Saved Bookmarks
This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.
| 2201. |
Question : What is Euchromatin? |
| Answer» Solution :The REGIONS of chromatin which are LOOSELY packed and transcriptionally active. | |
| 2202. |
Question : What is epistasis? |
| Answer» SOLUTION : The GENE that MASKS the EFFECT of other gene. | |
| 2203. |
Question : What is Energy? |
| Answer» SOLUTION :The transfer of ENERGY in an ECOSYSTEM between trophic LEVELS can be termed as energy flow. It is the key FUNCTION in an ecosystem. Energy flow is always unidirectional in an ecosystem. | |
| 2204. |
Question : What is endosperm ? Explain the types. |
Answer» Solution :Endosperm : The primary endosperm nucleus (PEN) divides IMMEDIATELY after fertilization but before the zygote starts to DIVIDE , into an endosperm . The primary endosperm nuleus is the result of triple fusion (two polar nuclei and one sperm nucleus) and thus has 3n number of chromosomes. It is nutritive tissue and regulatory structure the nourishes the developing embryo. Depending upon the mode of development three types of endosperm are recognized in angiosperms. They are nuclear endosperm cellular endosperm and helobial endosperm.  Nuclear endosperm : primary Endosperm Nucleus undergoes several mitotic division without cell wall formation thus a free nuclear condition exists in the endosperm. Examples : Coccinia , Capsella and Arachis. Cellular endosperm : Primary endosperm nucleus divides into 2 nuclei and it is immediately followed by wall formation . Subsequent divisions also follow cell wall formation. Examples : Adoxa , Helianthus and Scoparia. Helobial endosperm : Primary Endosperm Nucleus moves towards base of embryo SAC and divides into two nuclei. Cell wall formation. Helobial endosperm : Primary EndopsermNucleus moves towards base of embryo sac and divides into two nuclei. Cell wall formation TAKES place leading to the formation of a large micropylar and small chalazal chamber. The nucleus of the micropylar chamber undergoes several free nuclear division whereas that of chalazal chamber may or may not divide. Example : Hydrilla and Vallisneria. Ruminate endosperm : The endosperm with irregularity and unevenness in its surface forms ruminate ndosperm . Examples : Areca catechu, Passiflora and Myristica. |
|
| 2205. |
Question : What is endosperm? Describe endospermic and nonendo- spermic seeds. |
|
Answer» Solution :(1) The nutritive tissue formed in the embryo sac of a flowering PLANT following the fusion of a male GAMETE and the secondary nucleus of the female gametophyte is CALLED endosperm. (2) The product of this fusion, i.e., primary endosperm nucleus is therefore triploid (3n) in nature. (3) The primary endosperm nucleus divides and redivides by free nuclear DIVISION and forms a nutritive tissue, called endosperm. (4) In some seeds, for example, pea, bean, gram, groundnut, etc., the endorperm is completely utilised by the growing embryo before the development of the seed. (5) Owing to this, the cotyledons of these seeds become thick and fleshy, forming the nonendospermic seeds. (6) In seeds of castor, maize and wheat, on the other hand, the endosperm is not utilised by the developing embryo. (7) Instead, both endosperm and embryo develop simultaneously forming endospermic seeds. |
|
| 2206. |
Question : What is endosperm? Describe types of endosperm |
|
Answer» Solution :The primary endosperm cell divides repeatedly and froms a triploid endosperm tissue. The cells of this tissue are filled with reserve food materials and are used for the nutrition of the developing embryo. It has three types: Nucleated, Cellular, Hellobial. The cells of this tissue are rich with stored food and provide nutrition to developing embryo. (a) Free nuclear endosperm: It is the most common type of endosperm development, the PEN undergoes successive nuclear divisions to give rise to free nuclei. This stage of endosperm development is called free nuclear endosperm. (b) Multicellular endosperms: Nuclei are arranged in periphyery rgion and big vacuole is formed in centre of endosperm. Then division of cytoplasm starts. This process also starts from periphery and leads towards centre and muticellular endosperm comes into existence.The coconut water from tender coconut is nothing but free nuclear endosperm (made up of THOUSANDS of nuclei) and the surrounding white kernel is the cellular endosperm. Endosperm may either be COMPLETELY CONSUMED by the developing embryo (e.g pea, groundnut BEANS) before seed maturation or it may persists in the MATURE seed (e.g caster and coconut) and be used up during seed germination. |
|
| 2207. |
Question : What is endemism? |
| Answer» Solution :The SECIES which are restricted or confined to a PARTICULAR region are called endemism. | |
| 2208. |
Question : What is empirical approach and empirical law ? |
