Cell Bio Ch 12 & 13

Question 0

Cytoplasm

Answer 0

Cytosol and cytoplasmic organelles

Question 1

Nucleus

Answer 1

Contains genome; DNA and RNA synthesis

Question 2

Cytosol

Answer 2

Site of protein synthesis and degradation; constitutes more than 50% of the total volume of the cell

Question 3

Endoplasmic reticulum

Answer 3

Synthesis of most lipids; synthesis of proteins for distribution to many organelles and the plasma membrane
Also works as a store for Ca++ used in many signaling cascades

Question 4

Golgi apparatus

Answer 4

Receives lipids and proteins from the ER, then dispatches to different locations

Question 5

Mitochondria/chloroplast

Answer 5

Generates most of ATP to drive reactions

Question 6

Endosomes

Answer 6

Endocytosed materials first come to endosomes

Question 7

Lysosomes

Answer 7

Contain enzymes that degrade defunct Intracellular organelles

Question 8

Peroxisomes

Answer 8

Oxidation of toxic materials

Question 9

Three major forms of intracellular transport of proteins

Answer 9

Gated- between cytosol and nucleus
Transmembrane- translocators and transporters
Vesicular transport- membrane enclosed vesicles transport proteins from one compartment to another

Question 10

___________ direct proteins to the correct locations

Answer 10

Signal sequences; “routing tags” consisting of certain amino acid sequences

Question 11

____________ occurs continuously between the nucleus and the cytosol.

Answer 11

Bidirectional traffic

Question 12

Protein structure that provides structural support to the nuclear envelope

Answer 12

Nuclear lamina

Question 13

Nuclear pore complex (NPC)

Answer 13

Made up of 30 proteins called nuclear porins
Made of 4 subunits with tendrils on both sides
Tendrils inside nucleus form a basket shape
Pass 500 macromolecules per sec

Question 14

______________ direct proteins from the cytosol to the nucleus.

Answer 14

Nuclear localization signals (NLS)

Bind to proteins and bring them into the nucleus

Question 15

The import and export across NPC requires energy which is obtained by hydrolyzing ________ to ___________.

Answer 15

GTP to GDP

Question 16

________ is found in both the nucleus and the cytosol and is required for both import and export of proteins in the nucleus.

Answer 16

Ran

Question 17

Endoplasmic reticulum is organized in:

Answer 17

A net-like labyrinth of branching tubules and flattened sacs continuous from the nuclear membrane

Question 18

Internal space form by the continuous sheet of the nuclear membrane and the ER membrane

Answer 18

ER lumen

Question 19

________ ER produces proteins, and _______ ER produces lipids

Answer 19

Rough, smooth

Question 20

All proteins delivered to the exterior of the cell must pass through the ______

Answer 20

ER

Question 21

_________ makes up most of the cells lipids.

Answer 21

ER

Question 23

Types of protein translocation to ER

Answer 23

Co-translation translocation- proteins imported into the ER before complete synthesis.
Post-translation translocation- ribosomes complete protein synthesis and release protein before it is taken in be ER

Question 24

Many ribosomes attached to a single mRNA molecule

Answer 24

polyribosome

Question 25

Membrane bound and free ribosomes differ only in:

Answer 25

the proteins they are making

Question 26

Two components that guide the ER signal sequence

Answer 26

1. SRP (signal recognition particle) travels between ER membrane and cytosol, binds to signal sequences
2. SRP receptor

Question 27

The ______ on the protein directs the ribosome towards a translocator on the ER

Answer 27

signal sequence

Question 28

The ______ forms a pore in the membrane that allows the polypeptide to be _______.

Answer 28

translocator, translocated

Question 29

________ clips off the signal sequence and releases the mature protei into the ER.

Answer 29

Signal peptidase