Lecture 3 - Nucleus Flashcards
What are Western Blots?
The gold standard to detect specific proteins from cells or tissues
ALSO USED FOR protein quantification, cell fractionation, post-translational modification, and immunoprecipitations
how can you separate cellular organelles?
using a centrifuge at different forces to see: nuclei sediment, mitochondria, lysosomes, peroxisomes), (fragments of plasma membrane & ER sediment),
The Nuclear envelope is contiguous with the endoplasmic reticulum….
proteins and lipids have direct access to the nuclear envelope
The nucleus and ER may have arisen during evolution by…
invagination of the plasma membrane in ancestral archaea
What advantages does the genome enclosed inside the nucleus have?
physical protection, protesction from viruses, more complex regulation via compartmentalization
DNA is a template for what?
transcription of RNA
what functions does RNA have?
mRNA, rRNA, tRNA, RNA primers, ribozymes
Which is NOT true about the nucleus?
A. Contains nearly all the cell’s DNA.
B. Make DNA from DNA.
C. Make Protein from RNA.
D. Make RNA from DNA.
make proteins from RNA
what is the central dogma?
transcription, replication, and translation
What nucleotides do?
Are the building blocks of DNA (A, T, C, G) DNa also is made of phosphate and sugar
what protein production step(s) happens in the nucleus?
transcription and replication
what protein production step(s) happens outside the nucleus?
Translation
humans have how many pairs of chromosomes?
23
what is a chromosome?
a single very long molecule of double-stranded DNA
Does the chromosome occupy its own territory in the nucleus?
yes, each one
what is it called when the cell is in a resting phase or not dividing?
interphase
what is “beads on a string”
a chromatin that is made of linker DNA and core histones of nucleosome
what is a chromatin fiber?
packed nucleosomes
what does a histone do??
holds the DNA to the nucleosome
Can euchromatin and heterochromatin can be present in the same chromosome?
True
Define heterochromatin
define euchromatin
what is the nucleolus/nucleoli?
The site of ribosome synthesis
How do proteins and RNA get in/out of the nucleus?
through nuclear pore complexes
define pore complexes
a gel-like meshwork of nuclear pore proteins blocks larger proteins and RNA from passively diffusing in/out of the nucleus
what is nuclear import?
Define the nuclear lamina
cytoskeleton intermediate filaments lining the inner nucleus envelope
Nuclease digests the beads on a string, what is the sequence?
chromatin -> nucleosome -> histone and DNA double helix
histone H1 does what?
holds chromatin “beads” together for denseness
chromatin fiber is a section of a _______
chromosome
cohesins do what
create small DNA loops by binding
how do clamp proteins work?
ATP hydrolysis enlarge the loops and when the clamps come together it stope further looping
what do condensins do>
form loops with the loops
where do ribosomal subunits sythesize?
in the nucleus
