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NCERT Solutions for Class 11 Biology

NCERT Solutions for class 11 Biology is written by expert faculty members of Physics Wallah having decade of teaching experience. There are 15 chapters in NCERT text book of class 11 Biology. Each chapter having one or two exercise having questions from 15 to 35. Our team solved all questions with required information and diagram as per the requirement of CBSE.

Right strategy for the preparation of school exam with NEET starts from class 11. With proper mix of NCERT text book and reference book. For a student career class 11 is very important and must have clear strategies to excel.

Do you know about 85 percent questions asked in NEET 2019 are directly from NCERT text book. Out of this about 45 percent form NCERT class 11 text book and rest 65 form NCERT text book of class 12. This data explains the important of NCERT class 11 Biology text book importance. With Physics Wallah NCERT Solutions for class 12 Biology you will be ready will for all challenge.

How to start Class 11 Biology

Start your preparation with NCERT text book with NCERT solutions for class 11 Biology. Strat with the basics of class 11 Biology. Read first chapter of NCERT text book. Prepare your Notes form NCERT text book. While preparing notes form NCERT text book make sure you have added all important points given in class 11 biology section of Physics Wallah.

Do solve the MCQ given in Physics Wallah.Solve all questions mentioned in NCERT text book. Biology is subject of concept and diagram. While preparing Biology class 11 notes draw clear diagram mentioning all important points.

Tips to score Good Marks in Class 11 Biology

  1. Revision of the content is must to score good rank and marks in CBSE.
  2. Normally Students works hard just before the exam day which is very wrong strategy. If you study continuously in the pressure of exams and ultimate result is not satisfactory.
  3. Prepare the scheduled for one week and try to follow scheduled strictly.
  4. Divide the scheduled on the daily basis, fix the target on hour basis i.e number of questions should be completed in particular time frame. Or the particular topic should be covered in particular time frame.
  5. At the end of the day find out targets which you achieved. it will give you positive energy to complete the scheduled and to follow your daily targets.
  6. Every day you are achieving your daily targets. This will help you to achieve your final goal of getting good marks in your school exams as well as preparing yourself for competitive exams too.

Why Physics Wallah for Class 11 Biology

  1. It is very much essential for biology student who is aspiring for NEET along with wants a good performance in Board too that you have good command on diagrams of class 11th and 12th biology portion.
  2. In today’s scenario in NEET-UG very large section of questions have asked directly or indirectly on the diagrams and tables given NCERT books.
  3. Solve all questions of NCERT text book take help from NCERT Solutions For Class 11 Biology.
  4. A large no. of questions in JIPMER, AIIMS and NEET are based on Diagrams and content of NCERT tables, so keep it in mind, the importance of these.
  5. As you know class 11th content is very important, a student must learn with great interest, and make a habit of asking questions in regular class, never keep doubts with you.
  6. Doubts should be cleared as early as possible to achieve a great success, command and interest in particular subjects.
  7. You can take help from NCERT Solutions For Class 11 Biology.If you are not clearing your doubts on daily basis, they will accumulate day by day  and ultimately leads to development of fear with particular subject.
  8. On other side if you clear yours doubt on daily basis, it would create interest with subject and there would be no fear with subject as well as on exam days, you will love to attempt exams.
  9. Your handwritten notes play a vital role in achieving your goal of getting a good marks in CBSE too.
  10. Always prepare your own notes for every chapter, especially in case of biology there is no replacement of your own handwritten notes, use different colored pen to draw diagrams, topics, subtopics.
  11. Students you would be able to learn your class content in less time as compared to printed notes or notes taken from any other student, even you can revise and recall your whole chapter within few minutes if you are revising that from own handwritten notes.
  12. If you are in class 11th and preparing for UG Medical exams such as NEET, JIPMER, AIIMS and also willing to get good grades in CBSE exams then you should follow the all those points which we have discussed

Brief description of Important chapters of NCERT Solutions for Class 11 Biology

  • Chapter- 1: Cell the Unit of Life

In this chapter you will learn The Unit of Life ; Structure and Function, Cell wall; Cell membrane; Endomembrane system (ER, Golgi apparatus/Dictyosome, Lysosomes, Vacuoles); Mitochondria; Plastids; Ribosomes; Cytoskeleton; Cilia and Flagella; Centrosome and Centriole; Nucleus; Microbodies. Structural differences between prokaryotic and eukaryotic,  and between plant and animal cells. Cell cycle (various phases); Mitosis; Meiosis. Biomolecules – Structure and function of Carbohydrates, Proteins, Lipids, and Nucleic acids. Enzymes – Chemical nature, types, properties and mechanism of action.