| Answer» Solution :Mendel's EXPERIMENTS were well PLANNED to dtermine the relationship which GOVERN hereditary TRAITS. This rationale is called an empirical approach. Laws that were arrived from an empirical approach is known as empirical laws (Mendel's laws of inheritance). | |
| 2209. |
Question : What is embryo? Explain structure of monocot and dicot embryo. |
|
Answer» Solution :Embryo develops at the micro pylar end of the embryo sac where the zygote is situated. Most zygotes divide only after certain amount of endosperm is formed. This is an adaptation to provide assured nutrition to the developing embryo. Though the seeds differ greatly, the early stages of embryo development are similar in both MONOCOTYLEDONS and dicotyledons. The zygote gives rise to teh proembryo and subsequently to the globular, heart shaped and mature embryo. Typical dicot embryo: A typical dicotyledonous embryo consists of an embryonal axis and TWO cotyledons, The portion of embryonal axis above the level of cotyledons is the epicotyl which terminates with the plumule or stem tip. The cylindrical portion below the level of cotyledons is hypocotyl that terminates at its lower end in the radicle or ROOT tip. The root tip is covered wiht a root CAP. Embryo of monocotyledons: Embryos of monocotyledons possess only one cotyledon. In the grass family the cotyledon is called scutellum that is situated towards one side (lateral) of the embryonal axis. At its lower end, the embryonal axis has the radical and root cap enclosed in an undifferentiated sheath called coleorrhiza. The portion of the embryonal axis above the level of attachment of scutellum is the epicotyl. Epicotyle has a shoot apex and a few leaf primordia enclosed in a hollow foliar structure the COLEOPTILE. Note: Soak a few seeds in water (say of wheat, maize, peas, chickpeas, groundnut) over night. Then split the seeds and observe the various parts of the embryo and the seed. 
|
|
| 2210. |
Question : What is embryogenesis? Mention two important events that occur during embryogenesis. |
| Answer» Solution :The PROCESS of DEVELOPMENT of an EMBRYO from the zygote. Cell DIVISION and cell differentiation. | |
| 2211. |
Question : What is emasculation ? Why and when is it done? |
| Answer» Solution :Removal of anther from a BISEXUAL flower is called EMASCULATION. It is USED to AVOID self-pollination and is used in artificial hybridisation PROGRAMME. It is done before the dehiscence of anther. | |
| 2212. |
Question : What is emasculation ? |
| Answer» SOLUTION :The REMOVAL of anthers from the floral BUD before their DEHISCENCE. | |
| 2213. |
Question : What is Eltonian pyramid? |
| Answer» SOLUTION :Eltonian PYRAMID or ECOLOGICAL pyramid is a graphic representation of the trophic STRUCTURE and function at successive trophic levels of an ecosystem. | |
| 2214. |
Question : What is electrophoresis? |
| Answer» Solution :SEPARATION of DNA fragments under an ELECTRIC field through MATRIX | |
| 2215. |
Question : Electrocardiograph / ECG |
| Answer» Solution :The instrument which is used to RECORD action potentials generated in the HEART muscles is CALLED an electrocardiograph. | |
| 2216. |
Question : What is egg apparatus? |
| Answer» SOLUTION :The egg apparatus is a three celled structure LYING at the micropylar end of the embryo SAC. | |
| 2217. |
Question :What is effect of overpopulation on per capita income? |
| Answer» SOLUTION :Per CAPITA INCOME decreases with INCREASE in human POPULATION. | |
| 2218. |
Question : What isegg apparatus ? |
| Answer» SOLUTION :thetreecellsin themicropylarendof aovuleinwhichmiddleone ISTHE eggwithtwosynergidson the eithersidecalledegg APPARATUS . | |
| 2219. |
Question : What is ecosystem services? Why it is of much importance? |
| Answer» Solution :Ecosystem services are defined as the benefits that PEOPLE derive from NATURE. Study on ecosystem services ACTS as an effective tool for gaining knowledge on ecosystem benefits and their SUSTAINED use. Without such knowledge gain, the fate of any ecosystem will be at stake and the benefits they provide to us in future will become bleak | |
| 2220. |
Question : What is an Ecosphere? |
| Answer» Solution :The LARGEST and most NEARLY self-sufficient biological system is often designated as the ECOSPHERE, which includes all the LIVING organisms of the Earth, interacting with the physical environment to regulate their distribution, abundance, production and evolution | |
| 2221. |
Question : What is ecological succession ? Explain hudrarch succesion. |
|
