. This is an example of which one of the following types of reproduction?

[amp_mcq option1=”Vegetative propagation” option2=”Budding” option3=”Spore formation” option4=”Regeneration” correct=”option1″]

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The correct answer is A) Vegetative propagation.
Vegetative propagation is a form of asexual reproduction in plants where new individuals are produced from vegetative parts of the parent plant, such as roots, stems, or leaves, rather than from seeds or spores. In Bryophyllum, adventitious buds develop in the notches along the leaf margin; these buds can detach, fall to the ground, and grow into new plants, which is a classic example of vegetative propagation via leaves.
Budding is a type of asexual reproduction, but it typically involves the formation of a bud that develops into a new individual while attached to the parent (e.g., yeast, Hydra) or as a horticultural technique (bud grafting). Spore formation is a reproductive method found in fungi, bacteria, algae, and some plants like ferns and mosses. Regeneration is the ability of an organism to regrow lost body parts.

143. Depending on the requirements, plant nutrients are classified as micro

Depending on the requirements, plant nutrients are classified as micronutrients and macronutrients. Which one of the following is an example of a macronutrient?

[amp_mcq option1=”Manganese” option2=”Copper” option3=”Magnesium” option4=”Chlorine” correct=”option3″]

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The correct answer is C) Magnesium.
Plant nutrients are classified as macronutrients or micronutrients based on the quantity required by the plant. Macronutrients are needed in relatively large amounts, while micronutrients are needed in very small amounts. The primary macronutrients are Nitrogen (N), Phosphorus (P), and Potassium (K). Secondary macronutrients include Calcium (Ca), Magnesium (Mg), and Sulfur (S). Manganese (Mn), Copper (Cu), and Chlorine (Cl) are classified as micronutrients.
Magnesium is a component of chlorophyll, essential for photosynthesis, and activates many enzymes. Its requirement by plants is relatively high compared to micronutrients.

144. One way of incorporating desired characters into crop varieties is hyb

One way of incorporating desired characters into crop varieties is hybridization. In this process, there is crossing between genetically dissimilar plants. Which one of the following crossings will not refer to hybridization?

[amp_mcq option1=”Intervarietal” option2=”Interspecific” option3=”Intergeneric” option4=”Intragenic” correct=”option4″]

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The correct answer is D) Intragenic.
Hybridization refers to the crossing of genetically dissimilar individuals to produce offspring with a combination of traits from both parents. This can occur between different varieties of the same species (intervarietal), between different species (interspecific), or even between different genera (intergeneric). Intragenic refers to genetic changes or events (like mutation or recombination) occurring within a single gene, not involving the crossing of different individuals or groups.
Hybridization is a key technique in plant and animal breeding to introduce desirable traits from one genetic background into another. Intragenic studies focus on the structure, function, and alterations of individual genes.

145. Which one of the following animals has a four-chambered heart?

Which one of the following animals has a four-chambered heart?

[amp_mcq option1=”King cobra” option2=”Turtle” option3=”Chameleon” option4=”Crocodile” correct=”option4″]

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The correct answer is D) Crocodile.
Most reptiles (snakes like King cobra, turtles, lizards like Chameleon) have a three-chambered heart with two atria and a single ventricle, often partially divided. However, crocodiles are unique among living reptiles in possessing a complete four-chambered heart, similar to birds and mammals, which allows for complete separation of oxygenated and deoxygenated blood.
The four-chambered heart in crocodiles is an evolutionary adaptation that provides more efficient circulation, particularly beneficial for their active lifestyle and diving habits.

146. Which of the following best represents the cells of a meristem of

Which of the following best represents the cells of a meristem of plant?

[amp_mcq option1=”Dense cytoplasm, thin cell wall, large nuclei and absence of vacuoles” option2=”Dense cytoplasm, thin cell wall, large nuclei and large vacuoles” option3=”Dense cytoplasm, thin cell wall, small nuclei and absence of vacuoles” option4=”Dense cytoplasm, thick cell wall, small nuclei and large vacuoles” correct=”option1″]

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The correct answer is A) Dense cytoplasm, thin cell wall, large nuclei and absence of vacuoles.
Meristematic cells are undifferentiated plant cells that are actively undergoing cell division. Characteristics of these cells include dense cytoplasm, thin primary cell walls (as they are rapidly growing and dividing), relatively large and prominent nuclei (controlling the cell cycle), and usually small or absent vacuoles, which would otherwise occupy significant volume and potentially hinder rapid division.
Mature plant cells typically have thick cell walls and a large central vacuole that can occupy up to 90% of the cell volume. Meristematic cells are found in regions of active growth, such as root tips, shoot tips, and vascular cambium.

