CBSE Class 9 The Fundamental Unit of Life

Scroll down for PDF

CBSE Class 9 The Fundamental Unit of Life. Learning the important concepts is very important for every student to get better marks in examinations. The concepts should be clear which will help in faster learning. The attached concepts made as per NCERT and CBSE pattern will help the student to understand the chapter and score better marks in the examinations.

Chapter-5

The Fundamental Unit Of Life

1. All the living organisms are made up of fundamental unit of life called” cell”.

2. The cell is a Latin word for “a little room”.

3. The scientist Robert Hooke saw a little room in the cork (the bark of a tree) resembled the structure of a honeycomb. The use of the word “Cell” to describe these units is used till this day in Biology as” Cell Biology”.

4. The Compound Microscope consist eye piece,objective lens and condenser to observe a cell after putting a drop of Safranin (for plant cell) and methylene blue (for animal cell). ( Please refer to Fig. 5.1: Compound Microscope NCERT Book Page-57)

5. The scientist Leeuwenhoek saw free living cells in the pond water for the first time. ( father of microbiology)

6. The scientist Robert Brown discovered the nucleus in the cell.

7. The cell theory states that all the plants and animals are composed of cells, it was proposed by Schleiden and Schwann.

8. The cell theory was further expanded by Virchow by suggesting that “all cells arise from the pre-existing cells”.

9. The cells differ in size, shape, structure (Please refer to Fig. 5.2/5.3: Onion peel/Various cells in Human body, NCERT Book Page-57/58):Types of cells: Onion cells, Smooth muscle cell, Blood cells, Bone cell, Fat cell, Nerve cell, Ovum, Sperm etc. Each kind of cell performs specific function.

10. A single cell may constitute a whole organism as in Amoeba, Chlamydomonas, Paramecium and Bacteria; these are called as unicellular organisms. Whereas in multi-cellular organisms (Human beings) division of labor is seen.

11. The feature in almost every cell is same: Plasma membrane, nucleus and cytoplasm.

12. Plasma membrane: It is the outermost covering of the cell.

- It is called as selective permeable membrane (because it prevents movement of some materials).

- It helps in diffusion and osmosis

- Diffusion: movement of substance from high concentration to low concentration.

Eg; exchange of carbon dioxide or oxygen with external environment.

class_9_science_concept_3

osmosis: it is the passage of water from the region of high water concentration to a region of low water concentration through a selective permeable membrane.

class_9_science_concept_5

a) The cell gains water, if the medium surrounding the cell has a higher water concentration (Hypotonic solution) than the cell.

b) The cell maintains the same water concentration as the cell (Isotonic solution), water crosses the cell membrane in both directions.

c)The cell loses water, if the medium has lower water concentration (Hypertonic solution) than the cell.

Please click the link below to download pdf file for CBSE Class 9 The Fundamental Unit of Life.

Tags: 


Click on the text For more study material for Science please click here - Science

Latest NCERT & CBSE News

Read the latest news and announcements from NCERT and CBSE below. Important updates relating to your studies which will help you to keep yourself updated with latest happenings in school level education. Keep yourself updated with all latest news and also read articles from teachers which will help you to improve your studies, increase motivation level and promote faster learning

CBSE DATE SHEET 2020

Central Board of Secondary Education, CBSE is to conduct the 10th and 12th Board Examination 2020 from February 15, 2020. Due to University Admissions, CBSE has shifted Board Exams dates from 1 March to February 15 from 2019. This year too CBSE would be making changes...

Seven Motivational tips for every student

If you’re are a student or a learner and you doesn’t feel like study then this article is going to be very important for you, Reading constantly and Staying motivated as a student is one of the most challenging tasks and barriers to educational success. Education is...

Extension of dates by CBSE for Single Girl Child Merit (SGC) scholarship

CBSE has announced to extend dates for SGC scholarship. Previously the dates to submit the SGC scholarship form were 18 October 2019. Now dates have shifted. For online submission, the last date is 31st October. Whereas date for submission of hard copies of renewal...

CBSE examination board hike the fee for class 10th and 12th

The CBSE (Central Board Secondary Education) increased the examination fees for classes 10 and 12 of the 2020 boards, with no profit no loss principle, from Rs. 750 to Rs 1500, for all categories of students, including SC/ST candidates for all schools throughout India...

Requirements for admissions in CBSE affiliated Schools

CBSE gives an advanced form of education. They try to indulge students in interactions and teach application based subjects along with some others. Due to this preponderance of parents, they tend to admit their children in CBSE affiliated schools. General conditions...

×
Studies Today