The Various organism , both plants and animals differs in shape, size, food

1. CELL — STRUCTURE AND FUNCTIONS • The Various organism , both plants and animals differs in shape, size, food • habits and habitats. • But all of them has one common feature , they all are made up of one • tiny unit called cells. • In Biology, Cells are structural and functional unit of life. • In order to understand structure and functioning of an organism , we should • understand the structure of cell and function of various part of cells

2. Discovery of cells The cell was first discovered by Robert Hooke in 1665. Robert Hooke used a microscope to investigate the structure if thin slice of cork. He observed that cork has tiny compartment in it( see figure) and he named it as “cells”. This came from the Latin word Cella, meaning ‘a small room’ like monks lived in. Microscope used by Robert was primitive.With microscopes during this time having a low magnification, Hooke was unable to see that there were other internal components to the cells he was observing. Therefore, he did not think the "cellulae" were alive.His cell observations gave no indication of the nucleus and other organelles found in most living cells. In 1838 German scientist schleiden suggested that all plants are made of cells In 1839 German scientist Schwann suggested that all animals are made of cells. Drawing of the structure of cork by Robert Hooke Robert Hooke's microscope

3. CELL — STRUCTURE AND FUNCTIONS Cell theory Observations in previous slides leads to general cell theory of organism • All living organisms are composed of one or more cells • 2. The cell is the most basic unit of life • 3. All cells arise only from pre-existing cells

4. CELL — STRUCTURE AND FUNCTIONS The Cell • Cells are basic units of life. All the living things (Plant and Animals ) are made from cells. Just as a house is made of bricks , a living organism is made of cells. Thus cells are called building block of plants and animals. A baby, a palm tree and a bacteria are very different from each others but all of them are made of tiny cells. Our hands, legs, nose , eyes are made of cells. • The simplest organism like Amoeba consist of only one cell but complex organism human being is made of trillion of cells. Thus a cell is smallest unit of life which has a definite structure and perform a specific function. Most of the cells are very very small and can not be seen through nacked eye. • Cells are of two type • Plant cell • Animal cell Onion peel Brick wall

5. CELL — STRUCTURE AND FUNCTIONS Parts of A Cell • Each cell has number of smaller parts in it. Some of the parts are present in all type of cells ( plant cell as well as animal cells). But certain parts are found only in plant cell but not in animal cells and vice versa. • Important basic parts of all cells are: • Cell Membrane or Plasma Membrane. • Cytoplasm • Nucleus and • Mitochondria • 2. The part which is present only in plant cells are : • Cell wall • Chloroplast • Large vacuole • We will learn about these parts in details in subsequent slides.

6. Cell Membrane (Or Plasma Membrane) • Each cell is covered by a thin sheet of skin which is called cell membrane • Cytoplasm and nucleus id enclosed with in cell membrane. • Cell membrane protect the cell and also give it a shape • Cell Membranes has tiny pores into it • The membrane separates cells from one another and also the cell from the surrounding medium. • It controls the movement of substance “into the cell” and “out of cell” • Dissolved substance such as food (glucose) and oxygen can enter the cell whereas the waste products such as carbon dioxide can go out of the cells through pores in cell membrane.

7. Cytoplasm • Cytoplasm is a transparent , jelly like material which fills the cell between nucleus and cell membrane . • Cytoplasm is chemical factory of the cell. • Most of the chemical reactions which keeps cells alive , take place in cytoplasm. • Cytoplasm of a cell has many tiny structure in it called “organelle”. • Nucleus, mitochondria, golgi bodies, ribosomes are some of the organelles. • cytoplasm of plant contains chloroplast as well.

8. Nucleus • Nucleus is a large organelle present in all the cells. • In animal cell nucleus lies in the center of cell but in plant it is at the edge. • Nucleus is separated from cytoplasm by a membrane called nuclear membrane. • Nucleus control all the activities of the cells . • Nucleus contains thread-like structures called chromosomes. These carry genes and help in inheritance or transfer of characters from the parents to the offspring.

9. Nucleus • Gene is a unit of inheritance in living organisms. It controls the transfer of a hereditary characteristic from parents to offspring. This means that your parents pass some of their characteristics on to you. If your father has brown eyes, you may also have brown eyes. If your mother has curly hair, you might also end up having curly hair. However, the different combination of genes from parents result in different characteristics.