147. Lysosomes are sacs of the cell filled with digestive enzymes. These di

Lysosomes are sacs of the cell filled with digestive enzymes. These digestive enzymes are synthesized by

[amp_mcq option1=”Golgi bodies” option2=”smooth endoplasmic reticulum” option3=”rough endoplasmic reticulum” option4=”lysosome itself” correct=”option3″]

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The correct answer is C) rough endoplasmic reticulum.
Lysosomal enzymes are hydrolytic enzymes that are proteins. Proteins destined for secretion or for inclusion in membrane-bound organelles like lysosomes are synthesized on ribosomes attached to the rough endoplasmic reticulum (RER). These proteins are then processed within the RER and subsequently transported to the Golgi apparatus for further modification and packaging into vesicles, which bud off to form lysosomes.
Golgi bodies are involved in modifying, sorting, and packaging proteins and lipids. Smooth endoplasmic reticulum (SER) is involved in lipid synthesis, detoxification, and calcium storage. Lysosomes themselves are membrane-bound organelles containing the digestive enzymes; they do not synthesize the enzymes.

148. Which of the following combinations correctly represents the genetic m

Which of the following combinations correctly represents the genetic materials in prokaryotes and eukaryotes respectively?

[amp_mcq option1=”Nucleoid and Chromatin” option2=”Chromatin and Nucleoid” option3=”Nucleoid and Nucleolus” option4=”Nucleolus and Chromatin” correct=”option1″]

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The correct answer is A) Nucleoid and Chromatin.
Prokaryotes (like bacteria) lack a membrane-bound nucleus. Their genetic material (usually a single circular chromosome) is located in a region of the cytoplasm called the nucleoid. Eukaryotes (like plants and animals) have a membrane-bound nucleus containing their genetic material, which is organized into multiple linear chromosomes composed of DNA wrapped around proteins (histones) forming a structure called chromatin.
The nucleolus is a dense structure found within the eukaryotic nucleus, involved in ribosome synthesis, not the primary form of the entire genetic material itself. Chromatin is the complex of DNA and proteins that forms chromosomes within the nucleus of eukaryotic cells.

149. The organisms that prefer high salt concentration habitats refer to as

The organisms that prefer high salt concentration habitats refer to as

[amp_mcq option1=”alkaliphiles” option2=”calcifuges” option3=”halophiles” option4=”nitrophiles” correct=”option3″]

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Organisms that thrive in environments with high concentrations of salt are specifically referred to as halophiles. These organisms have adaptations that allow them to survive in conditions that would be lethal to most other forms of life, such as salt flats, salt lakes, and curing brines.
The question asks for the scientific term for organisms that prefer high salt concentrations. Halophiles are a type of extremophile organism.
Alkaliphiles are organisms that thrive in alkaline environments (high pH). Calcifuges are plants that avoid calcium-rich soils. Nitrophiles are organisms, typically plants, that prefer environments rich in nitrogen compounds, often associated with pollution or manure.

150. Which one of the following pairs is not correctly matched?

Which one of the following pairs is not correctly matched?

[amp_mcq option1=”Positively phototropic : Shoot” option2=”Positively geotropic : Root” option3=”Chemotropic : Pollen tube” option4=”Hydrotropic : Flower” correct=”option4″]

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Tropisms are directional growth responses of plants to external stimuli. They are named based on the type of stimulus and the direction of growth (positive if towards the stimulus, negative if away).
Positively phototropic growth means growth towards light (e.g., shoots). Positively geotropic growth means growth towards gravity (e.g., roots growing downwards). Chemotropic growth is a response to chemical stimuli (e.g., pollen tube growing towards the ovule guided by chemical signals). Hydrotropic growth is a response to water (e.g., roots growing towards water). Flowers are reproductive structures whose position and development are influenced by factors like light (photoperiodism for flowering) and hormones, but ‘hydrotropism’ is not a primary or characteristic tropic response of flowers themselves. Roots exhibit positive hydrotropism.
Other types of tropism include thigmotropism (response to touch) and thermotropism (response to temperature). The statement ‘Hydrotropic : Flower’ is the incorrectly matched pair as hydrotropism is characteristic of roots.
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