L-4 Cell Organelles
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Transcript of L-4 Cell Organelles
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Levels of Organization
atom - smallest unit of an element molecule - unit of 2 or more atoms organelle - structures with specific jobs inside a cell cell - smallest living unit tissue - group of same cells functioning together organ - structural unit of different tissues
organ system - two or more organs interacting organism - group of organ systems working together population - group of individuals of same kind community - all populations living in an area ecosystem - community and its physical environment
biosphere - region where life exists
all living organisms display levels of complexity
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(The fundamentalunit of life)
(A membrane bound structure
within a complex cell)
( A small groupof joined atoms)
(The smallest chemicalunit of a type of puresubstance or element)
(A collection ofspecialized cells)
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(where life is possible)
(living andnon living
environment)
(All organisms in agiven place & time)
(A group ofthe sametypeof organism
living in thesame place
and time)
(A structure consisting of
tissues organized to carry outspecific functions)
(Organs connected physically orChemically that function together)
(A living individual)
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THE CELLCELL WALL
non-living structure rigid
made primarily of a substance called cellulose
selectively permeable
found only in plant cells functions are - protect contents of cell (injury)
- regulate flow of materials in andout of cell
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CELL MEMBRANE
also called "plasma membrane"
flexible
structurally a phospholipid bi-layer head faces out and is "hydrophilic"
tail faces in and is "hydrophobic"
common to all living cells
outermost membrane in all cells except plants (cell wall is)
function -to regulate materials moving in and out of cell
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FLAGELLA and CILIA
flagellum is a long whip-like structure
contractile proteins allow a corkscrew action functions in propulsion (ex. human sperm cell)
cilium is a short hair-like structure
contractile proteins move in a co-ordinated wave motion
is used for locomotion and moving materials
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PROTOPLASM
a "gel" in which all other organelles are suspended
composition varies with different types of cells
contains proteins, fats, carbohydrates, vitamins, minerals,water, etc.
it can be sub-divided into two types (by location)
- nucleoplasm (in nucleus only)
- cytoplasm (in the rest of the cell)
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NUCLEUS usually the largest organelle is sac-like or spherical in shape usually only one nucleus per cell
found - the central portion of the animal cell- off to one side in plant cells
contains the genetic material functions - store house of genetic material
- co-ordination centre for all cell activities
NUCLEOLUS found in the nucleus oval or spherical bodies no outer membrane made up primarily of protein and RNA usually 1 to 4 per nucleus function -the synthesis of ribosomes
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NUCLEAR MEMBRANE
a double membrane surrounding the nucleus
flexible
selectively-permeable
regulates materials going in and out of nucleus
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CHROMATIN
found in the nucleus
long thin threads
are acidic
are given different names according to their shape
- long thin threads - chromatin
- short thick threads - chromosome
function - carrier of genetic information
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RIBOSOMES
smallest natural structure in the cell
made up of two spheres
- large sub-unit (Ls) found on top - small sub-unit (Ss) found on bottom
made up of RNA
usually found attached to the endoplasmic reticulum
when found free floating in cytoplasm called "endosomes" function -site of protein synthesis
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ENDOPLASMIC RETICULUM
hollow, tubular structure
meanders through the cytoplasm
connects the cell membrane to the nuclear membrane
exists in two forms- smooth E.R. - no ribosomes attached
- rough E.R. - ribosomes attached
functions - site of internal transportation
- site for chemical reactions
- makes fats and carbohydrates
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GOLGI APPARATUS
usually a system of double layered flattened sacs
lie one on top of the other
found close to the nucleus
functions -produces lysosomes
-makes membranes
-storage for lipids
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LYSOSOMES
single membrane
varies in shape and size (pleomorphic) formed in the region of the golgi apparatus
numbers per cell varies
have three important functions
- site of intra-cellular digestion
- destruction of harmful chemicals
- "autolysis" of damaged cells
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MITOCHONDRION rod shaped structure double walled
-outer wall - smooth and continuous -inner wall - highly convoluted
- finger-like projections called "cristae"- "elementary particles" on top of crista- "lamella" is space between cristae
number per cell varies greatly site of "aerobic respiration
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CENTRIOLES tubular structure found in two arrangements
-single tubule - centriole-double tubule - centrosome
- 2 centrioles perpendicular to each other found only in animal cells are close to the nucleus two major functions:
- with the production of cilia and flagella- "basal body" if embedded in cell membrane- assists in cell division
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VACUOLES
spherical structure
found through out the cytoplasm animal cells - many small ones
plant cells - few large ones
generally they hold materials to be eliminated from the cell
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GRANULAR INCLUSIONS smallest structure in the cell cell fragments found in cytoplasm (only in animal cells)
function is unknown
MICROFILAMENTS
pipe like structures found in the cytoplasm
provide shape andmovement for cell
MICROTUBULES
tiny tube like fibres composed of protein found in cilia and flagella transport materials
throughout the cytoplasm
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Endocytosis
the process by which the cell membrane wraps around aparticle and pinches off a vesicle inside the cell
Exocytosis
The process by which particles are released from a cell byfusing a particle filled vesicle off a vesicle with the cellmembrane
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Generalized Eukaryotic Cell