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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.
| 1851. |
What is called neuter flower |
| Answer» A\xa0flower\xa0in which both, male and female reproductive organs are absent is\xa0called\xa0a\xa0neuter flower. E.g. Ray florets of a sunflower\xa0plant. · A\xa0flower\xa0in which both, male and female reproductive organs are absent is\xa0called\xa0a\xa0neuter flower.\xa0Sunflower uses a method of cross-pollination for reproduction by attracting insects like bees and they spread the reproductive pollen from one\xa0flower\xa0to another\xa0flower. The ray florets of sunflower are often called as a\xa0neuter flower\xa0as it does not male or female parts. | |
| 1852. |
List out the significance of meiosis |
| Answer» \tMeiosis is responsible for the formation of *** cells or gametes that are responsible for sexual reproduction.\tIt activates the genetic information for the development of *** cells and deactivates the sporophytic information.\tIt maintains the constant number of\xa0chromosomes\xa0by halving the same. This is important because the chromosome number doubles after fertilization.\tIn this process independent assortment of maternal and paternal chromosomes takes place. Thus the chromosomes and the traits controlled by them are reshuffled.\tThe genetic mutation occurs due to irregularities in cell division by meiosis. The mutations that are beneficial are carried on by natural selection.\tCrossing over produces a new combination of traits and variations. | |
| 1853. |
What is importance of prophase I meiosis |
| Answer» - Meiosis is responsible for the formation of the gametes, responsible for sexual reproduction.- It activates the genetic information for the development of gametes.- It reduces the number of chromosomes to half in gametes cells and helps in maintaining the constant number of chromosomes. This is important because the chromosome number doubles after fertilization.- In this process an independent assortment of maternal and paternal chromosomes takes place. Thus the chromosomes and the traits controlled by them are reshuffled.- The genetic mutation occurs due to irregularities in cell division by meiosis and gives rise to new varieties. | |
| 1854. |
What are the significance of mitosis |
| Answer» \tMitosis results in the production of diploid daughter cells with identical genetic complement usually.\tCell divides by mitosis to restore the nucleo-cytoplasmic ratio.\tHelps in cell repair.\tMitotic divisions in the meristematic tissues result in a continuous growth of plants throughout their life. | |
| 1855. |
What is cytokine? Mention it\'s significance |
| Answer» Cytokines\xa0are a group of proteins secreted by cells of the immune system that act as chemical messengers.\xa0Cytokines\xa0released from one cell affect the actions of other cells by binding to receptors on their surface. Through this process,\xa0cytokines\xa0help regulate the immune response.\xa0They act through receptors, and are especially important in the\xa0immune system; cytokines modulate the balance between humoral and cell-based immune responses, and they regulate the maturation, growth, and responsiveness of particular cell populations. | |
| 1856. |
Write a 1 example of polygamous trees |
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Answer» Bearing some flowers stamens only and some with pistol and some with both on same or different flower The production of three types of flowers namely staminate flowers, pistillate flowers and bisexual flowers in the same plant is known as polygamous. E.g. Musa. |
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| 1857. |
What is called calyx |
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Answer» Sepal is also known as calyx Outer most whoral of the flower \tCalyx-\tThe calyx is the outermost whorl of the flower and the members are called\tThe calyx may be\xa0gamosepalous\xa0, when sepals are united or\xa0polysepalous\xa0when sepals are free. |
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| 1858. |
Chapter 2 questions answer pdf |
| Answer» | |
| 1859. |
What is the name of outer layer of the sponges? |
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Answer» It\'s not the name of the layer it is the name of the cell form by the layer Pinacocytes, which are epithelial-like cells, form the\xa0outermost layer\xa0of\xa0sponges\xa0and enclose a jelly-like substance\xa0called\xa0mesohyl. Mesohyl is an extracellular matrix consisting of a collagen-like gel with suspended cells that perform various functions. |
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| 1860. |
