cells Flashcards
components of all cells
plasma membrane
cytoplasm
cytoskeleton
ribosomes
chromosomes (dna + its protein)
Cytoplasm
where the chemical reactions of a cell take place
by definition, everything inside the cell except the nucleus, cytosol: fluid, part of the cytoplasm
use cytoplasm
2 cell types
prokareotics (bacteria/archaea) and ekaryotics,
an organism is made of only 1 of these cell types
all prokaryotics are unicellular
prokareotics have no organelles, have a DNA (1 circular chromosom) and about 10x smaller (bacterial cells)
cell/plasma membrane
Boundary between inside and outside the cell is called plasma membrane, cell membranes are a part of organelles. Eukaryotics only have a palsma membrane
cell membrane
2 layers of mostly phospolipids, with proteins embedded in them (glycoprotein: protein with carbohydrates stuck to them). also contains sterol (lipids) and some carbs
liquid at body temp, moves around
protein cell membrane examples
receptor
enzyme: breaks down chemical messenger and terminates its effect
channel: constantly open and lets solute pass in and out of cell
gated channel: only open at certain times
cell-identity marker: grycoprotein distingishing own body cells from foreign cells
cell-adhesion molecule: binds one cell to another
microvilli
cell extension tgat contains cytoskeleton, flid and enzymes for digestion, folded plasma membrane
shows the surface vs area dilema (most surfce with least area)
function of plasma membrane
boundary
cell-to-cell contact: needed to form tissues and for cell-to-cell recongniction
cell-to-cell recongniction
cell signaling: one cell releases chemicals that binds to receptors (proteins) of another cell
movement of molecule in/our of cell: through transporters or through bulk transportation
Selective permeability
because lipid layer is mostly hydrophobic, hydrophilics molecules dont pass so well without the presence of a transporter or of bulk transportation
small molecules pass
lipid soluble molecule pass
cytoskeleton
all cells haev it, dynamic, can be dismatled in one part and reassembled, chaneg of shape
cytoskeleton in eukareotics:
mechanical support and maintains chape of cell
cell motility: move entire parts of cell
anchor organells and enzymes
cell divisiom
cell extension
Flagella: complex set of protein that causes it to move, move entire cell, less numerous that cilia (sperm)
cilia: complex set of protein that causes it to move, moves over surface (respiratore track), or move entire cell
microvilli: folds of plasma membrane that serves to increase surface for absorbtion or secreation
outside plasma membrane
cell wall in all fungi, plants, some protist and almost all bacteria. aids in protecting cell, maintaining shape and prevents excessive water intake
in multicellular or colonial organisms,
intercellula junctions: adhere and communicate, some act like velcro while others are more permanent bonds
extracellular matrix: fluids + nutrients+ signalling molecules. provides support, nutrient and can affect gene expression (deifferential gene expression)
what is an organelle
specialized structure within a cell with a specific function, cell membrane enclosed, contains fluids. all aukaryotic cells have them. number may differ depending on cell type and activity of that cell
NOT RIBOSOMES not membrane enclosed or fluid and can dissasemble, they are called complexes
organelle plants only
central vacuoles, plastids, large cell walls (not organelle)
central vacuol
water storage, digestion, stores toxin and pigments, huge
