Cell Structure & Function

http://koning.ecsu.ctstateu.edu/cell/cell.html

Cell TheoryAll organisms are made up cells.The cell is the basic unit of all living things.All cells come from existing cells.

Definition of a cellA cell is the smallest unit that is capable of performing life functions. Basic building blocks of life.Smallest unit of an organism Grow, reproduce, use energy, adapt, and respond to their environment.

Examples of CellsAmoeba Proteus

Plant Stem

Red Blood Cell

Nerve Cell

Bacteria

Two Types of Cells Prokaryotic Cells

First cells to evolveSingle cell organisms No NUCLEOUS DNA ( heredity)

information contained in the cytoplasm

DNA is a long circular molecule( twisted rubber band)

Have strong web like cell walls.

EX – Bacteria and Archaea

Eukaryotic cellsEvolved from prokaryotic

cellsLargest cells. 10 times larger

than prokaryotic cellsHave a nucleusDNA (heredity) info

contained within the nucleus Yeast and amoeba are

single celled eukaryotes.EX – Plants and animals

Cell partsORGANELLES

Tiny membrane –bound structures that perform special functions inside the cell.

Cell Wall-outer most structure

Only found surrounding plant, fungal and bacterial cells.Made of celluloseIs rigid , strong and stiffProvides support and protection for the cellIt is like a wall that surrounds a medieval city.Animal cells do not have a cell wall.

Cell MembraneSurrounds all cells - In a plant cell , it lies beneath the cell wall - In animal cells it is the outer boundary (made of cholesterol)Made of proteins and lipidsProtective barrier that encloses the cell.Functions: - Protection - Control of movement of materials( nutrients, wastes) in/out of cell - Support - Maintains conditions of the cell IT IS LIKE THE BORDER OF A CITY

CytoskeletonWeb of proteins in cytoplasm of some cellsPresent in both plant and animal cellsMany organelles are attached to the cytoskeletonFunctions: - maintain cell shape - protect cell - Enables cellular motion - Plays an important part in intra-cellular transport - Important in cell division

Nucleus Identified in 1833 by Robert BrownFound in both plant and animal cellsLarge oval shapeCentrally located in cellsControls cell activitiesContains DNA

CytoplasmFound in both plant and animal cellsClear thick jelly-like materialLocated beneath cell membraneSupports and protects cell organellesIt is like the sidewalks that are found throughout the city!

Ribosome'sFound both in plants and animalsProduces proteinsSmallest organellesNot covered by a membrane unlike other organellesBrickyard of the city that supplies a city with what it is made of.

Endoplasmic reticulum (er)

Found in both and plant cellsNetwork of tubes found in the cytoplasmTransports proteins throughout the cellTwo types - Smooth ( no ribosome's) - Rough ( covered with ribosome's)Helps in the production of lipids

Mitochondria Found in both plant and animal cellsLooks like a jelly beanBreaks down sugar molecules to release usable energyPowerhouse or the main power source of the cellHave their own DNACan divide within a cellHas inner foldings (cristae) that increase the internal surface area

VacuolesFound in both animal and plant cells - in plant cells : very large and few - in animal cells: Many little ones Fluid filled sacs Store food water and waste Help in digestion within

the cell It is like a city’s warehouse

, water tower and garbage dumps!

LysosomesFound in animal cells onlySmall and round in shapeBreaks down larger food molecules into smaller ones Have digestive enzymes. Digests old cell parts It is like a city’s recycling center

Chloroplasts'Found in plant cells, algae and some prokaryotic cellsOval shapedGreen in color due to chlorophyllUses energy from the sun to make food for plantsPHOTOSYNTHESIS- Process by which cells use sunlight carbon dioxide and water to make sugar and oxygen.Sugar produced is used by mitochondria to make ATPIt is like SOLAR PANELS on city buildings.

Golgi complexDiscovered in 1898 by Camillo GolgiFound in both plant and animal cellsLooks like a flattened stack of membranes ( or pancakes!)Processes and packages molecules, like lipids and proteins , made by the cell out of the cells.It is like the city’s post office or UPS center!