Nucleus And Protein Trafficking Flashcards
___________permits passage of proteins via receptor mediated transport
Nuclear pore complex
The outer membrane of the nucleus contains_______and connects to_______
Ribosomes; Rough endoplasmic reticulum
The inner membrane attaches to
The nuclear lamina
The nuclear pore complex forms _______ which allows________ of ions
Aqueous channels; simple diffusion
The nuclear lamina provides _________ for the nuclear membrane
Mechanical support
Nuclear transcription is regulated by
Nuclear lamina
Hutchison Gifford progeria syndrome is caused by a mutation in the________ protein
Lamina A
What does A mutation in the Lamin A protein cause?
Inadequate structural support for the nuclear envelope, causing an abnormal shape
Chromatin is made up of
Nucleosomes
Nucleosomes are made up of
Histones
The 2 types of chromatin are
Heterochromatin, Euchromatin
Heterochromatin appears in_______and contains________genes
Clumps; inactive
Heterochromatin are usually________ as opposed to Euchromatin
Condensed
Constitutive heterochromatin contains repetitive, gene poor DNA sequences like
Centromeres and telomeres
A prime example Facultative Heterochromatin are_______ which result in the inactivation of one of the 2 ________ present in females but not males
Barr bodies; X chromosomes
Euchromatin contains_________as opposed to Heterochromatin
Active genes
Synthesis of mRNA and tRNA occur in
Euchromatin
Telomeres_______in size with every cell division
Decrease
Telomeres are located at the _______of chromosomes
Cap
Telomeres protect chromosomes from being______after each cell division
Degraded
________hold the chromosomes together down the centre
Centromeres
_________are formed on the centromere for microtubules to attach to during anaphase
Kinetochore
_________ is the site of rRNA transcription
Nucleolus
Do nucleolus have a membrane?
No
Nucleolus assembles________ around the rRNA transcripts to form ribosomes
Ribosomal proteins
After translation, a protein will go to a specific destination inside the cell if it has a _________ in its sequence
Targeting signal
Amino acid residues in a protein chain that enable targeting are called
Signal sequences
After a signal emerges from a ribosome, it is recognized and bound by a
Receptor or carrier
Nuclear localization signal (NLS) are recognized by______ which moves cargo from the cytoplasm to the nucleus
Importins
Nuclear Export Signals (NES) are recognized by_______ which move cargo from the nucleus to the cytoplasm
Exportins
NLS containing cargo (importing from cytoplasm to nucleus) include
Histones
Ribosomal proteins
Transcription factors
DNA replication factors
NES containing cargo (exporting from nucleus to cytoplasm) include
mRNA
tRNA
ribosomal subunits
Shuttling proteins
When importins reach the nuclear pore complex, they are triggered to release cargo by interaction with
RanGTP
