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InterviewSolution
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.
| 2001. |
List the events which occurs during following stages. 1) zygotene 2) pachytene 3) Anaphase -I |
| Answer» ZygoteneThe zygotene stage, otherwise called zygonema, from Greek words signifying "matched threads", happens as the chromosomes approximately line up with one another into homologous chromosome pairs. In some organisms, this is known as the bouquet stage as a result of the manner in which the telomeres bouquet toward one side of the core. At this stage, the synapsis of homologous chromosomes happens, encouraged by gathering of the central component of the synaptonemal complex. Pairing is achieved in a zipper-like style and may begin at the centromere (pro-centric), at the chromosome ends (terminal), or at some other portion. Individuals of a pair are equivalent long and in the position of the centromere. Therefore, pairing is very specific and definite. The paired chromosomes are known as bivalent or quadruplicate chromosomes.\xa0PachyteneThe pachytene stage, otherwise called pachynema, from Greek words signifying "thick threads". At this point, a quadruplicate of the chromosomes has framed known as a bivalent. This is the phase when homologous recombination, including chromosomal hybrid (traverse), happens. At this stage, the Non-sister chromatids of homologous chromosomes may exchange segments over regions of homology.\xa0\xa0\xa0Anaphase IKinetochore microtubules become short, pulling homologous chromosomes (which comprise of a couple of sister chromatids) to opposite poles. Nonkinetochore microtubules extend, pushing the centrosomes separated apart. The cell stretches for division down the center. Unlike in mitosis, just the cohesin from the chromosome arms is degraded while the cohesin encompassing the centromere stays secured. This enables the sister chromatids to stay together while homologs are segregated.\xa0 | |
| 2002. |
Differentiated between metaphase of mitosis and metaphase -I of meiosis. |
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Answer» Metaphase I of meiosis...The pair of chromosomes become arranged on the metaphase plate and are attached to the (now) fully formed meiotic spindle.. Metaphase of mitosis.. It is the third phase of mitosis in which duplicated genetic material (carried in the nucleus of a cell) is separated into 2 identical daughter cells.. |
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| 2003. |
Give the composition of mitotic appratus. |
| Answer» he\xa0mitotic\xa0apparatus\xa0consists\xa0of\xa0centrioles\xa0with\xa0the\xa0centre-spheres\xa0surrounding\xa0them,\xa0a\xa0cell\xa0division\xa0spindle\xa0with\xa0a\xa0system\xa0of\xa0microtubules,\xa0and\xa0an\xa0intermediate\xa0substance.\xa0Depending\xa0on\xa0the\xa0degree\xa0of\xa0development\xa0of\xa0astral\xa0rays\xa0around\xa0the\xa0centre-sphere,\xa0the\xa0mitotic\xa0apparatus\xa0is\xa0classified\xa0as\xa0astral\xa0(characteristic\xa0of\xa0most\xa0animal\xa0cells)\xa0or\xa0anastral\xa0(characteristic\xa0of\xa0plant\xa0cells).\xa0The\xa0mitotic\xa0apparatus\xa0is\xa0formed\xa0from\xa0macromolecules\xa0present\xa0in\xa0the\xa0interphase\xa0cell\xa0and\xa0from\xa0material\xa0synthesized\xa0before\xa0division.\xa0Its\xa0main\xa0components\xa0are\xa0ribonucleoproteins\xa0(about\xa090\xa0percent\xa0proteins\xa0and\xa06\xa0percent\xa0ribonucleic\xa0acid\xa0[RNA]).\xa0It\xa0also\xa0contains\xa0polysaccharides,\xa0lipids,\xa0and\xa0adenosine\xa0triphosphatase. | |
| 2004. |
Stage two benifits of mitosis. |
| Answer» \tGenetic stability-\xa0Mitosis helps in the splitting of chromosomes during cell division and generates two new daughter cells. Therefore the chromosomes form from the parent chromosomes by copying the exact DNA. Therefore, the daughter cells formed as genetically uniform and identical to the parent as well as to each other. Thus mitosis helps in preserving and maintaining the genetic stability of a particular population.\tGrowth-\xa0Mitosis help in increasing the number of cells in a living organism thereby playing a significant role in the growth of a living organism. | |
| 2005. |
Define synaptinemal complex. Give its significance. |
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Answer» |
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| 2006. |
Enlist the peculiar events which occur during s-phase and G2-phase of interphase. |
