B2.2 Organelles & Compartmentalisation

Question 1

What are organelles?

Answer 1

Structures that are separate subunits of cells and perform a specific function

Examples include the nucleus, mitochondria, and lysosomes.

Question 2

What is compartmentalisation in cells?

Answer 2

The use of membranes to isolate certain parts of the cell from the rest to form separate organelles.

Question 3

What is the function of phagocytic vacuoles and lysosomes in compartmentalisation?

Answer 3

They isolate toxic or damaging substances away from the cytoplasm.

Question 4

What is the advantage of separating the nucleus and the cytoplasm?

Answer 4

It allows mRNA to be modified before it binds to the ribosome, ensuring functional proteins are produced.

Question 5

What is the role of the mitochondrion?

Answer 5

A site of cellular respiration in which ATP is generated.

Question 6

What are the two types of ribosomes?

Answer 6

Bound ribosomes and free ribosomes.

Question 7

What does the Golgi apparatus do?

Answer 7

Processes and packages proteins, ultimately releasing them in Golgi vesicles.

Question 8

What is the function of vesicles in cells?

Answer 8

Transport and release substances produced by the cell by fusing with the cell membrane.

Question 9

What is the role of clathrin in vesicle formation?

Answer 9

Facilitates the formation of vesicles and plays a role in endocytosis.

Question 10

Where are membrane bound organisms found

Answer 10

eukaryotic cells only

Question 11

Uses of compartmentalisation

Answer 11

• 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.

Question 12

What are the components of the nuclear envelope?

Answer 12

Two membranes (inner and outer) with nuclear pores.

Question 13

What is the primary function of lysosomes?

Answer 13

Contain hydrolytic enzymes to destroy microbes and old cellular organelles.

Question 14

What is the main function of chloroplasts?

Answer 14

Responsible for photosynthesis.

Question 15

List the three distinct compartmentalised areas of chloroplasts.

Answer 15

• Intermembrane space
• Stroma
• Thylakoid space

Question 16

What is the significance of the double membrane around the nucleus?

Answer 16

Provides a barrier to protect genetic material from damage.

Question 17

What are the two membranes of the mitochondria called?

Answer 17

Inner and outer membrane.

Question 18

What is the function of the thylakoids in chloroplasts?

Answer 18

Absorb light energy to generate ATP.

Question 19

Types of ribosomes

Answer 19

bound & free

Question 20

What is the main role of the smooth endoplasmic reticulum?

Answer 20

Producing and storing lipids, including steroids.

Question 21

Describe the role of the Golgi apparatus compartments.

Answer 21

Organized into cis, medial, and trans compartments for protein modification and packaging.
cis= receives protein
medial=further modification
trans= packages for secretion

Question 22

What is the significance of the cristae in mitochondria?

Answer 22

Increase the surface area for vital enzymes necessary for ATP production.

Question 23

What is the function of the stroma in chloroplasts?

Answer 23

Contains enzymes and substrates for the Calvin cycle of photosynthesis.

Question 24

What is the role of clathrin in vesicle formation?

Answer 24

Protein that aids in the final stages of vesicle formation

Clathrin forms a coat around vesicles, facilitating their budding from membranes.

Question 25

Give an example of how macrophages use clathrin-mediated vesicles.

Answer 25

engulf and digest bacteria ## Footnote This process is part of the immune response to pathogens.

Question 26

How does clathrin facilitate the formation of lysosomes?

Answer 26

vesicle trafficking from the trans-Golgi network to lysosomes ## Footnote It forms clathrin-coated vesicles that transport enzymes like acid hydrolases.

Question 27

What is the significance of mannose-6-phosphate in lysosomal enzyme transport?

Answer 27

Mannose-6-phosphate-tagged enzymes are transported to lysosomes via clathrin-coated vesicles ## Footnote This tagging is crucial for directing enzymes to their proper cellular locations.

Question 28

What are organelles?

Answer 28

Organelles are specialised structures in cells with specific functions ## Footnote They contribute to the compartmentalisation and efficiency of cellular processes.

Question 29

What role does compartmentalisation play in cellular function?

Answer 29

allows development of specialised cell structures ## Footnote It maximises efficiency by concentrating reactants and separating harmful chemicals.

Question 30

Which structures are not considered organelles?

Answer 30

Cytoskeleton, cell wall, and cytoplasm ## Footnote Only membrane-bound structures that perform specific functions qualify as organelles.

Question 31

What is the function of the mitochondria and chloroplasts?

Answer 31

Mitochondria produce ATP, while chloroplasts produce glucose ## Footnote Both have folded membranes that increase surface area for efficient biochemical reactions.

Question 32

What is the role of the endoplasmic reticulum (ER)?

Answer 32

The ER is involved in protein synthesis and modification ## Footnote It has rough ER with ribosomes for export proteins and smooth ER for lipid synthesis.

Question 33

What is the difference between bound and free ribosomes?

Answer 33

Bound = ribosomes produce proteins for export Free =nribosomes produce proteins for use inside the cell ## Footnote This distinction affects the destination and function of the synthesized proteins.

Question 34

What is the function of vesicles in cells?

Answer 34

Vesicles transport and store materials in the cell, including proteins, lipids, and RNA ## Footnote They are crucial for intracellular transport and communication.

Question 35

What is the role of clathrin in the formation of vesicles?

Answer 35

Clathrin plays a key role in the formation of vesicles by coating them => brings together cytoskeleton ## Footnote This coating is essential for vesicle budding from membranes.

Question 36

Transport of protein to RER

Answer 36

1. instruction for hormone taken as mRNA from DNA 2. mRNA leaves through nuclear pore -> attaches to RER's ribosome 3. Ribosom assembles hormone (reads mRNA) 4. assembled protein piched off of RER in vesicle 5. moves to golgi 6. golgi packages protein in vesicle -> membrane