NCERT Solutions for Class 11 Biology

Welcome to the NCERT Solutions for Class 11 Biology. This page offers chapter-wise solutions designed to help students grasp key concepts easily. With detailed answers and explanations for each chapter, students can strengthen their understanding and prepare confidently for exams. Ideal for CBSE and other board students, this resource will simplify your study experience.

• Chapter 1 The Living World

  As the name simplifies this chapter is all about the living creature on this earth. Each organism is different from the other to a lesser or greater extent. Here we will discuss the criteria of the living organism, their identification, classifications and nomenclature i.e. their taxonomy, why organisms are grouped into some category or other.

• Chapter 2 Biological Classification

  A few letter word diversity is itself a huge variation of a living creature. Have you ever thought of the life form that surrounds us? This is the beauty of nature. In this chapter we will focussed an the R.H. Whittaker biological classification of living organisms. He classified it into 5 kingdoms monera, protista, fungi, plantae and animalia. Here some are microscopic and some are huge but all are living creatures. Whereas no place in biological classification for viruses. What does this mean do viruses non living. You have heard of different viral diseases that mean they have a tendency to multiply with living cells. This is because viruses when outside the host they are non living but when comes in contact with the host body it becomes living. This is a peculiar feature of the virus.

• Chapter 3 Plant Kingdom

  From the very beginning we studied about plants as they are autotrophs. They prepare their own food since plants are of diverse form as aquatic, herb, shrubs, trees according to the habitat they adapted to specific features. The first level of classification among plants depends whether they have well differentiated parts and secondly on the presence of vascular tissue and finally on the basis of ability if seed persistence. Kingdom plantae is classified into 5 division i.e. Thallophyta, Bryophytes, pteridophyte, gymnosperm, angiosperm and this chapter focus on their life cycle pattern.

• Chapter 4 Animal Kingdom

  Animals are the heterotrophs they can locomote from one place to another. This is very general that we have studied yet but many more features to explore. In this chapter we will discuss the different phylum and different physiological function. Most important is the body design and differentiation of varieties of animal. According to body design they are classified as porifera, coelenterata, platyhelminthes and many more.

• Chapter 5 Morphology of Flowering Plants

  Term morphology is the study of external or physical appearance of plants. The parts we see like flowers, leafs, stem, root are the morphological parts of plants. Wide varieties of plants are in our surrounding adapted to different physical features according to the habitat. Some are herbs like grass and huge trees like Eucalyptus with different patterns of leaf, root. In this chapter we will focus on the type of the root, leaf, stem and inflorescence. Seed producing plants are classified as monocot and dicot. Both of them have different types of root system and pattern of arrangement of leaf on stem. Yet one more important aspect is the modification of leaf stem. As we can see in cactus the fleshy leaf like structure is a modified stem known as phylloclade and different other features are explained in this chapter.

• Chapter 6 Anatomy of Flowering Plants

  This chapter is focussed on the of anatomy of the angiosperm which means the study of internal structure. The plants are made of plant cells and they are grouped to form tissue. Plant tissue that the tendency of cell division is meristematic tissue due to which the growth of plant parts remains continuous. Later the meristematic tissue becomes permanent. Permanent tissue is of two types: simple permanent and complex permanent. Internally the plant has a different arrangement of cell. That determines its shape and size. Monocots do not have well developed vascular tissue in comparison with dicot plants. Monocot leaf, stem and roots are distinct from dicot in various forms this is explained in anatomy of flowering plants.

• Chapter 7 Structural Organisation in Animals

  In the previous chapter we have discussed plant tissue but animals have varieties of tissue that provides them a typical structure and enables them to perform various functions. In this chapter we understand the animals tissues it type and their function and morphological anatomical structure including alimentary canal, nervous system, reproductive structure and excretory structure of earthworm, cockroach and frog. This helps to provide knowledge about various animals, what are the physiological functions that help to survive.

• Chapter 8 Cell: The Unit of Life

  Cells, honeycomb like structure or compartment are the basis of life. So interesting this was little tiny cell control and coordinate to perform various vital functions. Within the cell very minute structure called cell organelles are present and play their specific role like mitochondria known as powerhouse of the cell nucleus as brain of the cell and others with more important function. The cells have capacity for division mitosis and meiosis. This chapter makes us understand how chromosomes divide and distribute in daughter cells.

