IX-BIO CHAP-1(The Cell & Fundamental Unit of life)

ORGANSIATION OF LIVING WORLD

Structural order- In nature and individual organism has various character called as structural order.

Metabolism- All types of chemical reaction taking place in a body are collectively called as metabolism. It includes synthesized and splitting type of reaction.

a.      Anabolism- These are synthesis or combination type of chemical reaction of metabolism is called as Anabolism e.g. formation of proteins by Amino acid.

b.      Catabolism- These are splitting types of metabolism reaction called as catabolism e.g.Repsiration, digestion.

 Types of organism

a.       Unicellular and Single cellular- Those organism which have only one cell in his body, That cell which do all functions for life e.g. Amobea, paramecium.

b.      Simple Multicellular- Those organism whose body has few cells and different cells do different function e.g. Hydra, Sponges.

c.       Multicellular- Those organism whose body has billions of cells in the form of tissue and organ are called as complex multicellular. E.g. man, cat, Tree, rat.

 Organsiation Level- There is three level

(A) Individual level- This level includes one organism as one unit of life called as organic level or a individual level. It perform are the function like total metabolism reproduction, response, growth and development.

(B) Lower level- This level includes atom to organism.

a.       Molecular level- All organism made up of atoms. Atom combines to form molecule. Molecule combines to form complex molecule like protein nuclo protein. Complex molecule to form cell organelles which fees there combines to forms cell.

b.      Organismic Level- This level starts from cell and reach up to organism.                                                           

Cell- It is structural and function unit of life. It has all types of cell organelles and it performs all vital functions.                                                                                  

Tissue- It is a group of one type of cells and perform particular functions e.g. Epithelial,muscular.                                                                                                                                   Organ- It is a group of different types of tissues and performing a complete function. E.g. leaf, heart, eye.                                           

 Organ system- It is a group of various organs and other parts. It is well organized group and responsible for complete function for body called as organ system e.g. Nervous system, muscular system. These are ten organ systems in human body                                                                  

Organism or individual- It is a one single biological unit can live and do all the function like all metabolism, responsiveness, reproduction growth etc called as organism or individual.

c.       Higher Level-This level starts from organism and reaches to biosphere.                                                        

  Species: - It is group of one types of organism which are similar and live together and also inter breed among themselves freely to give fertile off spring called as species. E.g. Breeds of dog. Types of sparrow.                                                                                                                                          

d.      Population- It is total no of members of a species living in a giving area called as population.                                                                                                                                                             

e.      Community- It is an organized group of various organism and their population living together and depend on each other constitute community.                                                                                           f.  Ecosystem-It is a interdependence of various biotic component on abiotic factor called as ecosystem. In ecosystem an biotic communities depend on physical and climatic factor.               

g.       Biome- It is a geographical localized group of are biotic communities living there called as biome. It is group of various ecosystem                                                               Biosphere- It is largest unit of living organism present on earth. It is a largest level of organisms.

h.      Cell Type Structure with their discovers.                  

Cell – Robert Brooke.    

 Nucleus- Robert brown                                                                                                                          ProtoplazamJ.E.Purkanji.                                                                                                                          Cell theory- M.J.Shelidon, Swan, Virchow.

 Cell division- Walther Flaming.

Cell theory- The cell theory tells:--

a.       All organism are formed by cells and their products.

b.      Cell performs all vital function so considered as a unit of life.

c.       All cells are produce from pre-existing cells only so no cells are produced spontaneously.

Compare Prokaryotic and Eukaryotic cells.

Cell and size or shape

Largest cell in nature- Egg of ostrich.

Smallest cell in nature- pneumonia

Largest cell in man- Nerve cell

Smallest cell in man- R.B.C.

Rectangular-Plants skin

Polyhedral-(Eight, Twelve, sixteen sides) plants cells of skin cell

Oval-Egg cells, discoidal, R.B.C, W.B.C.

Elongated-Nerve cells

Spindle shaped-Smooth muscle

Branched-Skin pigment, heart muscle, cell organelles.

Cell Wall- It is present only in plant cell. It is hard ridged dead and made up of cellulose. It is fully permeable. It provides hardness to plant cell and shape.