| Answer» S phase – It is the stage during which DNA synthesis occurs. In this phase, the amount of DNA (per cell) doubles, but the chromosome number remains the same.G2\u200b\xa0phase – In this phase, the cell continues to grow and prepares itself for the division. The proteins and RNA required for mitosis are synthesised during this stage. | |
| 2007. |
Give an account of chromosomes and it\'s types. |
| Answer» Chromosomes are thread-like structures present in the nucleus, which carries genetic information from one generation to another. They play a vital role in cell division, heredity, variation, mutation, repair and regeneration.Based on the number of centromeres present\tMonocentric:\xa0having only one centromere\tHolocentric:\xa0having diffused centromere and microtubules are attached along the length of a chromosome\tAcentric:\xa0chromosome may break and fuse together to form a chromosome without a centromere. It cannot attach to the mitotic spindle\tDicentric:\xa0chromosomal aberration where chromosomes break and fuse together with two centromeres. They are also unstable as two centromeres tend to migrate to opposite poles resulting in fragmentation | |
| 2008. |
What is meant by endomembrane system explain it\'s types. |
| Answer» The Endomembrane system is a membranous component of the eukaryotic cell. The cytoplasm of the cell contains a system of membranous organelles that are suspended in it. The organelles are termed as a system even though they have different structures and functions as they are essential to the working of the cell. All these organelles work in coordination and they include the cell membrane,\xa0vacuoles, the nuclear membrane, lysosomes, Golgi complex,\xa0vesicles and the endoplasmic reticulum (ER).\xa0 | |
| 2009. |
Describe the cell membrane structure and it\'s functions. |
| Answer» The cell membrane is also known as the plasma membrane. It is the outermost covering of animal cells. It is a semi-permeable membrane composed of lipids and\xa0proteins. The main functions of the cell membrane include:\t\tProtecting the integrity of the interior cell.\t\t\tProviding support and maintaining the shape of the cell.\t\t\tHelps in\xa0regulating cell growth through the balance of endocytosis and\xa0exocytosis.\t\t\tThe cell membrane also plays an important role in\xa0cell signalling\xa0and communication.\t\t\tIt acts as a selectively permeable membrane by allowing the entry of only selected substances into the cell.\t | |
| 2010. |
Discuss the cell envelope and it\'s modification in prokaryotic cell. |
| Answer» Prokaryotic cell envelope possess chemically complex cell envelope. The cell envelope comprises of three layers: the outermost glycocalyx, the cell wall and the plasma membrane. All the three layers together act as a single protective unit.Bacteria is classified into two groups based on the response to the gram staining method −Gram positive:- Cells that take up the gram stain and are stained dark blue or purple.Gram negative:- Cells that do not take up the gram stain and are stained pink or light red.If glycocalyx is present as a loose sheath it is called slime layer. At times glycocalyx is present as thick and tough layer then it is called capsule.The cell wall determines the shape of the cell and also provides structural support to the cell. The plasma membrane is semi-permeable in nature.A special membranous structure called mesosome is formed by the extensions of plasma membrane into the cell.Bacteria may be motile or non-motile based on the presence of thin filamentous extensions called flagella. Flagella helps in motility. Bacterial flagella are composed of three parts −1.Filament2.Hook3.Basal BodyPili are elongated structures made up of pilin proteins. Fimbriae are small bristle like fibres which mostly help in attachment of the bacteria to different surfaces. | |
| 2011. |
Describe the features of prokaryotic cell. |
| Answer» Prokaryotic cells have different characteristic features. The characteristics of the prokaryotic cells are mentioned below.\t\tThey lack a nuclear membrane.\t\t\tMitochondria, Golgi bodies, chloroplast, and lysosomes are absent.\t\t\tThe genetic material is present on a single chromosome.\t\t\tThe histone proteins, the important constituents of eukaryotic chromosomes, are lacking in them.\t\t\tThe cell wall is made up of carbohydrates and amino acids.\t\t\tThe plasma membrane acts as the mitochondrial membrane carrying respiratory enzymes.\t\t\tThey divide asexually by binary fission. The sexual mode of reproduction involves conjugation.\t | |
