Download Cell Structures and Their Functions - GCG-42

Cell Structures and Their
Functions
Cell Structure
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Highly Organized
. Specialized structures called organelles in
a jelly like substance called
cytoplasm
Amount and type of organelles is related to
function
Functions of the Cell
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Basic Unit of Life -smallest part that still retains
characteristics of life
Protection And Support – cells secrete substances that
provide
Movement- occurs because of molecules that are located
in specific cells e.g. muscle cells
Communication-cells receive information that allow them
to communicate with each other eg nerves cell tells
muscle cells to contract
Cell metabolism and energy release- all the chemical
reactions that occur within the cell
Inheritance – each cell contains a copy of the genetic
information of the individual
The Organelles
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The Nucleus
Cytoskeleton
The Cell Membrane
Nucleoli and Ribosomes
Rough and Smooth Endoplasmic Reticulum
The Golgi Apparatus
Secretory Vesicles
Lysosomes and Peroxiisomes
Mitochondria
Centrioles
Cilia, Flagella and Microvilli
Cell Membrane
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Phospholipid Bilayer
Protection and Transport
Types of Transport
--Active ( requires ATP)
--Passive
Nucleus
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Contains the genetic material of cell (DNA)
Located near the center of the cell
Some cells lose their nucleus as they mature,
some have more than one nucleus bone cells
Nuclear envelop (outer and inner membranes
and nuclear pores)
Contains loosely coiled fibers called chromatin
consisting of DNA When a cell divides the
chromatin becomes more tightly coiled to form
the 23 pairs of chromosomes
DNA and RNA
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DNA has 4 nitrogenous bases : adenine,
guanine, cytosine and thiamine plus the sugar
deoxyribose
RNA has 4 nitrogenous bases : adenine,
guanine, cytosine and uracil plus the sugar
ribose.
Remember there are 64 sets of codons (a codon
is 3 base pairs) that encode for only 20 amino
acids
RNA
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mRNA
t RNA
r RNA
Nucleoli and Ribosomes
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Nucleoli- are rounded dense well defined
nuclear bodies with no surrounding
membranes
Ribosome's- are the organelles where
proteins are produced
-may be free
-attached to the endoplasmic reticulum
-made in the nucleus
Smooth and Rough
Endoplasmic Reticulum
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The ER is a series of membranes forming
sacs and tubules that extends from the
outer nuclear membrane into the
cytoplasm
Rough ER has ribosomes attached
indicting that it is synthesizing large
amounts of protein for export from the cell
Protein Synthesis
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Transcription
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Translation
Protein Synthesis
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DNA in nucleus is Transcribed to mRNA
mRNA is translated at the level of the
ribosomal subunits where the codons are
read and translated into amino acids
The amino acids form peptide bonds to
create one larger protein
The Golgi Apparatus
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Golgi Apparatus- closely packed stacks of curved
membrane –bound sacs.
Its function is to collect modify , package and
distribute proteins and lipids manufactured by
the Endoplasmic Reticulum
May also chemically modify the proteins by
attaching carbohydrates or lipids to them
Found in great number in cells tat make a great
deal of protein e.g. pancreas
Secretory Vesicles
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a vesicle is a small membrane bound sac that
transports or stores materials within cells
Secretory vesicles – pinch off from the golgi
apparatus and move to the surface of the cell .
Their membranes fuse with the cell membrane
and release contents to the exterior of the cell
Lysosomes and Peroximes
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Lysosomes are membrane bound vesicles
formed from the golgi apparatus . They
contain a variety of enzymes that
functions as intracellular digestive systems
Peroxisomes small membrane bound
vesicles containing enzymes that break
down fatty acids , amino acids and
hydrogen peroxide.
Mitochondria
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Mitochondria- small bean shaped, long
threadlike organelles that has inner and outer
membranes separated by a space. The outer
membranes have a smooth core but the inner
membrane has numerous folds called cristae
Site of ATP production within the cells and carry
out aerobic respiration.
Cytoskeleton
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Cytoskeleton- consists of proteins that
support the cell , hold organelles in place
and enable the cell to change shape.
Elements of Cytoskeleton
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Microtubules
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Microfilaments
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Intermediate filaments
Centrioles
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Centosome- a specialized zone of cytoplasm
close to the nucleus that is the center of
microtubule formation.
It contains the centrioles normally oriented
perpendicular to each other
Shaped like a cylinder and has nine triplets ,
each consisting of three parallel microtubules
joined together.