Module 1 Organelles (Lesson 2) Flashcards
What is the main function of the nucleus?
It stores genetic material (DNA) and controls gene expression.
What are the three main components of the nuclear architecture?
Nuclear envelope, nucleolus, and nuclear pore complex.
What is the nuclear envelope composed of?
Two phospholipid bilayers (inner and outer membranes) and the nuclear lamina.
What is the role of the nuclear lamina?
It provides structural support to the nucleus and interacts with nuclear pores.
What is the primary function of the nucleolus?
Ribosome biogenesis.
What are nuclear bodies, and do they have membranes?
They are membraneless sub-compartments within the nucleus that play roles in transcription and RNA processing.
What is the fundamental unit of chromatin structure?
The nucleosome (DNA wrapped around histone proteins).
What are the two major forms of chromatin, and how do they differ?
Euchromatin (loosely packed, transcriptionally active) and heterochromatin (densely packed, transcriptionally inactive).
What is the function of the nuclear pore complex (NPC)?
It regulates transport of molecules between the nucleus and cytoplasm.
What is a laminopathy?
A disease caused by mutations in nuclear lamins or associated proteins.
Why does the nucleus have a double membrane?
To separate and protect genetic material while allowing selective transport.
How does chromatin structure regulate gene expression?
Loosely packed euchromatin allows transcription, while tightly packed heterochromatin prevents it.
Why do nuclear pores need to be selective in transport?
To maintain nuclear compartmentalization and regulate cellular processes.
How does the nucleolus contribute to protein synthesis?
It produces ribosomal RNA (rRNA) and assembles ribosomal subunits.
What is the significance of phase separation in the formation of nuclear bodies?
It allows dynamic and reversible compartmentalization without membranes.
How does post-translational modification of histones affect chromatin structure?
Modifications like acetylation loosen chromatin for transcription, while methylation can either activate or repress genes.
Why is nuclear transport essential for cellular function?
It connects transcription (in the nucleus) with translation (in the cytoplasm).
How do nuclear transport proteins recognize cargo?
Cargo proteins have nuclear localization signals (NLS) or nuclear export signals (NES).
Why does the nuclear pore complex have FG-Nups (phenylalanine-glycine repeats)?
To create a selective barrier that allows only specific molecules to pass.
What happens when nuclear transport is disrupted?
Essential proteins and RNAs may not reach their destinations, leading to cellular dysfunction and disease.
How would you experimentally determine if a protein is localized to the nucleus?
Use fluorescence microscopy with a nuclear stain (e.g., DAPI) and an antibody or GFP-tagged protein.
What techniques can be used to study nuclear pore transport?
Fluorescence recovery after photobleaching (FRAP) and electron microscopy.
How would you test if a nuclear protein is essential for transcription?
Use siRNA knockdown or CRISPR to remove the protein and assess changes in gene expression.
What method could be used to determine if chromatin is in an open or closed state?
DNase sensitivity assays or chromatin immunoprecipitation (ChIP).
How would you isolate nucleoli for biochemical analysis?
Use differential centrifugation to separate nucleoli from the rest of the nucleus.
What experiment could you perform to study the effects of histone modifications?
Treat cells with histone acetylase or deacetylase inhibitors and analyze gene expression changes.
How could you determine whether a protein interacts with nuclear lamins?
Use co-immunoprecipitation (Co-IP) or yeast two-hybrid assays.
If a disease is suspected to be caused by defective nuclear transport, what assay could confirm this?
Analyze nuclear protein localization using immunofluorescence microscopy.
How would you measure the rate of nuclear export of a specific protein?
Use time-lapse fluorescence microscopy with an NES-tagged protein.
What would be the best approach to test if a mutation in lamin A causes nuclear instability?
Express mutant lamin A in cells and analyze nuclear shape using electron or fluorescence microscopy.
