Fundamental Unit Of Life : Class IX Biology : Fill in the Blanks |
1. A -------------is the basic structural and functional unit of all life forms. |
Ans: cell |
2. Study of structure and composition of cell is called as ------------ |
Ans: “Cytology”. |
3. Cell was first observed by “Robert Hooke” in a dead cork slice in the year 1665. He described about this in his book ----------------- |
Ans: “Micrographic”. |
3. The word cell was derived from a Greek word ---------- which means small room. |
Ans: “Cellulae” |
4. First living cell was discovered by ------------- |
Ans: A.V. Leeuwenhoek |
5. The term protoplasm was coined ---------- in 1839. |
Ans: by purkinje |
6. Protoplasm was discovered by ------------ and named as sarcode. |
Ans: “Felix Dujardin” |
7. --------- is an aggregate of various chemicals such as water, ions, salts and other organic |
molecules like proteins, carbohydrates, fats, nucleic acids, vitamins etc. |
Ans: Protoplasm |
8. Two biologists, “Schleiden and Schwann” gave the “Cell theory” which was later on expanded by ------------- |
Ans: “Rudolf Virchow ”. |
9. ---------- are the exceptions of cell theory. |
Ans: Viruses |
10. --------------- cell are primitive and incomplete and have less developed nucleus without nuclear membrane and nucleolus. e.g. Bacteria |
Ans. Prokaryotic cells: |
2. What is the advantage of multicellularity over unicellularity? |
Ans- Division of labor. |
3. What are the chromosomes made up of? |
Ans- DNA & proteins |
4. A cell placed in a solution swells up. What kind of solution is it? Why does it happen? |
Ans- It is a hypotonic sol ution & water enters the cell by endosmosis causing the cell to swell up. |
5. Why are lysosomes known as “suicidal bags”? |
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. |
6.Why is the nucleus so significant in a cell? |
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 |
7. Differentiate between plant and animal cells. |
1. PLANT CELL |
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 |
ANIMAL CELL |
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. |
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 |
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