which plant kingdoms known as first terristerial plant and posses vascular tissue? |
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Answer» Pteridophyta A N S W E RPteridophyte are also called as vascular cryptogams. They show the first vascular property in the plant kingdom. Vascular plants are those plants, who have xylem and phloem. |
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| 1861. |
Circulatory system of earthworm? |
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Answer» Tnx Another important organ system is the circulatory system. The earthworm has a closed circulatory system. An earthworm circulates blood exclusively through vessels. There are three main vessels that supply the blood to organs within the earthworm. These vessels are the aortic arches, dorsal blood vessels, and ventral blood vessels. The aortic arches function like a human heart. There are five pairs of aortic arches, which have the responsibility of pumping blood into the dorsal and ventral blood vessels. The dorsal blood vessels are responsible for carrying blood to the front of the earthworm’s body. The ventral blood vessels are responsible for carrying blood to the back of the earthworm’s body. Jnv Where r u from Nice qué. |
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| 1862. |
The person who are brain dead are living or non-living ....? |
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Answer» Lekin unke pass consciousness he nhi to vo living kaise huye kyunki consciousness Ek defining property hoti h living beings ke ...? Thanks... How.. ?.. Living |
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| 1863. |
At which position trachea get branched into bronchioles? |
| Answer» The\xa0respiratory zone\xa0includes the structures of the lung that are directly involved in gas exchange: the\xa0terminal bronchioles\xa0and alveoli. ... This is a blood-air barrier through which gas exchange occurs by simple diffusion.\xa0In\xa0the mediastinum, at the level of the fifth thoracic vertebra, the\xa0trachea\xa0divides\xa0into\xa0the right and left primary\xa0bronchi. The\xa0bronchi branch into\xa0smaller and smaller passageways until they terminate\xa0in\xa0tiny air sacs called\xa0alveoli. | |
| 1864. |
What is the name of male and female spore of red algae |
| Answer» Certain cells of the tetrasporophyte undergo meiosis to produce tetraspores, and the cycle is repeated. In the life cycle of Polysiphonia, and many other\xa0red algae, there are separate\xa0male and female\xa0gametophytes, carposporophytes that develop on the\xa0female\xa0gametophytes, and separate tetrasporophytes. | |
| 1865. |
Which cell organelles has two membrane ? |
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Answer» Mitochondria and chloroplast has double membranes. Mitochondria and chloroplast |
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| 1866. |
What is special about following Gymnosperms- (i) Sequoia (ii) coralloid roots of Cycas. |
| Answer» The coralloid roots of Cycas are symbiotically associated with nitrogen fixing blue-green algae, Anabaena cycadae and Nostoc punctiforme. In the middle cortex of coralloid roots, there occurs a broad blue green zone, which is known as algal zone. Coralloid roots are irregular, negatively geotropic, dichotomously branched coral like roots which do not possess root hair and root caps. | |
| 1867. |
Write a 5 Pigments name of red algae |
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Answer» r- Phycoerythrin ,c- phycocynine , carotene, xanthophyll, chlorophyll-a etc, Red algae are different from other groups except for diatoms. Listed below are general characteristics of Red Algae.\tLack of flagella and\xa0centrioles\tPresence of photosynthetic pigments\tFound both in marine and freshwater\tThey show biphasic or triphasic life cycle patterns.\tThey are a multicellular, filament, blade structure.\tStored food is in the form of starch and polymers of galactan sulphate\tA pit connection (hole in the septum)\xa0is formed between two algal cells.\tHave a diffuse growth pattern- Apical growth, Complex oogamy (triphasic)\tThese group of red algae is\xa0generally found in tropical marine locations\tThe mode of nutrition may either be saprophytic, parasitic or also epiphytic. |
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| 1868. |
Mention the uses of pteridophytes |
