COMPONENTS OF THE CELL: MAJOR PARTS OF THE CELL Flashcards
★ no nucleus but has a
nucleoid
★ unicellular
★ does not have membrane
bound organelles
★ DNA suspended on
cytosol
PROKARYOTIC
★ has a nucleus
★ multicellular
★ have membrane bound
organelles
★ DNA suspended on nucleus
EUKARYOTIC
★ cell’s primary barrier
PLASMA MEMBRANE
★ protects the cytoplasm from external environment
PLASMA MEMBRANE
comprises of phospholipids, cholesterol, membrane
proteins, glycolipids, glycoproteins
PLASMA MEMBRANE
plasma membrane mostly consist of
phospholipids
○ with a negatively charged phosphate group (sugar,
bases, nucleic acids, RNA) with polar covalent bonds
○ hydrophilic
○ faces outward
★ head
two nonpolar fatty acid chains
○ hydrophobic
○ oriented inward and are together shielded from
wate
★ tails
these phospholipids group together to form a
two-layered barrier called a
phospholipid bilayer
____ phospholipid bilayer makes the
plasma membrane selectively permeable
middle portion
what can pass in plasma membrane
lipids and small, nonpolar molecules such as oxygen
and carbon dioxide can freely pass
from high concentration solute to low
concentration solute
osmosis
proteins, carbohydrates, and cholesterol
molecules are embedded in the membrane so that they
look like a mosaic
mosaic
★ due to the natural viscosity of the membrane,
which allows the protein molecules to freely float and
drift in the membrane
fluidity
★ in the fatty acid tail of the phospholipids
kinks
○ prevents adjacent phospholipids molecules from
packing too close together which causes the
increase in the fluidity of the bilayer
kinks
molecule which act as regulators of fluidity
○ helps w/ stabilizing cell membrane
cholesterol
★ - allows passage of molecules and substances
permeable
example of permeable:
lipids, alcohol, small molecules (oxygen, nitrogen, water, carbon dioxide)
○ is plant cell permeable or impermeable?
permeable
is permeable passive or not?
passive
no substance can pass
impermeable
examples of impermeable:
polar and large molecules (proteins, nucleic acid, amino acids, glucose)
★ only solvents can pass through
semi-permeable
MEMBRANE PROTEINS
★ channel proteins
★ carrier proteins
★ cell recognition protein
★ receptor proteins
allow transport of certain molecules (small
molecules) through the membrane selective permeable
★ channel proteins
○ forms a channel or passageway that simply allows
certain substances to move from one side to the
other
★ channel proteins
receive certain molecules but change their shape to
be able to move these substances across the
membrane very specific with the molecules that
they transport across the plasma membrane
★ carrier proteins
○ helpful in recognizing the presence of pathogens so
that certain immune responses can be elicited
cell recognition proteins
○ have a shape that allows only specific molecules to
bind to them
○ when a molecule binds to a receptor protein, the
protein changes its shape which brings about
particular cellular responses
○ any shape
receptor proteins
system of interconnected protein filaments from their
nucleus to the plasma membrane
CYTOSKELETON
★ structural framework and support that has diverse
functions
★ dynamic network
○ change shape kineme
CYTOSKELETON
straight, long, and hollow cylinders that consist of
globular proteins called tubulin
MICROTUBULES
○ alpha and beta-tubulin proteins come together by
forming ____
dimers
microtubules released by centrosomes
spindle fibers
organized by ___-or MTOCs
○ MTOCs in animal cells are in the form of centrosomes
microtubule-organizing centers
maintain cell shape, regulate cellular traffc, and move
chromosomes during cell division
MICROTUBULES
★ long and flexible fibers composed of actin proteins
MICROFILAMENTS
○ `thinnest component of the cytoskeleton
★ occur in a bundle of meshlike networks
MICROTUBULES
contains two chains of globular actin monomers twisted
into a helical manner
MICROFILAMENTS
moves actin filament to have
muscle contraction
myosin filament
muscle contraction and relaxation
★ support the cell and facilitate movement
MICROFILAMENTS
have characteristics that lie between that of
microfilaments and microtubules
INTERMEDIATE FILAMENTS
★ made of a variety of proteins
★ form a ropelike assembly of fibrous polypeptides
INTERMEDIATE FILAMENTS
★ maintain cell shape, anchor the nucleus and other
organelles, cell to cell junction, anchor of cell to the
environment
★ stronger than actin filaments but less dynamic
INTERMEDIATE FILAMENTS
★ entire region of the cell between the nucleus and the
plasma membrane
CYTOPLASM
★ where all the subcellular structures are suspended
CYTOPLASM
semifluid solution that consists of water and
inorganic and organic molecules
cytosol
★ rigid structure that surrounds the cell
★ surrounds the cell membrane for extra protection
CELL WALL
★ most abundant organic compound
cellulose
○ gram positive -
violet
○ gram negative -
pink
★ plant cells contains ____ like cellulose
mesh
○ outer layer of the cell wall
○ contains pectin
★ middle lamella
○ helps the cell wall to bind to the
plasma membrane
pectin
○ between middle lamella and plasma membrane
○ composed of cellulose and microfibrils
★ primary cell wall
○ turgor pressure - ________
○ __________- - base that pulls water in an upward
direction in plants
○ transpiration pull - _______-
crunchy plants
capillary action
trees
