Cell the unit of life class 11 notes

What is a Cell? A cell is defined as the most basic, structural and functional unit of all living organisms. Essentially, a cell is a structure that contains organelles which provide the necessary functions to sustain itself. However, not all cells are the same. Plants have cells that are vastly different from animals. One of the primary differences between the two is the absence of cell walls in For more information on Cell Structure and its Function Animal, watch the below video Cell Theory This scientific theory, initially formulated by Matthias Schleiden and Theodor Schwann, proposed that all living organisms are composed of cells, and new cells are formed from pre-existing cells. Even though the theory was put forth by Schleiden and Schwann, other notable scientists have contributed to this theory, turning its status from a theory to a universally accepted fact. Prokaryotic Cells Prokaryotic cells are unicellular microorganisms and one of the most ancient organisms on earth. There are many types of prokaryotes, some of which are extremophiles. Others are photoautotrophic, able to produce nutrients from the energy of the Sun. A typical prokaryotic cell is made up of a single membrane, and therefore, all the reactions occur within the cytoplasm. They can be free-living or can be found within the gut of other organisms, such as ruminants (cows and buffaloes). Eukaryotic Cells Unlike prokaryotic cells, eukaryotic cells possess a nucleus enclosed within a membrane. All mul...

Cell: The Unit of Life Notes Class 11 Biology Chapter 8 → All organisms are composed of cells. → Some are composed of a single cell and called unicellular organisms while others, like us, are composed of many cells and called multicellular organisms. → The cell is the fundamental structural and functional unit of all living organisms. → Unicellular organisms explain that a cell is capable of independently existing and of performing the essential functions of life. → Robert Hooke was the first person to describe the cell in 1865 when he used a microscope built by him to examine a thin slice of cork. → In 1831, Robert Brown made an important discovery when he reported the presence of a small sphere in the cells of the orchid root. This rounded body which later came to be called the ‘nucleus’ was thought to be of common occurrence in the cells. → In 1838, Matthias Schleiden, a German Botanist, examined a large number of plants and observed that all plants are composed of different kinds of cells which form the different tissues of the plant. → Same time, Theodore Schwann (1839), a British Zoologist, also studied different types of animal cells. He observed the nuclei in these cells had a thin outer layer which is today known as the ‘plasma membrane’. → Schwann proposed the hypothesis that the bodies of animals and ( plants are composed of cells and products of cells. → Schleiden and Schwann combined their views and formulated the cell theory. → In 1855 when Rudolf Virchow fir...

• They have no membrane bound nucleus and organelles. • They include bacteria, blue-green algae, mycoplasma & PPLO (Pleuro Pneumonia Like Organisms). • They are generally smaller and multiply more rapidly than the eukaryotic cells. • They vary in shape & size. E.g. Bacteria have 4 basic shapes: Bacillus, Coccus, Vibrio and Spirillum. It is a chemically complex protective covering. It is made of 3 tightly bound layers. • Glycocalyx: Outer layer. Its composition and thickness vary in different bacteria. It may be a slime layer (loose sheath) or capsule (thick & tough). • Cell wall: Middle layer. Seen in all prokaryotes except mycoplasma. It gives shape to the cell and provides a structural support to prevent the bacterium from bursting or collapsing. • Plasma membrane: Inner layer. It is semi-permeable in nature and interacts with the outside. This is structurally similar to that of the eukaryotes. Based on the types of the cell envelopes and response to Gram staining (developed by Gram), bacteria are 2 types: • Gram positive: They take up and retain the gram stain. • Gram negative: They do not retain the gram stain. 2. Mesosomes & Chromatophores (Membranous structures) Mesosome is formed by the infoldings of plasma membrane. It includes vesicles, tubules & lamellae. Functions: Mesosomes help • In cell wall formation. • In DNA (chromosome) replication. • In distribution of chromosomes to daughter cells. • In respiration and secretion processes. • To increase the surface area...