| Answer» \tThe pteridophytes are found in cool, damp, shady places.\tThe main plant body is a sporophyte which is differentiated into true root, stem and leaves, possess well-differentiated vascular tissues.\tThe sporophytes bear sporangia that are subtended by leaf-like appendages called\xa0sporophylls, which may form distinct compact structures called\xa0strobili or cones.\tThe sporangia produce spores by meiosis in spore mother cells, the spores germinate to give rise to thalloid gametophytes called\tThe gametophytes bear male and female *** organs called\xa0antheridia and archegonia, respectively.\tWater is required for transfer of antherozoids to the mouth of archegonium and fusion of male gamete with the egg present in the archegonium result in the formation of zygote.\tZygote produces a multicellular well-differentiated sporophyte which is the dominant phase of the pteridophytes. | |
| 1869. |
The living word by |
| Answer» Complete your question.... | |
| 1870. |
What is the significsnce of mitosis |
| Answer» \tMitosis results in the production of diploid daughter cells with identical genetic complement usually.\tCell divides by mitosis to restore the nucleo-cytoplasmic ratio.\tHelps in cell repair.\tMitotic divisions in the meristematic tissues result in a continuous growth of plants throughout their life. | |
| 1871. |
What do term ref tides signify |
| Answer» Red-tides:\xa0Red tides are caused by the red dinoflagellates (Gonyaulax) that multiply rapidly in sea and impart it a red colour. They release large amounts of toxins in water that can cause death of a large number of aquatic animals. | |
| 1872. |
What is monocotlyden leaf |
| Answer» Monocot plants have leaves that are characteristically longer and slender.\xa0Stomata in monocot leaves are dumb-bell shaped.\xa0Monocot leaves are amphistomatic – which means the stomata are present on lower as well as the upper surface | |
| 1873. |
Define photolysis of water |
| Answer» Photolysis\xa0is the splitting of\xa0water\xa0molecules in the presence of light into proton, electron and oxygen. It takes place during non-cyclic photophosphorylation. The protons are used to reduce NADP and electrons are fed to photosystem II. The splitting or decomposition of a chemical compound by means of light energy or photons. Supplement. For example, the\xa0photolysis of water\xa0molecule in photosynthesis occurred under the influence of light. When photons are absorbed, it causes the hydrogen to bind to an acceptor, subsequently releasing the oxygen. | |
| 1874. |
Tap root system ..? |
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Answer» All the best. ??? 5 ? Kitne chapter aayenge. ? Physics? Oh... To kal Konse subject ka h ? |
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| 1875. |
Where is adipose tissue present |
| Answer» Adipose tissue\xa0is a specialized connective\xa0tissue\xa0consisting of lipid-rich\xa0cells\xa0called adipocytes. As it comprises about 20-25% of total body weight in healthy individuals, the main function of\xa0adipose tissue\xa0is to store energy in the form of lipids (fat). Adipose tissue is commonly known as\xa0body\xa0fat. It is found all over the\xa0body. It can be found under the\xa0skin\xa0(subcutaneous fat), packed around internal\xa0organs\xa0(visceral fat), between muscles, within\xa0bone marrow\xa0and in\xa0breast\xa0tissue. | |
| 1876. |
What are living organisms classified |
| Answer» The\xa0classification\xa0of\xa0living things\xa0includes 7 levels: kingdom, phylum, classes, order, families, genus, and species. The most basic\xa0classification\xa0of\xa0living things\xa0is kingdoms. Currently, there are five kingdoms.\xa0A large variety of plants, animals, and microbes found on earth and differ in size, shape, colour, habitat, and many other characteristics. So, studying each of them is impossible. Therefore, scientists have devised mechanisms to classify all living organisms on certain rules and principles that allow identification, nomenclature, and finally classification of an organism. | |
| 1877. |
Frog has osmoreceptor in his mouth |
| Answer» A frog will eat just about any living thing he can fit in his mouth, but he also has sensitive taste buds. He will occasionally spit out hastily grabbed prey if the taste is unpleasant. The taste buds are on the surface of his tongue and the inside of his mouth. Completely aquatic frogs in the Pipidae family do not have tongues, but they have taste discs in their mouth tissue to receive taste sensations. Osmoreceptors present in the mouth of frog are involved in detecting osmotic pressure and maintain the salt and water balance in the body fluids. Male recognises a mature female by swollen abdomen. | |
| 1878. |
.Write any two advantages of scientific names. |