Answer» Solution :That occurrence of relatively definite sequence of communties over a long period of time in the same area resulting in establishment of stable or climax community is known as ecological or biotic succession. Hydrosere : It involves the ecological succession in a newly formed pond, lake (or any open water areas) and successional series progress from hydric to the mesic conditions . It involves the following ecological succession . - Pioneer stage : The pioneers are phytoplankton consisting of unicellular and colonial forms of green plants algae near the surface of water. They are followed by zooplanktons like Amoeba. Paramecium and VORTICELLA .Death and DECOMPOSITION of phytoplankton and zooplankton produce organic matter , which mixes with silt and form a soft mud which favours the growth of next stage of plants. - Submerged stage : In a pond or lje where water is less than 10 feet deep , there may be entirely submeregd and free floating plants and some submerged and rooted at the BOTTOM . e.g ., Hydrilla , vallisneria , Elodea , Ceratophyllum etc. Death and decay of these plants and dead materials sinking to the bottom and addition of sand and silt around the plants results in rise in rise of soil at the bottom . This makes at pond of lake more shallow and UNSUITABLE for the submerged species but suitable for rooted floating plants. Floating stage: It consists of rooted hydrophytes with roots , rhizome or root stock attached at the bottom of the pond. Some of these plants have their leaves spread over the surface of water while some have free floating leaves e.gNymphaea, Nelumbo , Trapa , Salvia , Azolla etc. the large leaves of many of these plants cut off light to the submerged plants. Hence with very little light it becomes of the pond or lake and the edges become more shallow (1-3 ft) - Read swamp stage : In shallow water marshlyplants like Typha, Rumes , Sagittaria invade and establish . These plants are rooted at the bottom and are partly submerged but their shoots. extend well above the water . They cut light from the floating plants and they find it less favourable. Such plants die adding the organic matter to the soil . In course of time , the edges of the pond or lake is converted into water- saturated place(marshy place) favourable for the marsh - meadow stage. - Marsh -meadow stage: (Sedge - meadow stage)Marshy edges with one or two inches of water of ponds or lakes favour the growth or members of family Cyperaceae and Gramineae such as Carex , Cyperus , Juncus ,Eleocharis, Fucus, Sedges and tall grases , forminga meadow (mat) like vgetation. Slowly the surface water driesup and develops a mesic condition in the area and the marshy vegetation dissappears gradually. - woodland stage: In the moist climate , the woodland stage consists of shrubs and small trees like salix (shrubby willows) . populus (cotton wood ) and tress willows . The pioneers of this will be those that can tolerate partial water- lodged conditions around their roots . The woody plants in the REGION cast shade and make the soil dry by their vigorous transpiration and holding the wind - brone soil and accumulating plant debris . Meneralizaton and soil formation favours the growth of herbs among the shrubs and trees . - Forest stage: It is the climax stage during course of time, in which the soil becomes rich in humus and organic matter and supports climax community . it may be tropical deciduous or monsoon or monsoon forests in regions of moderate rainfall , tropical rain forests in areas with heavy rainfall and mixed forests or Quercus (oak), Acer and Alnus in temperate regions 
|
|
| 2222. |
Question : What is ecological succession. Mention its stages. |
| Answer» Solution :The gradual and FAIRLY predictable change in the species composition of a given AREA is CALLED ecological SUCCESSION. | |
| 2223. |
Question : What is ecological succession ? Distinguish primary succession from secondary succession. |
|
Answer» Solution :The GRADUAL and fairly predictable change in the species COMPOSITION of a given area is called ecological succession. Primary Succession TAKES place in an area which was ORIGINALLY bare. Secondary Succession : takes place in a newly created bare area, which earlier had VEGETATION and animals. |
|
| 2224. |
Question : (a) What is ecological succession? |
| Answer» Solution :The GRADUAL and FAIRLY PREDICTABLE change in the species composition of a GIVEN area. | |
| 2225. |
Question : What is ecological succession? |
| Answer» Solution :The sequential GRADUAL and predictable change in the SPECIES composition in an area is CALLED ecological SUCCESSION. | |
| 2226. |
Question :What is ecological succession? Distinguish primary succession from secondary succession. |
| Answer» SOLUTION :The gradual and FAIRLY predictable CHANGE in the SPECIES composition of a GIVEN area is called ecological succession. | |
| 2227. |
Question : What is ecological hierarchy? Name the levels of ecological hierarchy. |
Answer» SOLUTION :The INTERACTION of ORGANISMS with their environment results in the establishment of GROUPING of organisms which is called ecological hierarchy. 
