Transcript StudentsLecture 2(ribosome modification).

 Organelles

do the work of cells
each structure has a job to do

keeps the cell alive; keeps you alive
They’re like
mini-organs!
Model Animal Cell
 Function


________________ center of cell
________________ DNA

instructions for building proteins
 Structure


nuclear ____________
nucleolus


________________ factory
chromosomes

________________





Determines __________ of
cell.
Nuclear DNA is the hereditary
blueprint and is attached to
proteins, forming long fibers of
chromatin.
During reproduction, chromatin
coils up into structures called
chromosomes.
Enclosing the nucleus is a
nuclear membrane which is a
double membrane perforated
with pores through which
materials enter and leave the
nucleus.
The ________________
consists of parts of chromatin
DNA combined with RNA and
proteins and is where
ribosomes are made
 Function


__________ factories
read instructions to build proteins from DNA
 Structure


some free in __________
some attached to __________
Ribosomes on ER



Ribosomes are composed of ________________ RNA
(rRNA) and ribosomal proteins (known as a
Ribonucleoprotein or RNP)
It translates messenger RNA (mRNA) into a polypeptide
chain (e.g., a protein)
Ribosomes consist of 1 ________________ subunit and 1
________________ subunit and both work as one to
translate the mRNA into a polypeptide chain during protein
synthesis
ribosomes
build proteins
 Function



works on _____________
helps complete the
proteins after ribosome builds
them
makes_____________
 Structure


_____________ ER
 ribosomes attached
 works on proteins
_____________ ER
 makes membranes

“Rough” refers to the appearance of
________________ over the surface of
the organelle giving it a bumpy or
“rough” appearance.

Network of interconnected flattened
sacs with two main functions. One is to
________________ and the second is to
make ________________ that are
secreted by the cell.

Ribosomes of R.E.R. synthesize the
antibody’s polypeptides, which assemble
into functional proteins inside the E.R.
that are exported from the ER via a tiny
sac called a transport vesicle. This takes
the protein to where it will carry out its
function in the cell.






Continuous with the R.E.R. and is an interconnected
network of tubules that ___________ ribosomes
Contains ___________ in its membrane.
Actively works to synthesize ___________, including fatty
acids, phospholipids, and steroids.
Each product is made of a particular kind of cell (SER in
cells of ovaries and testis synthesize the steroid sex
hormones.)
SER in liver is more extensive as it is a huge regulatory site
for metabolism in the bodily system (regulation of blood
sugar in the system and regulation of harmful chemicals
from drugs and other substances)
As the amount of drug increases in the system, more SER is
created to metabolize it and thus a larger dose is required
to achieve a similar effect, such as sedation. Leads to
tolerance of drugs and foreign substances.





_______________,
_______________, and
_______________ cell products
which are mainly proteins
Named after Italian physician
Camillo Golgi
Is a stack of _______________
___________ called cisternae
formed of membranes that are
not interconnected
Size and layers of Golgi
apparatus depends on how
active the cell is in secreting
proteins
Performs several functions in
close partnership with the SER
by receiving and modifying
substances created by the ER

One side of it serves as a receiving dock for transport
vesicles and is referred to as the __________ face

Takes _______ materials and modifies them chemically

Other side of Golgi is the shipping center and is referred to
as the _________ face and functions to ‘______________
and _________________’ molecules into different
batches for different destinations

When modification is finished, transport vesicles are
created for exporting these chemicals out of the plasma
membrane or another organelle, such as a lysosome

Function
food


used to make energy
& recycle



Structure


digest broken organelles
membrane sac of digestive enzymes
Also known as a “_________________________”
 Produced
by the _______________ and the
_________________________
 Consist of digestive (hydrolytic) enzymes
enclosed in a membranous sac.
 Process: R.E.R. puts enzymes and
membranes together, Golgi apparatus
chemically refines enzymes and releases
mature lysosomes.
 Demonstrates the main theme of
_________________________.
 Lysosomal membrane encloses a
compartment where digestive enzymes are
stored safely isolated form the rest of the
cytoplasm (similar to stomach lining and HCl
acid content.)
 Lysosomes
are the cells' garbage disposal
system. After the bacterium is enclosed in
a vacuole, vesicles containing lysosomal
enzymes (sometimes called primary
lysosomes) fuse with it. The pH becomes
more acidic and this activates the
enzymes. The vacuole thus becomes a
secondary lysosome and degrades the
bacterium.
 Lysosomes also degrade worn out
organelles such as mitochondria
Lysosomes have several types of digestive functions:
1. Fuse with food vacuoles to release molecules such as
amino acids for example and leave the lysosome to be
reused by the cell
2. Help destroy harmful bacteria (breakdown the
bacterial wall inside of white blood cells), serve as
recycling centers for damaged organelles (digests parts
of organelles and making its molecules available for
construction of new organelles),
3. Works in embryonic development to destroy the
webbing that joins the fingers of human embryos
 If lysosomes lack enzymes to digest particular molecules
or organelles, it can lead to very fatal complications
(Tay-Sachs disease ravage the nervous system by not
being able to digest lipids and they build in excess in
the brain and cause major brain damage)

6 weeks
15 weeks

Peroxisomes may resemble a lysosome, however,
they are not formed in the Golgi complex.

They bud off from the ER and are self replicating
Peroxisomes in the liver function to rid the body of
toxic substances such as fatty acids, hydrogen
peroxide, purines

Perosixomes also participates in the synthesis of
cholesterol, bile acids, lipids used to make
myelin.
Peroxisomes in plant cells participate is such
functions as
 symbiotic nitrogen fixation
 Function
moving material
around cell
 storage

small food
particle
 Structure

membrane sac
vacuole filled w/
digestive enzymes
vesicle
vesicle filled w/
digested nutrients
plant cell
food vacuole
central vacuole
animal cells
contractile
vacuole
Function in general cell ____________________
 Membranous sacs that come in different shapes
and sizes and have a variety of functions. Plants
have large vacuoles and may help cell grow by
absorbing water. They also may store chemicals
or waste products for metabolism-pigments that
attract pollinators, as well as poisons that
protect against plant-eating animals.
 The control of water concentration in a cell is a
major function. Paramecium [single celled water
dwelling organism] have two contractile vacuoles
that take in water and contract frequently to
regulate the concentration of water in the cell
to prevent the cell from being too dilute and
eventually bursting.

cytoplasm
jelly-like material holding
organelles in place
vacuole & vesicles
transport inside cells
storage
cell membrane
cell boundary
controls movement
of materials in & out
recognizes signals
lysosome
food digestion
garbage disposal &
recycling
 Making

to replace, repair & grow,
the cell must…




more cells
copy their DNA
make extra organelles
divide the new DNA & new organelles
between 2 new “daughter” cells
organelles that do this work…


nucleus
centrioles
 Function

help __________ cell division

only in __________ cells
 Structure

__________ pair in each cell