CH. 3 ~ CELLS
CELL STRUCTURE
AND
ORGANELLES
Eukaryotic and Prokaryotic
Cells
Organisms that are
Eukaryotic:
Every organisms that is
not bacteria:
–
–
–
–
Animals
Plants
Fungus
Protists
Organisms that are
Prokaryotic:
Every bacterial cell
– Eubacteria
– Archeabacteria
Eukaryotic vs. Prokaryotic Cells
Eukaryotic Cells
• Large
• Have chromosomes
• Have membranebound organelles
– Nucleus
– Mitochondria
– Centrioles
– (theory of
endosymbiosis)
Prokaryotic Cells
• Small
• No chromosomes,
only small circle of
DNA (plasmid)
• No membranebound organelles.
Eukaryotic Cells are Larger than
Prokaryotic cells
Cell Wall
• A rigid structure found on the outside of
plant, fungal and bacterial cells
• Permeable – allows most substances to
enter freely
• Composed of cellulose and protein
• Located OUTSIDE of the cell membrane
• Structure relates to function:
– The rigid structure of the cell wall provides
support and structure for the organisms
Cell Membrane
• Surrounds ALL cells
• Semi-permeable – only allows certain
substances to pass through
• Contains proteins that help to pass
materials through.
• “Phospholipid bilayer”
• Flexible and “fluid”
Cytosol/Cytoplasm
• Fluid inside the cell that contains the
organelles and allows reaction to occur
• Composed mostly of water and plays a
role in diffusion of materials across the cell
membrane.
Nucleus
• Membrane-bound organelle
• Found only in Eukaryotes
• Controls the cell functions
and processes
• Contains DNA that directs the formation of
necessary proteins. (genetic blueprint)
Nucleolus
• An organelle within the nucleus that
produces ribosomes and RNA
Ribosomes
• small organelles that are
sites of protein synthesis
• Take information from the
DNA (delivered to the
ribosome by RNA) and use
it to make protein
• Sometimes found on the
ER (or the rough
endoplasmic reticulum),
but also found in the
cytoplasm of ALL cells
Endoplasmic reticulum (ER) –
• Endoplasmic reticulum (ER) –
detoxification and transport.
• Attached to the nuclear membrane and
zigzags through the cell
• Rough or smooth
– Rough = has ribosomes
– Smooth = no ribosomes
Golgi Apparatus (Bodies)
• Packaging and distribution
• Flattened, layered, sac-like organelles
which are located near the nucleus.
MITOCHONDRIA
•
•
•
•
•
•
“Powerhouse” of the cell
Converts food into energy (ATP)
Inner and outer membrane
Has it’s own DNA (endosymbiotic theory)
Found in Eukaryotes only
Found in both plants and animals
CHLOROPLASTS
• Converts sunlight, water and carbon dioxide to
sugar and oxygen through photosynthesis
– Has chlorophyll – pigment that captures the sun’s
light.
• Inner and outer membrane
• Found in Eukaryotes only
• Found only in plants
(producers/autotrophs)
Lysosomes
• Contain enzymes to break down old
organelles or kill the cell.
Centrioles
• only in animals cells. Make the spindle for
cell reproduction
•
•
•
•
VACUOLE
Contains water
(Can also store nutrients, waste products)
Large in plants, small in animals
Controls “turgor pressure”
in plants.
• Flagella – long whip-like tail for movement
• Cilia – short hairs for movement
Animal
•
•
•
•
No cell wall
No chloroplast
Small vacuoles
Has centrioles
Plant
• Cell wall
• Chloroplasts
• Large vacuole
• No centrioles
MITOCHONDRION – these are spherical to rod shaped organelles with a
double membrane. Its inner membrane lies in many folds to make projections
called cristae. They convert energy stored in glucose into ATP (adenosine
triphosphate). CYTOPLASM – it is a jelly-like material around the nucleus
containing the organelles.
AMYLOPLAST- it is a starch-storing, colorless plastid which occurs only in
plant storage tisues.
CENTROSOME – it is a small body containing centrioles. It provides the
microtubules and helps in cell-division. ROUGH ENDOPLASMIC RETICULUM
– it is a complicated system of interconnected, membranous, infolded,
convoluted sacks that are located in the cell’s cytoplasm. Its rough appearance
is due to the ribosomes that cover it. It transfers materials through the cell and
produces proteins in sacks called cristernae.
SMOOTH ENDOPLASMIC RETICULUM – it is similar to the rough ER, infact it
buds off from it. The space within it is called the ER lumen. It contains enzymes
and produces and digests fats and membrane proteins.
RIBOSOMES – these are small organelles composed of RNA-rich cytoplasmic
granules and are sites of protein synthesis.
GOLGI BODY – these are flattened, layered, sac-like organelles which are
CELL MEMBRANE - this thin surrounding layer is made up of proteins and fats.
It is semipermeable i.e. it allows a few substances to pass through while
blocking the others.
LYSOSOME – also known as cell vesicles, they are round organelles
surrounded by a membrane and help in the digestion of cell nutrients as they
contain the digestive enzymes.
NUCLEUS – it is spherical in shape and contains the DNA chromosomes
alongwith the nucleolus and many other organelles. It controls the protein
synthesis thereby controlling many important functions the cell. It is surrounded
by a nuclear membrane.
NUCLEOLUS – it is an organelle within the nucleus and produces the RNA
(ribonucleic acid).
NUCLEAR MEMBRANE – it is the membrane surrounding the nucleus.
VACUOLE – it is a large space filled with fluid within a plant cell which helps
the cell to maintain its shape.
MITOCHONDRION – these are spherical to rod shaped organelles with a double
membrane. Its inner membrane lies in many folds to make projections called cristae.
CENTROSOME – it is a small body containing centrioles. It provides the microtubules
and helps in cell-division.
CYTOPLASM – it is a jelly-like material around the nucleus containing the organelles.
ROUGH
ENDOPLASMIC RETICULUM – it is a complicated system of interconnected,
membranous, infolded, convoluted sacks that are located in the cell’s cytoplasm. Its
rough appearance is due to the ribosomes that cover it. It transfers materials through the
cell and produces proteins in sacks called cristernae.
SMOOTH ENDOPLASMIC RETICULUM – it is similar to the rough ER, infact it buds off
from it. The space within it is called the ER lumen. It contains enzymes and produces and
digests fats and membrane proteins.
GOLGI BODY – these are flattened, layered, sac-like organelles which are located near
the nucleus.
SOME MORE CELL ORGANELLES: PEROXISOMES – cell organelles containing
enzymes that catalyze the production and breakdown of Hydrogen Peroxide.