Transcript Cell structure

Cell structure
 There are 2 classes of cells
 Prokaryotes
 Bacteria
 Eukaryotes
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Plants
Animals
Fungi
protists
Prokaryotic cells:
 The work Prokaryote means “before the
Nucleus”.
 Prokaryotes originated before cells with
nucleus evolved.
 They are single-celled organisms
 They do not have a nucleus
 They do not have membrane bound
organelles.
Prokaryotes are divided
into 2 domains:
 Bacteria
 Archaea
 Discovered in the late 1970s
 lived at high temperatures (Thermal vents,
hot springs…) or produce methane
Eukaryotic cells:
 Eu- means “true”
 Karyon means “kernel” (referring to the
nucleus)
 Has a membrane bound nucleus
 Has membrane bound structures called
organelles
Organelles
 Organelles are membrane-bound
structures with particular functions within
eukaryotic cells.
Organelles are used:
 To perform metabolic functions
 Provide structural support
 For motility (movement)
Nucleus:
 The nucleus is the center of all activities inside
the cell. This is where all of the genetic
information is located.
 It is the control center of the cell
Endoplasmic Reticulum
(ER)
 It is an extension of the nuclear envelope
(the membrane around the nucleus)
 It forms a continuous compartment that
folds over and over into flattened sacs
and tubes.
There are 2 types of
Endoplasmic reticulum:
 1. Rough ER – has ribosomes attached
to its outer surface
 2. smooth ER – does not have
ribosomes.
Ribosome
 Could be free floating or bound to the
Endoplasmic reticulum.
 Responsible for making proteins.
 Ribosomes are NOT bound by a
membrane
Golgi apparatus
 Has a folded membrane that looks like a
stack of pancakes.
 the Golgi apparatus “sorts” and
“Packages” proteins getting them ready
to be shipped out of the cell.
Mitochondria
 The power house of the cell
 This is were the bodies energy units (ATP) are
produced.
 Mitochondria have 2 membranes.
 The inner membrane is highly folded to provide
more surface area. this is called Cristae
 It has its own DNA (maternal DNA)
 It is thought to have evolved from bacteria that
took up permanent residence in the cell.
 Not found in plant cells
lysosomes
 Vesicles that bud from Golgi bodies
 It takes part in intracellular digestion.
 They contain enzymes that break down
carbohydrates, proteins, nucleic acids,
and some lipids.
Peroxisome
 They participate in the metabolism of
fatty acids and many other metabolites.
 Peroxisomes harbor enzymes that rid the
cell of toxic peroxides
Cytoplasm
 The clear, gelatinous fluid inside a cell.
Organelles unique to
plants:
 Chloroplast
 This is the
organelle
responsible for
photosynthesis
 It is similar to the
mitochondria in
animal cells.
 Vacuoles – responsible for maintaining
the shape of the plant cell. Plant cells
cannot increase by expanding the
cytoplasm, they increase the size of the
vacuole.