|
|
| 2228. |
Question : What is ecological density, crude density and population density ? |
Answer» SOLUTION :
|
|
| 2229. |
Question : What is Eco-san? |
| Answer» Solution :It is Ecological sanitation toilet which is USED in CERTAIN areas of KERALA and Sri LANKA. | |
| 2230. |
Question : What is ecological niche. |
| Answer» SOLUTION :The INTERACTION of ORGANISMS with their ENVIRONMENT RESULTS in the establishment of grouping of organisms which is called ecological hierarchy. | |
| 2231. |
Question : What is earth.s average temperature ? |
|
Answer» `15^(@)C` |
|
| 2232. |
Question : What is eclogical succession? How Hydrarch succession is different from Xerarch succession. |
|
Answer» Solution :The gradual and fairly predictable change in the species COMPOSITION of a given area is called as ecological SUCCESSION. Generally, Hydrarch succession takes PLACE in wetter areas and successional series progress from hydric to the mesic condition. Where as the XERARCH succession takes place in dry areas and the series progress from Xeric and Mesic conditions. |
|
| 2234. |
Question : What is due to evolution new and definite species are evoluted ? |
|
Answer» IDENTIFICATION of species |
|
| 2236. |
Question :What is Down.s syndrome ? Give its symptoms and cause. Why is it that the chances of having a child with Down.s syndrome increases if the age of the mother exceeds forty years ? |
| Answer» Solution : Down.s syndrome is a human genetic disorder caused due to trisomy of chromosome no. 21. Such individuals are aneuploid and have 47 chromosomes (2n + 1). The symptoms include mental retardation, growth abnormalities, constantly open mouth, dwarfness etc. The REASON for the disorder is the non-disjunction (failure to separate) of homologous chromosome of pair 21 during meiotic division in the ovum. The chances of having a child with Down.s syndrome increase with the age of the mother (+40) because ova are present in females. Since their BIRTH and THEREFORE older cells are more PRONE to chromosomal non-disjunction because of various physico-chemical exposures during the mother.s life-time. | |
| 2237. |
Question : What is downstream processing ? |
| Answer» Solution :A series of PROCESSES involved in the separation and purification of gene product before it is READY for marketing as a FINISHED product. | |
| 2238. |
Question : What is double fertilization? Describe fertilized embryo sac with a neat labelled diagram. |
|
Answer» Solution :One of the male gamete moves towards the EGG cell and fuses with the nucleus thus completing the syngamy. This leads to zygote formation which further develops into an embryo. The other male gamete move towards the two polar nuclei located in the central cell and fuses with them to produce triploid primary endosperm nucleus (PEN). Since two types of fusions, syngamy and TRIPLE fusion takes place in an embryosac the phenomenon is CALLED as double fertilization.  Fertilized embryosac exhibit degenerating synergids towards MICROPYLAR end and a fertilized egg cell called diploid zygote. Antipodals towards the chalazal end also degenerate. Central cell becomes primary endosperm cell with a triploid primary endosperm nucleus. Primary endosperm cell develops in to the endospetm by repeated mitotic division. The cells of endosperm are filled with food reserves and thereby nourish the DEVELOPING embryo. |
|
| 2239. |
Question : What is done in seed bank from the following ? |
|
Answer» Seed is stored for LONG duration. |
|
| 2240. |
Question : What is double circulation? |
|
Answer» SOLUTION :The movement of BLOOD twice through the heart during one ciruculation cycle is called double CIRCULATION. BODY `rarr` heart `rarr` lungs `rarr` heart `rarr` body is the course of double circulation. |
|
| 2241. |
Question : What is double fertilization? Descirbethe process in brief. |
|
Answer» Solution :1. Double fertilization : (1) Out of the tow male GAMETES PRODUCED by the male gametophyte in angiosplerms, one unites with the female gamete and the other with the secondary nucleus. (2) Since both the male gametes take part in fertilization and fertilizationoccurs twice, it is called double fertilization. (3) During double fertilization, the pollen tube on reaching the ovule enters the embryo sac through micropyle and bursts. (4) Owingto this , the two male gametes contained in the pollen tube, are SET free. (5) Out of the two male gametes, one unites with the egg or female gamete and other with the secondary nucleus of the embryo sac, forming a triploid or triple fusion nucleus, called the primary endosperm nucleus. (6) The process involving the fusion of one of the male gametes with the egg nucleus, resulting in the formation of a diploid zygote is called syngamy. (7) The process involving the fusion of a haploid nucleus of male gamete with the diploid secondary nucleus to form a triploid primary endosperm nucleusis called triple fusion. (8) The reproductive process in which nonmotile male nuclei ar carried to the egg cell through a pollen tube is called SIPHONOGAMY. (9) After fertilization, certain changes take place in the ovule leading to thedevelopment of a seed. (2) Significance of double fertilization : Double fertilization is of GREAT significance, for the following reasons : (1) Double fertilization leads to the formation of triploid endosperm which ensures better nourishment of the developing embryo. (2) Doublefertilization leads to the formation of an embryo whichgives rise to a new plant. (3) Double fertilization is essential for the formation of viable seeds. (4) Double fertilization restores diploid condition by the fusion of two haploid gametes. (5) Double fertilization brings about the recombination of characters. 