 Plazma membrane- It is outer most membrane in animal cells and inner to cell wall in plant cell. It is soft elastic little ridged and living membrane made up of proteins and fats. It is selectively permeable. It provides shape and rigidity to animal cell also control the transportation of various substances from outside to inner side.

 Cytoplasm-  It is jelly like granulated viscous fluid present around the nuclear membrane and inner to cell membrane called cytoplasm. It has various food substances, waste substances, and raw material and cell organelles.

 Ribosomes- These are round dot like structure present in cytoplasm or jointed with E.R. Ribosomes helps in the formation of useful protein like D.N.A. and other needed by cell, during cell division and formation of other originals.

 Endoplasmic Reticulum- These are complex network of membranes bounded tubules arised from infolds of cell membrane. These are smooth when ribosomes are not present and these are rough which ribosomes are present. These E.R. helps in the providing path and transportation various substance within the cell also from the outside to inside.

 Nucleus

 Nucleus- It is round oval shape structure centrally located in animals, around side words in plant cell. The nucleus is made up of various substances. The wall of nucleus is  called as nuclear membrane and formed by protein. In side of this membrane Chromatin material and nucleolus is present. The nucleolus is round structure inside nucleus  and control activities of all  and cell division. The chromatin has network of ribbon like structure. These ribbon are called as chromosomes. Each chromosomes has two thread called as chromatids, both chromate are joint at centromere. Each chromosome has  various segment called as genes. Each genes carries genetic information for next cell and generation Nucleus control all the activities of cells and process.

 Chromosomes are long thread like structure present in the nucleus of a cell which contain hereditary information of the cell.

Diploid- It is paired condition of chromosomes. i.e., a cell which has full number of chromosomes with two of each kind. The diploid number of chromosomes is specific for a species and every cell has diploid number of chromosomes.

Haploid- It is set of  unpaired chromosomes. i.e., a cell which has half the number of chromosomes with one of each kind. Gametes have haploid set of chromosomes.

Q-Difference between Diploid and Haploid?

Ans:-

 Mitochondria- It is rod shaped oval structural present in cytoplasm. It has two walls. The outer wall is smooth by inner wall as infold Finger like structure called as cristae. Within a cristae ground material is filled called as matrix. Matrix control respiratory enzymes. Therefore food is oxidized in mitochondria and release energy. This energy then packed in A.T.F. Due to production energy mitochondria is called the powerhouse of cell.

 Plastids- These are coloring pigments present in plant cell only. They are of three types.

(a) Leucoplasts- These are colourless plastids present fleshy parts of plants. These plastid helps in the storage of organic substance like protein, fats & carbohydrate E.g. Reddish, fruits.

Chromoplasted—These plastid give all the colour to flower and fruits accept green colour. These pigments helps to attract insects for pollination.

Chloroplast- It is green colouring  pigments of plastid. It has chlorophyll which  is bean shaped structure in which there is a sequence of sacs in the form of membrane bounded flattened structure called as grana. In Grana light reaction of photosynthesis takes place. Around grana these is storma ground material which has photosynthesis enzymes. In storma dark reaction of photosynthesis takes place. In chloroplasts food is prepared by photosynthesis so it is called as kitchen of cell.

 Golgi apparatus-  They are membrane bounded fluid filled vesicles stack of many flattened cisternae. They are nearer to nucleus in animal cell. Present scattered in cytoplasm in plant cells and called dictyosomes. The golgi apparatus as way station or assembly area for storage processing and packaging of various substances and secretions like enzymes, protein, Cellulose, milk etc, So it is called as export firm.

 Vacuoles- These are fluid filled membrane bounded spaces in cells. In plant cell the Vacuoles

 Are big in size and less in no, but in animals cells in size and more in no. Its membrane is called as Tonoplast and fluid in it cell sap. This sap contains watery solution of various compounds minerals and waste substances. It has storing Nature.

 Lysosomes- It is a small vesicle surround by single membrane in which a digestive enzyme is filled when Lysosomes burses then its enzymes get mixed in cytoplasm then cell dies and prevent further damage to body. Therefore Lysosomes are called as demolition squads or suicidal bag. The main function of Lysosomes is to fight infection, distribution of old cells and organelles.