| 2012. |
Write a detailed note on cell theory and it\'s developmental history. |
| Answer» CELL THEORY\tSchleiden and Schwann together formulated the cell theory.\tRudolf Virchow (1855) first explained that cells divided and new cells are formed from pre-existing cells.\tCell theory states that\tAll living organisms are composed of cells and products of cells.\tAll cells arise from pre-existing cells. | |
| 2013. |
Diffusion of gases occurs in alveolar region not in other parts.why? |
| Answer» Each alveolus is made up of highly-permeable and thin layers of squamous epithelial cells. Similarly, the blood capillaries have layers of squamous epithelial cells. Oxygen-rich air enters the body through the nose and reaches the alveoli. The deoxygenated (carbon dioxide-rich) blood from the body is brought to the heart by the veins. The heart pumps it to the lungs for oxygenation. The exchange of O2 and CO2 takes place between the blood capillaries surrounding the alveoli and the gases present in the alveoli.Thus, the alveoli are the sites for gaseous exchange. The exchange of gases takes place by simple diffusion because of pressure or concentration differences. The barrier between the alveoli and the capillaries is thin and the diffusion of gases takes place from higher partial pressure to lower partial pressure. The venous blood that reaches the alveoli has lower partial pressure of O2 and higher partial pressure of CO2 as compared to alveolar air. Hence, oxygen diffuses into blood. Simultaneously, carbon dioxide diffuses out of blood and into the alveoli. | |
| 2014. |
Diffusion of gases occurs in alveolar region not in other parts .why? |
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Answer» Each alveolus is made up of highly-permeable and thin layers of squamous epithelial cells. Similarly, the blood capillaries have layers of squamous epithelial cells. Oxygen-rich air enters the body through the nose and reaches the alveoli. The deoxygenated (carbon dioxide-rich) blood from the body is brought to the heart by the veins. The heart pumps it to the lungs for oxygenation. The exchange of O2 and CO2 takes place between the blood capillaries surrounding the alveoli and the gases present in the alveoli.Thus, the alveoli are the sites for gaseous exchange. The exchange of gases takes place by simple diffusion because of pressure or concentration differences. The barrier between the alveoli and the capillaries is thin and the diffusion of gases takes place from higher partial pressure to lower partial pressure. The venous blood that reaches the alveoli has lower partial pressure of O2 and higher partial pressure of CO2 as compared to alveolar air. Hence, oxygen diffuses into blood. Simultaneously, carbon dioxide diffuses out of blood and into the alveoli. I don knw the answer |
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| 2015. |
Q.A person in comma is considered as dead or alive? |
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Answer» Alive Mentally dead but physically alive Explanation:-Someone who is in a coma is unconscious and will not respond to voices, other sounds, or any sort of activity going on nearby. The person is still alive, but the\xa0brain is functioning at its lowest stage of alertness. You can\'t shake and wake up someone who is in a coma like you can someone who has just fallen asleep Alive |
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| 2016. |
Who is the father of taxonomy ?¿ |
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Answer» Carlvan linneaus Father of biology Carolus Linnaeus, who gave an organism classification, named as \'father of taxonomy\'. |
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| 2017. |
How to write the anatomy of earthworm in short?...? |
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Answer» Okk... Thanks ? Anatomy of EarthwormExternally, a thin non-cellular cuticle covers the body wall of the earthworm. Underneath this cuticle, a layer of the epidermis, followed by two muscle layers and coelomic epithelium (inner layer) is sheathed. The epithelium consists of a single layer of glandular columnar epithelium. |
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| 2018. |
What is rectal papilla? |
