Lecture 7 Flashcards
(15 cards)
What defines the cell nucleus in eukaryotic cells?
The cell nucleus is a double-membraned organelle containing genetic material.
Describe the structure of the nuclear envelope.
The nuclear envelope is composed of two concentric membranes that form a phospholipid bilayer.
What role do nuclear pore complexes play in cellular function?
They serve as the sole channels for regulated exchange of molecules, crucial for gene expression regulation.
How is the outer membrane of the nuclear envelope associated with the Rough Endoplasmic Reticulum (RER)?
The outer membrane is continuous with the RER, which is involved in protein synthesis and modification.
What is the nuclear lamina and what is its function?
The nuclear lamina is a fibrous meshwork that provides structural support and is involved in chromatin attachment and gene regulation.
Explain the role of Ran GTPase in nuclear pore function.
Ran GTPase is involved in a GTP-dependent process that regulates the traffic of molecules between the nucleus and cytoplasm.
What is the composition of chromatin in the nucleus?
Chromatin is composed of DNA wrapped around histone proteins.
Differentiate between histone acetylation and methylation.
Histone acetylation generally enhances gene expression, while methylation can either activate or repress gene expression.
What is the role of the nucleolus in the cell nucleus?
The nucleolus is the site of ribosome assembly and synthesizes ribosomal RNAs.
How do eukaryotic ribosomes differ from prokaryotic ribosomes in terms of structure?
Eukaryotic ribosomes are 80S with large (60S) and small (40S) subunits, while prokaryotic ribosomes are 70S with large (50S) and small (30S) subunits.
What is the function of histone acetyltransferases (HATs)?
HATs are enzymes that acetylate histones, affecting gene accessibility and transcription.
Describe the composition and function of the nucleoplasm.
Nucleoplasm is a viscous substance containing water, proteins, ions, nucleic acids, and enzymes, playing a role in various nuclear functions.
What is the role of protein modifications such as glycosylation in the Rough Endoplasmic Reticulum?
Glycosylation is a modification process that aids in protein folding and stability, crucial for proper function and transport.
What is the significance of chromatin attachment sites (LADs) in the nucleus?
LADs influence gene accessibility and transcription rates by interacting with the nuclear lamina.
How do histone deacetylases (HDACs) function in gene regulation?
HDACs remove acetyl groups from histones, often leading to gene repression by compacting chromatin structure.
