Week 5 - Secretory System

Question 1

Exocytosis

Answer 1

The process of fusing a vesicle with the plasma membrane to release its contents outside the cell.

Question 2

Endocytosis

Answer 2

The process of bringing materials into the cell via vesicle formation from the plasma membrane.

Question 3

Phagocytosis

Answer 3

“Cell eating” — engulfing large particles (e.g., bacteria) into the cell.

Question 4

Pinocytosis

Answer 4

“Cell drinking” — nonspecific uptake of fluid and dissolved solutes.

Question 5

Receptor-Mediated Endocytosis

Answer 5

Specific uptake of molecules through receptors and clathrin-coated vesicles.

Question 6

Clathrin

Answer 6

A protein that forms a coated pit/vesicle during receptor-mediated endocytosis.

Question 7

Vesicle

Answer 7

A small membrane-bound sac used for transport of materials within the cell.

Question 8

COP II

Answer 8

A coat protein complex that transports vesicles from the ER to the Golgi (anterograde).

Question 9

COP I

Answer 9

A coat protein complex that transports vesicles from the Golgi back to the ER (retrograde).

Question 10

Cisternae

Answer 10

Flattened membrane-bound sacs that make up the Golgi apparatus.

Question 11

Cis Golgi Network

Answer 11

The entry face of the Golgi — receives vesicles from the ER.

Question 12

Golgi Stack

Answer 12

The middle region of the Golgi where modification (like glycosylation) happens.

Question 13

Trans Golgi Network

Answer 13

The exit face of the Golgi — sorts and sends materials to final destinations.

Question 14

Nuclear Envelope

Answer 14

The double membrane that encloses the nucleus.

Question 15

Nuclear Pores

Answer 15

Gateways in the nuclear envelope that allow molecules (like mRNA) to enter/exit.

Question 16

Endoplasmic Reticulum (ER)

Answer 16

Membrane network involved in protein and lipid synthesis.

Question 17

Rough ER

Answer 17

Studded with ribosomes; makes membrane and secretory proteins.

Question 18

Smooth ER

Answer 18

Lacks ribosomes; makes lipids, detoxifies drugs, stores calcium.

Question 19

Endomembrane System

Answer 19

Group of organelles (ER, Golgi, lysosomes, plasma membrane, etc.) that work together in trafficking and membrane flow.

Question 20

Lysosomes

Answer 20

Organelles with digestive enzymes; break down waste and macromolecules.

Question 21

Protein Sorting

Answer 21

The process of directing proteins to their correct destinations using targeting signals.

Question 22

Signal Sequences

Answer 22

Short amino acid sequences that direct a protein to a specific organelle (e.g., ER, mitochondria).

Question 23

Nuclear Localization Signals (NLS)

Answer 23

Tags that target proteins to the nucleus through nuclear pores.

Question 24

Signal Recognition Particle (SRP)

Answer 24

A ribonucleoprotein that guides ribosomes translating ER-bound proteins to the ER membrane.

Question 25

Glycosylation

Answer 25

The addition of sugar chains to proteins, mostly in the ER and Golgi; helps with folding, stability, and function.

Question 26

Hydrophobic

Answer 26

Water-fearing, nonpolar; tends to cluster away from water (e.g., lipid tails).

Question 27

Hydrophilic

Answer 27

Water-loving, polar or charged; dissolves in water (e.g., phosphate heads of lipids).

Question 28

Cell Theory

Answer 28

1) All organisms are made of cells, 2) Cells are the basic unit of life, 3) All cells come from preexisting cells.

Question 29

Dynamic Instability

Answer 29

Refers to microtubules rapidly growing and shrinking — important for cell shape and division.

Question 30

Motor Proteins

Answer 30

Proteins (like kinesin, dynein, myosin) that use ATP to move cargo along cytoskeletal tracks.

Question 31

Myosin

Answer 31

A motor protein that moves along actin filaments, involved in muscle contraction and cell movement.

Question 32

Topological Equivalence

Answer 32

Organelles that can exchange contents without crossing a membrane (e.g., ER lumen ↔ Golgi lumen ↔ outside the cell).