10. protoplasm. • All the living matter in cell is called protoplasm. Protoplasm includes cytoplasm, nucleus and other organelle. • Most of protoplasm is made up of compound of only four elements: carbon, hydrogen, nitrogen and oxygen. • Some of the compound present in protoplasm are water, carbohydrates, protein, fats , nucleic acids and mineral salts. • A unique combination of elements and compounds provides living nature to protoplasm.

11. Mitochondria • Mitochondria are known as powerhouse of the cell. • Mitochondria are tiny rod shaped or spherical organelle which are found in all cell. • Mitochondria provide energy for all the activities of the cell. • The biochemical process of breaking down the nutrients known as cellular respiration.

12. Cell Wall • Plant cells have thick cell wall around them • The cell wall is made of tough material called cellulose • Cell wall give shape and support to the plant. • Cell wall also hold the plants cells together and give plant most of the strength • Cell wall is present only in Plant cell. • Cell wall is non-living part of the plant cells.

13. Chloroplast • Chloroplast are green colored organelle present in cytoplasm of the plant only • The process of making food by plant known as photosynthesis takes place in chloroplast. • The green color of chloroplast is due to the presence of green pigment called chlorophylls • Chloroplasts work to convert light energy of the Sun into sugars that can be used by cells. • Chloroplast only found in plant cells and some protists such as algae 

14. Large Vacuole Storage Bins to the Cells Vacuoles are storage bubbles found in cells They are found in both animal and plant cells but are much larger in plant cells. The vacuole is filled with a liquid called “cell sap” which contain dissolved sugars and salts Pressure of liquid (called sap) pushes on the outer parts of the plant cell keeping the plant cell firm. Vacuoles might store food or any variety of nutrients a cell might need to survive. They can even store waste products so the rest of the cell is protected from contamination

15. Organisms show Variety in Cell Number, Shape and Size • There are millions of living organisms all of which are made are of different shapes and sizes. Their organs also vary in shape, size and number of cells. Let us study about some of them. The differences can be listed down in three categories • Different organism has different number of cell in their bodies • This is called variety in number of cells (or variety in ‘cell number’ • The cells in multicellular organism(plants and animals) have many different shape • This is called variety in shape of cells • The cells in multicellular organism have many different sizes • This is called variety in size of cells

16. Variety in Number of cells A million is thousand thousand (1000,000). A billion is a thousand million. A trillion is a thousand billion. • All the living organism are made up of cells. But number of cells varies from organism to organism. • Unicellular Organism : • Some organism(plant and animal) are made up of single cell called unicellular. Uni means one and cellular mean cell • Example Amoeba, Paramecium, Euglena,chlamydomonas and bacteria

17. A unicellular organism can perform all the necessary life functions • A single-celled organism, like amoeba, captures and digests food, respires, excretes, grows and reproduces. • Similar functions in multicellular organisms are carried out by groups of specialised cells forming different tissues. Tissues, in turn, form organs. An ameoba, a simple unicellular organism

18. Multicellular Organism : Organism which is made of many cells are called multicellular organism. Multi means many and cellular means having cells. Depending on it’ s size multicellular organism may be made up of million, billions or trillions of cells joint together. Organism : Anything that can live on it’s own

19. Multicellular Unicellular Organism with one cell Organism with two or more cells These organism are can be seen with naked eye. These organism are very small and need to be seen with a microscope These organism need all its parts to survive • Common names are • Microscopic organism • Micro organism • Really small living things • Common names are • organisms • Eukaryotic • Birds, reptiles etc. Example: Amoeba,Bacteria,Unicelluar Fungi,Unicellular yeast Example: Birds, Humans, reptiles Have a higher degree of specialization where the cells works and functions together to create living organism

20. Variety in shapes of cells There are many types of cells in the bodies of multicellular organisms. • These cells differs in shapes. For example , the shape of nerve cell in animal is different from muscle cell • The Nerve cell is long and branched (having thread like branch) where as muscle cell is pointed at both ends and has a spindle shape. • The different shape of the cells are related to their function which they have to perform in the body of an animal (or plant)

21. Epithelial cell (like chick cell) Spherical red blood cellsof humans Long branched nerve cell White blood cell Spindle shaped muscle cells Cartilage Cell (Soft bone cell) Bone Cell

22. Epidermal Cell (Plant Cell) Xylem Cell (Tube like cell) Phloem Cell (Sieve tube cell) Photosynthesis cell Mesophyll cell of leaf

