Fundamental Unit Of Life : Class IX Biology : Fill in the Blanks
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1. A -------------is the basic structural and functional unit of all life forms.
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Ans: cell
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2. Study of structure and composition of cell is called as ------------
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Ans: “Cytology”.
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3. Cell was first observed by “Robert Hooke” in a dead cork slice in the year 1665. He described about this in his book -----------------
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Ans: “Micrographic”.
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3. The word cell was derived from a Greek word ---------- which means small room.
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Ans: “Cellulae”
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4. First living cell was discovered by -------------
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Ans: A.V. Leeuwenhoek
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5. The term protoplasm was coined ---------- in 1839.
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Ans: by purkinje
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6. Protoplasm was discovered by ------------ and named as sarcode.
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Ans: “Felix Dujardin”
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7. --------- is an aggregate of various chemicals such as water, ions, salts and other organic
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molecules like proteins, carbohydrates, fats, nucleic acids, vitamins etc.
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Ans: Protoplasm
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8. Two biologists, “Schleiden and Schwann” gave the “Cell theory” which was later on expanded by -------------
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Ans: “Rudolf Virchow ”.
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9. ---------- are the exceptions of cell theory.
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Ans: Viruses
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10. --------------- cell are primitive and incomplete and have less developed nucleus without nuclear membrane and nucleolus. e.g. Bacteria
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Ans. Prokaryotic cells:
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2. What is the advantage of multicellularity over unicellularity?
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Ans- Division of labor.
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3. What are the chromosomes made up of?
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Ans- DNA & proteins
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4. A cell placed in a solution swells up. What kind of solution is it? Why does it happen?
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Ans- It is a hypotonic sol ution & water enters the cell by endosmosis causing the cell to swell up.
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5. Why are lysosomes known as “suicidal bags”?
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Ans- They secrete powerful digestive enzymes to digest the worn out and damaged cell organelles as well as the cell itself when it loses its functional ability.
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6.Why is the nucleus so significant in a cell?
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Ans- Nucleus has the following important functions-
(i) It controls all cell activities
(ii) It contains hereditary material that transmits hereditary information from one generation to the next
(iii) It helps in cell division
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7. Differentiate between plant and animal cells.
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1. PLANT CELL
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1- Surrounded by two membranes- cell wall & cell membrane.
2- Possess three types of plastids chloroplasts, chromoplasts, leucoplasts.
3- Do not possess lysosomes.
4- Nucleus is towards the periphery.
5- Centrioles are absent
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ANIMAL CELL
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1- Surrounded only by cell / plasma membrane.
2-Do not possess plastids.
3-Possess lysosomes
4 -Nucleus is in the center ..
5-Centrioles present & help in cell division.
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8. Give the major functions of the following cell organelles-
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(a) Endoplasmic reticulum RER-- Synthesis of proteins as it has ribosomes attached to it
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SER- Synthesis of lipids required for making cell membrane
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(b) Golgi apparatus-----------Storage & packaging of various products.
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(c) Mitochondria------Production of ATP(Adenosine Triphosphate) which is a source of energy.
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(d) Ribosomes ---Protein synthesis
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(e) Golgi ApparatusStorage & packaging of various products.
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(f) LysosomesDigestion of worn out & damaged organelles
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