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    • Posted by Sivan Karthick 7 years ago

    CBSE > Class 11 > Biology
    • 1 answers

    Saba Elias 7 years ago

    Mycoplasma is also known as molliates. It is the simplest and smallest living organism Discovered in the pleuro field of cattle suffering from pleuropnemonia . Often called MLO OR PPLO (pleuropnemonia like organism) Cell wall is absent in them. Plasma membrane forms the outer boundary of the cell. They are pleomorphic

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    • Posted by Annudita Bharti 7 years ago

    CBSE > Class 11 > Biology
    • 1 answers

    Kunal Bhardwaj 7 years ago

    ✶ P3+3 A3+3 G(3) General floral formula of the Liliacaeae: Flowers actinomorphic and hermaphrodite with 6 undifferentiated tepals in two whorls of three, the same number and arrangement of stamens, and a superior ovary with 3 fused carpels. Individual species and genera may have more or less derived formulas.

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    • Posted by Jugal Goswami 7 years ago

    CBSE > Class 11 > Biology
    • 1 answers

    Ayushi Ayushi 7 years ago

    The main difference between MHC class 1 and 2 is that MHC class 1 molecules present antigens to cytotoxic T cells with CD8+ receptors whereas MHC class 2 molecules present antigens to helper T cells with CD4+ receptors.

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    • Posted by Ishita Ishita 7 years ago

    CBSE > Class 11 > Biology
    • 6 answers

    Říý@ ?? 7 years ago

    U r most wlcm. .......??

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    Ishita Ishita 7 years ago

    Thank u

    1Thank You

    Říý@ ?? 7 years ago

    Intercellular - relating to, involving, or occurring in the space between the cells of a multicellular organism or in the space between cells of closely associated unicellular microorganisms (such as bacteria). Intracellular -existing, occurring, or functioning within a cell

    1Thank You

    Ishita Ishita 7 years ago

    Thnks yogita

    1Thank You

    Yogita Ingle 7 years ago

    (i) Intracellular digestion, occurs inside the living cells with the help of lysosomal enzymes. Food particle is taken in through endocytosis. It forms a phagosome, which fuses with a lysosome. The digested material pass into the cytoplasm. The undigested matter is thrown out by exocytosis. It occurs in Amoeba, Paramecium, etc.
    (ii) Extracellular digestion In case of coelenterates digestion occurs in gastrovascular cavity. This cavity has gland cells which secrete digestive enzymes over the food. The partially digested fragmented food particles are ingested by nutritive cells. It occurs in Hydra, Aurelia, etc.

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    Ishita Ishita 7 years ago

    Plz answer anyone??

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    • Posted by Shri Shukla 7 years ago

    CBSE > Class 11 > Biology
    • 1 answers

    Saba Elias 7 years ago

    1. The new plants produced by artificial vegetative propagation will be exactly like the parent plants. Any desirable feature of the parent plant will be replicated in the new plants. 2. The fruit trees grown form seed may take many years before they start to bear fruit. But the fruit trees grown form cuttings or by grafting start to bear fruits much earlier. 3. The plants grown by vegetative propagation usually need less attention in their early year than the plants grown from seeds. 4. Many plants can be grown from just one parent plants by artificial propagation. 5 we can also get seedless plant by artificial propagation.

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    • Posted by Sruthika S 7 years ago

    CBSE > Class 11 > Biology
    • 0 answers
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    • Posted by Bilal Saeed 7 years ago

    CBSE > Class 11 > Biology
    • 1 answers

    Meghna Thapar 5 years, 4 months ago

    The citric acid cycle, shown in —also known as the tricarboxylic acid cycle (TCA cycle) or the Krebs cycle—is a series of chemical reactions used by all aerobic organisms to generate energy through the oxidation of acetate—derived from carbohydrates, fats, and proteins—into carbon dioxide. The cycle provides precursors including certain amino acids as well as the reducing agent NADH that is used in numerous biochemical reactions. Its central importance to many biochemical pathways suggests that it was one of the earliest established components of cellular metabolism; it may have originated abiogenically.

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    • Posted by Lily ☺ 7 years ago

    CBSE > Class 11 > Biology
    • 1 answers

    Ayushi Ayushi 7 years ago

    One of their classification is as monocot and dicots. Monocots and dicots differ from each other in four structures: leaves, stems, roots and flowers. ... Another main difference in monocot and dicot leaf is that monocot leaf has an equal number of stomata on either side, but dicot has more stomata at its lower surface.

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    • Posted by Lily ☺ 7 years ago

    CBSE > Class 11 > Biology
    • 1 answers

    Ayushi Ayushi 7 years ago

    There are six sphincter present in a digestive system. They are - The mouth is separated from the esophagus by the upper esophageal sphincter. The division between the esophagus and the stomach is the cardiac sphincter, or lower esophageal sphincter. Dividing the lower stomach from the small intestine is the pyloric sphincter. Between the small intestine and colon is the ileocecal sphincter. The exit from the body at the **** is actually two different sphincters the internal **** sphincter, and the external **** sphincter.