|
|
| 2242. |
Question : What is dominance? On with reference to the Mendelian laws of inheritance, define the term dominance. |
| Answer» Solution :A GENE or a CHARACTER expressed in heterozygous CONDITION of an organism is known as dominance. | |
| 2243. |
Question : What is done to find out the reason of allergy ? |
|
Answer» BLOOD TEST of PATIENT is done |
|
| 2244. |
Question : What is DNA replication in prokaryotes called? Why? |
| Answer» SOLUTION :DNA REPLICATION in prokaryotes is CALLED theta `(theta)` replication because this DNA is circular in shape. | |
| 2245. |
Question : What is DNA polymorphism ? Why is it important - to study it ? |
|
Answer» Solution :Polymorphism (variation at genetic level) arises due to mutations. Allelic sequence variation has traditionally been DESCRIBED as polymorphism if more than one VARIANT (ALLELE) at a locus occurs in human population with a frequency greater than 0.01. In simple terms, if an INHERITABLE mutation is observed in a DNA population at high frequency, it is referred to as DNA polymorphism. Polymorphism become very useful identification tool in forensic applications. Further, as the POLYMORPHISMS are inheritable from parents to children, DNA fingerprinting is the basis of paternity testing, in case of disputes. |
|
| 2246. |
Question : What is DNA repair. |
|
Answer» SOLUTION : (i) Genomic stability is maintained in all living organisms which is essential for their survival. (ii) DNA is unique because it is the only macromolecule where the REPAIR system exists, which recognises and removes mutations. (iii) DNA is subjected to various types of damaging reactions such as spontaneous or environmental agents or natural ENDOGENOUS threats. Such damages are corrected by repair ENZYMES and proteins, immediately after the damage has taken place. (iv) DNA repair system plays a major role in maintaining the genomic / genetic integrity of the organism. DNA repair systems protect the integrity of GENOMES from genotoxic stresses. |
|
| 2247. |
Question : What is Dobson unit? |
| Answer» Solution :TOTAL ozone. One DU is the number of MOLECULES of ozone that would be required to create a layer of pure ozone 0.01 MILLIMETRE thick at a temperature of `0^@` C and a pressure of 1 atmosphere. | |
| 2248. |
Question : What is DNA polymorphism? Mention its siguificance. |
| Answer» Solution :Usually a gene exists in two alternative FORMS, but some time a gene may exist in more than two alternative forms. This phenomenon of a gene occurring in multiple forms for a character LOCATED on the same locus in different organisms is CALLED multiple allelism or Gene polymorphism. A,B, AB, O BLOOD groups are the best examples of multiple allelism. | |
| 2249. |
Question : What is DNA fingerprinting? Mention its applications |
|
Answer» Solution :The TECHNIQUE which is used to identify the similarities of the DNA fragments of TWO individuals is called DNA fingerprinting. Applications i. It is used as a powerful sorensic tool to solve the problems of paternity, rape, murder etc. II. It is used in the diagnosis of genetic diseases. iii. It is used in the determination of phylogenetic status of animals,genetic diversities etc. |
|
| 2250. |
Question : What is DNA fingerprinting ? |
| Answer» Solution :DNA FINGERPRINTING is a TEST to IDENTIFY andevaluate the GENETICINFORMATION. | |