Cellular Structure: Subcellular Organelles

Contains genes, genetic info (DNA) is replicated for passage to daughter cells, DNA transcribed to RNA for use in protein synthesis (cytoplasm)

Composed of DNA (long duplexed strands) and associated proteins

Individual lengths of DNA with their associated proteins

Highly extended, necessary form transcription, diffuse

Highly condensed form, usually not transcribed

Complex, multipart structure within nucleus that provides scaffolding for transcription, repression of transcription, DNA replication

Component of nucleoskeleton, dense meshwork of intermediate filaments that line nuclear envelope
during interphase: lamins are bound on one end to nuclear envelope and on other to chromosomes
during mitosis- lamins are phosphorylated, nuclear envelope destabilized
dephosphorylation at end of mitosis- reformation of envelope
LMNA- mutations create laminopathies- no other gene results in so many diverse phenotypes

Composed of actin and actin-binding proteins

Non-membrane bound structure within a nucleus where ribosomal DNA is transcribed to ribosomal RNA

Two unit membrane, separated by perinuclear cistern- confluent with lumens of RER but have unique populations of lipids and IMPs

Openings in nuclear envelope that allow movement of molecules between the nucleoplasm and cytoplasm
guarded by a set of membrane-associated proteins- nuclear pore complex- regulates passage of molecules through pore

Process by which cells regulate their replication
G1- growth phase
S- Synthesis of DNA- chromosomes duplicated
G2- when cell gets ready for mitosis, duplicates centrosomes
M- Mitosis- when nuclear membrane breaks down, chromosomes condense, cell divides into 2 daughter cells- cytokinesis- cell division
G1, S, and G2- interphase
M: prophase(chromatin condenses), metaphase (chromosomes line up in middle of cell), anaphase (sister chromatids separate), telophase (nuclear envelopes form around 2 sets of daughter chromatids)
Go- quiescent (not dividing), chromatids decondense, RNA and protein synthesis begins

In cytoplasm
synthesize ATP
maintain appropriate Ca ion levels
holds the key regulators of cell death
two membranous sacs
inner compartment- matrix
space between membranes- intermembranous space
inner membrane- infoldings to increase SA- cristae
-has a lot of cardiolipid- phopholipid- impermeable to small molecules and ions
positive correlation between oxidative energy requirements of cell type and number of mitochondria it contains

Precipitated calcium phosphate
major Calcium ion buffers- maintain cytoplasmic Ca concentrations
elevated Ca in cytoplasm causes mitochondria to stop ATP production, pump Ca ions into matrix where they precipitate

Provide protected site for synthesis of polypeptide chain encoded in an mRNA and to participate in the assembly of amino acids necssary to form this protein
composed of rRNA and ribosomal proteins- two subunits- small 40S and big 60S- leave nucleus separately through nuclear pores
inactive state: small subunit separate from large
polyribosomes- work together in groups to translate a single mRNA
free polysomes- synthesis of proteins for cell's own use
attached (on RER)- associated with synthesis of proteins for export and with synthesis of IMPs