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    • Posted by Kuldeep Singh 7 years ago

    CBSE > Class 11 > Biology
    • 2 answers

    Říý@ ?? 7 years ago

    Morphology is the branch of science which deals with the study of form and structure. In botany. It generally means the study of external features, forms and relative positions of different organs on plants.

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    Ritu Thapliyal 7 years ago

    Chapter 5 of ncert

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    • Posted by Vishnu Aishu 7 years ago

    CBSE > Class 11 > Biology
    • 1 answers

    Vishnu Aishu 7 years ago

    Answer???

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    • Posted by Hemant Ritesh Sourashtriya 7 years ago

    CBSE > Class 11 > Biology
    • 2 answers

    Kunal Bhardwaj 7 years ago

    In 1815 AD, a Swedish chemist J.J. Berzelius put forward vital force theory to explain the origin of organic compound. According to this theory, organic compound are formed and synthesized only within living species( plants and animals ). ... This theory defied the vital force theory.

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    Kunal Bhardwaj 7 years ago

    The Pressure Flow Hypothesis, also known as the Mass Flow Hypothesis, is the best-supported theory to explain the movement of sap through the phloem. ... This creates turgor pressure, also known as hydrostatic pressure, in the phloem. Movement of phloem sap occurs by bulk flow (mass flow) from sugar sources to sugar sinks.

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    • Posted by Ishita Ishita 7 years ago

    CBSE > Class 11 > Biology
    • 2 answers

    Ishita Ishita 5 years, 8 months ago

    Really???

    1Thank You

    S.Sai Arvind 7 years ago

    10 million times

    1Thank You

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    • Posted by Simran Cruz 7 years ago

    CBSE > Class 11 > Biology
    • 1 answers

    Meghna Thapar 5 years, 4 months ago

    Differences between arteries, veins and capillaries:

     

    Artery

    Vein

    Capillary

    (i) It is a thick walled blood vessel.

    It is a thin walled blood vessel.

    It is an extremely narrow blood vessel having very thin walls.

    (ii) It carries blood from the heart to different parts of the body.

    It brings blood from the different parts of the body to the heart.

    They form an extensive network throughout all living cells in the body and connect arteries and veins.

    (iii) It can dilate or constrict depending on the regulatory requirement of the body.

    It cannot dilate or constrict.

    It can dilate or constrict according to the requirement of the tissue.

    (iv) It does not contain any valve.

    It contains simple valves which permit blood flow only towards the heart.

    It does not contain any valves.

     

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    • Posted by Wajeed Patel 7 years ago

    CBSE > Class 11 > Biology
    • 1 answers

    Chesta Pawan Manchanda 7 years ago

    Phycobiont refers to the algal component of the lichens and mycobiont refers to the fungal component. Both of these are present in symbiotic relationship in which Algae prepare food for Fungi due to presence of chlorophyll whereas the fungus provides shelter to algae and absorbs water and nutrients from the soil.

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    • Posted by Faizan Khan?? 7 years ago

    CBSE > Class 11 > Biology
    • 2 answers

    Říý@ ?? 7 years ago

    Femur is the longest bone which is thighbone. The smallest bone is stapes whish is the third bone of the three ossicles present in the middle ear.

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    Maitri Patel?☺?? 7 years ago

    Longest:femur and smallest:stapes

    1Thank You

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    • Posted by Bhargavi Bhargavi 7 years ago

    CBSE > Class 11 > Biology
    • 1 answers

    Jasmine Jasmine 7 years ago

    These are six type of enzyme are as follow : oxidoreductases, transferses, isomerases, hydrolases, lyases, ligases

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    • Posted by Anushri Mondal 7 years ago

    CBSE > Class 11 > Biology
    • 2 answers

    Yakshi ? 7 years ago

    After reading ur question firstly i thought ....in which language are u talking.....then i got realised after reading prakul's answer???

    1Thank You

    Prakul Goel 7 years ago

    Sino auricular node is located in the wall of right auricle of superior vena cava _Has capacity of self excitation -acts as a pacemaker -controlled by cardio vascular centre present in medulla oblongata of brain

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    • Posted by Anushri Mondal 7 years ago

    CBSE > Class 11 > Biology
    • 2 answers

    Christin Mathew 7 years ago

    No

    0Thank You

    Divyansh Pal 7 years ago

    I will send you send me your no

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    • Posted by Ritu Thapliyal 7 years ago

    CBSE > Class 11 > Biology
    • 4 answers

    Říý@ ?? 7 years ago

    Guttation is the process of loss of water from the uninjured part or leaves of the plant in the form of water droplets is called guttation.