  1. Cell is a structural and functional unit of living beings which consists of a membrane covered mass of protoplasm.Life exists only in the form of cells.
  2. Cytology is the study of form and structure of cells as well as their organelles with the help of microscope.
  3. Cell biology is the branch of biology that deals with the study of structure, biochemistry, physiology, reproduction or division, evolution and genetics of cells.
  4. Lamarck in 1809 said that no body can have life if its constituent parts are not formed of cells.
  5. Cell was discovered by Robert Hooke in 1665.He was a mathematician and physicist who joined Royal Society of London as curator of instruments in 1662.He developed a compound microscope and with the help of it he saw honey comb like structure of the thin section of the cork.He named these as cellulae.He published his findings in the form of book Micrographia
  6. Cells of Robert Hooke were actually empty dead spaces separated by cell wall.  First living cell was observed by AV Leeuwenhoek.He (1674-1683) examined a number of single celled organism (bacteria, protozoan), sperms and erythrocytes etc with the help of his microscope.
  • Chapter- 2: Structural Organisation in Animals

Basic principles of Classification, Need for Classification, Nomenclature, Levels of Classificaiton, Species concept, Diploblastic and triploblastic organisation, Symmetry, Coelom, Acoelomates, Pseudocoelomates, Eucoelomates, Methods of formation of eucoelom. Basic principles of classification-The terms systematics, taxonomy and classification are often used interchangeably. G. Simpson (1961) has distinguished these terms as follows

Systematics ( Gk. systema – order or sequence )

This term was coined by Linnaeus. The study of diversity of organisms, their comparative and evolutionary relationship based on comparative anatomy, ecology, physiology, biochemistry and other field is known as systematics.

Taxonomy (taxis – arrangement, nomos – law)

This term was coined by de Candolle (1813). It is the branch of biology which deals with the study of principles and procedures of classification, nomenclature and identification. Taxonomic knowledge requires the study of morphology, cytology, embryology, biochemistry, genetics and ecological relationship etc. Linnaeus is considered as father of taxonomy. But according to Turril taxonomy can be of following types:

  1. Taxonomy-Taxonomic study deals with collection and identification of organisms on the basis of gross morphology, compilation of flora and monographs.
  2. Taxonomy-Taxonomic study deals with arranging species into natural classification on the basis of all available evidences.
  3. Taxonomy-Taxonomic study deals with biological aspects of taxa like intraspecific population, speciation, rate of evolution and evolutionary trends.
  4. Classification-It is a subtopic of taxonomy or systematics that deals with arranging organisms into groups or categories according to a systematic plan on the basis of their similarities, differences and relationships.

Need for classification

Biological classification is the scientific procedure of arrangement of organisms into groups on the basis of their similarities and dissimilarities and arranging them in a hierarchy of categories. Following are the reasons which satisfy the need for classification

  1. Classification helps in knowing the relationship among different groups of organisms.
  2. There are about 1.25 million animal species have been discovered, identified and described so far, they have diversity in structure, habits, habitats and mode of life, it is not possible to study every organism but study of one or two organism of a group can give sufficient relative information about essential features of the group.
  3. Location of different organisms is different. It means all kinds of organisms do not occur in one locality.
  4. Fossils cannot be studied without the help of a good system of classification.
  5. Relationship and simplicity or complexity found in different organisms of various texa explains the evolution.
  • Chapter- 3: Transport in Plants

Absorption of water: Introduction, Types of soil water, Water Potential, Diffusion, Imbibition, Osmosis, Plasmolysis, Mechanism of water absorption; Ascent of Sap: Definition, Mechanism of Ascent of Sap; Transpiration: Definition, Types of Transpiration, Mechanism of Stomatal opening and closing, Factors, Significance of Transpiration, Antitranspirants.

In flowering plant the substances that would need to be transported are water, mineral nutrients, organic nutrients and plant growth regulators. Over small distances substances move by diffusion and by cytoplasmic streaming supplemented by active transport. Transport over longer distances proceeds through the vascular system (the xylem and the phloem) is called Translocation.

