BIOL 112 - Cell Size and Endomembrane System

Q1: What are prokaryotic cells?

A1: Simple, unicellular organisms with no nucleus and no membrane-bound organelles.

Q2: What structures are found in prokaryotic cells?

A2: DNA (in cytoplasm), ribosomes, cytoskeleton, cell wall, capsule, flagella, pili, fimbriae.

Q3: What is the function of the prokaryotic cell wall?

A3: Gives protection, shape, and rigidity.

Q4: What is peptidoglycan and where is it found?

A4: A polymer of sugars and amino acids found in bacterial cell walls.

Q5: How do bacterial and archaeal membranes differ?

A5:

• Bacteria: Lipids with ester bonds.

• Archaea: Lipids with ether bonds.

Q6: How are archaea different from bacteria?

A6: Archaea live in extreme environments, have pseudo-peptidoglycan walls, and ether-linked membranes.

Q7: What are eukaryotic cells?

A7: Complex cells with a nucleus, organelles, and often multicellular.

Q8: Name 4 key organelles in animal cells and their functions.

A8:

• Nucleus: Stores DNA

• Mitochondria: Makes energy

• ER: Makes proteins/lipids

• Golgi: Modifies and ships proteins

Q9: What structures are unique to plant cells?

A9:

• Cell wall: Supports shape

• Chloroplasts: Photosynthesis

• Central vacuole: Stores sap and pressure

• Plasmodesmata: Connects cells

Q1: What is the main function of ribosomes?

A1: Ribosomes translate RNA to produce proteins.

Q2: What are ribosomes made of?

A2: Ribosomal RNA (rRNA) and proteins.

Q3: What are the two types of ribosomes?

A3:

• Free: float in cytosol

• Bound: attached to rough ER

Q4: What does the rough ER do?

A4: Synthesizes and modifies proteins, especially transmembrane and secreted proteins.

Q5: What does the smooth ER do?

A5: Makes lipids, steroids, and carbohydrates; detoxifies drugs.

Q6: What’s the difference between rough and smooth ER?

A6: Rough ER has ribosomes; smooth ER doesn’t.

Q7: What is the Golgi apparatus' main job?

A7: Modifies, sorts, and packages proteins into vesicles.

Q8: What do the cis and trans faces of the Golgi do?

A8:

• Cis face: receives from ER

• Trans face: ships to membrane or organelles

Q9: What do lysosomes do?

A9: Break down materials using digestive enzymes in a low pH environment.

Q10: What is autophagy vs. heterophagy?

A10:

• Autophagy: digests cell parts

• Heterophagy: digests materials from outside

Q11: What happens if lysosomes break open?

A11: Their enzymes may destroy the cell.

Q12: What’s the main role of vacuoles?

A12: Store water, waste, or nutrients (especially in plant cells).

Q13: What’s the role of vesicles?

A13: Transport materials between organelles or to/from the membrane.

Q14: How do vesicles interact with the cell membrane?

A14: They fuse to release contents (exocytosis) or embed membrane proteins.

Q15: What does the nucleus do?

A15: Stores, protects, replicates, and expresses genetic info.

Q16: What does the nucleolus do?

A16: Makes rRNA and assembles ribosomes.

Q17: What are nuclear pores for?

A17: Allow molecules to move between the nucleus and cytosol.

Q18: What is the nuclear envelope?

A18: A double membrane surrounding the nucleus.

Q19: What is the nuclear lamina?

A19: A supportive mesh of intermediate filaments under the envelope.

Q20: What is the nuclear matrix?

A20: A fiber framework inside the nucleus, similar to a cytoskeleton.

Q21: What is the endomembrane system?

A21: A group of connected membranes (nucleus, ER, Golgi, lysosomes, vacuoles, plasma membrane) that transport materials using vesicles.