| Answer» **** papilla: A skin tag that projects up from the junction between the skin and the inside lining of the ****.\xa0**** papillae\xa0tend to occur with\xa0****\xa0fissures and may be detected on a digital examination of the **** or with a scope. Removal is only necessary if the\xa0**** papillae\xa0are causing symptoms.\xa0**** papillae\xa0are acquired structures that arise from the base of the\xa0rectal\xa0columns of Morgagni at the dentate line. Hypertrophied\xa0**** papillae\xa0are essentially skin tags that pro- ject up from the dentate line or from the junction between the skin and the epithelial lining of the ****.\xa0 | |
| 2019. |
"Blood tissue is a connective tissue". Justify. |
| Answer» Connective tissue is a major supporting tissue in the body that provides structural framework and support to different tissues. Blood is regarded as a connective tissue because as the blood is circulated throughout the body due to pumping action of heart, it carries different materials and gases from one part of the body to another. Hence, it connects different tissues and organs of the body and thus, called as a connective tissue. | |
| 2020. |
Write a detailed note on nervous tissues. |
| Answer» Nervous or the nerve tissue is the main tissue of our nervous system. It monitors and regulates the functions of the body. Nervous tissue consists of two cells: nerve cells or\xa0neurons\xa0and glial cells, which helps transmit nerve impulses and also provides nutrients to neurons. Brain, Spinal Cord, and nerves are composed of nervous tissue, they are specialized for being stimulated to transmit stimulus from one to another part of the body rapidly.Structure Of Nervous Tissue\tIt is made of nerve cells or neurons, all of which consists of an axon. Axons are long stem-like projections emerging out of the cell, responsible for communicating with other cells called the Target cells, thereby passing impulses\tThe main part is the cell body which contains the nucleus, cytoplasm and cell organelles. Extensions of the cell membrane are referred to as processes.\tDendrite is a highly branched processes, responsible for receiving information from other neurons and synapses (specialized point of contact). Information of other neurons is provided by dendrites to connect with its cell body.\tInformation in a neuron is unidirectional as it passes through neurons from dendrites, across the cell body down the axon. | |
| 2021. |
Define muscular tissue.Describe it\'s types and features. |
| Answer» Muscular tissue is a specialized tissue in animals which applies forces to different parts of the body by contraction. It is made up of thin and elongated cells called muscle fibers. It controls the movement of an organism.The cytoplasm in the muscle fibers is called sarcoplasm. It contains a network of membrane called the sarcoplasmic reticulum. The membrane surrounding the muscle fibers is called sarcolemma.Properties of Muscular Tissue\t\tContractibility– It is the ability of muscle cells to shorten forcefully.\t\t\tExtensibility– A muscle has the ability to be stretched.\t\t\tElasticity– The muscles have the ability to recoil back to its original length after being stretched.\t\t\tExcitability– The muscle tissue responds to a stimulus delivered from a motor neuron or hormone.\tTypes of Muscular TissueThe muscular tissue is of three types:\t\tSkeletal Muscle Tissue\t\t\tSmooth Muscle Tissue\t\t\tCardiac Muscle Tissue\t | |
| 2022. |
What is glandular epithelium? Describe it\'s types and mention it\'s significance. |
| Answer» \tGlandular epithelium is a type of epithelial tissue which covers the glands (both exocrine and endocrine) of our body.\xa0Their main function is secretion.\xa0Both endocrine and exocrine glands produce their secretions through the glandular epithelium via special cells called goblet cells.\xa0\tGlandular epithelium in the reproductive tract is called endocervical glandular epithelium and helps in sexual functions by secreting lubricating fluid during sexual excitation.\t\xa0The glandular\xa0epithelium also lines the intestine where it helps in the absorption of nutrients. Thus it aids in digestion.\xa0Thus glandular epithelium is a multifunctional tissue that combines with other tissues to perform vital functions of the body. | |
| 2023. |
What is epithelial tissues? Explain and it\'s types. |