Diffusion

  1. It is the movement of particles of a substance from a region of its higher concentration to the region of its lower concentration until the molecules are evenly distributed throughout the available space.
  2. No energy expenditure takes place.
  3. In diffusion, molecules move in a random fashion, the net result being substances moving from regions of higher concentration to regions of lower concentration.
  4. It is a slow process and is not dependent on a living system.
  5. Diffusion rates are affected by the gradient of concentration, the permeability of the membrane separating them, temperature and pressure.
  6. It is an important factor in the supply of carbon dioxide for photosynthesis and the loss of water vapour from the leaves during transpiration.

Facilitated diffusion

  1. Substances that have a hydrophilic moiety, find it difficult to pass through the membrane. Membrane proteins provide sites at which such molecules cross the membrane. They do not setup a concentration gradient. A concentration gradient must already be present for molecules to diffuse even if facilitated by the proteins. This process is called facilitated diffusion.
  2. In facilitated diffusion special proteins help move substances from a low to a high concentration this would require input of energy.
  3. Facilitated diffusion is very specific. It allows cell to select substances for uptake. It is sensitive to inhibitors which react with protein side chains.
  4. The proteins form channels in the membrane for molecules to pass through. Some channels are always open, other can be controlled. Some are large, allowing a variety of molecules to cross.
  5. The porins are proteins that form huge pores in the outer membranes of the plastids, mitochondria and some bacteria allowing molecules upto the size of small proteins to pass through e.g. water channels are made up of eight different types of aquaporins.
  • Chapter- 4: Photosynthesis in Higher Plants

Definition, Structural organisation of chloroplast, Photosynthetic pigments, Mechanism of photosynthesis, Factors influencing photosynthesis, Photorespiration, Blackman’s law of limiting factors.

The ultimate source of energy for entire life on earth is solar energy. The only mechanism by which the solar energy can be trapped on earth is photosynthesis. By photosynthesis, the light energy is transformed into chemical potential energy and stored in the molecules of organic food, i.e. sugar molecules in plants. Besides this, photosynthesis is the only mechanism of generation of oxygen on earth. Hence; photosynthesis may be described as the lifeline for the biotic world.

Definition-It is described as synthesis of organic food from inorganic material by using energy of light in presence of chlorophyll. Meyer defined photosynthesis as the process of transformation of radiation energy to chemical potential energy. It is an anabolic and endergonic process, which uses the light energy inorder to photochemcially reduced CO2 into the carbohydrates.

Von Niel (1931) was first to suggest that source of O2 released in photosynthesis was H2O and not CO2. This conclusion was given on the basis of the comparative analysis of reactants and products of photosynthesis in bacteria and higher plants. Bacteria do not use H2O as source of H; they do not release O2. Plants use H2O as source of H, they release O2.

  • Chapter- 5: Respiration in Plants

Definition, Types of respiration, Mechanism of aerobic respiration, mechanism of anaerobic respiration, Respiratory quotient.

Cellular Respiration- It is the mechanism of breakdown of food materials within the cell to relase energy and the trapping of this energy for synthesis of ATP.

  1. The breakdown of complex molecules to yield energy takes place in the cytoplasm and in the mitochondria.
  2. The breaking of the CC bonds of complex compounds through oxidation within the cells leading to release of considerable amount of energy is called respiration.
  3. The compounds that are oxidized during this process are known as respiratory substrates.

Mitochondria

  1. They are associated with aerobic respiration.
  2. They are limited by smooth outer membrane and contain a highly invaginated inner membrane which has a special role in energy transduction. The gap between these two membranes is called as the inter membrane space (perimitochondrial space). The inner membrane is selectively permeable to a few molecules like water, O2 and CO2.However, its permeability to protons is very low or absent, which is a significant factor for ATP synthesis.
  3. The stalked particles on the mitochondrial crests are called FoF1 complex, which were previously referred to as oxysomes or elementary particles.
  4. The inner chamber of mitochondria is filled with a dense and granular mitochondrial matrix, which contains 70% of respiratory enzymes, 70s type of ribosomes, circular DNA, RNA and several ions.
  • Chapter- 6: Mineral Nutrition
  1. Types of Nutrition: Introduction, Types of Nutrition; Mineral Nutrition: Introduction, Soil as source, Criteria of essentiality, Importance of macro and micro elements, Ion absorption, Biofertilizers.
  2. Mineral and nitrogen nutrition in plants
  3. Introduction
  4. The chemical substance that works as raw material for body building and maintaining its functions is termed as nutrient.
  5. The first study in inorganic or mineral nutrition was carried out by Van Helmont in 1648.
  6. An essential element is the one which has a specific structural or physiological role and without which plants cannot complete their life cycle.

