Cell Structure and Functions Flashcards
Prokaryotes is
- single-celled (unicellular)
- the smallest and the simplest cells
Cytoplasm/ Protoplasm of prokaryotes enclosed by
plasma membrane
Prokaryotes has no
- cytoskeleton (filamentous network of protein)
- membranous organelles
Cell wall of prokaryotes made of
peptidoglycan (maintain cell shape)
Gram negative bacteria has
- thinner cell wall
- does not retain the gram stain
Gram positive bacteria has
- thicker cell wall
- retain the gram stain (purple)
Prokaryotes has
- mesosomes (infolding of plasma membrane, site of cellular production)
- ribosomes (synthesis protein)
- genetic material (‘naked’ circular DNA-nucleoid)
- pili (attach to surface)
- high metabolic and growth rate
- short life time
Only some prokaryotes has
- capsule (limit phagocytosis)
- plasmid (small circular DNA - store important genes)
- flagella (movement in liquid environment)
Prokaryotes grow and reproduce by
binary fission
Main groups of eukaryotes
animal and plant cells
Eukaryotes is bounded by
plasma membrane
Eukaryotes contain
- cytoskeleton (supporting matrix of protein)
- membrane-bound organelles
Cell wall enclose
the plasma membrane of plants, bacteria, fungi, algae and some archae (not in animals and protozoa)
Cell wall made of
- cellulose (plant)
- peptidoglycan (bacteria)
Cell wall is
tough, usually flexible but sometimes rigid
Cell wall functioned as
protection and supports against mechanical stress
Plasma membrane enclosed the
cytoplasm/ protoplasm
Plasma membrane made of
phospholipid bilayer with embedded proteins
Plasma membrane is
semi-permeable (selectively permeable)
Functions of plasma membrane
- separating the interior from the environment
- provide shape
- as cell adhesion
- ion channel conductance
- cell signaling (cell interact with their environment and other cells around them)
- attachment point for the cytoskeleton
Cilia is
- the projections from the cell
- motile and non-motile (primary)
Primary cilia are found on
every cell in human body (sensory)
Functions of cilia
- movement
- sweep substances across cell surface
Cilia is made up of
microtubules covered by plasma membrane
Microtubules is
hollow cylinders made up of repeating protein structures
Arrangement of microtubules (in a ring)
- Primary cilia (nine triplets 9+0)
- Motile cilia (nine pairs surround two central microtubules 9+2)
- Basal body/ centriole (anchor cilium to the cell)
Flagella is
projections from the cell
Flagella is made up of
microtubules covered by plasma membrane
Arrangement of flagella (in a ring)
nine pairs surround two central microtubules (9+2)
Function of flagellum
movement
Cytoplasm is
viscous gel, enclosed within the cell membrane
Cytoplasm consist of
- Cytosol (liquid component of the cytoplasm - mixture of cytoskeleton filaments, dissolved molecules and water)
- Organelles
Cytoplasm functions as
medium for most cellular activities
Cytoskeleton is
- skeleton of cytoplasm
- a dynamic structure
Cytoskeleton made of
filamentous protein network
Cytoskeleton present in
plant and animal cells
Functions of cytoskeleton
- maintains cell shape, enables cellular motion
- play important roles in intercellular transport and cell division.
Cytoskeleton included three types of fibres which is
- microfilament
- microtubules
- intermediate filaments
Functions of microfilaments
- muscle contraction and movements of certain cells
- provide support (more in muscle cells and amoeboid)
Microfilaments is
- major portion of cytoskeleton, two chains twisted around one another
- thinnest filaments, flexible and strong