Cells and Organelles Flashcards
Name organelles in a typical human cell (11)
Nucleus, ER, Golgi, Mitochondria, Plasma membrane, Peroxisomes, Lysosomes, Cytoskeleton, Microfilaments, Microtubules, Intermediate filaments
Describe organelles
sub cellular compartments featured in eukaryotic cells, usually membrane bound (except ribosomes), specialised for unique functions
4 components of nucleus
nuclear membrane, nuclear lamina, chromatin, nucleolus
5 components of the plasma membrane
phospholipid bilayer, cholesterol, carbohydrates, proteins, lipid/membrane rafts
4 compartments of mitochondria
outer membrane, inter membrane space, inner membrane (cristae), matrix
detailed functions of mitochondria (2)
ATP production: TCA (krebs cycle), electron transport chain (needs cytochrome C on inner membrane), oxidative phosphorylation
Apoptosis (release of cytochrome C from mitochondria to cytosine initiates apoptosis)
Name ER definition and functions of rER and sER
Definition: complex set of membranes continuous with nuclear membrane
rER: associated with ribosomes, protein synthesis/folding/modifications
sER: no ribosomes, lipid synthesis, calcium storage
Name Golgi apparatus definition and functions
Definition: stack of flattened membrane bound discs (cisternae) and vesicles
Functions: received proteins from ER, modifies them and sorts them for eventual destination in or out of cell
Function of lysosomes and characteristics
degrade unwanted molecules, approx. 50 degenerative enzymes (acid hydrolyses), optimum pH 5
Peroxisome definition and function
definition - membrane bound organelle performing large numbers of biochemical reactions
functions - contains oxidative enzymes such as catalase, break down of fatty acids (b-oxidation)
functions of cytoskeleton (6)
organises cell structure, maintains correct cell shape, supports fragile plasma membrane, provides mechanical linkages allowing cell/tissue to bear stress, facilitates organelle movement, allows cells to adopt specific behaviours (growth, division, motility)
3 types of cytoskeleton
microtubules, microfilaments, intermediate filaments
intermediate filament function and 3 types of different filaments found in different cell types
function - structural role, provides mechanical strength
keratin - skin epithelial cells
vimentin- fibroblasts
lamins - nuclei of eukaryotic cells
intermediate filament function in nucleus
in nuclear lamina (composed of lamins), nuclear organisation, nuclear membrane support, chromatin organisation
microtubules function and polymers
function - dynamic structures: cell movement, intracellular support of organelles, mitotic spindle
polymers of a and b tubulin
microtubules role in intracellular organelle support
kinesins move cargo away from centrosome
dyneins vice versa
what is the cytoskeleton component of cilia and flagella? what are they composed of?
axonemes, allow for bending, primarily composed of microtubules and dynein
microfilaments function and polymers of…
function - dynamic processes like cell shape change, cell motility and cell structure
polymers of actin
what do cells do in tissues and organs, what structure makes this possible?
work together as aggregates to cooperatively perform a given function, possible through cell junctions
cell junction definition and function
definition - transmembrane protein complexes
function - connects plasma membrane to adjacent cells, the basement membrane and the cytoskeleton
what anchoring junctions are cell-cell, and what is their cytoskeleton made of?
adherens (actin) and desmosomes (intermediate filaments)
what anchoring junctions are cell-extra cellular matrix, and what is their cytoskeleton made of?
focal adhesions (actin) and hemidesmosomes (intermediate filaments)
tight junction functions
function as ‘gates’ and ‘fences’
gates control regulation of paracellular permeability
fences form apical and basolateral intramembrane diffusion barriers
name of channel forming junctions, type of contact, composition and function
GAP junction, cell-cell contact, composed of hexamers and connexins, allows passage of small molecules
which cell had no nucleus, describe it
red blood cell (erythrocyte), biconcave shape, anucleate, lives for 120 days and functions to carry oxygen to tissues
name 2 examples of a cell with enriched rER and golgi organelles to carry out their specific functions
plasma cells - produce large amounts of antibodies
fibroblasts - forms connective tissues
name 3 cells enriched with sER for their specific function
hepatocytes - lipid biosynthesis
leydig cells - steroid hormone biosynthesis
muscle cells - calcium store needed
name condition caused by defective hemidesmosome components, and effects of condition
epidermolysis bullosa, very fragile skin prone to blistering, skin tears easily upon touch and is painful
name 3 cells where defective cilia may cause problems in cellular functions
respiratory epithelial cells - mucus clearance from airways
brain ependymal cells - circulation of CSF
epithelial cells lining fallopian tubes - help ovum to move to uterus
name the process of defects in microtubules and the disease it can cause
Tau protein dissociates from microtubules in alzheimer’s disease, resulting in microtubules disassembly
name the disease caused as a result of lysosome storage disorders, and the process of defection
Tay-Sachs disease, accumulation of gangliosides (type of lipid with a carbohydrate protein) in brain and spinal cord
what defective cellular structure can cause cancer, and how?
adherens junctions - epithelial tumours lose e-cadherin (forms part of adherens junction)