• Chapter 9 Biomolecules

  As discussed above the organism is made of cells. They perform vital function. The cells are made of organic macromolecule through these number of metabolic activities that occur and lead the building block of our body. These biomolecules are carbohydrate, protein, lipids, vitamins, nucleic acid etc. In this chapter we will get information regarding the linkage of carbohydrate i.e. glycosidic bond , protein linkage ie. peptide bond and more. Only 20 amino acids are yet known as the combination as these 20 amino acids make millions of proteins, protein are the building block unit of the cell. Emphasis on nucleic acid on how these formed their structure and functions.

• Chapter 10 Cell cycle and Cell Division

  The fundamental unit of life the cell plays a vital functions one of which is its division. For this the cell enters into an interphase which is 95% of the cell cycle and 5% is the division phase or M phase. There are two type of cell division first is mitosis which is also called equational division because the same number of Chromosomes are present in the parental cell and newly formed daughter cell. Second type is meiosis which is a reductional division where the chromosome from diploid in the mother cell gets reduced into a haploid or half set of chromosomes that only occur in the reproductive cell. While reading this chapter it will be more clear and understandable how step by step the cell undergoes various chromosomal change and finally new daughter cells are formed.

• Chapter 11 Transport in Plants

  For all the living creatures whether they are microscopic organism plants or animals, everyone needs nutrients for their survival. Plants are stationary and can not locomote yet very interestingly plant adapted the various modes of transport of food, water and essential minerals. Transportation is performed by vascular bundles xylem and phloem. Xylem helps in unidirectional flow of water and minerals from ground through root and transport to various parts of plants. Whereas the food prepared by the leaves through photosynthesis is translocated to various plant parts through phloem. In this chapter we will come to know the various mechanisms of transportation of water and food.

• Chapter 12 Mineral Nutirtion

  Minerals are the naturally occurring substances that are essential less or more to the metabolic activities in living organisms. Minerals are the growth factors to the plants also. If plants do not get sufficient amounts of nutrients it leads to deficiency disease like necrosis, immature fall, yellow leaf curling of leaf, stunted growth etc. some nutrients are required in less quantity; they are known as micronutrients but if they are required in large quantities they are said to be macronutrients. If in case the nutrient gets rich or uptake of nutrient is more than that of standard value it leads to toxicity like other organism plants also need balanced amounts of nutrient. In this chapter we will come to know different metal on and nonmetal ions are used by plant growth and deficiency and toxicity affect the plant growth and cause of disease.

• Chapter 13 Photosynthesis in Higher Plants

  From our childhood we are knowing about plants are autotrophs they synthesize their own food by the process of photosynthesis. This chapter will help us to reveal photosynthesis more in detail where and how the process occurs and what is the role of chlorophyll. How chlorophyll trap sunlight, what are the role of photosystem P680 and 700. What is actually step by step process how the co2 uptake occurs which to its reduction and finally the carbohydrate are formed. Formation of carbon compounds are explained through C3 cycle or Calvin cycle, C4 cycle.

• Chapter 14 Respiration in Plants

  Stomata are the tiny pores present on the surface of the leaf for exchange of gases. plant uptakes co2 from the atmosphere and releases oxygen from the stomatal pore. In this chapter we will discuss glycolysis breaking down 6 carbon compound glucose into 3 carbon. Pyruvic acid and Tricarboxylic acid cycle and Electron transport chain in detail.

• Chapter 15 Plant Growth and Development

  Growth and development means increase in size and maturity of the plant respectively. There are certain growth regulators that control the growth and development of plants. In this chapter we will study the geometric and arithmetic growth model with different phytohormone like auxin, gibberellin, cytokinin, abscisic acid, ethylene with this we will focus on photoperiodism and vernalisation. These two phenomenon are influenced by abiotic components like farther is based on intensity of light period and later one on cold temperature. We will come to know about interaction of abiotic components with plants.