    0Thank You

    Ritu Thapliyal 7 years ago

    U always give a nice answer

    0Thank You

    Ritu Thapliyal 7 years ago

    Thank you

    0Thank You

    Hritik Gupta 7 years ago

    Guttation is the exudation of drops of xylem sap on the tips or edges of leaves of some vascular plants, such as grasses. Guttation is not to be confused with dew, which condenses from the atmosphere onto the plant surface.

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    • Posted by Rea Rea 7 years ago

    CBSE > Class 11 > Biology
    • 2 answers

    Yogita Ingle 7 years ago

    An electromagnetic pulse (EMP) is an intense burst of electromagnetic (EM) energy caused by an abrupt, rapid acceleration of charged particles, usually electron s. An EMP can contain energy components over a large part of the EM spectrum , from very-low-frequency ( VLF ) radio to ultraviolet ( UV ) wavelengths.

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    Saba Elias 7 years ago

    Electromagnetic pulse

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    • Posted by Krishna Baghel 7 years ago

    CBSE > Class 11 > Biology
    • 2 answers

    Yogita Ingle 7 years ago

    It is the pulling force responsible for lifting the water column. As water is lost in form of water vapour to atmosphere from the mesophyll cells by transpiration, a negative hydrostatic pressure is created in the mesophyll cells which in turn draw water from veins of the leaves.
    The negative tension is then gradually transmitted downwards via xylem tissues of the leaf, stem and finally to the roots. As a result there is a continuous upward movement of water column in the plant. 1 atm. pressure can raise water to a height of more than 32ft. So a tension of 13 atm is needed to raise water to a height of 416 feet, scientist have measured this tension to be more than 75 atm. in case of trees, more than 400 feet in height.
    Thus the transpiration pull acts as pull from above on the-whole of water column of the plant which pushes the water column of xylem vessels of roots lowers leaves i.e. in an upward direction. This is how ascent of sap is affected in plants.
    The whole process can be compared to a person (transpiration pull) pulling a bucket full of water with a steel rope (unbroken and continuous water column)

    2Thank You

    Prachi Pandey 7 years ago

    Respiration

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    • Posted by Rajebhau Kharar 7 years ago

    CBSE > Class 11 > Biology
    • 1 answers

    Meghna Thapar 5 years, 4 months ago

    Micronutrients are needed in very small Amounts by the plants, but if their concentration decreases, then it causes deficiency symptoms and if it increases it causes toxicity. The nutrient is considered to be toxic which reduces the dry weight of tissue by about 10 percent.Nutrients that plants require in larger amounts are called macronutrients. About half of the essential elements are considered macronutrients: carbon, hydrogen, oxygen, nitrogen, phosphorus, potassium, calcium, magnesium, and sulfur.

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    • Posted by Říý@ ?? 7 years ago

    CBSE > Class 11 > Biology
    • 4 answers

    Ayushi Ayushi 7 years ago

    Your wellcome

    2Thank You

    Říý@ ?? 7 years ago

    Tnk u Yogita & Ayushi.......??........

    1Thank You

    Yogita Ingle 7 years ago

    Osmosis is the process in which solvent molecules moves through a semi-permeable membrane from a region of higher concentration to a region of lower concentration until the amount of fluid is equalised on both sides of the semipermeable membrane.  

    The fluid that passes through the semipermeable membrane is known as the solvent, while the dissolved substance in the fluid is known as the solute.  The mixture of solvent and solute makes up a solution.

     

    2Thank You

    Ayushi Ayushi 7 years ago

    Osmosis is a vital process in biological systems, as biological membranes are semipermeable. In general, these membranes are impermeable to large and polar molecules, such as ions, proteins, and polysaccharides, while being permeable to non-polar or hydrophobic molecules like lipids as well as to small molecules like oxygen, carbon dioxide, nitrogen, and nitric oxide. Permeability depends on solubility, charge, or chemistry, as well as solute size. Water molecules travel through the plasma membrane, tonoplast membrane (vacuole) or protoplast by diffusing across the phospholipid bilayer via aquaporins (small transmembrane proteins similar to those responsible for facilitated diffusion and ion channels). Osmosis provides the primary means by which water is transported into and out of cells. The turgor pressure of a cell is largely maintained by osmosis across the cell membrane between the cell interior and its relatively hypotonic environment.

