Exam 1 9/6 Kingsley Flashcards
Why is inner nuclear membrane important?
Meshwork of intermediate filaments; lamin A, B, C represses DNA expression of genes that are no longer needed
Chromosome compartmentalization within nucleus
Location of each portion of chromosome may allow for transcriptional activation or repression. Nuclear lamin-associated (border) less active due to more nucleosomes
Histones
DNA binding proteins
Components of nucleosome
2 copies of H2A, H2B, H3, H4. Forms octamer
dsDNA wound around histone octamer is called:
nucleosome
___ binds linker DNA between nucleosomes
H1
Histones can be:
acetylated, methylated, phosphorylated
Constitutive heterochromatin
closed
What DNA should be constitutive?
genes from embryonic development
Facultative heterochromatin
Can be open or closed
Euchromatin
Open
What DNA should be open?
things that we will always be making. ex: actin
Characteristics of constitutive chromatin
Closed, DNA methylated. More histone methylation on H3K9, H3K27
What opens DNA to be transcribed?
Acetylation
Euchromatin may be associated with:
histone acetylation
How does acetylation induce open DNA?
removes positive charge, decreases DNA affinity
Euchromatin has:
fewer histone methylations (H3K4me); less likely to have methylated DNA
Nucleolus
active site of transcription
Annulate lamella is present in:
cells with high mitotic index
True or false: most cells have annulate lamella
False. found in cells like cancer cells or stem cells
NLS
Nuclear localization signal; “importins”
NLS signal sequence is:
PKKKRKV
NES
Nuclear export signal; “exportins”
What binds exportins?
short hydrophobic sequence (leucine) or RNA. Both regulated by Ran or GTP binding proteins
SER another name
agranular reticulum
RER another name
granular reticulum
SRP
signal recognition peptide
What is SRP important for in RER?
essential for the targeting of proteins for secretion or membrane insertion; “docking”
RER is the site for:
protein synthesis, protein folding, post translational modification
What post-translational modifications occur in the RER?
core glycosylation, disulfide/hydrogen bonds, chaperone-mediated folds
Most proteins from RER are delivered to:
golgi
Golgi apparatus has __ faces, called:
2; cis (faces toward rER), trans (faces away from rER towards cell membrane)
What occurs in the golgi apparatus?
PTM; protein sorting
What component of the cell helps mediate bidirectional transport?
COP proteins
COP II is associated with what protein?
kinesin
COP I is associated with:
dynein
Can you name any cell types that use constitutive exocytosis?
salivary glands (euchromatin)
True or false: pinocytosis is specific regarding what molecules are brought into the cell
False - it is non-specific
True or false: potocytosis is clathrin dependent
False - clathrin independent
Types of intake in cells:
-pinocytosis
-potocytosis
-endocytosis
-phagocytosis
Pinocytosis is an important regulatory mechanism for:
regulating membranes; removal of excess cell membrane; balancing fluid content
Potocytosis is a type of:
receptor-mediated endocytosis
Potocytosis involves what protein?
caveola (caveolin protein)