Download 7.3 Structures and Organelles

7.3 Structures and Organelles
7.3 Structures & Organelles
Division of Labor
cells have a division of labor and contain
special structures that work together to carry
out life processes
Internal Structure
· eukaryotic cells are highly organized structures
· surrounded by a membrane and contain
membrane-bound organelles that perform specific
functions
· the organelles are anchored in the cytoplasm by
the cytoskeleton - a network of protein fibers
· ROLE: structural support and to help move
organelles
Organelles involved in
Protein Production
· much of the cell is devoted to making proteins
· proteins are made of amino acids and have
unique characteristics (size, polarity, acidity)
· since proteins carry out critical functions, they
need to be made correctly
microtubules (long hollow tubes) - act as tracks for
organelle movement...also help in cell division
microfilaments (tiny threads) - enable cells to move,
muscle contraction
· cytoplasm fluid is know as cytosol and is mostly
water
Nucleus
· the nucleus stores the DNA
· DNA contains instructions for making proteins
ROLE: Two major demands of the nucleus
1. DNA must be protected
2. information must be available
· surrounded by double membrane called the
nuclear envelope
· nuclear envelope has holes called nuclear pores
that are used for transport
· most nuclei contain a small spherical area called
a nucleolus (site where ribosomes are assembled
form proteins and RNA)
Ribosomes
· ribosomes are tiny organelles that link amino
acids together to make proteins
· can be free or attached to ER
· ROLE: manufactures proteins
7.3 Structures and Organelles
Endoplasmic Reticulum (ER)
· the endoplasmic reticulum(ER) is an interconnected
network of thin folded membranes
· ROLE: modifies proteins and cellular pathways
Rough ER
covered with ribosomes
makes the bulk of proteins and modifies them for export
Smooth ER
makes lipids
breakdown toxins
Golgi Apparatus
· ROLE: processing, packaging, and secreting
organelle of the cell
· system of membrane stacks (like pancakes)
· works with ER in modifying proteins
Mitochondria
Vesicles
· vesicles - small membrane-bound sacs that
divide materials in the cytoplasm and transport
materials within the cell
· ROLE: supply energy to the cell
· processes your food energy into cellular energy
your cells can use
· bean shaped and has two membranes
outer - barrier from cytosol
inner - membrane is folded to increase surface area
(cristae)
· have their own ribosomes and DNA
· cells that require more energy contain more
mitochondria
Lysosomes
Vacuoles
· fluid-filled organelles
· ROLE: store water, food, inorganic ions, enzymes,
and wastes
· animal cell vacuoles are small
· in plants they contain one very large vacuole (up to
90% of the cell)
animal cell
plant cell
· small circular organelle
· ROLE: contains collective enzymes that break
down lipids, carbs, proteins, DNA and
RNA, bacteria, viruses, and old cell parts
· common in animals, fungi, protists...not usually
in plants
7.3 Structures and Organelles
Centrosomes and Centrioles
· centrosomes ROLE: produce
microtubules
· in animal cells it contains two
small structures called
centrioles
· centrioles - short microtubules
that help with cell division
· centrioles can also form cilia
and flagella
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Cell Wall
lies outside of cell membrane
ROLE: support, protections, and shape
found in algae, plants, and bacteria
made of cellulose in plants and algae
cell wall
cell
membrane
Chloroplasts
· photosynthesis reactions (solar energy --> food
energy)
· two membrane system and contain ribosomes
and DNA
· contain membrane stacks - thylakoids
· contain chlorophyll (green)
animal cells
· centrioles
· lysosomes
· small vacuole
lysosome
plant cells
· chloroplasts
· cell wall
· large vacuole
large
vacuole
centrioles
cell wall
small vacuole
chloroplasts