cell structure Flashcards
Name 5 properties of the cell membrane briefly
separate interior + exterior has phospholipid bilayer used in cellular processes attachment surface for cell wall selectively permeable to ions + organic molecules
what molecules can and cannot cross the cell membrane
charged ions + glucose CAN’T CROSS
O2 + CO2 + H20 + NO can cross by diffusion
what does the phospholipid bilayer consist of
hydrophilic outer heads = polar
hydrophobic fatty acid tails - inner core = non polar
embedded proteins
what cellular processes is the cell membrane used for
cell adhesion
ion conductivity
signalling
why can’t charged ions pass through the membrane
can’t pass through hydrophobic regions ( not through inner core)
so can’t pass through core of phospholipid bilayer
why is the membrane called fluid mosaic
fluid = components move around mosaic = variety of lipids + proteins --> can form complexes
what does the mother centriole do in a centrosome
older one in pair
helps making cilia + flagella
how does the centrosome make the mitotic spindle
centrosome nucleated tubules interact with chromosome
builds spindle
how are centrosomes used in prophase
associated with nuclear membrane
what are 3 properties of lysosome
contain hydrolytic enzymes + digest cellular components
used with macrophages
contain 50+ diff enzymes active at pH 5
what is cytosol + its function
intracellular fluid where organelles held
separated into compartments by membranes
what is a vacuole
closed compartment contain organic + inorganic molecules + enzymes in solution
formed by fusion of multiple membrane vesicles
describe 4 functions of the vacuole
role in autophagy
aid in lysis + forming vesicles
helps maintain balance between biogenesis + degradation of cell structures
what is autophagy
vacuole helps to break down proteins in cell + prevents build up of misfolded proteins
beta amyloid —> Alzheimers
what are the main functions of mitochondria
ATP synthesis for: antibodies, enzymes, hormones –> using ribosomes to make proteins
ATP to regulate cell metabolism (need for ion channels in membrane)
can be specific –> detoxify ammonia in liver
sensitive to hormones = oestrogen receptors
what are extra functions of mitochondria
regulate apoptosis Ca2+ signalling cell metabolism steroid synthesis cell membrane potential
what does cytoskeleton contain
microfilaments made of actin protein
microtubules = tubular protein
intermediate filaments
dynamic structure
what is the structure of golgi
flat tubes connected to ER
transports vesicles around
what are the functions of Golgi apparatus
synthesises macromolecules
modify, sort + packages macromolecules for exocytosis/used in cell
carb synthesis
modify + complete synthesis of complex lipids + proteins (glyco lipids + proteins)
modifies proteins from ER + transport lipids around cell
describe the structure of RER
network of continuous channel membrane
inner + outer surfaces
inner portion = exterior
ribosomes attached to exterior
what are the functions of RER
makes lysosome enzymes + secretes proteins (glycosalyation)
makes integral membrane proteins that are embedded in membrane (ion channels)
what is glycosalyation
adding carb chains to proteins – adds stability + allows tracking of molecules in cell signalling
what is the structure of SER
network of continuous channel membrane
inner + outer surfaces
inner portion = exterior
what is the main function of SER
phospholipid, steroid, lipid synthesis
what areas secrete lipids, phospholipid + steroids + what’s special about these areas
ovaries, testes, oil glands
they have loads of SER
what does SER do in muscles
regulate Ca2+ conc in muscle cells
what are other functions of SER
steroid + carbs, drug detox,
by attaching onto cell membrane
how are vesicles used by cell for organising substances
separated from cytosol
so inside vesicle diff to cytosol env
what are the functions of vesicles
transport metabolism buoyancy control enzyme storage chemical reaction chambers
what is function of ribosomes
makes proteins
how are proteins made at ribosome
mRNA transcribed copy from DNA
tRNA - amino acid adapter
one end matches mRNA code matches with specific amino acid
how does nucleus control cell activities
maintains gene activity
regulate gene expression
what is formed in the nucleus and how is DNA packaged
tRNA, mRNA, ribosomes formed
DNA packaged into chromatin
why does the nucleus need nuclear pores
impermeable to large molecules
what are histone proteins used for in the nucleus
they compress DNA so can fit inside cell
what is nucleolus made of
proteins + RNA
what is the main function of nucleolus
transcribe + modify rRNA + integrate ribosomal proteins –> immature proteins
how is RNA synthesis regulated in the nucleolus
stress sensor based on cellular env
what is function of peroxisomes
catalyse breakdown of toxic substances (H2O2)
clean up H2O2 in water + lipid metabolism
what are the characteristics of prokaryotes
flagella protective capsules + sometimes mesosomes 70s ribosomes peptidoglycan cell wall nucleoid no Golgi apparatus no membrane bound organelles 1 plasmid - no true chromosomes
what colour is gram positive
purple
what is the shape of cell and cell wall if it is gram positive + colour
puprple
rod shaped
thick cell wall
what are the characteristics of the cell of gram positive
thick cell wall - dye doesn’t wash out easily + mesh for strength –> otherwise sensitive to osmotic changes + spherical shaped
single cell membrane
lots peptidoglycan - single cell membrane
destroyed by steaming Not boiling
rod shaped = spore forming
what colour is bacteria that is gram negative
pink/red
what is the shape of cell and cell wall if it is negative + colour
complex + thin peptidoglycan cell wall
pink/redish
complex wall –> dye diffuses out easily
what is gram negative cell wall specially made of and why does it help
lipopolysaccharides:
structural integrity
resist chemical attack
how do antibiotics cause cell lysis of bacteria
antibiotics alters peptidoglycan synthesis for cell wall –> cell wall can’t form –> cell lysis
what is function of microscopes + what is the function
can image single molecules within cells
point spread function allows sharper image
