Histology: Anatomy of the Cell Flashcards
what is the composition of a cell (5)
- water
- protein
- lipid
- carbohydrate
- inorganic
what type of cells have the most water
embryonic
what does the cytoskeleton of a cell determine and what is it made of
- determines shape and fluidity
- made of thin, intermediate filaments and microtubules
what are inclusions
other structures in the cytoplasm, may or may not be membrane-bound
what kind of things are embedded in the phospholipid bilayer
cholesterol, integral and peripheral proteins
what else is associated with a phospholipid (hydrophilic head, hydrophobic tail)
- glycerol (but this is interchangeable)
function of mitochondria
energy production
function of rough ER
protein synthesis
function of smooth ER
cholesterol/lipid synthesis + detoxification
function of golgi apparatus
modifications and packaging of secretions
function of lysosomes
hydrolytic enzymes of intracellular digestion
function of nuceus
contains genetic code
are inclusions permenant /dispensable and are there for a long/short time
- dispensable
- short
how might an inclusion appear in a cell
- synthesis by the cell
- taken in endocytotically
what are examples of inclusions
glycogen, pigment, lipid droplets, presecretion product
how do the different components of the cytoskeleton attach to the cell membrane and each other
anchoring and joining proteins
describe the features of microfilaments
fine strands of actin that can associate and dissociate
what do intermediate filaments do
bind intracellular elements together and to the cell membrane
where are neurofilaments from
nerve cells
where are glial fibrilliary acidic proteins from
glial cells of nervous systsem
where are desmins from
muscle cells
where are cytokeratins from
epithelial cells
where are vimentins from
mesenchymal cells
where are filasens from
lens of the eye
where are lamins from
nucelus of all cells
descibe the features of microtubules
hollow tubes of alternative alpha and beta tubulin subunits that can associate and dissociate
where do microtubules originate
centrosome - MTOC
what are MAPs and what is their function
microtubule associated proteins - stabilising
what structures are microtubules important in
cilia, flagella and mitotic spindle
what are kinesin and dyesin and their functions
motor ATPases that attach to and move microtubules but can also ‘drag’ organelles and vesicles whilst moving
what way does kinesin move stuff
towards periphery of the cell
what way does dyenin move stuff
towards centre of the cell
what is at the core of the MTOC and what is the core made of
centrioles - made of specialised microtubule segments
what is the nucleus enclosed by
an inner and outer nucleur membrane making a nuclear envelope
what allows the nucelus to be continuous with the cytoplasm
nucleur pores
what allows the nucleur membrane to be continuous with the rough ER
its studded with ribosomes
what allows the nucleus to be continuous with the smooth ER
perinucleur cisterna - holes between the membranes to the ER/golgi
where are mRNA and tRNA transcribed
nucleus
where is rRNA transcribes
nucleolus
what is the nucleolus
dense area in the nucleus
what is the difference between euchromatin and heterochromatin
euchromatin is more dispersed and undergoing transcriptin whereas heterochromatin is more condensed and not undergoing transcription
where are ribosomes formed and what are they made of
- nucleolus
- small subunit that binds DNA and a larger subunit that binds that catalyses peptide bond formation
what is the ER
network of interconnecting membrane bound compartments
what is a polysome
cluster of ribosoomes held together by a strand of mRNA undergoing translation by each ribosome
describe the rough ER
studded with ribosomes and its amount in the cell varies with cell activity
what is rough ER associated with
protein synthesis and glycoprotein formation initiation
describe the process of protein synthesis
- free ribosome attaches to mRNA
- ER signal peptide present, translation initiated and growing peptide inserted into a pore in rough ER
- peptide forms in rough ER and signal sequence removes
- ribosome detaches
- most proteins go to smooth ER
what occurs in the smooth ER
- continues proccessing proetins
- role in lipid synthesis
what is the structure of the golgi complex
group of flattened membrane bound cisternae (discs) arranged into sub-compartments
what are the functions of the golgi apparatus
- transports arriving vesicles from smooth and rough ER
- modifies and packages macromolecules synthesis by ER
- add sugars, cleave some proteins, sort into vesicles
describe the layout of the mitochondria
- inner and outer membranes
- inner membrane is folded into christae to increase SA
what are the fucntions of the mitochondria
- generates energy via oxidative phosphorylation
- synthesis some lipids and proteins
describe mitochnodria DNA
circular and system for protein production
what are the 3 types of intracellular junctions
- anchoring
- communicating
- occluding
what do occluding junctions do and where are they found
- stop diffusion
- between adjacent cells
what are the names for occluding junctions
zonula occludens/tight junctions
what do zonula occludens do
join actin bundles of adjacent cells
what do desmosomes do and what are they also known as
- join adjacent cells via submembrane intermediate filaments
- macula adherens
where are macula adherens common and what do they do there
skin - mechanical stability
what is a junctional complex and where are they found
close association of several types of junctions, found in certain epithelial tissues
what do communicating junctions do and how do they do this
- allow selective diffusion between adjacent cells
- circular patch with pores allowing certain molecules through
what are the pores in communicating junctions made from
connexon proteins
what are communicating junctions also called and where are they found
- gap junctions
- epithelia, smooth and cardiac muscle
what are the types of transport in/out a cell
- diffusion
- transport proteins
- vesicular transport (endocytosis/phagocytosis)
how is endocytosis often mediated
receptors
