BIOLOGY - cell structure ,organisation and levels of organisation

cell smallest biological unit that possess all the characteristics of a living organism what size & shape does it ranges from millimetres to micros depending n its function what is the name of the structures in the cell organelles name and describe 2 types of cells prokaryotic - is a cell that lacks a nucleus eukaryotic - is a cell that possess a clearly defined nucleus organelle is a tiny cellular structure that preforms specific functions within a cell palisade cell animal cell cell wall- description -structure located around the cell surface membrane of plant cells. - are full permeable cell wall - functions -provide mechanical support around the plant cell -gives plant cells specific shape -prevent cell bursting during endosmosis cell surface membrane - description - structure that surrounds cytoplasm of all cells - selectively permeable with receptors for cell respiration cell surface membrane - functions - control entry and exit in and out of the cell -maintains a constant internal environment in cells cytoplasm -jelly like fluid within a cells membrane but not inside a cell's nucleus -controls all contents of the cell cytoplasm - functions - site for chemical reactions -provides a physical structure for the cell nucleus - description its location varies [ plant cell -edge + animal cell -centre ] nucleus - functions -controls functions & activities of the cell - carries genetic material of the cell vacuole - description animal cells have temporary vacuoles while plant cells have large vacuole vacuole - functions -stores salts,ions ,sugars ,wastes ,pigments in cell sap. - supports plant cells and keep the cell firm. endoplasmic reticulum is a network of parallel membranes that form tunnels through the cytoplasm 2 types of ER Rough ER and Smooth ER functions of rough ER - transport RNA from nucleus to ribosomes -provides large surface area for attachment of ribosomes -transport proteins [ via vesicles ] that ribosomes produce to the GOLGI BODY or rest of the cell -responsible for protein synthesis using ribosomes ribosomes Are produced by Golgi body and they are responsible for protein synthesis * NB -they are very small beads of RNA (ribonucleic acid) functions of smooth ER -synthesis of lipids and hormones -transport lipids and steroids chloroplasts -functions Capture energy from sunlight and use it to produce food for the cell chloroplasts - description organelles found in cytoplasm of green plants mitochondria - description Powerhouse of the cell, organelle that is the site of ATP (energy) production Mitochondria release large amounts of energy in the form of adenosine triphosphate (ATP) during the process of respiration NB for mitochondria the cells that need tons of energy must have tons of mitochondria to give energy .e.g. muscle cell