Cell Organelles Structures within a cell that are

Cell Organelles Structures within a cell that are used to live, grow and reproduce.

Cell Membrane Location - surrounding the cell. ▪ the outermost membrane in animal cells but inside of the cell wall in plant cells Description - a fluid mosaic of a phospholipid bilayer, with proteins, and other macromolecule strands embedded in it or attached to it Function - controls the movement of substances into and out of the cell

Cell Membrane

Cell Membrane

Cell Wall Location - the outermost layer of some cells (especially plant cells but never animal cells) Description - thick, rigid, composed of cellulose and lignin ▪ not a complete wall – looks more like a scaffold around the cell Function - protection ▪ support ▪ gives cell shape.

Cell Wall

Cilia Location - extensions of the outer surface of the cell membrane of any cell that moves itself, or needs to move substances outside itself. These are NOT found on all cells Description - long, thin Function - movement of free swimming protista (like paramecium) ▪ movement of extracellular material (like the cilia lining your tracheal cells)

Cilia The small “hairy” structures on the outside of the Paramecium are cilia Internal structure of cilia and flagella (9+2 arrangement)

Flagellum Location - extensions of the outer surface of the cell membrane of motile (movable) cells, like sperm or Euglena (protist) Description - longer than cilia Function - movement of the swimming cell

Flagellum

Plastids Location - throughout plant cells Description - (see chloroplast as an example) Function - Leucoplasts – store starch (e. g. in potato cells) - Chromoplasts store coloured pigments in colourful fruit cells (like tomato)

Leucoplasts are the whitish, circular structures in the cell shown here.

Chromoplasts Red, circular structures in this diagram are chromoplasts found in a red pepper cell.

Cytoskeleton n Location – found beneath the cell membrane and branching throughout the cytoplasm. Description – Long thin tubes or fibres Function – provides support to animal cells and aids in moving material throughout the cell.

Centrioles Location - two at 90 o to each other form the centrosome used in mitosis Description - not membrane bound, made of small tubules Function - as a centrosome organize the spindle fibres used in mitosis. they “anchor” and “organize” the formation of cilia and flagella

Centrioles

Nucleus LOCATION - usually in the center of the cell DESCRIPTION - membrane bound: a double phospholipid bilayer membrane makes up the outer surface▪ pores in membrane▪ outer membrane continuous with the endoplasmic reticulum FUNCTION - control center of cell, ie. contains DNA which acts as a template for the manufacture of protein.

Nucleus Close up of nucleus → Nucleus within cell ↓

Chromatin Location - in the nucleus Description - unwound DNA ▪ “chromatin is thin” (coiled DNA molecules are called chromosomes) Function - template for the production of protein

Chromatin

Nucleolus Location – found inside the nucleus Description – small, spherical ▪ not membrane bound ▪composed of protein and nucleic acids Function – important in the formation of ribosomes

Endoplasmic Reticulum Location - a network throughout the cytoplasm – attached to (or continuous with) the outer nuclear membrane Description - membrane bound: channels or canals which are composed of a single membrane layer ▪ rough ER has ribosomes attached ▪ smooth does not Function - rough: the ribosomes attached produce proteins destined for export from the cell. The inside of the E. R. modifies these proteins and then puts them into vesicles to send to the Golgi - smooth: manufacture lipids (fats) and processes toxins

Endoplasmic Reticulum

Endoplasmic Reticulum This picture shows how the endoplasmic reticulum works with the Golgi.

Ribosome Location - on the surface of the E. R. (rough E. R. ) or free throughout the cytoplasm Description - not membrane bound ▪ ▪ 2 subunits (large and small) Function - site of protein synthesis

Ribosome This diagram shows the two subunits (large and small) of a ribosome.

Ribosomes can be found on the endoplasmic reticulum, or free-floating in the cytoplasm.

Golgi Body (Complex) Location - between the E. R. and the cell (outer) membrane Description - membrane bound: a single membrane layer outlining several stacked structures ▪ looks like a slightly curved stack of pancakes Function - modifies proteins destined for secretion by adding other molecules to them ▪ sends these proteins to the cell membrane in secretory vesicles

Golgi Body (Complex)

Lysosome Location - pinch off of the golgi apparatus but scattered throughout the cytoplasm Description - membrane bound: by a membrane layer ▪ full of enzymes Function - 3 functions all related to the enzymes they contain; 1. digest the contents of a dead cell from the inside out 2. digest food particles engulfed by cell (by endocytosis) 3. digest invaders like bacteria and viruses engulfed by white blood cells

Lysosome

Mitochondrion Location - scattered throughout the cytoplasm Description - membrane bound: have a double membrane layer Have their own DNA Function - the different parts are surfaces and spaces where the many steps of cellular respiration occur (results in the production of cellular energy molecules called ATP (adenosine triphosphate))

Mitochondrion

Mitochondrion

Chloroplast Location - only in photosynthesizing cells, found in the cytoplasm ▪ more on the sides of cells toward the direction of light Description - membrane bound by a double membrane layer – contain chlorophyll – have their own DNA. Have stacks of membranes call thylakoids Function – where photosynthesis occurs

Chloroplast

Vacuole Location - usually one large central one in plant cells, but many scattered throughout in animal cells Description - membrane bound by a single membrane layer ▪ contain water and other dissolved substances Function - temporary storage of food, water, and waste

Vacuole