Cell biology and interactions Flashcards
What is the nuclear envelope?
A porous double membrane surrounding the nucleus.
What supports the inner membrane of the nucleus?
Nuclear lamina, a protein layer.
What do nuclear pores facilitate?
Exchange of materials such as proteins and RNA between nucleus and cytoplasm.
What are histones?
Proteins that help package DNA into chromatin.
What are the two classes of chromatin?
- Heterochromatin
- Euchromatin
What characterizes heterochromatin?
Tightly condensed and generally inactive in transcription.
What characterizes euchromatin?
Less condensed and contains actively transcribed genes.
What is the nucleolus?
Membraneless part of the nucleus that assembles ribosomes.
What is the main function of the cytoskeleton?
Provides scaffolding and structural support within cells.
What are the three types of cytoskeletal filaments?
- Microfilaments
- Intermediate filaments
- Microtubules
What is the role of actin in microfilaments?
Involved in muscle contractions and maintaining cell shape.
What are the functions of microfilaments?
- Resisting tension
- Cytokinesis
- Cell-to-cell junctions
- Muscular contraction
- Cytoplasmic streaming
- Signal transduction
How do intermediate filaments differ from microfilaments?
More stable and heterogeneous in composition.
What is a key function of intermediate filaments?
Maintain cell shape by bearing tension.
What is epithelial-mesenchymal transition?
A process involving filaments important in wound healing and cancer metastasis.
What is the composition of intermediate filaments?
- Vimentins
- Keratin
- Neurofilaments
- Lamin
What are microtubules made of?
Alpha and beta tubulin.
Describe the structure of microtubules.
Hollow cylindrical filaments made of protofilaments with a diameter of 25nm.
What roles do microtubules play in cells?
- Intracellular transport
- Cytoskeleton of cilia and flagella
- Synthesis of cell wall in plants
- Mitotic spindle
What is the structure of centrioles?
Microtubules arranged in 9 triplet sets.
What is the ‘9+2’ arrangement in cilia and flagella?
Microtubules in nine doublets surrounding two additional microtubules.
What is ATP Synthase?
An enzyme that synthesizes ATP from ADP and inorganic phosphate.
What is a key feature of mitochondria?
They can form complex branched networks.
What is the role of ribosomes in the endoplasmic reticulum?
They synthesize proteins.