 Centrosome- It is Hyaline structure having microtubules around it with two small round granules called centrioles and whole structure is called as centrosomes. It helps in the cell division by producing aster rays and spindle fibers. It is only present in animals cells.

Microtubules- These are cytoplasm very fine thin ridged tubular structure made up of tubulin proteins and helps to determination the shape of cell and cell organelle. They are alos formed during cell division.

Micro-filaments-These are very small filament made up of actin and myosin they have contractile nature so help in motility.

Cilia-These are very small hair like projection of cytoplasm outside the cell> they are more in number and help in the locomotion and catching food E.g. Paramecium.

Flagella-It is one whip like microtubules originated from centrioles and helps in Locomotion, in catching food. They are 1 or 2 in No.

Q-Difference between plant and animal cell.

Ans

 Homologous chromosomes are a pair of chromosomes which are exactly similar in structure, i.e., same shape and size. Human beings have 23 pairs of homologous chromosomes in each body cell.

Chromatids- It refers to a thread like strand formed from a chromosome, during the early stages of cell division. Each chromosome consists of two units of chromatids.

Centromere- It is part of a chromosome that attaches to the spindle during cell division. Centromere forms a region where two chromatids remain joined along with their length.

Structure of chromosomes can be studied during metaphase stage when they are  the shortest and thickest.

8. Give the major functions of the following cell organelles-

(a) Endoplasmic reticulum 
RER-- Synthesis of proteins as it has ribosomes attached to it
SER- Synthesis of lipids required for making cell membrane
(b) Golgi apparatus-----------Storage & packaging of various products.
(c) Mitochondria------Production of ATP(Adenosine Triphosphate) which is a source of energy.
(d) Ribosomes      ---Protein synthesis
(e) Golgi ApparatusStorage & packaging of various products.

f) LysosomesDigestion of worn out & damaged organelles  

The Cell & Fundamental Unit of life some imp points

 Introduction    
The word cell is derived from the Latin word “cellula” which means “a little room”
It was the British botanist Robert Hooke who, in 1664, while examining a slice of bottle cork under a microscope, found its structure resembling the box-like living quarters of the monks in a monastery, and coined the word “cells”
In the year 1838, Matthias Schleiden, a German botanist, first proposed the idea that all plants consist of cells
The Dutch scientist A.V.Leeuwenhoek, in 1674, discovered the minute forms of life such as bacteria and single celled animals in a drop of water
In 1839, Theodar Schwann, another German botanist, asserted that all plants and animals are made up of cells
In 1831, Robert Brown discovered the nucleus in the cell 
J.E.Purkinje, in 1840, used the term protoplasm to describe the juicy, slimy gelatinous contents of the cell
In 1885, Rudolf Virchow expressed that all cells arise from pre-existing cells
In 1932, two German Scientists, Ruska and Knoll, invented the electron microscope 
Endoplasmic Reticulum (ER) This is a complex network of tubes, the lumen of which is filled with fluid. Two types of  endoplasmic reticula are seen.They are:   Cell - A Unit of Life
Organisms may be broadly classified into two kinds:  Unicellular  and  Multicellular

Cells of onion peelAll living organisms, whether plants or animals, are made up of microscopic units called cells. The cell occupies the same central position in biology as the atom in the physical sciences.
All living beings, plants and animals, start their life with a single cell. Some organisms exist as a singlecell and carry out the various metabolic life processes such as assimilation, respiration, reproduction, excretion, etc., that are essential for their survival. These are known as unicellular organisms.

Structure of Cell---Cells vary in shape and size. They may be oval, spherical, rectangular, polygonal, spindle shaped, star shaped, rod-shaped or totally irregular like the nerve cell. The diversity in cells is in accordance with the role or function it has to perform as part of the tissue or organ system. In general, there is no typical shape for cells.

Cell Membrane (Plasma Membrane)  ---Cell membrane is present in both plant and animal cells. It is living, elastic and made of proteins and lipids (fats). Its function is to provide a mechanical barrier for the protection of the inner cell contents and to regulate the movement of molecules in and out of the cell.  