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    • Posted by Vivek Yadav 7 years ago

    CBSE > Class 11 > Biology
    • 3 answers

    Saba Elias 7 years ago

    -The helical polypeptide molecules may fold in itself and assumes a complex but specific form. -it may be rod shaped or spherical or any other form. These specific geometrical shapes are known as tertiary structure of proteins. -It is 3D structure of proteins. -It is maintained by disulphite bond and H bond,ionic bond,hydrophobic interaction, hydrophilic interaction, vanderwall force Tertiary structure is affected by:- PH, temperature, chemical The tertiary structure is mainly observerd in globular proteins

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    Yogita Ingle 7 years ago

    • Bonds between neighboring amino acids results in further folded structure
    • Tertiary structure depends upon the primary structure
    • Creates active sites of enzymatic proteins
    • Some of the tertiary structures are spherical forming Globular proteins; while some others are like long fibers forming Fibrous proteins

    2Thank You

    Vivek Yadav 7 years ago

    Protein

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    • Posted by Sakshi Singh 7 years ago

    CBSE > Class 11 > Biology
    • 2 answers

    Saba Elias 7 years ago

    1) Direction of diffusion is from higher concentration to lower concentration but in osmosis the direction from lower concentration to higher concentration. 2) nature of medium in diffusion in any medium but in osmosis nature of medium is always in liquid medium. 3)nature of molecules in diffusion may be solid or liquid or gases but in osmosis it is always water or any other solvent molecules.

    1Thank You

    Sivan Karthick 7 years ago

    diffussion means moment of particle from higher concentration to lower concentration but Osmosis means moment of water particle from higher concentration to lower concentration through diffusion diffusion is any particle but osmosis means only moment of water

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    • Posted by Uday Shankar 7 years ago

    CBSE > Class 11 > Biology
    • 0 answers
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    • Posted by Swaggy Harshit⚘ 7 years ago

    CBSE > Class 11 > Biology
    • 3 answers

    Rani Layek 7 years ago

    Wha bahut jldi pehchan liye

    0Thank You

    Swaggy Harshit⚘ 7 years ago

    Rani..? Tum vhaii phale wali rani ho kya..?

    1Thank You

    Rani Layek 7 years ago

    Yes

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    • Posted by Sivan Karthick 7 years ago

    CBSE > Class 11 > Biology
    • 1 answers

    Saba Elias 7 years ago

    Svedberg unit is a measure of particle size dependent on the speed with which the particles sediment in the ultracentrifuge. S=1×10 to the power -13 The ribosomes are of 3 types namely 70s and 80s 70s are found in prokaryotes and 80s are found in eukaryotes

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    • Posted by Sivan Karthick 7 years ago

    CBSE > Class 11 > Biology
    • 4 answers

    Kunal Bhardwaj 7 years ago

    http://www.biologydiscussion.com/cell/plasma-membrane/top-4-historical-models-of-plasma-membrane-cell-biology/83448

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    Kunal Bhardwaj 7 years ago

    This is also known as unit membrane model. This model was proposed by Davson Daniell and Robertson. When surface tension measurements made on the membranes, it suggests the presence of proteins. After the existence of proteins the initial lipid bilayer model proposed by Gorter and Grendel was modified. It was suggested that surface tension of cells is much lower than what one would expect if only lipids were involved. It may also be observed that if protein is added to model lipid water system, surface tension is lowered. This suggested indirectly the presence of proteins. On this basis Davson and Danielli proposed that plasma membrane contained a lipid bilayer with protein on both surfaces. Initially they supposed that proteins existed as covalently bonded globular structures bound to the polar ends of lipids. Subsequently they developed the model in which the protein appears to be smeared over the hydrophilic ends of the lipid bilayer. This model makes its popularity for a long time. With the availability of electron microscope later, fine structure of plasma membrane could be studied. Definite plasma membrane of 6 nm to 10 nm (10nm = 100 Å; 1 nm = 10_6mm) thickness was observed on surface of all cells, and plasma membranes of two adjacent cells were found to be separated by a space, 1-15nm wide.

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    Kunal Bhardwaj 7 years ago

    2. Unit Membrane Model (Protein-Lipid Bilayer-Protein):

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    Kunal Bhardwaj 7 years ago

    The following points highlight the top four historical models of Plasma Membrane. The models are: 1. Lipid and Lipid Bilayer Models 2. Unit Membrane Model (Protein-Lipid Bilayer-Protein) 3. Fluid Mosaic Model 4. Dannelli Model. 1. Lipid and Lipid Bilayer Model: This model to explain the structure of plasma membrane was given by Overton, Gorion and Grendel. Previously only indirect information was available to explain the structure of plasma membrane. In 1902, Overton observed that substances soluble in lipid could selectively pass through the membranes. On this basis he stated that plasma membrane is composed of a thin layer of lipid. Subsequently, Gorter and Grendel in 1926 observed that the extracted from erythrocyte membranes was twice the amount expected if a single layer was present throughout the surface area of these cells. On this basis they stated that plasma membrane is made up of double layer of lipid molecules. These models of Gorter and Grendel could not explain the proper structure of plasma membrane but they put the foundation of future models of membrane structure.

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