Question

Chapter 5 : Fundamental Unit of Life



1) Who discovered cells, and how was it discovered ?


2) Why the cell is called the structural and Functional unit of life?


3) How do substances like CO2 and water move in and out of the cell? Discuss.


4) Why is the plasma membrane called a selectively permeable membrane?


5) Name two organelles we have studied that contain their own genetic material?




Answer it in short!

Answer 1

1. Robert Hooke discovered cells in 1665.It was discovered as Hooke actually saw the dead cell walls of plant cells (cork) as it appeared under the microscope and he noticed that the cells Walls of plant was made of small building blocks. He named It cells.
2. Cells are called the strutural and functional unit because everything in the Universe is made of cells and it is the smallest Functional unit of all things of the Universe.
3. The substances like CO2 and water move in and out of a cell by diffusion from the region of high concentration to low concentration. When the concentration of CO2 and water is higher in external environment than that inside the cell, CO2 and water moves inside the cell.
4. It is because , Plasma membrane allows some material to pass through it while on the same time it blocks other material from entering through it… In other words its selects materials that can enter the cell… that`s the reason it is called as selectively permeable membrane.
5. Mitochondria and Plastid are the two orgenells that contain their Own genetic energy.

Answer 2

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Answer 1 : Robert Hook in 1665 observed by his self made microscope the 
small compartments in a dead cell i.e. cork cells . he coined a term cell which was called room in Greek.

Answer 2 : Cell is called structural and fundamental unit of life because from cells tissues are formed . And from tissues  organs are formed . From organs organ system are formed . from organ system organisms are formed . So without cells the life isn't possible 

Answer 3 : Substance like CO2 and O2 moves through tiny pores in outermost layer (epidermis) . These tiny holes are called stomata covered by guard cells . These guard cells helps to opening and closing of stomata by K+ (potassium ) ion concentration . 

Answer 4 : Plasma membrane is selectively permeable because it is made from a lipid bilayer and proteins are sticking to the membrane . It allows some materials only to pass out like water or in . 

Answer 5 : Plastids and mitochondria 
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