Standard VIII Unit 1 LIFE’S MYSTERIES IN LITTLE CHAMBERS QUESTION BANK QUESTIONS, ANSWERS AND POINTS TO REMEMBER

ANJANA ASOKAN MK B. Ed - NATURAL SCIENCE NSS COLLEGE CHANGANASSERY

POINTS TO REMEMBER • MICROSCOPE - Used to magnify objects - Compound microscopes are microscopes in which more than one lens is used - Eye piece , knob , objective lens , stage and clip , condenser , mirror - Preparation Of observation material • DISCOVERY OF CELL - Robert Hooke • MILESTONES IN THE HISTORY OF CELL BIOLOGY – 1831 , 1838 , 1839 , 1858 • CELL THEORY • CELL – Functions – Resist foreign particles - Synthesis biomolecules - Release energy from nutrients

• ANIMAL CELL AND PLANT CELL

• MITOCHONDRION - Power house of cell - Helps in storage and production of energy • ENDOPLASMIC RETICULUM – Conduction of materials inside the cell takes place through this , known as cytoskeleton • RIBOSOME – Centre of protein synthesis • VACUOLE – Covered by Tonoplast.

• GOLGI COMPLEX – Collects secretions like enzymes , hormones ,mucous in small vesicles • NUCLEUS AS REGULATORY CENTRE OF THE CELL • PROKARYOTES – Nucleus is absent • EUKARYOTES – Nucleus is present • BIOMEMBRANES • PLASTIDS – CHROMOPLAST ,CHLOROPLAST AND LEUCOPLAST • CENTROSOME & LYSOSOME

COMPOUND MICROSCOPE

PLANT

MITOCHONDRION

ENDOPLASMIC RETICULUM

RIBOSOME

VACUOLE

GOLGI COMPLEX

NUCLEUS

NUCLEUS

ROBERT HOOKE

BORN : 18 JULY 1635 DIED : 3 MARCH 1703

ROBERT BROWN

BORN : 21 DECEMBER 1773 DIED : 10 JUNE 1858

M J SCHLEIDEN

BORN : 5 APRIL 1804 DIED : 23 JUNE 1881

THEODOR SCHWANN

BORN : 7 DECEMBER DIED : 11 JANUARY 1882

RUDOLF VIRCHOW

BORN : 13 OCTOBER 1821 DIED : 5 SEPTEMBER 1902

QUESTIONS

PART A - EACH QUESTION CARRIES 1 MARK 1. State whether the statement is True / False (a)Ribosome is the power house of cell (b)Endoplasmic reticulum is also known as cytoskeleton 2. Scientist Who made remarkable contributions in cell biology are given below. Who among them proposed cell Theory? (a)Robert Brown (b) Rudolf Virchow (c) Theodor Schwann (d)M J Schleiden 3. Who 1st observed the cells with the help of simple Microscope? 4. The study of cell is known as ______

5. Who discovered the Nucleus? 6. Who found out that the body of a plant is made up of Cells? 7. Who found out that the body of animals is made up of cells? 8. Who found out that the new cells arise only from existing cells? 9. _______ is the powerhouse of cell 10. Identify the cell organelle

11. Which cell organelle is the Centre of protein synthesis in the cell? 12. Vacuole is covered by a characteristic membrane called ______ 13. In which cells we can see plenty of Golgi complexes?

14. In which parts of the body we can see mitochondrion abundantly? 15. In which part of the cell genes are found? 16. Find out the correct statement (a) Protoplasm is formed by all materials in the cell including cytoplasm and plasma membrane (b) Protoplasm is formed by all materials inside the plasma membrane (c) Protoplasm is cytoplasm inside the cell, except the nucleus. (d) Protoplasm and cytoplasm are same materials. 17. In the cell of bacteria cyanobacteria and mycoplasma, no nucleus is seen.These organisms are called ______ (a) Prokaryotes (b) Eukaryotes

18. When mango ripens, its colour changes to yellow. What is the reason behind this? 19. ______ are the cell organelle that are exclusively found in plant cell 20. ______ is the cell organelle that is found only in animal cell 21. Give examples of Eukaryotes 22. Centrioles that play a major role in cell division are seen in the _______ 23. Robert Brown discovered Nucleus in ________ 24. Write any two parts of microscope 25. What is the function of nuclear pore?

PART B - EACH QUESTION CARRIES 2 MARK 1. What is the function of microscope? 2. Why is a mirror fixed in a microscope? 3. How can we calculate magnification power of microscope? 4. What is cell biology? 5. What are called compound microscopes? 6. What are the main two concepts of cell theory? 7. What is protoplasm and cytoplasm? 8. What is the function of mitochondrion? 9. What is the function of endoplasmic reticulum? 10. Identify the cell organelle and write a short note about the organelle

11.The Endoplasmic reticulum is also known as cytoskeleton. Why? 12. 13.

What is the function of vacuole? Identify the cell organelle and what is the function of the cell organelle?

14. 15. 16. 17. 18.

