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Biology 12
THE CELL:
A. Structure & Function of Cell Organelles
Organelle
Nucleus
nucleolus
nuclear
envelope
chromosome
chromatin
vacuole
vesicle
smooth ER
Structure
Lg. central, darker body in the cell
(largest organelle), contains thin
strands of chromatins and the
nucleolus, bounded by a double
membrane
Contained in the nucleus, small dense
collection of specialized DNA, no
membrane, may be 2 or more
Function
Control center of the cell since the
contained DNA determines what
proteins are made and so the
structure and functioning of the cell.
DNA codes for rRNA and proteins
nec for formation of ribosome
subunits, the more active a cell is in
protein synthesis the more nucleoli
present
Double layer of phospholipids bilayer, Regulates what enters or leaves the
has pores made of circular
nucleus especially via the Rough ER
arrangement of proteins, continuous
but also the pores allow RNA to
with the ER
leave nucleus
DNA (alpha double helix), made of
Each sequence of nitrogenous bases
hundreds of nucleotides joined in a
gives the code for a specific
specific sequence by covalent and
sequence of amino acids that will
hydrogen bonds, visible due to
eventually make a needed protein.
shortening of chromatin
The proteins can give rise to
structures or chemicals
Invisible form of DNA, contains the
necessary for the functioning of the
same nucleotides but the strand is in
cells or the organism as a whole
thin threads rather than condensed as
Same as chromosome
a chromosome
Membrane bound sac that contains
Large, found in plants, due to fluid
water and dissolved substances
within gives shape and structure to
the cell (turgor)
Tiny version of a vacuole
Transport, secretory, excretory
forms, all carry substances around
the cell and to or from the cell
memb.
Continuous with the rough er and the Receive proteins from the rough ER
nuclear envelope, has no ribosomes
to be pkg for transport to Golgi
on surface, tube-like
body, make steroids(gonads and
adrenal gland) for export,
peroxisomes are made (in the liver)
for detoxifying drugs etc.
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Rough ER
Golgi body
Lysosome
Tube-like canals that arise from outer
membrane of nucleus, has ribosomes
attached to the membrane, continuous
with the smooth er
Stack of flattened vacuoles, 5-6,
curved with the inner surface facing
the nucleus
Vacuole filled with hydrolytic
enzymes
Plasma
membrane
Phospholipid bilayer with surface and
embedded proteins, semipermeable
(porous)
Ribosome /
polysome
Tiniest organelle, made of 2 subunits
of rRNA and many types of proteins,
no membrane
Mitochondria
Kidney shape usually, double
membrane (inner called cristae), fluid
called the matrix contains important
enzymes
Proteins are made on the surface and
inserted into the cisternae to be
modified and moved onto the smooth
er for secretion
Receive, store, modify, and pkgs
substances for export (secrete),
lysosomes are made here
Digests incoming substances
contained in vesicles, can cause the
self destruction of the cell when it
burst
Regulates what enters and leaves the
cell by its selectively permeable
nature, keeps cell organelles in small
space, allows attachment of
cytoskeleton
Site of protein synthesis when the
two subunits come together on a
mRNA strand, can work in groups
called polysomes making many
molecules of the same protein
Cellular respiration, breakdown of
molecules of glucose provide the
energy to build an ATP molecule –
energy source for organelles