Ch 15 - Intracellular Compartments and Protein Transport

Question 1

autophagy

Answer 1

mechanism by which a cell ‘eats itself’, digesting molecules and organelles that are damaged or obsolete

Question 2

clathrin

Answer 2

protein that makes up the coat of a type of transport vesicle that buds from either the Golgi apparatus (on the outward secretory pathway) or from the plasma membrane (on the inward endocytic pathway)

Question 3

coated vesicle

Answer 3

small membrane-enclosed sac that wears a distinctive layer of proteins on its cytosolic surface. it is formed by pinching-off of a protein-coated region of cell membrane

Question 4

endocytosis

Answer 4

process by which cells take in materials through an invagination of the plasma membrane, which surrounds the ingested material in a membrane-enclosed vesicle (see also pinocytosis and phagocytosis)

Question 5

endomembrane system

Answer 5

interconnected network of membrane-enclosed organelles in a eukaryotic cell; includes the endoplasmic reticulum, Golgi apparatus, lysosomes, peroxisomes and endosomes

Question 6

endoplasmic reticulum (ER)

Answer 6

Labyrinthine membrane-enclosed compartment in the cytoplasm of eukaryotic cells where lipids and proteins are made.

Question 7

endosome

Answer 7

membrane-enclosed compartment of a eukaryotic cell through which material ingested by endocytosis pass on its way to lysosomes

Question 8

exocytosis

Answer 8

process by which most molecules are secreted from a eukaryotic cell. these molecules are packaged in membrane-enclosed vesicle that fuse with the plasma membrane, releasing their contents to the outside.

Question 9

Golgi apparatus

Answer 9

membrane-enclosed organelle in eukaryotic cells that modifies the proteins and lipids made in the endoplasmic reticulum and sorts them for transport to other sites

Question 10

lysosome

Answer 10

membrane-enclosed organelle that breaks down worn-out proteins and organelles and other waster materials, as well as molecules taken up by endocytosis; contains digestive enzymes that are typically most active at the acid pH found inside these organelles

Question 11

membrane-enclosed organelle

Answer 11

any organelle in a eukaryotic cell that is surrounded by a lipid bilayer - for example the ER, Golgi apparatus and lysosome

Question 12

nuclear envelope

Answer 12

double membrane surrounding the nucleus. consists of outer and inner membranes, perforated by nuclear pores

Question 13

nuclear pore

Answer 13

channel through which selected large molecules move between the nucleus and the cytoplasm

Question 14

peroxisome

Answer 14

small membrane-enclosed organelle that contains enzymes that degrade lipids and destroy toxins

Question 15

phagocytic cell

Answer 15

a cell such as a macrophage or neutrophil that is specialized to take up particles and microorganisms by phagocytosis

Question 16

phagocytosis

Answer 16

the process by which particulate material is engulfed (‘eaten’) by a cell. prominent in predatory cells, such as Amoeba proteus, and in cells of the vertebrate immune system, such as macrophage

Question 17

pinocytosis

Answer 17

type of endocytosis in which soluble material are taken up from the environment and incorporated into vesicles for digestion (literally, ‘cell drinking’)

Question 18

Rab protein

Answer 18

one of a family of small GTP-binding proteins present on the surfaces of transport vesicles and organelles that serves as a molecular marker to help ensure that transport vesicles fuse only with the correct membrane

Question 19

receptor-mediated endocytosis

Answer 19

mechanism of selective uptake of material by animal cells in which a macromolecule binds to a receptor in the plasma membrane and enters the cell in a clathrin-coated vesicle

Question 20

rough endoplasmic reticulum

Answer 20

region of the endoplasmic reticulum associated with ribosomes and involved in the synthesis of secreted and membrane-bound proteins

Question 21

secretion

Answer 21

production and release of a substance from a cell

Question 22

secretory vesicle

Answer 22

membrane-enclosed organelle in which molecules destined for secretion are stored prior to release

Question 23

signal sequence

Answer 23

amino acid sequence that directs a protein to a specific location in the cell, such as the nucleus or mitochondria

Question 24

SNARE

Answer 24

one of a family of membrane proteins responsible for the selective fusion of vesicles with a target membrane inside the cell

Question 24

tethering protein

Answer 24

filamentous transmembrane protein involved in the docking of transport vesicles to target membranes

Question 25

transport vesicle

Answer 25

membrane vesicle that carries proteins from one intracellular compartment to another - for example, from the endoplasmic reticulum to the Golgi apparatus

Question 26

unfolded protein response (UPR)

Answer 26

molecular program triggered by the accumulation of misfolded proteins in the endoplasmic reticulum. allows cells to expand the endoplasmic reticulum and produce more of the molecular machinery needed to restore proper protein folding and processing

Question 27

vesicular transport

Answer 27

movement of material between organelles in the eukaryotic cell via membrane-enclosed vesicles.