Criteria for essentiality (Proposed by Arnon and Stout)

  1. It is indispensable for the growth of plants.
  2. The element is directly involved in the nutrition of plants. It becomes a component of either a structural or functional molecule. The element may additionally have a corrective effect on mineral balance and other soil conditions.
  3. A plant is unable to complete its vegetative or reproductive phase in the absence of the element.
  4. The element cannot be replaced by any other element.
  5. The absence or deficiency of the element produces disorders. These disorders are a direct result of the lack or deficiency of the element.
  6. The element alone can correct the disorders produced by its absence or deficiency. 16 elements have been found to be essential. They are C, H, O, N, P, K, S, Mg, Ca, Fe, B, Mn, Cu, Zn, Mo, Cl.Others are called nonessential elements.

Chapter- 7: Plant Growth and Development

  • Growth curve, Introduction of Growth regulators, Auxins, Gibberellins, Cytokinins, ABA, Ethylene, Photoperiodism, Vernalization.
  • Plant growth and development
  • Growth-It is an irreversible permanent increase in size of an organ or its parts or even of an individual cell.
  • It is regarded as one of the most fundamental and conspicuous characteristics of a living being.
  • It is accompanied by metabolic processes that occur at the expense of energy.
  • Growth curve-This is obtained by plotting growth rate of a plant against time. Growth curve resembles the shape of ‘S’ and so it is named as sigmoid curve.

The growth curve consists of three phases of growth. They are

  • Lag phase: This is the first phase of growth. In this period, growth is slow but steady. Since new cells are formed from meristematic zones, this phase is also called formative phase.
  • Log phase: This is the second phase of growth. This is a period of maximum growth. In this phase, plant shows rapid increase in its height. It is also called logarithmic phase or exponential phase.
  • Senscent phase: This is the third phase during which plant exhibits declining growth activity. This phase corresponds to maturity of cells. The log phase is followed by senescent phase.

Frequently Asked Question (FAQs)

Q1. What is the best way to us the NCERT textbook for class 11 Biology?

Ans. NCERT textbook is considered as one of the best books for class 11 Biology for CBSE board as well as for competitive entrance exams like NEET. In the year 2019, almost 90 percent of questions asked in NEET are directly from the NCERT textbook. The right approach to read the NCERT textbook is. Start from the first chapter read the theory given in the textbook and understand the concepts behind it.

Read the bullet points given in the boxes and try to prepare notes of all important points given in the textbook. Once you complete the theory part try to solve all questions given in the exercise of the textbook and use Physics Wallah NCERT Solutions for class 11 Biology for reference.

Q2. How NCERT class 11 biology can help me to score good marks in class 11?

Ans. In all most, all CBSE schools the recommend book is NCERT class 11 Biology. The syllabus of CBSE is well explained in NCERT textbooks. When you are preparing for your school exam either it is unit text or half-yearly or final exam questions are asked directly from NCERT exercise of theory parts.

Read all examples given in the textbook complete the exercise make your notes and solve all MCQ based questions given in the Exercise. You can do more practice form NCERT exemplar of NCERT it consists of very good quality questions which enhanced your learning and understanding in the chapter.

Q3. What are the most important chapters of class 11 biology in the NCERT textbook?

Ans. All chapter is equally important to build a solid foundation of class 11 biology still there are few topics which need more attention like Diversity in the living world, Cell structure, and functions, Structural organization in plants and Plant physiology, Reproduction in plants, Structural organization in animals, Human physiology, Human reproduction, Genetics, and Evolution is again very important and need time to understand, Biology and human welfare, Biotechnology and its applications, Ecology and Environment.

Q4. NCERT textbook is enough for a good foundation of class 11 Biology?

Ans. Yes NCERT textbook for class 11 Biology is self-sufficient and you don’t require any other reference book for your school as well as a competitive entrance exam. Read thoroughly the NCERT class 11 Biology textbook to have clarity in the concept try to note down important points and diagrams as well.

Q5. How to prepare notes to form the class 11 Biology textbook?

Ans. Notes are the most important and key part of Biology on which you must work. Preparing good quality notes will help you to achieve your goal and effective revision. Start preparing notes from the NCERT textbook as well as your school class make sure you are adding diagrams on your notes with proper tagging of important points and parts of diagram this will help you to remember the important points. Make a separate section for important points of chapter mentioning all-important points and information.

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