| Answer» \tTYPES OF TISSUES\xa0STRUCTURE\xa0FUNCTIONEXAMPLE\xa0Simple SquamousIt forms a single layer of flat cells which is in contact with the basal lamina.It helps in the filtration or diffusion of molecules.Lining of Bowman\'s capsuleSimple CuboidalIt forms a single thick layer and is made of cube-shaped cells.\xa0It helps in secretions.Lines the salivary glandsSimple Columnar\xa0It forms a uni-layered, elongated shaped cells.It helps in the secretion of digestive fluids and absorbs nutrients.Lining layer of intestinal mucosa\xa0Pseudostratified\xa0It appears 2-3 layered (but in actual it is single layered).It helps in removing mucus.Lines the respiratory tracts\xa0Stratified SquamousIt consists of squamous (flattened) epithelial cells arranged in layers over a basal membrane.\xa0It forms a protective layer, block diffusion/microbes.\xa0Epidermis of skinTransitionalThe shape of the surface cells changes/ transition depending on the degree of stretch.It allows considerable stretching.Lining of the urinary bladder\t | |
| 2024. |
What is the full form of ICBN and ICZN ? |
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Answer» 1. ICBN: International code of Botanical nomenclature. 2.ICZN: International code of Zoological Nomenclature 1.\xa0ICBN: International Code of Nomenclature of Bacteria2. ICZN: International Code of Zoological Nomenclature. |
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| 2025. |
Which cell division keeps genetic homogeneity? |
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Answer» Mitosis keeps genetic homogeneity Gene cell |
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| 2026. |
Define crossing over? |
| Answer» Crossing over\xa0is the swapping of genetic material that occurs in the germ line. During the formation of egg and sperm cells, also known as meiosis, paired chromosomes from each parent align so that similar DNA sequences from the paired chromosomes cross\xa0over\xa0one another.\xa0Crossing over occurs\xa0between prophase I and metaphase I and is the process where two homologous non-sister chromatids pair up with each other and exchange different segments of genetic material to form two recombinant chromosome sister chromatids. | |
| 2027. |
Why is interphase also called preparatory phase? |
| Answer» Interphase is also called preparatory phase because during this phase of cell cycle, cell prepares for division by undergoing cell growth and DNA replication. | |
| 2028. |
Describe the events taking place during interphase. |
| Answer» The events taking place during the interphase are G1 phase,GO phase and S phase | |
| 2029. |
Why is mitosis calles equational divisions? |
| Answer» Mitosis\xa0is the process of\xa0cell division\xa0wherein the chromosomes replicate and gets equally distributed into two daughter cells. The chromosome number in each daughter cell is equal to that in the parent cell, i.e., diploid. Hence,\xa0mitosis\xa0is\xa0known as equational division.\xa0Mitosis\xa0produces 2 diploid cells. The old name for\xa0meiosis\xa0was\xa0reduction/\xa0division.\xa0Meiosis\xa0I reduces the ploidy level from 2n to n (reduction) while\xa0Meiosis\xa0II divides the remaining set of chromosomes in a\xa0mitosis-like process (division). | |
| 2030. |
Distinguish between karyokinesis and cytokinesis. |
| Answer» Karyokinesis\xa0is defined as the division of the nucleus during the M phase of the cell cycle. ... The daughter chromosome is separated into two daughter nuclei.\xa0Cytokinesis, on the other hand, is defined as the division of the cytoplasm during the M phase of the cell cycle.\xa0Karyokinesis\xa0is followed by the\xa0cytokinesis\xa0in the mitotic division. In\xa0plant\xa0cells, the cytoplasm of the parent cell is divided by the formation of a cell plate in the middle of the parent cell. In\xa0animal\xa0cells, a cleavage furrow is formed by the plasma membrane, separating the two daughter cells. | |
| 2031. |
What are examples of thallose liverworts and leafy liverworts? |
| Answer» Liverworts\tThe liverworts grow usually in moist, shady habitats.\tThe plant body of a liverwort is thalloid, the thallus is dorsiventral and closely appressed to the substrate.\tAsexual reproduction in liverworts takes place by fragmentation of thalli, or by the formation of specialized structures called\tGemmae are green, multicellular, asexual buds, which develop in small receptacles called\xa0gemma cups\xa0located on the thalli.\tThe sporophyte is differentiated into a foot, seta, and capsule.\tAfter meiosis, spores are produced within the capsule, the spores germinate to form free-living gametophytes. | |
| 2032. |
"Blood tissue is a connective tissue " Justify |