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Answer» 1. Organise and classify - the organism can be easily categorised, this really helps making it easier to understand the characteristics of a specific organism in an organised chart.2. Clarity and precision - these names are unique with each creature having only one scientific name. Helps avoid confusion created by common names. 1. Organise and classify - the organism can be easily categorised, this really helps making it easier to understand the characteristics of a specific organism in an organised chart.2. Clarity and precision - these names are unique with each creature having only one scientific name. Helps avoid confusion created by common names.3. Universal recognition - scientific names are standardised and accepted universally.4. Stability - the names are retained even if the species are shifted to another genera based on new knowledge.5. Inter specific relationship - binomial terms help understand the similarities and differences between different species belonging to the same genera, useful in establishing a relationship between the two. |
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| 1879. |
Pteridophytes show independent alternation of generation. Explain. |
| Answer» The plant life cycle includes alternation of generations, wherein two generations - a haploid gametophytic one alternates with a diploid sporophytic one to complete a life cycle.\xa0The gametophytes produce sporophytes, and sporophytes produce gametophytes. While in some species the gametohytes and sporophytes are isomorphic and inistinguishable from each other, in case of Pteridophytes especially ferns the two forms are separate, free-living andindependent of each other, giving rise to heteromorphic alternation of generations. | |
| 1880. |
Which aquatic fern made a close association with anabaena? |
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Answer» Bcz aquatic fern which is Azolla is a biofertilizer.the algae anabeana fixes atmospheric nitrogen in symbiotic association with Azolla. Anabaena azollae maintains a mutually beneficial symbiotic relationship with the water fern Azolla, which provide the cyanobacteria with a safe environment in exchange for nitrogen. Azolla is grown in tropical and temperate climates in calm bodies of water. |
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| 1881. |
Explain how hypothalamus function as endocrine gland |
| Answer» ollowing are the important functions of the hypothalamus:\tIts main function is maintaining the body’s internal balance- homeostasis.\tIt also connects the endocrine and the nervous system.\tHypothalamus stimulates or inhibits many of the body’s activities in order to maintain homeostasis, such as regulating body temperature, appetite and body weight, heart rate and blood pressure, etc.\tIt is involved in many essential functions of the body, including:\tChildbirth.\tEmotions.\tSleep cycles.\tBalancing body fluids.\tAppetite and thirst control.\tBlood pressure and heart rate. | |
| 1882. |
Define metabolism. |
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Answer» The sum total of all biochemical reactions occurring in a body is called metabolism. Sum total of all the reactions occuring together in an organism whether unicellular or multicellular is metabolism. Metabolism is the total amount of the biochemical reactions involved in maintaining the living condition of the cells in an organism. All living\xa0organisms require\xa0energy for different essential processes and for producing new organic substances.The metabolic processes help in growth and reproduction and help in maintaining the structures of living organisms. The organisms respond to the surrounding environment due to metabolic activities. All the chemical reactions occurring in the living organisms from digestion to transportation of substances from cell to cell require energy. |
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| 1883. |
What is meant by gut wall ???? Used in the definition of coelom and others. |
| Answer» The outer walls of ailementary canal | |
| 1884. |
What is looking living? |
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Answer» Thank you Living things are made up of cells and are capable of carrying out various cellular activities. The different features that best describe what a living thing is, are mentioned below:\tGrowth is usually defined by the increase in mass and number of individual organisms. Humans visibly grow up to a certain age, but the cells keep on dividing and thus new cells in the body keep on replacing the old ones.\tReproduction\xa0is the process by which an organism produces an individual like its own. |
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| 1885. |
Describe the structure of cilium and flagellum |