Cytoplasm  ---The part of the cell between the cell membrane and the nuclear membrane is called the cytoplasm. The cytoplasm consists of the matrix and the organelles. The matrix is a transparent semi fluid substance. When active, it is always in a state of movement. The organelles are found embedded in the cytoplasm. They have definite shape, structure and function. All the metabolic activities of the cell such as synthesis, secretion, digestion and energy generation, are performed by the different cell organelles. Cell organelles can be seen only with the help of an electron microscope.

Following are the Important Cell-organelles:

> Tubes with a smooth surface are called smooth endoplasmic reticula. They secrete lipids.

> Tubes with spherical bodies (ribosomes) attached are known as rough endoplasmic reticula.   

The functions of the endoplasmic reticulum are to form the skeletal framework of the cell, to provide a pathway for the distribution of nuclear material from one cell to the other and to synthesize fats, steroids and cholesterol with the help of enzymes secreted by the cell.  

Golgi Apparatus   
Also known as Golgi Complex or Golgi Bodies, they consist of tiny, elongated, flattened sacs (cisternae), which are stacked parallel to one another along with some vacuoles and clusters of vesicles.

The function of the golgi body is to secrete certain hormones and enzymes. It also forms lysosomes and peroxisomes. The golgi body is usually found close to the nucleus.   

Lysosomes   These are tiny, spherical, sac-like structures scattered all over the cytoplasm. Their main function is digestion. They contain powerful destructive enzymes capable of digesting all organic material, and hence called “digestive bags”.  

Lys Lysosomes present in white blood cells are capable of digesting bacteria and viruses. During starvation, lysosomes digest proteins, fats and glycogen in the cytoplasm, and supply energy to the cell. They are also capable of digesting worn out cell organelles, or even digesting the entire damaged cell containing them. Hence, “suicide bag” is a sobriquet that is often used for Lysosomes.  These organelles are found in the liver and kidney cells. They are small, membrane-bound sacs, and contain powerful oxidative enzymes.Their chief function is to remove toxic substances.

Ribosomes   These are spherical, granular particles which occur freely in the matrix or remain attached to the rough endoplasmic reticulum. Ribosomes contain RNA (ribonucleic acid) and proteins. Their function is to provide the surface for protein synthesis.  

Centrosome   This is found in the cytoplasm near the outer surface of the nucleus and contains two cylinders called centrioles. The centrosome is found only in the animal cell. The centrosome and the centrioles play an important role by forming the poles of the spindle during cell division.   

Mitochondria   These may be cylindrical, rod-shaped or spherical and distributed in the cytoplasm. Each mitochondrion is bound by a double membrane. The inner membrane is folded into ridges called cristae, which increase the surface area of the membrane. It is in the mitochondria that the sugar is finally burnt during cellular respiration. The energy thus released is stored as high-energy chemicals called ATP (adenosine triphosphate). Hence, mitochondria are termed as the “power house” or the “power plant” of the cell. The body cells use the energy stored in ATP for synthesis of new chemical compounds, the transport of these compounds and for mechanical work.  

Plastids   These organelles are found only in plant cells.   
Plastids are of three types:   Chloroplasts   Chromoplasts   Leucoplasts  

Plastids They are green and found in leaves. The green colour is due to the presence of chlorophyll.

Plastids They are yellow, orange and red, and found in flowers and fruits.  

Leucoplasts   They are colourless and found in roots, seeds and underground stem

The function of the chloroplast is to trap solar energy for photosynthesis. Chromoplasts impart colour to flowers to attract insects for pollination. Leucoplasts store food in the form of carbohydrates, fats and proteins.   

Nucleus   This is a prominent, spherical or oval structure found at the centre of the cell. It is the controlling centre of all cell activities and has been described as the brain of the cell. It regulates all metabolic and hereditary activities of the cell.   
The nucleus is composed of the following structures:   
Nuclear Membrane   : Nucleoplasm   Nucleolus   Chromatin network

Nuclear Membrane   This is a double-layered membrane which separates the nucleoplasm from the cytoplasm. The nuclear membrane has minute pores which allow the selective transfer of material between the nucleoplasm and the cytoplasm.  

Nucleoplasm   Within the nuclear membrane, completely filling up the space, is a clear, semi-solid, granular substance or matrix called the nucleoplasm. The nucleolus and the chromatin network lie suspended in the nucleoplasm.   