| Answer» \xa0Connective tissues have cells scattered throughout an extracellular matrix. They connect different body systems. Blood is considered as a type of connective tissue because of two reasons.(i) Like the other connective tissues, blood is mesodermal in origin.(ii) It connects the body systems, transports oxygen and nutrients to all the parts of the body, and removes the waste products. Blood has an extra-cellular matrix called plasma, with red blood cells, white blood cells, and platelets floating in it. | |
| 2033. |
Write a detailed note on nervous tissuea |
| Answer» The cells of nervous tissue are highly specialized and the cells of this tissue are called nerve cells or\xa0neurons.\tNervous tissue stimulates and transmits the stimulus very rapidly from one place to another within the body.\tThe brain, spinal cord and nerves are composed of the nervous tissue.\tA neuron consists of a cell body which comprises of nucleus and cytoplasm, from which long thin hair-like parts arise.\tThe neuron has a single long part, called the axon, which transmit the nerve impulse to body parts.\tThe neuron has short, branched parts called dendrites.\tMany nerve fibers combine together by connective tissue and form a nerve.\tNerve impulse enables animals to move rapidly in response to stimuli. | |
| 2034. |
Describe muscular tissue. Describe its types and features |
| Answer» ANSWERMuscle tissue is a soft tissue that composes muscles in animal bodies and gives rise to muscles\' ability to contract.\xa0There are mainly three types of muscle tissue:-1)Skeletal(Striated) Muscle:Structure:\xa0Skeletal muscle is called "striated" because of its appearance consisting of light and dark bands visible using a light microscope. A single skeletal muscle cell is long and approximately cylindrical in shape, with many nuclei located at the edges (periphery) of the cell.Function:\xa0\tMovement of the skeleton under conscious control, including movement of limbs, fingers, toes, neck, etc.\tMovement of tissues of facial expression under conscious control, e.g. ability to smile and to frown.2)Smooth(Non-Striated) Muscle: Structure:\xa0Unlike Skeletal and Cardiac muscle tissue, Smooth muscle is not striated. Smooth muscle\xa0fibres\xa0are small and tapered - with the ends reducing in size, in contrast to the cylindrical shape of\xa0a skeletal\xa0muscle. Each smooth muscle\xa0fibre\xa0has a single centrally located nucleus. Function:\xa0Contractions of smooth muscle constrict (i.e. narrow = reduce the diameter of) the vessels they surround. This is particularly important in the digestive system in which the action of smooth muscle helps to move food along the gastrointestinal tract as well as breaking the food down further. Smooth muscle also contributes to moving fluids through the body and to the elimination of indigestible matter from the gastrointestinal system.3)Cardiac(Semi-Striated) Muscle: Structure:\xa0Cardiac muscle\xa0fibers\xa0are striated, branched (sometimes described as Y-shaped), and have a single central nucleus. These\xa0fibers\xa0are attached at their ends to adjoining\xa0fibers\xa0by thick plasma membranes called intercalated discs. Function:\xa0Pumping of blood through the heart: Alternate contraction and relaxation of cardiac muscle pumpsDe-oxygenated blood through the Right Atrium and Right Ventricle to the lungs, and oxygenated blood through the Left Atrium and Left Ventricle to the aorta, then the rest of the body. | |
| 2035. |
What is glandular epithelium? Describe its types and mention its significance. |
| Answer» Glandular epithelium is a type of epithelial tissue which covers the glands (both exocrine and endocrine) of our body. Their main function is secretion. Both endocrine and exocrine glands produce their secretions through the glandular epithelium via special cells called goblet cells. Glandular epithelium in the reproductive tract is called endocervical glandular epithelium and helps in sexual functions by secreting lubricating fluid during sexual excitation. The glandular epithelium also lines the intestine where it helps in the absorption of nutrients. Thus it aids in digestion. Thus glandular epithelium is a multifunctional tissue that combines with other tissues to perform vital functions of the body. | |
| 2036. |
What is epthelial tissues? Explain its types |