| Answer» \tCilia and flagella are hair-like outgrowths of the cell membrane.\tCilia and flagella help in cell movement.\tCore of cilia and flagella is called the\xa0axoneme, possesses a number of microtubules running parallel to the long axis.\tThe axoneme usually has nine pairs of doublets of radially arranged peripheral microtubules, and a pair of centrally located microtubules. Such an arrangement of axonemal microtubules is referred to as the\xa09+2 array.\tThe central tubules are connected by bridges and is also enclosed by a central sheath, which is connected to one of the tubules of each peripheral doublets by a\xa0radial spoke\xa0and hence there are nine radial spokes.\tThe peripheral doublets are also interconnected by\xa0linkers.\tBoth the cilium and flagellum emerge from centriole-like structure called the\xa0basal bodies. | |
| 1886. |
What are the stages taking place in interphase? |
| Answer» During interphase a number of changes take place so as to prepare the cell for division. During this period, the cell experiences growth and DNA replication.The interphase is divided into three phases, which are as follows:(i)\xa0G1 phase (Gap 1):\xa0During this phase, the cell is metabolically active and continuously grows and prepares its DNA for replication.(ii)\xa0S phase (Synthesis):\xa0During this phase, DNA synthesis or replication takes place. In this phase, the amount of DNA per cell doubles, but the number of chromosomes remain the same.(iii)\xa0G2 phase (Gap 2):\xa0During this phase, proteins and RNA synthesis take place so to prepare the cell for mitosis. The cell growth continues during this phase. | |
| 1887. |
What is mitosis? Give brief among of the mitosis in animal cell? |
| Answer» Mitosis is a cell division that occurs in animal cells where each mother cell divides into 2 daughter cells. The number of chromosomes in the mother cell is identical to that in each resulting daughter cell. This is why mitosis is sometimes called an ” Identical Reproduction of Cells”. | |
| 1888. |
What are homologous chromosomes ? What happen to homologous chromosomes during meiosis? |
| Answer» Homologous chromosomes are the chromosomes which are similar but not identical. These are similar in length, gene position and centromere location. The stage in which paired homologous chromosomes get shortened and thickened is diplotene stage of Prophase1 of Meiosis1. The homologous chromosomes undergo genetic recombination. The chromosomes reduce to homologous chromosomes in meiosis 1 and then to sister chromatids in meiosis2. The homologous chromosomes first exchange their DNA in next phase they orient themselves randomly at the equator. Reduction division of homologus chromosomes takes place in meiosis. | |
| 1889. |
Pls anyone answer to my question pls |
| Answer» | |
| 1890. |
What are homologous chromosomes ? What happen to homologous chromosomes during meiosis |
| Answer» Homologous chromosomes are the chromosomes which are similar but not identical. These are similar in length, gene position and centromere location. The stage in which paired homologous chromosomes get shortened and thickened is diplotene stage of Prophase1 of Meiosis1. The homologous chromosomes undergo genetic recombination. The chromosomes reduce to homologous chromosomes in meiosis 1 and then to sister chromatids in meiosis2. The homologous chromosomes first exchange their DNA in next phase they orient themselves randomly at the equator. Reduction division of homologus chromosomes takes place in meiosis. | |
| 1891. |
Write six differences between mitosis and meiosis |
| Answer» Organisms grow and reproduce through cell division. In eukaryotic cells, the production of new cells occurs as a result of mitosis and meiosis. These two nuclear division processes are similar but distinct. Both processes involve the division of a diploid cell, or a cell containing two sets of chromosomes (one chromosome donated from each parent).In mitosis, the genetic material (DNA) in a cell is duplicated and divided equally between two cells. The dividing cell goes through an ordered series of events called the cell cycle. The mitotic cell cycle is initiated by the presence of certain growth factors or other signals that indicate that the production of new cells is needed. Somatic cells of the body replicate by mitosis. Examples of somatic cells include fat cells, blood cells, skin cells, or any body cell that is not a *** cell. Mitosis is necessary to replace dead cells, damaged cells, or cells that have short life spans.Meiosis is the process by which gametes (*** cells) are generated in organisms that reproduce sexually. Gametes are produced in male and female gonads and contain one-half the number of chromosomes as the original cell. New gene combinations are introduced in a population through the genetic recombination that occurs during meiosis. Thus, unlike the two genetically identical cells produced in mitosis, the meiotic cell cycle produces four cells that are genetically different. | |