Nucleolus   This dense, spherical granule found in the nucleus contains RNA (ribonucleic acid) which is responsible for protein synthesis in the cytoplasm.  

Chromatin Network   These are very fine thread-like, coiled filaments uniformly distributed in the nucleoplasm. At the time of cell division, the chromatin becomes thick and ribbon like and are known as chromosomes. The chromosomes contain genes, which are composed of DNA (deoxy-ribonucleic acid). Genes are responsible for storing and transmitting hereditary characteristics from one generation to another. A gene is the functional unit of a chromosome. Genes are arranged in single linear order along the chromosome. One gene may be responsible for a single characteristic, or a singlecharacteristic maybe transmitted by a set of genes. 

The structure of the cell that we have studied so far is that of a eukaryotic cell. How is a prokaryotic cell different from a eukaryotic cell?   The main difference between these two cell types is that prokaryotic cells do not have a nuclear membrane. The nuclear material consists of a single chromosome and lies in the cytoplasm. The nuclear region in the cytoplasm is called nucleoid. Membrane-bound organelles are absent. Prokaryotic cells are found in bacteria and cynobacteria (blue-green algae).

NOTE—Q.no.1 to 30 carry two marks each.Q.no.31 to 35 carry three marks each. 
Q.1 Differentiate between chloroplasts and chromoplasts. 
Q.2 Why were the cells remained undiscovered for a long time? 
Q.3 Name the unit used to express cell size. Express its value in metres. 
Q.4 What is the function of albumen and yolk in an egg? 
Q.5 What is the composition and function of cytoplasm? 
Q.6 Describe the structure of nucleus. 
Q.7 What is the importance of cilia and flagella ? 
Q.8 Describe the various levels of organization.
Q.9 Why do plant cells have cell wall? 
Q.10 Classify the living organisms on the basis of the cell number. 
Q.11 What advantage does amoeba derive by changing shape? 
Q.12 A hen’s egg can be seen easily. Is it a cell or a group of cells? Give reason. 
Q.13 Are the cells in an elephant larger than the cells in a rat? Justify your answer. 
Q.14 Why do vaccum packed chips not get spoiled? 
Q.15 How does boiling of milk prevent its spoilage? 
Q.16 A child is suffering from cholera. Answer the following------ 
(a) Name the causative agent and mode of transmission for the disease. 
(b) State any two preventive measures against the disease. 
Q.17 What are toxins? How do they affect our body? 
Q.18 Why is yeast used in baking industry? 
Q.19 Why are certain microbes commonly called biological nitrogen fixers ? 
Q.20 What are the different modes of transmission of communicable diseases? 
Q.21 How are microorganisms useful in fuel production? 
Q.22 “Milk tastes sweet while curd tastes sour”. Give a suitable reason to justify this statement. 
Q.23 What was the reason for Irish Famine in 1740-41 ? 
Q.24 What is food poisoning? What are its symptoms? Name a bacteria and virus that cause this disease. 
Q.25 How does the drying method help to preserve the food items? 
Q.26 Why is salt used in the preservation of meat and fish? 
Q.27 How is canning of food done? 
Q.28 Name two acids added in carbonated beverages. Why are these acids used? 
Q.29 Write two importance of food preservation. 
Q.30 How do bacteria cause damage to teeth? 
Q.31 Name two factors that affect the shape of the cell. Explain by giving an example. 
Q.32 Define the following terms --- (i) organelles (ii) cell membrane (iii) cytoplasm 
Q.33 A child suffering from chicken pox was taken to a doctor. The doctor told the parents that they should have got their child vaccinated earlier. Answer the following- 
(i) How vaccination would have helped the child to develop immunity against the disease? 
(ii) Name two viral diseases for which vaccinations are available for children other than chicken pox. 
(iii) Name two methods used for administering vaccines . 
Q.34 Define Rancidity , Food Preservation and Bioaugmentation. 
Q.35 What is pasteurization? Why is it done? Why is pasteurized milk stored under refrigerator?IX Biology:Extra marks Guess Solved Question paper : Cell and its FunctionIX The Cell & Fundamental Unit of life