What are called Prokaryotes? What are called Eukaryotes? What is the function of Biomembranes? Why biomembranes also known as selectively permeable membrane? How prokaryotes different from eukaryotes?

19. Certain parts of a cell are given below. Choose suitable parts to complete the table • Cell wall • Nucleus • Lysosome • Cell membrane • Centrosome • Vacuole • Ribosome Seen only in plant Seen only in animal cells cells

20. 21. 22.

When mango ripens , its colour changes to yellow.What is the reason? What do you know about Lysosomes? What is the function of Centrioles?

23.

Fill in the blanks

24. Find out the relationship between the given word pairs and on the basis fill in the blanks. .Robert Brown :: (a) Theodor Schwann :: Found out that the body of animals are made up of cells .Rudolf Virchow :: Observed dividing cells and inferred that new cells are arise only from existing cells MJ Schleiden :: (b) 25. Tabulate the differences between plant cell and animal cell

PART C - EACH QUESTION CARRIES 3 MARK 1. Identify the following parts and their use

2. Explain how the light is adjusted in a microscope?

3. Match the following Robert Brown

Rudolf Virchow

M J Schleiden

Theodor Schwann

Found Out that the body of a plant is made up of cells Discovered the Centre of cell and named it the nucleus Found out that body of animal is made up of cells Observed dividing cells and inferred that new cells arise only from existing cells

1858

1839

1838

1831

4. What are the main functions performed by the cells? 5. Why is the nucleus considered as the regulatory Centre of the cell? 6. What are the peculiarities of the following part of the nucleus Nucleolus,Nucleoplasm and Chromatin reticulum 7. Which are the three types of plastids? 8. What is the function of chromoplasts? 9. Complete the illustration given below

10.

Complete the concept map related to the structure of animal cell

11.Identify the parts A,B,C,D,E marked in the plant cell

12.

Write the functions of chloroplast ,mitochondrion and endoplasmic reticulum

13. Fill in the blanks Function and Cell organelle peculiarities Centre of protein (a) synthesis (b) Mitochondrion Collects cell (c) secretions like enzymes, hormones, mucous etc. in small vesicles. (d) Vacuole 14.

Copy the given diagram

Identify, name and label the parts, by the hints given below.

(a) They are seen as a network in the nucleoplasm. (b) Play a major role in the synthesis of ribosomes 15. Explain discovering of cells 16. Comment on Lysosome 17. Write a short note on centrosome 18. What is cell organelle and give two examples with their function 19. What is the properties and functions of leucoplasts? 20. What is the use condenser in a microscope? 21. Why do we use a slide made of glass to place the material to be observed? 22. Anagha and Priya placed the sections of plantain root on glass slides. After some time the materials on Anagha’s slide dried up. But Priya’s slide was suitable for observation .What may be the reason for this?

23. Tabulate the different parts of nucleus and their function 24. What is the difference between simple microscopes and electron microscopes? 25. Fill in the blanks on the basis of Milestones in the history of cell biology 1831 : ______ 1838 : ______ 1839 : ______ 1858 : ______

ANSWERS

PART A 1. (a)False (b)True 2. M J Schleiden and Theodor Schwann 3. Robert Hooke 4. Cell Biology 5. Robert Brown 6. M J Schleiden 7. Theodor Schwann 8. Rudolf Virchow 9. Mitochondrion 10. Golgi Complex 11.Ribosome 12. Tonoplast 13. Glandular Cells

14. Abundantly seen in cells of liver, brain and muscles where energy requirement is high. 15. Chromatin Recticulum 16. (b) 17. Prokaryotes 18. The chloroplast is changed to chromoplast 19. Plastids 20. Centrosome 21. Amoeba, plants and animals 22. Centrosome 23. 1831 24. Objective lens , eye piece 25. They help in the conduction of materials to and from the nucleus

PART B 1. The function of microscope is to magnify objects 2. Mirror mounted in a microscope to reflect light on the substance to be observed 3. The magnification power of a microscope is the result of multiplying the numbers seen in the objective lens and the eye piece 4. Cell Biology is a branch of science which deals with the study of the cell 5. Microscopes in which more than one lens used are called compound microscopes. 6. . The body of all organisms is made up of cells . Cells are the structural and functional units of organisms 7. All substances Inside the cell membrane constitute the Protoplasm. Cytoplasm is the part of the Protoplasm excluding the nucleus 8. Helps in the production and storage of energy 9. Conduction of materials inside the cell takes place through this organelle . It provides firmness and shape to the cell

10. Ribosome Ribosome is the Centre of protein synthesis in the cell. Seen either attached to the endoplasmic reticulum or free in the cytoplasm 11.The Endoplasmic recticulum is also known as cytoskeleton as it provides firmness and shape to the cell 12. Stores water,salts,excretory materials ,etc. 13. Golgi Complex, Collects cell secretions like enzymes, hormones, mucous, etc. In small vesicles 14. Cells in which nucleus is absent is called Prokaryotes 15. Cells in which nucleus is present is called Eukaryotes 16. Biomembranes regulate the exchange of materials between cells and between cell organelles and cytoplasm. 17. Biomembranes are called selectively permeable membrane as they allow only the essential materials to pass 18. In the cells of bacteria ,cyanobacteria and mycoplasma no nucleus is seen. These organisms are called prokaryotes .But in the cells of

amoeba ,animals and plants a well defined nucleus covered by membrane is seen . These organisms are called eukaryotes . 19.

