largest structure in the nucleus consists of nucleolar organizers,
ribosomal RNA, and proteins
Function:
primarily serves as the site of ribosome
synthesis and assembly.
NUCLEUS
Notable structure within the cell o The genetic control centre of the cell -chromatin (network of dark-staining threads)
Surrounded by nuclear envelope
Function
directs cell division
control protein synthesis and many of the metabolic activities of the cell
CELL MEMBRANE
The border of the cell
About 8 nm thick
A semi-permeable membrane
Composed of proteins and lipids
Unit membrane Model - tripartite arrangement of the plasma membrane (protein-lipid-protein)
CELL MEMBRANE
Fluid Mosaic model- protein molecules penetrated into the lipid layers and not continuous in on the surface of lipid
CELL MEMBRANE
Function:
It supports and protects the cell. Regulates the movement of material in and out of the cell
Facilitated diffusion- scattering of particles, from high concentration to lower concentration
Active transport- process resembling facilitated diffusion in that it involves association of molecules to be transported with a membrane area of low concentration to high concentration
Pinocytosis- engulfing of particles
ENDOPLASMIC RETICULUM
A large interconnecting membrane of tunnels
Continuous with the nuclear envelope
ROUGH ENDOPLASMIC RETICULUM
network of interconnected flattened sacs
is studded with ribosomes
Function:
to make protein( secretory protein)
to make more membrane channeling products both to the outside of the cell, via the membrane
SMOOTH ENDOPLASMIC RETICULUM
network of interconnected tubules
lack of ribosomes
Function:
Synthesizing and secreting of certain steroid hormones, enzymes of carbohydrate metabolism, and enzymes of lipid synthesis.
GOLGI APPARATUS (or GOLGI BODY)
Named from Camillo Golgi, n Italian biologist and physician
A series of from 3 to 20 parallel flattened sacs closely stacked together, cisternae
End of the sacs bud off various vesicles
Function:
receives and modifies and packages the substances manufactured by ER,
MITOCHONDRIA (or MITOCHONDRION)
Are spherical to rod-shaped structures from 0.2 to 7μm; a doubled layer membrane
Cristae (complex folding of inner membrane)
Mobile structures, capable of changing their shapes
"powerhouse of the cell"
Function:
produced energy in the form of ATP
LYSOSOMES
Produced by the rough ER and the Golgi apparatus.
Two Greek words, "breakdown body"
Are membrane bound, dense- appearing structures that contain enzymes( acid hydrolases)
Function:
acts as waste- disposal units, digesting and removing foreign material
"suicidal bag"
VACUOLES
enclosed compartments which are filled with water containing inorganic and organic molecules including enzymes
in solution
Function:
Digestion; storage of chemicals, cell enlargement; water balance
RIBOSOMES
Tiny spherical structure
Bodies in which the amino acids are bound together Site of protein synthesis
Site of protein synthesis
CENTROSOMES
quite near the nucleus
Inside of it is the centriole Centriole-
Centriole -
pair of small rod-like structure
there are attached microtubules in the wall
Function:
active in the process of cell division(mitosis)
CYTOSKELETON
an intracellular matrix that supports cell shape and function
The matrix is a dynamic structure composed of three main proteins
Has three components:
microfilaments
microtubules
intermediate filaments
Actin filaments - red
Microtubules - green
MICROTUBULES
tiny cylindrical elements of animal cells about 20 to 25 nm in diameter
composed of tubulins
Function: provide rigidity and shape in one area
Tracts for organelle movement within the cell
Basis of ciliary and flagellar movement
Microtubules in gen fixated cell
MICROFILAMENTS
smaller than microtubules ranging in diameter from 4 to 7 nm
Solid helical rods composed of actin
Function:
providing motive force for cell contraction amoeboid movement, and possibly intracellular transport
CYTOPLASM
Protoplasm that surrounds the nucleus
A semi-liquid substance that composes the foundation of the cell
Within the cytoplasm are a number of different organelles