B2.2 Organelles and Compartmentalization Flashcards
(13 cards)
What distinguishes organelles from other cellular structures?
Key Point: Organelles are membrane-bound structures specialized to perform specific functions.
What is the function of the nucleus in a eukaryotic cell?
Key Point: The nucleus controls cell activities and contains DNA.
Function: Regulates gene expression, DNA replication, and synthesis of RNA.
Explain the significance of the plasma membrane.
Key Point: The plasma membrane forms the outer boundary of cells.
Function: Regulates the passage of substances, maintains internal environment, and allows cell communication.
How did ultracentrifuges and cell fractionation contribute to cell biology?
Key Point: These techniques allowed for the isolation and study of organelles.
Significance: Enabled scientists to study the structure and function of organelles in detail.
What is the primary advantage of separating the nucleus and cytoplasm in eukaryotic cells?
Key Point: Separation allows for the regulation of gene expression. Ex. Transcription occurs in the nucleus, while translation occurs in the cytoplasm.
What would happen if mRNA immediately met ribosomes in eukaryotic cells?
Errors in protein synthesis would increase, and gene regulation would be less controlled.
Explain the significance of the plasma membrane in a eukaryotic cell.
The plasma membrane regulates the passage of substances into and out of the cell, maintaining internal conditions and facilitating communication with the external environment.
Explain the benefits of compartmentalization in eukaryotic cells compared to prokaryotes.
Compartmentalization allows for specialization of cellular functions, spatial separation of processes, efficient energy production, protein sorting, isolation of harmful substances, and enhanced adaptability and regulation of cellular activities.
What are the four key adaptations of the mitochondrion for the production of ATP by aerobic cell respiration?
- Double membrane structure, 2. Small intermembrane space, 3. Large surface area of cristae, 4. Compartmentalization of enzymes in the matrix.
What are the three key adaptations of the chloroplast for photosynthesis?
- Large surface area of thylakoid membranes with photosystems, 2. Small fluid volumes inside thylakoids, 3. Compartmentalization of enzymes and substrates in the stroma.
What are the functions of free ribosomes and membrane-bound ribosomes?
Free ribosomes synthesize proteins for use within the cell, while membrane-bound ribosomes (on the rough ER) synthesize proteins for secretion or for incorporation into cellular membranes.
How does clathrin play a role in the formation of vesicles?
Clathrin helps shape and invaginate the membrane during vesicle formation, particularly in endocytosis, allowing cells to internalize substances from the extracellular environment.
Why aren’t cell walls, cytoskeleton, or cytoplasm considered organelles?
They are not enclosed by membranes.
Examples: Cell walls provide structure, cytoskeleton is made of proteins, and the cytoplasm is a gel-like substance.