| Answer» \tIt consists of cells which form membranes.\tThis membrane covers the body surface and the glands.\tThe covering or protective tissues in the animal body are epithelial tissues.\tEpithelium covers most organs and cavities within the body.\tIt also forms a barrier to keep different body systems separate.\tThe skin, the lining of the mouth, the lining of blood vessels, lung alveoli and kidney tubules are all made of epithelial tissue.\tThe cells are tightly packed and form a continuous sheet.\tThey have only a small amount of cementing material between them and almost no intercellular spaces.\tThese are divided into four types:-\xa0\xa0SIMPLE\tThe cells are extremely thin and flat and form a delicate lining.\tThe lining of oesophagus and the mouth are covered with squamous epithelium.STRATIFIED\tThe cells are arranged in many layers to prevent wear and tear.\tSince they are arranged in a pattern of layers, the epithelium is called stratified squamous\tThe skin, which protects the body, is made of squamous epithelium.COLUMNAR\tThe columnar (meaning ‘pillar-like’) epithelium facilitates movement across the epithelial barrier.\tIt is present where absorption and secretion occur, as in the inner lining of the intestine, tall epithelial cells are present.\tIn the respiratory tract, the columnar epithelial tissue also has cilia, which are hair-like projections on the outer surfaces of epithelial cells.\tThese cilia can move, and their movement pushes the mucus forward to clear it. This type of epithelium is thus ciliated columnar epithelium.CUBOIDAL\tCuboidal epithelium (with cube-shaped cells) forms the lining of kidney tubules and ducts of salivary glands, where it provides mechanical support.\tEpithelial cells often acquire additional specialisation as gland cells, which can secrete substances at the epithelial surface.\tSometimes a portion of the epithelial tissue folds inward and a multicellular gland is formed.\tThis is glandular epithelium. | |
| 2037. |
Cells can be different shapes and sizes. What are the reasons for this diversity? |
| Answer» Cells are of different shape, size and structure according to the function they need to perform. So, if all the cells become of same size, shape and structure, it will be very difficult for multicellular organisms including humans to adapt better to the environment and survive. Also, the division of labour among the cells will be lost thus leading to difficulties in survival.Nerve cells are usually branched and very long as they need more surface area to transmit the signals. Due to their long size they can easily carry messages in each and every portion around the body.In mammals, after maturation, the nucleus disappears from the RBC to provide adequate space for hemoglobin to carry oxygen. Nucleus is responsible for cell division so the blood cells don\'t divide, they are produced by other cells within bone marrow. This is an adaptation which allows the red blood cell to carry more oxygen. | |
| 2038. |
What are mesosomes? Mention their functions. |
| Answer» Mesosome is a convoluted membranous structure formed in a prokaryotic cell by the invagination of the plasma membrane. Its functions are as follows:(1)\xa0These extensions help in the synthesis of the cell wall and replication of DNA. They also help in the equal distribution of chromosomes into the daughter cells.(2)\xa0It also increases the surface area of the plasma membrane to carry out various enzymatic activities.(3)\xa0It helps in secretion processes as well as in bacterial respiration. | |
| 2039. |
What are the characteristics of prokaryotic cell? |
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Answer» \xa0The characteristics of prokaryotic cells are:\tMembrane bound cell organelles such as Mitochondria, Golgi apparatus, Chloroplasts are absent.\tA membrane bound well defined nucleus is absent.\tGenetic material is circular DNA and occurs naked in the cell cytoplasm. It is attached to the cell membrane and called nucleoid.\tThe cell size ranges from 0.1 to 5.0 micrometre in size.\tThe cell wall is a rigid structure which is made up of polysaccharides. The characteristics of prokaryotic cells are:Membrane bound cell organelles such as Mitochondria, Golgi apparatus, Chloroplasts are absent.A membrane bound well defined nucleus is absent.Genetic material is circular DNA and occurs naked in the cell cytoplasm. ... The cell size ranges from 0.1 to 5.0 micrometre in size. |
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| 2040. |
What would happen if the plasma membrane rupture of breakdown? |
| Answer» Answer: If the plasma membrane ruptures or breakdown then the cell will not be able to exchange material from its surrounding by diffusion or osmosis. Thereafter the protoplasmic material will be disappeared and the cell will die. | |