Seen only in plant cells Cell wall Vacuole

Seen only in animal cells Centrosome Lysosome

20. When mango ripens chloroplasts change to chromoplast, starch is converted to sugar .This is the secret behind the change in the colour and taste of mango. 21. Lysosome contains the digestive enzymes that are required for the destruction of foreign substances entering the cell. It is seen in animal cell

22. Centriole plays a major role in cell division are seen in the centrosome 23.

24. (a) Discovered the Centre of the cell ,and named it the Nucleus (b) Found that the body of plant is made up of cells 25.

PART C 1.

Eye piece: Magnifies the image produced by the microscope Knob : It is used for initial focusing Objective lens : Gather light from the specimen , magnifies the image of the specimen Stage and clip : stage and clips hold the slides in place Condenser : Focus the light on to the specimen Mirror : Used to direct light 2. In the microscope, the part fixed below the stage is to reflect light on the material to be observed. This arrangement which is fixed in a metal ring has two planes, a plane mirror to reflect sunlight and a concave mirror to reflect artificial light. The lens in the condenser that is fixed on the lower side of the stage focuses light on the material to be observed. Diaphragm, a part of the condenser, helps to regulate the intensity of light.

3. Robert Brown Rudolf Virchow

M J Schleiden Theodor Schwann

Discovered the Centre of cell and named it the nucleus Observed dividing cells and inferred that new cells arise only from existing cells Found out that body of plant is made up of cells Found out that the body of an animal is made up of cells

4. (¡) Resist foreign particles (¡¡) Synthesis biomolecules (¡¡¡)Release energy from nutrients

1831 1858

1838 1839

5. Nucleus is the most important Part of our body. Nucleus control all the cellular activities. The cellular activities takes place due to the actions of various hormones. The nucleus determines the kind of enzymes to be produced. 6. Nucleolus : They are spherical bodies, that play a major role in the synthesis of ribosomes. Nucleoplasm : It is the fluid part of the nucleus . Nucleolus and chromatin reticulum are seen here. Chromatin reticulum : They are seen as a network in the nucleoplasm. They carry genes 7. Chromoplast , chloroplast and leucoplast 8. Chromoplasts imparts colour to flowers and fruits .It synthesis and store carotenoid pigments.

9.

10.

a)Nucleus b)cell organelles c)Nucleoplasm d)chromatin reticulum

e)Nucleolus f)Lysosome g)Endoplasmic reticulum h)Mitochondrion i)Golgi Complex j)centrosome 11. A) Chloroplast B)Mitochondrion C)Endoplasmic reticulum D)Vacuole E)Nucleus 12. Chloroplast : Chloroplast helps in photosynthesis

Mitochondrion : Helps in the production and storage of energy Endoplasmic reticulum : Conduction of materials inside the cell takes place through this organelle. It provides firmness and shape to the cell 13. (a) Ribosome (b) Produce and store energy (c) Golgi Complex (d) stores water ,salts ,excretory materials.

14.

15. Robert Hooke was the first scientist who observed cells with the help of a simple microscope .He observed the section of cork through a microscope and called the tiny chambers seen in the section cell. 16. Lysosome contains the digestive enzymes that are required for the destruction of foreign substances entering the cell. It is seen in animal cells. 17. Centrosome is the cell organelle that is found only in animal cells . The centrioles that play a major role in cell division are seen in the Centrosome. 18. Cell organelles are the specific parts seen in the cytoplasm to perform psychological functions . Mitochondrion – Helps in the production and storage of energy Ribosome – Centre of protein synthesis

19. Leucoplasts are colourless plastids. Food storage is the function of Leucoplasts.

20. Lens in the condenser focusses light on the materials to be observed. Diaphragm helps to regulate the intensity of light. 21. A transparent surface is required to pass light on the material to be observed. So glass slide is used to place it. 22. To avoid drying up it is needed to add a few drops of glycerine on slide. Priya has done it. 23. Nucleolus Nuclear pore Nucleoplasm Nuclear membrane Chromatin reticulum

Functions Plays major role in synthesis of ribosomes Helps in the conduction of materials to and from the nucleus Nucleolus and chromatin reticulum are seen here It covers the nucleus They carry genes

24. Simple microscope : Magnifies a object 2000 times its actual size , Light source is used to see objects Electron microscope : Magnifies objects million times , Electrons are utilized instead of light source 25 . 1831 – Robert Brown – Discovered the centre of the cell and named it the nucleus 1838 – M J Schleiden – Found out that the body of a plant is made up of cells 1839 – Theodor Schwann – Found out that the body of animal is made up of cells 1858 – Observed dividing cells and inferred that new cells arise only from existing cells