| 1892. |
What are the three process take place in interphase? |
| Answer» \tThere are three stages of interphase: G1\xa0(first gap), S (synthesis of new DNA ), and G2\xa0(second gap).\tCells spend most of their lives in interphase, specifically in the S phase where genetic material must be copied.\tThe cell grows and carries out biochemical functions, such as protein synthesis, in the G1\xa0phase.\tDuring the S phase, DNA is duplicated into two sister chromatids, and centrosomes, which give rise to the mitotic spindle, are also replicated.\tIn the G2\xa0phase, energy is replenished, new proteins are synthesized, the cytoskeleton is dismantled, and additional growth occurs. | |
| 1893. |
Evolution of life...?? |
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Answer» Mai badhiya hu... Iss tym pk bro Nii aa the h... Diwali pe aaye the... Legendary Ye kaisa answer hai ? |
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| 1894. |
What are the components of plasma membrane |
| Answer» It is composed of the following constituents:\tPhospholipids – forms the ultimate fabric of the membrane\tPeripheral proteins – present on the outer or inner surface of phospholipid bilayer but are not implanted in the hydrophobic core\tCholesterol – folded between the hydrophobic tails of phospholipid membrane\tCarbohydrates – found to be attached to the lipids or proteins on the extracellular side of the membrane, leading to the formation of glycolipids and glycoproteins\tIntegral proteins – found to be implanted in the phospholipid bilayer | |
| 1895. |
Describe the well labelled diagram of modification of stem and explain in detail |
| Answer» Stems of various plants have undergone modifications to perform different functions.Underground stems or storage stems:Examples: Rhizomes, Corms, tubersIn ginger and banana, the underground stem is called a rhizome. The underground stem in Colocasia (arvi) is known as corm. Rhizomes and corms are underground stems, modified for the storage of food. Also, these stems help in vegetative reproduction of these plants. The tips of the underground stem in potato plants become swollen due to the accumulation of food. The potato is a tuber that helps in the storage of food and bears eyes on it. Subtended by a leaf scar, these eyes bear buds that give rise to new plants.Supportive stemsExample: tendrilThe stem in some weak plants bear thin, slender, and spirally-coiled structures called tendrils that help the plant get attached to nearby structures for support. Tendrils are found in cucumbers, melons, and other members of the family Cucurbitaceae.Protective stemsExample: ThornsThe stem in bougainvillea and citrus plants (like lemon and orange) bear sharp, pointed structures called thorns, which provide protection to the plant from herbivores.Photosynthetic stemsExample: OpuntiaThe stem in the Opuntia is green. It carries out the process of photosynthesis in the absence of leaves.Others stem modificationsIn some plants, underground stems such as grasses spread in the soil and help in perenation. These stems are called runners.The short lateral stem called the offset in some aquatic plants (such as Eichhornia) bears leaves and tufts of roots at the node and gives rise to new plants. | |
| 1896. |
Notes of chapter 18 |
| Answer» | |
| 1897. |
Chapter 9 biomolecules Notes |
| Answer» This content has been hidden. One or more users have flagged this content as inappropriate. Once content is flagged, it is hidden from users and is reviewed by myCBSEguide team against our Community Guidelines.\xa0If content is found in violation, the user posting this content will be banned for 30 days from using Homework help section.\xa0Suspended users will receive error while adding question or answer. Question comments have also been disabled. Read community guidelines at https://mycbseguide.com/community-guidelines.htmlFew rules to keep homework help section safe, clean and informative.Don\'t post personal information, mobile numbers and other details.Don\'t use this platform for chatting, social networking and making friends. This platform is meant only for asking subject specific and study related questions.Be nice and polite and avoid rude and abusive language. Avoid inappropriate language and attention, vulgar terms and anything sexually suggestive. Avoid harassment and bullying.Ask specific question which are clear and concise.Remember the goal of this website is to share knowledge and learn from each other. Ask questions and help others by answering questions. | |