| 2041. |
What would happen to the life of a cell if there was no Golgi apparatus? |
| Answer» If there was no Golgi apparatus, various substances would not be in a position to be transformed in proper forms for further use. Certain substances, like protein and lipid, are important for the formation of plasma membrane. Hence the absence of Golgi apparatus will hamper the formation of new cells during cell division. | |
| 2042. |
Differentiate between isogamous,anisogamoua and oogamous ? |
| Answer» 1.Isogamous- in which both gametes are same in shape and size. 2.Anisogamous- in which gametes aren\'t same in shape and size. Gametes are different. 3.Oogamous- in which female gamete is large and non motile while male gamete is small and motile | |
| 2043. |
example of axil |
| Answer» \t\tThe flower with its pale is sessile, and is placed in the\xa0axil\xa0of another bract in such a way that the pale is exactly opposed to it, though at a slightly higher level.\t\t\tThe bract is not, however, the one from which the axis terminating in the flower arises, but is a bract produced upon it, and gives origin in its\xa0axil\xa0to a new axis, the basal portion FIG.\t\t\tOne argument that has been adduced in support of the\xa0axillary bud theory is derived from the Palaeozoic type Cordaites, in which each ovule occurs en an axis borne in the\xa0axil\xa0of a bract.\t\xa0\the female flowers are equally simple, consisting of a bract, from whose\xa0axil\xa0arises usually a very short stalk, surmounted by two carpels adherent one to the other for their whole length, except that the upper ends of the styles are separated into two stigmas.\t | |
| 2044. |
FUNGI..... |
| Answer» Gud mrng brooo.... | |
| 2045. |
Explain the term Exarchxylem |
| Answer» Exarch xylem is the arrangement in which the protoxylem (the first\xa0formed primary xylem cells in a plant shoot/root)\xa0is directed towards the periphery and metaxylem (later formed primary xylem cells in a plant shoot/root) is directed\xa0towards the centre. Its development follows a centripetal pattern and is characteristics of roots.\xa0 | |
| 2046. |
Explain the term Metaxylem |
| Answer» The first formed xylem elements are called protoxylem, while the later formed primary xylem is called metaxylem. | |
| 2047. |
Explain the term cortex |
| Answer» The exterior portion of the cerebrum is called the cortex or the cerebral mantle. The cortex is extremely convoluted, due to which, it has a large surface area.\xa0 | |
| 2048. |
Explain the term Protoxylem |
| Answer» Protoxylem is the initially formed Xylem that develops before the plant organ is completely grown and Metaxylem is formed later. | |
| 2049. |
Explain the structure and function of stomatal apparatus with suitable diagrams. |
| Answer» Stomatal apparatus is a pair of guard cells with or without surrounding subsidiary cells which function as a value to open or close a stomatal pore for gaseous exchange and transpiration.\xa0Each stoma is made of two bean-shaped cells called the guard cells. The guard cells are dumb-bell shaped in grasses. They contain chloroplasts and small vacuoles. They are thick-walled in the area of contact and thin-walled elsewhere. As the guard cells swell up due to endosmosis, their thin-walled sides expand. The thick walls of the two guard cells also bend outwardly and create a pore in between them. | |
| 2050. |
Describe the salient features of meristematic tissues and it\'s types. |
| Answer» \tMeristematic Tissue:Meristematic tissues are growth tissues and found in the growing regions of the plant. According to their position in plant, meristems are apical, lateral and intercalary.\tApical meristem - Apical meristem is present at the growing tips of stems and roots and increases the length of the stem and the root.\tLateral meristem – Lateral meristems are found beneath the bark. The girth of the stem or root increases due to lateral meristem (cambium).\tIntercalary meristem - Intercalary meristem is the meristem at the base of the leaves or internodes (on either side of the node) on twigs. It increases the length of the organs such as leaves and internodes.Characteristics of Meristematic Tissues:\tTheir cells are similar in structure and have thin cellulose cell walls.\tThe cells are active and have dense cytoplasm.\tThey contain few vacuoles or no vacuoles at all.\tThe meristematic cells are compactly arranged and do not contain any intercellular space between them. | |