NEET SECTION - A [BOTANY - MCQ]

B. spraying cytokinins
Explanation:
Ageing/necrosis/senescence usually accompany with loss of chlorophyll and rapid breakdown of protein. Cytokinins increase the protein and chloroplast synthesis. Hence, ageing/necrosis/senescence problem in tissue culture is overcome by spraying cytokinin.

C. Two distinct photosystems
Explanation:
Emerson's effect was discovered by Robert Emerson in 1957. He observed that when 700 nm wavelength is used for photosynthesis then it proceeds very slowly, but when light of shorter wavelength (650 nm) is used then it proceeds very fast. It means when higher wavelength of light is simultaneously supplied with a shorter wavelengths, then rate of photosynthesis increased. So, the discovery of the Emerson effect showed the existence of two distinct reaction centres and photochemical reactions. It showed the existence of Photosystems I and II.

D. Young anthers/Testes of grasshopper
Explanation:
Meiosis takes place in reproductive organs. It results in the formation of gametes with half the normal chromosome number. Young anthers/Testes of grasshopper are the best materials to study meiosis.

A. Chromosomes will not segregate
Explanation:
Anaphase promoting complex helps in the transition of the chromosome from metaphase to anaphase. The anaphase-promoting complex attaches to the chromosomes aligned at the equator during metaphase and allows the segregation of the chromatids.

D. (i)-(C), (ii)-(A), (iii)-(D), (iv)-(B)
Explanation:
Dodo belongs to Mauritius. Quagga is an extinct subspecies of South Africa. Thylacine are a breed of wold which originally belong to Australia. Stellar is a sea cow variety which originally belonged to Europe.

B. All of these
Explanation:
Ex situ conservation means off-site conservation. It protects an endangered species of plant or animal outside its natural habitat. While ex situ conservation comprises some of the oldest and best known conservation methods, it also involves newer methods also like cryopreservation etc.

B. endemic
Explanation:
The species confined to a particular region and not found elsewhere is termed as endemic.

D. Primary treatment
Explanation:
Primary or physical treatment is the process of removal of small and large, floating and suspended solids from sewage through two processes of filtration and sedimentation.

D. All of these

C. Tertiary consumer

A. 630

A. sporozoites
Explanation:
Female Anopheles mosquito injects sporozoites (sickle-shaped) into the human body.

B. Cholera and tetanus

B. T-lymphocytes

A. DNA damage
Explanation:
Transformation of normal cells into cancerous neoplastic cells may be induced by physical, chemical or biological agents. These agents are called carcinogens. Ionising radiations like X-rays and gamma rays and non-ionizing radiations like UV rays causes DNA damage leading to neoplastic transformation.

A. Hydrophobic region
Explanation:
Typically, a protein will span the plasma membrane a number of times, with hydrophobic (water-hating) regions in the membrane and hydrophilic (water loving) regions inside the cell or outside of the cell.

A. Both Chloroplasts and Mitochondria
Explanation:
The organelle ribosomes are found in plastids (plastidoribosomes) and mitochondria (mitoribosomes)

C. Amyloplast, elaioplast, and aleuroplasts
Explanation:
Leucoplasts are colourless plastids found in endosperm, tubers, roots and other nonphotosynthetic tissues of plants. They serve various functions, for example, storage of starch, lipids, or proteins. There are three types of special leucoplasts;
i. amyloplasts which are starch containing leucoplasts, e.g., potato tuber,
ii. elaioplasts which are colourless plastids and store lipids, e.g., tube rose,
iii. aleuroplasts which are protein storing plastids, e.g., aleurone cells of maize grain, endosperm cells of castor.

A. Mutations inhibit the production of telomerase.

D. 7.5

C. Colour blindness

A .Dizygotic twins

D. Are capable of producing secondary xylem and phloem
Explanation:
The vascular bundle which has cambium are called open vascular bundles. They are found in dicot stem and root. Open vascular bundles contain an interfascicular cambium. Phloem and xylem are not in direct contact with each other in that case. Secondary growth occurs in the cambial tissues. So, open bundles produce secondary xylem and phloem in between the primary phloem and xylem. These are either collateral or bicollateral.

A. Summer
Explanation:
The activity of cambium is maximum during summer or spring, hence the wood elements are larger in size with a wide lumen.

A. Superior

D. All except (iii)
Explanation:
All statements are true except (iii).
The correct statement is given below:
A bud is present in the axil of petiole in both simple and compound leaves, but not in the axil of leaflets of the compound leaf.

A. Well developed nucellus

B. Statement (c) is incorrect.
Explanation:
Sporopollenin is one of the most resistant organic material and cannot be degraded by any enzyme known so far.

A. Thalloid
Explanation:
The plant body of a liverwort is thalloid. The thallus is dorsiventral and closely appressed to the substrate. The leafy members have tiny leaf-like appendages in two rows on the stem-like structures.

A. Rhodophyceae
Explanation:
The members of Rhodophyceae are commonly called red algae because of the predominance of the red pigment, r-phycoerythrin in their bodies.

C. Five
Explanation:
Artificial classification systems primarily relied on easily observable, superficial morphological features like leaf shape, color, and habit, often focusing heavily on vegetative characteristics or the structure of the androecium, without giving equal weightage to both vegetative and sexual features, which often led to closely related species being separated due to their reliance on a limited set of characteristics.

C. Double fertilisation
Explanation:
Double fertilisation involving two types of fusions, syngamy and triple fusion takes place in an embryo sac is an event unique to flowering plants.

D. Pomegranate

D. Seven cells and eight nuclei

A.  Pasteur
Explanation:
Pasteur was the first to propose that diseases were caused by microscopic organisms. The final proof of germ theory came when Pasteur was able to grow the anthrax bacillus in culture. Although anthrax had been isolated by Robert Koch, opponents believed that the spores he found could have been containments in his culture medium. Pasteur placed a drop of blood from a sheep dying of anthrax into a sterile culture and allowed the bacilli to grow. He repeated this process until none of the original cultures remained in the final dish. The final culture produced anthrax when injected into sheep, showing that the bacillus was responsible for the disease.

A. Convert (oxidise) ammonia or ammonium compounds into nitrates.
Explanation:
Nitrifying bacteria are chemolithotrophic organisms that include species of the genera Nitrosomonas, Nitrosococcus, Nitrobacter, and Nitrococcus. These bacteria get their energy through the oxidation of inorganic nitrogen compounds. Types include ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB).
Many species of nitrifying bacteria have complex internal membrane systems that are the location for key enzymes in nitrification: ammonia monooxygenase (which oxidizes ammonia to hydroxylamine), hydroxylamine-oxidoreductase (which oxidizes hydroxylamine to nitric oxide - which is oxidized to nitrite by a currently unidentified enzyme), and nitrite oxidoreductase (which oxidizes nitrite to nitrate).

C.  All of these
Explanation:
Lion (Panthera leo), leopard (P. pardus), jaguar (Panthera onca), snow leopard (Panthera uncia), and tiger (Panthera tigris) belong to genus Panthera.

B. Both Monographs and Flora
Explanation:
Flora contains the actual account of the habitat and distribution of plants in a given area. Monographs contain information on any one taxon. Hence, Both monographs and flora are used in the preparation of taxonomic tools which identifies and classifies plants and animals.

A. facilitate identification of unknown organisms.
Explanation:
Biological classification is the scientific arrangement of organisms in a hierarchical series of groups and sub groups on the basis of similarities and differences in their traits. It helps in building evolutionary pathways and in identifying new organisms.