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
plastids
chromoplasts: make and store pidgemnt
amyloplasts: store starch (colourless)
chloroplast: photosynthesis
energy transformes in plants
chloroplasts: photpsynthesis, convert light energy into energy stored in sugars
mitochondria: cellular respiration, transfer chemical energy in carbs, aa, FA into chemical energy in ATP
both contain 1 circular chromosone (DNA + protein) and ribosomes
all eukaryotes
nucleus/nucleolus
ribosomes
golgi apparatus
peroxisomes
nucleus
surrounded by nuclear envelope: double cell membrane, phospholipids, with nuclear pores (allow passage in and out), contains 1 or more nucleoli
usually in center, more prominent organelle, spherical or oval
protects and stores DNA, transcription takes place here
influences cell structure and function: diffirential gene expression determine which protein get made, protein determine cell shape and function
chromosomes
46 in human somatic cells, 23 in reproductive cells
DNA + protein
nucleolus
DNA transcription into rRNA here, where protein + rRNA put together to make ribosomal subunit
not enclosed by cell membrane, so not organelle
ribosomes
complex (not an organelle) 2 different subunit
each subunit contains rRNa and proteins
not surrounded by membrane
transcription, make protein
can be on rER (enzymes to be packaged into lysomes, proteins to be secreted ex hormones, proteins inserted into plasma membrane ex receptors etc) or free in cytoplasm (for proteins for cytoplasm ex: cytoskeleton, enzymes in nucleus) in eukaryotics
free in cytoplasm in prokaryotic
endoplasmic reticulim
rough ER: ribosomes on surface, makes protein
smooth ER: makes lipids, drug detox, stores Ca 2+
golgi apparatus
modifies protein and lipids
sorts: proteisn made on rER passes to the golgi which directs them into other organelles or to the plasma membrane
make lysosomes
endomembrane system
collection of organelles and membranes that work together to make, package, label and ship proteins and other molecules
proteins arrive from rER by vesicles, modifed by golgi, packaged into different vesicle types
Path 1: exocytosis (released out of cell by secretory vesicle/vacuole (little bubble))
Path 2:vesicle membrane to be incorporated into plasma membrane (empty little bubble), extracellular fluid
Path 3:vesicles becomes lysosome containing acid hydrolase enzymes
peroxisomes
membranous sacs, contains enzymes to detoxify sustances such as alcohol, also breaks for FA into shorter ones for mitochndria, abundant in liver cells
mitochondria
cellular respiration by using glucoes, aa or FA
produce heat from energy from broken bonds of glucoes, aa or FA (thats why FA produces more energy, more bonds to break)
only in animals
lysosomes
centrioles (not organelle)
lysosomes
enzymes and low pH, sac filled with digestives (hydrolutic) enzymes
when 4 macromolecules are damaged, get digested by lysosomes
damaged or old cell parts
bacteria
because of low pH, good to keep seperate to not randomly digest cell components
centrioles
composed of mainly a protein called tubulin, not an organelle
help with cell division
