Lecture 7 - Cytoplasmic Organelles

Question 1

O-linked glycosylation occurs in which of the following locations?

A. Mitochondrial matrix

B. Rough ER

C. Golgi medial stack

D. Lysosome

Answer 1

C. Golgi medial stack

Question 2

Vesicles transported from the ER to the TGN are coated with which of the following coatings?

A. Clathrin

B. COPII

C. COPI

D. Dark chocolate

Answer 2

B. COPII

Question 3

Cardiolipin is associated with which of the following membranes?

A. TGN

B. Outer mitochondrial membrane

C. Inner mitochondrial membrane

D. Smooth ER

Answer 3

C. Inner mitochondrial membrane

Question 4

Which of the electron transport chain complexes receives protons and electrons from succinate?

A. Complex I

B. Complex II

C. Complex III

D. Complex IV

Answer 4

B. Complex II

Question 5

Define:

Cytoplasm

Answer 5

Portion of the cell between the nucleus and plasma
membrane, including the membrane-bound organelles

Question 6

Define:

Cytosol

Answer 6

• Portion of the cell between the nucleus and the plasma
membrane exclusive of the membrane-bound organelles;

• The cortical cytoplasm just under the plasma membrane
has a distinct arrangement of cytoskeletal elements which
excludes organelles and maintains the stiff gel form of the
cell.

Question 7

What is:

A system of basophilic, membrane-bound, interconnected
tubules and flattened compartments within the cytosol
studded on its cytsolic surface with ribosomes.

Answer 7

Rough Endoplasmic Reticulum

Question 8

Lipid synthesis occurs in association with the _______
leaflet of the ER.

Answer 8

cytosolic

Question 9

Translocation to the luminal leaflet requires what protein?

Answer 9

flippases

Question 10

N-linked or O-linked glycosylation:

• Connection of oligosaccharides through the hydroxyl group of
Threonine, serine, or hydroxylysine

• Occurs within the Golgi system

Answer 10

O-linked

Question 11

N-linked or O-linked glycosylation:

• Connection of oligosaccharides to amino group of asparagine
• Begins in the ER
• Requires a dolichol carrier

Answer 11

N-linked

Question 12

Functions of Smooth ER? (3)

Answer 12

• Detoxification (detoxifies lipid-soluble and water-soluble
substances into water-soluble compounds)

• Synthesizes phospholipids and cholesterol, which are
lipids necessary for turnover of cell membranes (both the
plasma membrane as well as the membranes of
organelles)

• Abundant in steroid-producing cells

Question 13

Function of the Golgi Apparatus? (4)

Answer 13

• Sorts products into different pathways; Vesicles are targeted from Golgi apparatus to the apical or basolateral membranes of the cell.
• Location of posttranslational modifications
• Site for the assembly of proteoglycans
• Sulfation

Question 14

Cis-face, Trans-face, or Medial compartment of Golgi:

• Site where most glycosylation takes place
• Subdivided into cis, medial, and trans compartments

Answer 14

Medial

Question 15

vesicles transported from the RER to the Cis-Golgi are coated with?

Answer 15

COPII

Question 16

What proteins contain the KDEL signal?

Answer 16

Vesicles being transported from Golgi to RER:

• These vesicles contain RER proteins that must be returned to the RER.
• The proteins contain a KDEL signal (Lys-Asp-Glu-Leu)

Question 17

Vescicles being transported between cisternae of the medial compartment of the Golgi are coated with what?

Answer 17

COPI

Question 18

vesicles leaving from the trans golgi face are coated with what?

Answer 18

• These vesicles are coated with clathrin which is removed shortly after
leaving the TGN.

Question 19

Lysosomes are formed where?

Answer 19

Golgi apparatus

Question 20

Lysosome membranes have:

A. Proteins that transport breakdown products into the
cytoplasm.

B. Hydrogen ion ATPase pumps

C. A and B

D. None of the above

Answer 20

C. A and B

Question 21

Lysosomes can be formed via:

A. Endocytosis

B. Autophagy

C. Phagocytosis

D. All of the above

Answer 21

D. All of the above (formed, or pathway? go over)

Endocytosis:
• Small molecules are taken up by the cell and directed to vesicles called endosomes, which eventually form lysosomes
Autophagy:
• Worn-out organelles are broken down by lysosomal activity
Phagocytosis:
• Phagocytic vesicles are formed by cells specialized for the uptake of bacteria, viruses, and large particles.

Question 22

Which type of exocytosis does not require a triggering reaction?

Answer 22

• Constitutive secretory pathway:
• Does not require a triggering reaction

• Selective exocytosis:
• Of stored granules
• Requires triggering signal

Question 23

Which of the following bind to a primary lysosome to become a secondary lysosome?

A. Endosomes

B. Phagosome

C. Autophagosome

Answer 23

B. Phagosome

Endosome - Slide 22

Phagosome and Autophagosome - Slide 23

Question 24

Which of the following reduces CoQ?

A. Complex 1

B. Complex 2

C. Complex 3

D. Complex 4

E. Complex 5

Answer 24

A. Complex 1

OUTLINE THE COMPLEXES, slide 26-28

Question 25

Which has a higher affinity for electrons, Complex V or Complex II?

Answer 25

Complex V, as you travel down the chain electron affinity MUST increase so that the electrons keep moving.

Question 26

\_\_\_\_\_\_\_\_ are associated with: • ATP synthetase: F1 particles ATP synthesis • Electron transport chain components • Transport proteins • Cardiolipin. • Proteins for generation of energy and export and import

Answer 26

Cristae

Question 27

What does Cardiolipin do?

Answer 27

increases the IMPERMEABILITY of the inner mitochondrial membrane

Question 28

Which of the following is not in the mitochondrial matrix? A. Mitochondrial DNA B. Enzymes for the break-down of pyruvic acid, fatty acids, and amino acids C. Machinery for expression of mitochondrial genome D. VDAD

Answer 28

D. VDAD

Question 29

The function of the respiratory chain is to transport the ____ to \_\_\_\_\_, leading to oxidative phosphorylation.

Answer 29

electrons, oxygen

Question 30

Review figure 2-24

Question 31

T/F: The inner mitochondrial membrane is impermeable to hydrogen ions.

Answer 31

True

Question 32

From Anaerobic to the end of aerobic respiration you start with \_\_\_\_\_\_\_ and end with \_\_\_\_\_\_.

Answer 32

Energy-rich glucose molecule, End with: low energy carbon dioxide, water, and a lot of ATP

Question 33

What does the endosymbiotic theory suggest?

Answer 33

that mitochondria evolved from prokaryotes • Mitochondria may have been derived from α-proteobacteria which were capable of oxidative phosphorylation. • Instead of being digested, the α-proteobacteria may have been retained as symbionts. • Mitochondria have circular DNA (similar to prokaryotes).

Question 34

T/F: Many mitochondrial genes may have been transposed to nuclear DNA.

Answer 34

True

Question 35

T/F: You get your mitochondria from your father

Answer 35

False • Mitochondrial DNA follows maternal inheritance patterns.

Question 36

What is the function of Peroxisomes and what enzyme do they contain?

Answer 36

Catalase • Catalase utilizes hydrogen peroxide as a substrate to oxidize other molecules such as ethanol • Oxidize a variety of substances to hydrogen peroxide (hence their name) and break down hydrogen peroxide using catalase • Synthesize lipids such as cholesterol • Synthesize lysine • Synthesize bile acids from cholesterol