All flashcards
Flashcard 1: What is the main function of lysosomes in animal cells?
Answer: Acidic degradation of macromolecules and organelles. These organelles contain hydrolytic enzymes that break down waste and engulfed materials in an acidic environment.
Flashcard 2: What is the approximate pH inside a lysosome?
Answer: About 5. The low pH optimizes the activity of acid hydrolases for efficient macromolecule breakdown.
Flashcard 3: Which organelle carries out H2O2-producing oxidation and contains catalase?
Answer: Peroxisome. It detoxifies harmful substances by oxidizing them and neutralizing resulting peroxides with catalase.
Flashcard 4: What is the primary function of mitochondria in eukaryotic cells?
Answer: ATP production via oxidative phosphorylation. These organelles harness energy from nutrients through the electron transport chain and ATP synthase.
Flashcard 5: Which mitochondrial membrane contains the electron transport chain complexes?
Answer: Inner mitochondrial membrane. This membrane houses proteins for electron transfer and proton pumping during cellular respiration.
Flashcard 6: What is the mitochondrial intermembrane space used for during respiration?
Answer: Proton accumulation to create a gradient. Protons are pumped here during electron transport, establishing an electrochemical gradient that drives ATP synthesis.
Flashcard 7: Which organelle performs photosynthesis in plants and algae?
Answer: Chloroplast. It converts light energy into chemical energy using pigments and enzyme systems in its membranes and stroma.
Flashcard 8: In chloroplasts, where do the light reactions occur?
Answer: Thylakoid membrane. Photosystems and electron transport chains in these membranes capture light and generate ATP and NADPH.
Flashcard 9: In chloroplasts, where does the Calvin cycle occur?
Answer: Stroma. This fluid matrix contains enzymes for carbon fixation, using products from light reactions to synthesize sugars.
Flashcard 10: What is the main role of vacuoles in plant cells?
Answer: Storage and maintenance of turgor pressure. Central vacuoles store nutrients, waste, and water, providing structural support through osmotic pressure.
Flashcard 11: Which structure is responsible for intracellular protein degradation via ubiquitin tagging?
Answer: Proteasome. It targets misfolded or unnecessary proteins marked with ubiquitin for proteolysis in the cytosol.
Flashcard 12: Which organelle is non-membrane-bound but essential for protein synthesis?
Answer: Ribosome. Composed of rRNA and proteins, it translates mRNA into polypeptides in both cytosol and on ER.
Flashcard 13: Identify the organelle: ATP production, double membrane, and its own circular DNA.
Answer: Mitochondrion. These features enable aerobic respiration and reflect its endosymbiotic origin with independent replication.
Flashcard 14: Identify the organelle: hydrolytic enzymes, acidic lumen, and autophagy function.
Answer: Lysosome. These characteristics allow it to digest cellular debris and recycle components through degradation processes.
Flashcard 15: Identify the organelle: lipid synthesis and detoxification; lacks ribosomes on its surface.
Answer: Smooth endoplasmic reticulum. Its smooth surface and functions distinguish it from the rough ER, focusing on non-protein metabolic roles.
Flashcard 16: Which trafficking route delivers newly synthesized lysosomal enzymes from the Golgi?
Answer: Trans-Golgi to endosome to lysosome. Enzymes are tagged with mannose-6-phosphate in the Golgi for vesicular transport to endosomal compartments that form lysosomes.
Flashcard 17: Which process brings extracellular material into endosomes and often to lysosomes?
Answer: Endocytosis. This mechanism internalizes extracellular substances into vesicles that fuse with endosomes, leading to lysosomal degradation.
Flashcard 18: What is the key advantage of organelle compartmentalization in eukaryotic cells?
Answer: Separates incompatible reactions and concentrates enzymes/substrates. Compartmentalization enhances efficiency by isolating processes and optimizing local conditions for specific reactions.
Flashcard 19: What is the primary function of the rough endoplasmic reticulum (RER)?
Answer: Synthesis of secreted and membrane proteins. Studded with ribosomes, it facilitates translation of proteins destined for export or insertion into membranes.
Flashcard 20: What is the function of the nucleolus?
Answer: rRNA synthesis and ribosomal subunit assembly. Located within the nucleus, it specializes in producing ribosomal components essential for protein synthesis.
Flashcard 21: What is the nuclear envelope composed of, and what is its key transport feature?
Answer: Double membrane with nuclear pore complexes. This structure encloses the nucleus, with pores allowing selective transport of molecules like RNA and proteins between nucleus and cytoplasm.
Flashcard 22: What is the primary function of the nucleus in a eukaryotic cell?
Answer: Stores DNA and regulates gene expression. It acts as the cell's control center by housing genetic material and directing transcription to manage cellular activities.
Flashcard 23: What is the primary function of the smooth endoplasmic reticulum (SER)?
Answer: Lipid synthesis, detoxification, and Ca2+ storage. Lacking ribosomes, it performs metabolic functions crucial for cellular homeostasis and signaling.
Flashcard 24: Which organelle modifies, sorts, and packages proteins for secretion or delivery?
Answer: Golgi apparatus. It processes proteins from the ER, adding modifications like glycosylation before directing them to their destinations.
Flashcard 25: Which face of the Golgi receives ER vesicles, and which face ships products?
Answer: Cis receives; trans ships. The cis face accepts incoming vesicles, while the trans face dispatches processed molecules, reflecting the organelle's polarized structure.