B2.2 Organelles & Compartmentalisation Flashcards
What are organelles?
Structures that are separate subunits of cells and perform a specific function
Examples include the nucleus, mitochondria, and lysosomes.
What is compartmentalisation in cells?
The use of membranes to isolate certain parts of the cell from the rest to form separate organelles.
What is the function of phagocytic vacuoles and lysosomes in compartmentalisation?
They isolate toxic or damaging substances away from the cytoplasm.
What is the advantage of separating the nucleus and the cytoplasm?
It allows mRNA to be modified before it binds to the ribosome, ensuring functional proteins are produced.
What is the role of the mitochondrion?
A site of cellular respiration in which ATP is generated.
What are the two types of ribosomes?
Bound ribosomes and free ribosomes.
What does the Golgi apparatus do?
Processes and packages proteins, ultimately releasing them in Golgi vesicles.
What is the function of vesicles in cells?
Transport and release substances produced by the cell by fusing with the cell membrane.
What is the role of clathrin in vesicle formation?
Facilitates the formation of vesicles and plays a role in endocytosis.
Where are membrane bound organisms found
eukaryotic cells only
Uses of compartmentalisation
- pH maintanence
- isolation of toxic/damaging substances
- flexibility of changing number & position of organelles
Organelles can be found in both prokaryotic and eukaryotic cells, but membrane-bound organelles are exclusive to eukaryotic cells.
What are the components of the nuclear envelope?
Two membranes (inner and outer) with nuclear pores.
What is the primary function of lysosomes?
Contain hydrolytic enzymes to destroy microbes and old cellular organelles.
What is the main function of chloroplasts?
Responsible for photosynthesis.
List the three distinct compartmentalised areas of chloroplasts.
- Intermembrane space
- Stroma
- Thylakoid space
What is the significance of the double membrane around the nucleus?
Provides a barrier to protect genetic material from damage.
What are the two membranes of the mitochondria called?
Inner and outer membrane.
What is the function of the thylakoids in chloroplasts?
Absorb light energy to generate ATP.
Types of ribosomes
bound & free
What is the main role of the smooth endoplasmic reticulum?
Producing and storing lipids, including steroids.
Describe the role of the Golgi apparatus compartments.
Organized into cis, medial, and trans compartments for protein modification and packaging.
cis= receives protein
medial=further modification
trans= packages for secretion
What is the significance of the cristae in mitochondria?
Increase the surface area for vital enzymes necessary for ATP production.
What is the function of the stroma in chloroplasts?
Contains enzymes and substrates for the Calvin cycle of photosynthesis.
What is the role of clathrin in vesicle formation?
Protein that aids in the final stages of vesicle formation
Clathrin forms a coat around vesicles, facilitating their budding from membranes.
Give an example of how macrophages use clathrin-mediated vesicles.
engulf and digest bacteria
This process is part of the immune response to pathogens.
How does clathrin facilitate the formation of lysosomes?
vesicle trafficking from the trans-Golgi network to lysosomes
It forms clathrin-coated vesicles that transport enzymes like acid hydrolases.
What is the significance of mannose-6-phosphate in lysosomal enzyme transport?
Mannose-6-phosphate-tagged enzymes are transported to lysosomes via clathrin-coated vesicles
This tagging is crucial for directing enzymes to their proper cellular locations.
What are organelles?
Organelles are specialised structures in cells with specific functions
They contribute to the compartmentalisation and efficiency of cellular processes.
What role does compartmentalisation play in cellular function?
allows development of specialised cell structures
It maximises efficiency by concentrating reactants and separating harmful chemicals.
Which structures are not considered organelles?
Cytoskeleton, cell wall, and cytoplasm
Only membrane-bound structures that perform specific functions qualify as organelles.
What is the function of the mitochondria and chloroplasts?
Mitochondria produce ATP, while chloroplasts produce glucose
Both have folded membranes that increase surface area for efficient biochemical reactions.
What is the role of the endoplasmic reticulum (ER)?
The ER is involved in protein synthesis and modification
It has rough ER with ribosomes for export proteins and smooth ER for lipid synthesis.
What is the difference between bound and free ribosomes?
Bound = ribosomes produce proteins for export
Free =nribosomes produce proteins for use inside the cell
This distinction affects the destination and function of the synthesized proteins.
What is the function of vesicles in cells?
Vesicles transport and store materials in the cell, including proteins, lipids, and RNA
They are crucial for intracellular transport and communication.
What is the role of clathrin in the formation of vesicles?
Clathrin plays a key role in the formation of vesicles by coating them
=> brings together cytoskeleton
This coating is essential for vesicle budding from membranes.
Transport of protein to RER
- instruction for hormone taken as mRNA from DNA
- mRNA leaves through nuclear pore -> attaches to RER’s ribosome
- Ribosom assembles hormone (reads mRNA)
- assembled protein piched off of RER in vesicle
- moves to golgi
- golgi packages protein in vesicle -> membrane