23. shapes of cells • Cells are of different shape and size so that they can perform different functions. This is called specialization of the cell to do different job. • Human body is made up of about 20 different types if cells and each type perform different function. Some of the examples of animal cells are: • Nerve cells, Muscle cells,Epithelial cell, Red blood cell, White blood cells , bone cell and cartilage cells. Details of nerve cells • Nerve cell is very long and has wire like projections coming out of it. • The large length of nerve cells makes it carry messages to long distance in the body. • Wire like projections of the nerve cell help it to make many contacts with other nerve cell so that message from brain can be sent to all other parts of the body. • Since Nerve cell receive and send message , they help to control and coordinate the working of different part of the body

24. Muscle cells brings about the movement of body part by contracting and relaxing. • Epithelial cells are rectangle in shape. These cells forms a thin layer on the body parts and protect the cell below them from injury. • Red Blood cells are spherical in shape. RBC carry oxygen around the body. • White Blood cells have irregular shape, WBC eat up or kill bacteria which enter the blood and save us from many diseases. • Epidermal cells forms a layer around the plant organs and protect the cells below for injury. • Xylem cells are the tube like plant cell having thick and strong walls which carry water and mineral from roots of the plant to leave. • Phloem cell are also tube like plant cell having thin wall which carry the food made by leave to all parts of the plant • Mesophyll cells of leave are the photosynthetic plant cells.

25. Amoeba cell has no fixed shape. Amoeba cell keeps on changing its shape continuously. • The shape of Amoeba changes because amoeba can make it cytoplasm flow in any direction it wants to. • Amoeba cell has finger like projections of varying length protruding out of it’s body which are called pseudopodia (means false foot) • Amoeba can produce pseudopodia on any side by pushing the cytoplasm in that side. • Amoeba also uses pseudopodia to catch (engulf) the food particle in water. • Note: WBC (White blood cell) present in blood can also change shape.

26. Variety in size of cell • The cells are of many different sizes. The size of cells in living organism may vary from very small (in micro meter 10-6 ) or it may be as large as few centimeter. • Since Most of cells are very small hence can not be seen through naked. • Bacteria mycoplasma is the smallest cell having the size of only 0.1 micrometer. • Even the long cells are so thin that it can not be seen through naked eyes. • Biggest cell (which can be seen in naked eye) is ostrich eggs. • The size of the cell is not related with size of the body of an animal, size of cell is related to its function.

29. Cells, Tissue, Organs, Organ System and organism Cells: A Cell is the smallest unit of life which has s definite structure and perform a specific function. They are of many different shape and sizes. Most of the cells are specialized to perform particular function. Muscle Cell Tissue: a multicellular organism is made up of millions of cells. The cells in a multi cellular organism do not work in as single cell , they work in group of similar cells. The group of similar cells which works together to perform a particular function is called Tissue . For example: in animal , muscle tissue

30. Organs: The bodies of animals and plants are made up of different types of tissues. The different tissues combine together to form a organ. These organs perform different tasks for the plant and animals. We can now say that , an Organ is a collection of different tissues which work together to perform a particular function in the body of organism. Multicellular organisms are made up of many different organs which do different jobs for organism. Some of the organs which are found in bodies of animal (including human being) are Heart, Stomach, Brain, Lungs, Kidney, Liver, Intestine, Mouth, Eyes and Hands Function of Stomach is to digest food Function of Heart is to pump blood around the body

31. Lungs are the organs of breathing. The function of lungs is to take in oxygen and give out carbon dioxide. Function of brain is to cover all parts of body Stem carries water and mineral from root to leaves and prepared food from leave o other parts. It also holds branches and leaves Root absorb water and dissolved mineral salts from the soil

32. Leaves prepares food for plant by the process of photosynthesis Flowers are reproductive organs which leads to formation of fruits and seeds

33. Organ System: The various organs in an organism do not work separately. Organs works in group.a group og

38. CELL — STRUCTURE AND FUNCTIIONS • Tissues • Animal cells and plant cells can form tissues, like muscle tissue. A living tissue is made from a group of cells with a similar structure and function, which all work together to do a particular job. Here are some examples of tissues: • muscle • the lining of the intestine • the lining of the lungs • phloem (tubes that carry dissolved sugar around a plant) • root hair tissue (for plants to take up water and minerals from the soil)

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41. CELL — STRUCTURE AND FUNCTIIONS Toppers Tutorial TT

42. CELL — STRUCTURE AND FUNCTIIONS