Chapter 8: Cytoplasmic Membrane Systems

Front 1

Endomembrane system

Back 1

Includes organelles such as the endoplasmic reticulum, Golgi complex, endosomes, lysosomes, and vacuoles functioning as part of a coordinated unit.

Front 2

Membranes divide the ___________ of eukaryotic cells into distinct compartments.

Back 2

Cytoplasm

Front 3

Materials are shuttled between organelles in membrane-bound ___________________

Back 3

transport vesicles

Front 4

Biosynthetic pathway

Back 4

Synthesis, modification and transport of proteins

Front 5

Secretory pathway

Back 5

When proteins are discharged (secreted) from the cell

Front 6

Constitutive secretion

Back 6

In a continuous fashion

Front 7

Regulated Secretion

Back 7

In response to a stimulus

Front 8

During regulated secretion, materials to be secreted are stored in large, membrane-bound _________________

Back 8

secretory granules

Front 9

Endoplasmic Reticulum (ER)

Back 9

Comprises a network of membranes that penetrates much of the cytoplasm

Front 10

The composition of the luminal inside ER membranes is different from the surrounding ____________

Back 10

cytosolic space

Front 11

Rough ER

Back 11

Composed of a network of flattened sacs (cistenae)

Front 12

Smooth ER functions:

Back 12

Synthesis of steroid hormones in enocrine cells

Detoxification in the liver of various organic compounds

Starting point of the biosynthetic pathway

Front 13

A ______________ at N-terminus attaches to secretory proteins

Back 13

signal sequence

Front 14

Secretory proteins synthesized on membrane-bound ribosomes have their signal sequence recognized by a __________________

Back 14

signal recognition particle (SRP)

Front 15

Binding to the ER occurs through 2 sequential interactions

Back 15

SRP must interact with a SRP receptor

Then the ribosome interacts with the translocon, which is a protein-lined channel

Front 16

Release of SRP requires

Back 16

GTP-binding proteins (G proteins)

Front 17

Upon entering the RER lumen, the signal sequence is cleaved by a ____________

Back 17

signal peptidase

Front 18

Contributing factors to variation of organelle lipid contribution

Back 18

Organelle-specific enzymes for lipid conversion

Inclusion/Exclusion process during vesicle formation

Lipid-Transfer proteins that bind and transport lipids without the use of vesicle transport

Front 19

Glycosylation in the RER

Back 19

Addition of sugars is catalyzed by glycosyltransferases

Core segment of each carbohydrate chain is put together on a lipid carrier

Core carbohydrate is modified by oligosaccharyltransferase

Front 20

Accumulation of misfolded proteins triggers the

Back 20

unfolded protein response (UPR)

Front 21

Golgi Complex

Back 21

Stack of flattened cisternae

Front 22

The _____ face of the Golgi faces the ER;

The _____ face is on the opposite side of the stack

Back 22

cis

trans

Front 23

The cis Golgi network (CGN)

Back 23

functions to sort proteins for the ER or the next Golgi station

Front 24

The trans Golgi network

Back 24

functions in sorting proteins either to the membrane or various intracellular destination

Front 25

Materials are carried between compartments using ___________

Back 25

coated vesicles

Front 26

Protein coats have 2 distinct functions:

Back 26

Cause the membrane to curve and form a vesicle

Select the components to be carried by vesicle

Front 27

COPII-coated vesicles

Back 27

Move materials from ER "forward" to the ERGIC and Golgi complex

Front 28

COPI-coated vesicles

Back 28

Move materials from ERGIC and Golgi "backward" to ER

Front 29

Clathrin-coated vesicles

Back 29

Move materials from the TGC to endosomes, lysosomes, and plant vacuoles

Front 30

COPII-Coated Vesicles

Back 30

Transporting Cargo from the ER to the Golgi Complex

Front 31

Proteins are maintained in an organelle by 2 mechanisms:

Back 31

Retention of resident molecules that are excluded form transport vesicles

Retrieval of escaped molecules back to the compartment where they reside

Front 32

Sorting and Transport of Lysosomal Enzymes

Back 32

Lysosomal proteins are tagged with phosphorylated mannose residues

Tagged lysosomal enzymes are recognized and captured by mannose 6-phosphate receptors

Front 33

Sorting and Transport of Non-lysosomal proteins

Back 33

Secretory proteins aggregate in dense granules that emerge form the TGN

Plasma membrane proteins have different sorting signals in the cytoplasmic domain

Polarized cells segregate apical membrane proteins and lateral/basal membrane proteins at the TGN into separate carriers

Front 34

Exocytosis

Back 34

Discharge of a secretory vesicle or granule after fusion with plasma membrane

Front 35

Lysosomes contain acid hydrolases which can:

Back 35

digest every type of biological molecule

Front 36

Autophagy

Back 36

An organelle is surrounded by a double membrane and a structure called an autophagosome is produced

Front 37

Vacuole

Back 37

Membrane-bound, fluid-filled compartment

Front 38

The vacuole membrane (tonoplast) contains:

Back 38

an active transport system to keep a high concentration of ions so that water enters by osmosis

Front 39

Endocytosis

Back 39

Uptake of cell surface receptors and bound extracellular ligands

Front 40

Phagocytosis

Back 40

Uptake of particulate matter

Front 41

Endocytosis divided into two categories

Back 41

Pinocytosis - nonspecific uptake of extracellular fluids

Receptor-mediated endocytosis - uptake of specific extracellular ligands following their binding to receptors

Front 42

Endocytic pathway

Back 42

After internalization vesicle-bound materials are transported in vesicles and tubules known as endosomes

Early endosomes are located near the periphery of the cell. It sorts materials and sends bound ligands to the late endosomes.

Front 43

Phagocytosis

Back 43

Process of engulfment

For the uptake of large particles

Plasma membrane takes up a particle and pinches off to form a phagosome

The phagosome fuses with a lysosome and the material is digested within the phagolysome

Front 44

Uptake of Proteins into Mitochondria

Back 44

Movement into the matrix is voltage-dependent

Chaperones are involved in unfolding the protein and later refolding it inside the mitochondrion

Front 45

Uptake of proteins into Chloroplasts

Back 45

most chloroplast proteins are imported from the cytosol

out and inner envelope membranes contains translocation complexes to facilitate import of the proteins

chaperones unfold proteins in cytosol and fold them in the chloroplasts

proteins include a transit peptide sequence