• Chapter 16 Digestion and Absorption

  Animals are heterotrophs, they feed on others to get nutrients for survival. Different organisms had adapted various methods of intaking food. In this chapter we will discuss human digestion and absorption. Humans get food from plant and animal products that are rich in certain and might contain essential nutrients like carbohydrate, protein, lipids, and vitamins for various metabolic activities. In this chapter the main areas of focus is digestive gland and how digestion of different macromolecules occurs and is absorbed by the intestine. Regulatory mechanism and disorders.

• Chapter 17 Breathing and Exchange of Gasses

  In the previous chapter we discussed breaking down food into simpler substances like glucose, amino acid and fatty acid. Each and every physiological activities in our body is interconnected to each other. We know about breathing, inhaling oxygen and exhaling of co2. How efficiently our body organ coordinates ,digested foods comes into blood and the air inhaled through the respiratory tract reaches to lungs and finally to the blood where oxidation of food occurs to produce energy for various vital functions of the body. This chapter covers the respiratory system of the human, function of different parts of the respiratory system, Breathing mechanism, Regulatory mechanism on and Disorder of respiratory system.

• Chapter 18 Body Fluids and Circulation

  Blood is one of the connective tissues, a body fluid that performs various functions like transportation of nutrients, exchange of gases removal of waste material. This chapter covers the component of blood, blood vessels, circulation, of blood, structure of heart, working of heart completing cardiac cycle one cardiac cycle complete less than one second producing heart sound lub and dub due to closure of tricuspid and bicuspid second sound due to closure of semilunar valve respectively. Here in this chapter electrocardiograph explains the electrical activity of the heart which is used for clinical diagnosis of heart. Regulatory mechanism of heart activity and disorder of the circulatory system.

• Chapter 19 Excretory products and their Elimination

  Human body produces various harmful substances due to different metabolic activities that have to be removed by our body such as urea,Uric acid ,ammonia ,co2 etc. This work is performed by the kidney, lungs and skin. The nitrogenous waste like urea, uric acid and ammonia are removed and filtered from the blood through the kidney. Various organisms have different excretory organs like protonephridia, nephridia, green gland, malphigian tubule and the most advanced or complex one is kidney. This chapter focus on the structure of the kidney, it unit nephron ,countercurrent mechanism the process of concentration of urine. Regulatory mechanisms like rennin. angiotensin mechanism and disorders of excretory system.

• Chapter 20 Locomotion and Movement

  These chapters make us feel very excited how animals can move their hand, neck and other body parts so they can locomote from one place to another. Movement and locomotion can be done by contraction and relaxation of muscle. In this chapter we will come to know about the type of muscle and their function. Smooth muscles perform involuntary action whereas unsmooth muscles or straited muscle perform voluntary action. Here we will also understand the mechanism of muscle contraction most common is the sliding filament mechanism. Role of actin and Myosin in contraction. Human skeletal system various types of bones and the joint and disorder of muscular system.

• Chapter 21 Neural Control and Coordination

  Humans are the most advanced mammals. Humans can memorise, think, create , feel the sense all the work done is through our brain. In this chapter we will cover the Human Nervous system, Brain, Spinal cord and the nerve that arises from them. In your previous class you have read about a unit of the nervous system is neuron or nerve cell. These nerve cells are the longest cells in humans and perform the function of transmission of signal from brain to other part or from other part of body towards brain. Chapter reveals the structure of the brain and their parts. Brain works still when we are in sleep, we see with the eye, we smell with the nose and other senses but Brain interprets what we see, the taste, smell and feel. Here we will also cover the structure and working of the human eye and ear.

• Chapter 22 Chemical Coordination and Integration

  In the previous chapter we discussed the nervous system and its working but control and coordination in the organism is incomplete without an endocrine system or hormonal system. Both these systems work in synchronised manner to make all physiological functions to perform. Digestion, respiration, reproduction to all are regulated Neurally and chemically by these two systems. This chapter will surprise you with how metabolic activities are controlled by hormones. These chemical messages are responsible for growth, respiratory process, digestion and other. There are various type of hormone made of protein aminoacid and steroid. These hormones bind with receptors and regulate various mechanisms.