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Bio- Fundamental unit of life Cheat Sheet (DRAFT) by

class 9 NCERT bio chapter 6

This is a draft cheat sheet. It is a work in progress and is not finished yet.

intro

Cells-­---> all living organisms
Tissue­s--­--> group of cells
Organs­---­-> group of tissues
Organ system­s--­--> group of organs
Organi­sm-­---> group of cells

Imp discov­eries

1665
Robert Hooke
cells (cork)
1674
Leeuwe­nhoek
living cells (pond)
1831
Robert Brown
nucleus
1839
Purkinje
coined the term "­pro­top­las­m"
1838-39
Schleiden & Schwann
cell theory
1855
Virchow
cell theory
1940
-
discovery of electron microscope

CELL THEORY

~Cells are the basic structural unit of life
~Cells are the basic functional unit of life
~All cells arise from pre-ex­isting cells
 

Defi­nit­ions

Cell:
the structural and functional unit of life. every living organism is made up of cells
Unicel­lular organism:
organisms made of single cells that carry out all functions. Ex- amoeba, bacteria, Chlamy­dom­onas, etc. Usually prokar­yotic
Multic­ellular organism:
organisms made of multiple cells. Ex- plants and animals. Usually eukaryotic
Cell organe­lles:
membrane bound organelles present in cells to support functions performed by it
Diffusion:
movement of solid, liquid or gas particles from a region of higher to lower conc.
Osmosis:
movement of water particles from a region of higher to lower conc. thru a semi-p­erm­eable membrane
Cell division:
the process by which new cells are made
Mitosis:
process by which most of the cells divide for growth. Each mother­/parent cell divides to form 2 identical daughter cells thats have the same no. of chromo­somes as the mother cell (helps in growth and repair of tissues)
Meiosis:
a process where a single mother­/parent cell divides twice, to produce four daughter cells that each contain half the original amount of chromo­somes. These cells are our sex cells – sperm in males, eggs in females (helps in reprod­uction)