| 1898. |
Define Annelida..?? |
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Answer» Okay! ? \tThe body surface of Annnelids is distinctly marked out into segments or metamere and, hence, the phylum name Annelida.\tThey exhibit organ-system level of body organization, bilateral symmetry,they are triploblastic, metamerically segmented and coelomate animals.\tAquatic annelids possess lateral appendages called asparapodia. For example-\xa0Nereis |
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| 1899. |
What is a coelom |
| Answer» Coelom is a fluid filled space between the body wall and gut wall and lined by mesoderm on all of its sides. The presence or absence of body cavity or coelom plays a very important role in the classification of animals. Animals that possess a fluid filled cavity between body wall and digestive tract are known as coelomates. Annelids, mollusks, arthropods, echinodermates, and chordates are examples of coelomates. On the other hand, the animals in which the body cavity is not lined by mesoderm are known as pseudocoelomates. | |
| 1900. |
What is alternation of generation.draw the diagram of diplontic pattern with example. |
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Answer» two plant bodies - haploid and diploid. The haploid plant body produces gametes by mitosis and is termed as gametophyte. After fertilisation, the zygote also divides by mitosis to produce a diploid sporophytic plant body. Haploid spores are produced by this plant body by meiosis, which in turn, divide by mitosis to form a haploid plant body once again. Thus, during the life cycle of any sexually reproducing plant, there is an alternation of generation between gamete producing haploid gametophyte and spore producing diploid sporophyte.(A) Haplontic life cycle: Sporophytic generation is represented only by the one-celled zygote. There are no free-living sporophytes. Meiosis in the zygote results in the formation of haploid spores. The haploid spores divide mitotically and form the gametophyte. The dominant, photosynthetic phase in such plants is the free-living gametophyte. This kind of life cycle is termed as haplontic.\xa0Many algae such as\xa0Volvox,\xa0Spirogyra\xa0and some species of\xa0Chlamydomonas\xa0represent this pattern.(B) Diplontic life cycle: The diploid sporophyte is the dominant, photosynthetic, independent phase of the plant. The gametophytic phase is represented by the single to few-celled haploid gametophyte. This kind of lifecycle is termed as diplontic.\xa0All seed-bearing plants i.e. gymnosperms and angiosperms, follow this pattern.(C) Haplo-diplontic life cycle: Bryophytes and pteridophytes, interestingly, exhibit an intermediate condition (haplo-diplontic); both phases are multicellular and often free-living. However, they differ in their dominant phases. \xa0In plants, both haploid and diploid type of cells can divide by mitosis. This ability leads to the formation of two plant bodies - haploid and diploid. The haploid plant body produces gametes by mitosis and is termed as gametophyte. After fertilisation, the zygote also divides by mitosis to produce a diploid sporophytic plant body. Haploid spores are produced by this plant body by meiosis, which in turn, divide by mitosis to form a haploid plant body once again. Thus, during the life cycle of any sexually reproducing plant, there is an alternation of generation between gamete producing haploid gametophyte and spore producing diploid sporophyte.(A) Haplontic life cycle: Sporophytic generation is represented only by the one-celled zygote. There are no free-living sporophytes. Meiosis in the zygote results in the formation of haploid spores. The haploid spores divide mitotically and form the gametophyte. The dominant, photosynthetic phase in such plants is the free-living gametophyte. This kind of life cycle is termed as haplontic.\xa0Many algae such as\xa0Volvox,\xa0Spirogyra\xa0and some species of\xa0Chlamydomonas\xa0represent this pattern.(B) Diplontic life cycle: The diploid sporophyte is the dominant, photosynthetic, independent phase of the plant. The gametophytic phase is represented by the single to few-celled haploid gametophyte. This kind of lifecycle is termed as diplontic.\xa0All seed-bearing plants i.e. gymnosperms and angiosperms, follow this pattern.(C) Haplo-diplontic life cycle: Bryophytes and pteridophytes, interestingly, exhibit an intermediate condition (haplo-diplontic); both phases are multicellular and often free-living. However, they differ in their dominant phases. |
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