Class 11 Biology Chapter 8 Notes introduces you to the basic unit of life, that is, cell. There are innumerable types of living and nonliving organisms on earth; cells are the building blocks of each living organism. If you go through Vedantu’s NCERT Biology Class 11 Chapter 8 notes thoroughly you will get to learn about cells, their microstructure and functions of each micro-organelle. Based on the number of cells present in the body, organisms are broadly classified into two groups- unicellular and multicellular organisms. The cell is the smallest, basic structural, and functional unit of living things; hence it is generally referred to as ‘building blocks of life. Cells are capable of independent existence and performing essential functions of life. All organisms including plants and animals are made up of one or more cells and all that cells come from pre-existing cells. Robert Hooke was the scientist who first discovered cells in a piece of cork. Different Types of Cell In the human body, different types of cells are present such as hepatocytes in the liver, nephrons in the kidney, neurons in the brain, etc. The different types of cells are grouped to form tissues. These tissues perform specific functions. Cell Theory In 1839, two scientists named Schleiden who was a German botanist, and Schwann who was a British zoologist, announced the cell theory. The modern theory of the cell includes- • Every living organism is made up of cells. • The cell is said to be the basic...

Class 11Cell The Unit of Life – Get here the Notes for Class 11 Cell The Unit of Life. Candidates who are ambitious to qualify the Class 11 with good score can check this article for Notes. This is possible only when you have the bestCBSE Class 11 Biology study materialand asmart preparation plan. To assist you with that, we are here with notes. Hope these notes will helps you understand the important topics and remember the key points for exam point of view. Below we provided the Notes of Class 11 Biology for topic Cell The Unit of Life. • Class: 11th • Subject: Biology • Topic: Cell The Unit of Life • Resource: Notes CBSE Notes Class 11 Biology Cell The Unit of Life Candidates who are pursuing in Class 11 are advised to revise the notes from this post. With the help of Notes, candidates can plan their Strategy for particular weaker section of the subject and study hard. So, go ahead and check the Important Notes for Class 11 Biology Cell The Unit of Life from this article. Class 11 Biology Notes for Cell The Unit of Life Class 11 Key Points, Important Questions & Practice Papers Hope these notes helped you in your schools exam preparation. Candidates can also check out the Key Points, Important Questions & Practice Papers for various Subjects for Class 11 in both Hindi and English language form the link below. Class 11 NCERT Solutions Candidates who are studying in Class 11 can also check Class 11 NCERT Solutions from here. This will help the candidates to know the solut...

Why do we need to learn about cells? The cell is fundamental to all life. All diseases, for example, Alzheimer’s, dengue, diabetes, cancer, TB, etc., are caused at the cellular level. Understanding how the cell works helps us find better treatments for diseases. Besides diseases, there are many other applications of cell biology. Studying the DNA of ancient skeletons that have been dug up, making better crops, solving murders, and many more! In this unit, learn how cells of all organisms - from bacteria to human beings - are essentially similar, and how they work.

Class 11 Biology Notes for Cell The Unit of Life – Get here the Notes, Question & Practice Paper of Class 11 Biology for topic Cell The Unit of Life. Candidates who are ambitious to qualify the Class 11 with good score can check this article for Notes, Question & Practice Paper. Below we provided the link to access the Notes, Important Question & Practice Paper of Class 11 Biology for topic Cell The Unit of Life. You can practice the questions and check your answers from the solutions given after question. By practicing this resources candidates definitely get the idea of which his/her weak areas and how to prepare well for the examination. • Class: 11th • Subject: Biology • Topic: Cell The Unit of Life • Resource: Notes, Important Question & Practice Paper Class 11 Biology Notes for Cell The Unit of Life Candidates who are pursuing in the Class 11 are advised to solve the Question Paper and revised the notes from this post. With the help of Notes, candidates can plan their Strategy for particular weaker section of subject and study hard. So, go ahead and check the Important Question & Practice Paper for Class 11 Biology Notes for Cell The Unit of Life from the link given below in this article. Class 11 Biology Notes for Cell The Unit of Life