Cells and organelles 2

Question 1

What are the three main systems that most eukaryotic organelles belong to?

Answer 1

• Protein expression
• Secretion
• Uptake and degradation

Question 2

What is the main central role for mitochondria in eukaryotic cells?

Answer 2

To generate chemical energy

Question 3

What does the cytosolic monolayer of a membrane face?

Answer 3

Cytosol

Question 4

What does the non-cytosolic monolayer of a membrane face?

Answer 4

Either cell exterior or the interior space of an organelle

Question 5

What is the lumen of the ER topologically equivalent to?

Answer 5

The exterior of the cell

Question 6

What is the diameter of a typical eukaryotic animal cell?

Answer 6

5–10 µm

Question 7

How much bigger are eukaryotic cells compared to bacteria?

Answer 7

1000 times bigger

Question 8

What are the characteristics of eukaryotic cells?

Answer 8

Internal membranes with specialisation and vesicular transport, packaged DNA in a nucleus, contain endosymbiont organelles

Question 9

What structures do plant cells uniquely contain?

Answer 9

• Cell wall
• chloroplasts
• vacuole

Question 10

What systems do most organelles belong to?

Answer 10

• Protein expression
• Secretion
• Uptake and degradation

Question 11

What are the three major pathways in the secretory system?

Answer 11

• Consecutive pathway (direct transport)
• Regulated secretory pathway (Mature secretory granule)
• Lysosomal pathway (Recycling endoscope)

Question 12

How do vesicles move toward and away from the Golgi?

Answer 12

Transport vesicles are pulled by motor proteins ( kinesis or dynein) along microtubules

Question 13

What does kinesis do?

Answer 13

Transports vesicles away from a organelle along the microtubule

Question 14

What does dynein do?

Answer 14

Pulls vesicles back to the organelle

Question 15

Where do most microtubules emanate from?

Answer 15

Centrosome

Question 16

What is typically located near the centrosome?

Answer 16

The golgi

Question 17

What do lysosome contain?

Answer 17

About 6- different types of degradative enzymes

Question 18

What is the function of lysosomes?

Answer 18

Degrade obsolete membrane-bound organelles via autophagy

Question 19

What tag is added to proteins destined for lysosomes?

Answer 19

Mannose-6-phosphate residues

Question 20

How are lysosomes formed?

Answer 20

From fusion of transport vesicles from the trans-golgi with late endoosomes

Question 21

What is the function of endosomes?

Answer 21

They intersect the secretory and endocytic pathways

Question 23

What is clarthrin- mediated endocytosis

Answer 23

aA macromolecule binds to a specific receptor in the Claritin- coated pit invagination and vesicle formation

Question 24

What is the role of dynamin in endocytosis?

Answer 24

Forms a ring around the pit causing a conformational change using GTP

Question 25

Where does degradation happen without membrqanes>

Answer 25

In the cytosol by proteosomes

Question 26

What is the structure of a proteasome?

Answer 26

A central barrel complex with a narrow core lined with proteolytic enzymes

Question 27

What tags protein for proteasome degradation?

Answer 27

Ubiquitin

Question 28

What is the function of of Ubiquitin proteasome system (UPS)

Answer 28

Degrades abnormal proteins

Question 29

What are the enzymes involved in ubiquitination?

Answer 29

- E1 - Activating - E2 - Conjugating - E3 - Ligase

Question 30

What happens after a protein is degraded by the proteasome?

Answer 30

Ubiquitin is released and reused

Question 31

What are microtubules made of?

Answer 31

Alpha and beta tubilin

Question 32

What is the function of microtubules?

Answer 32

Intracellular movement of organelles and vesicles; form mitotic spindle

Question 33

What are microfilaments made of?

Answer 33

Double strands of actin

Question 34

What s the role of actin and myosin in microfilaments?

Answer 34

Provide contractile force enabling cell movement

Question 35

What are intermediate filaments formed from?

Answer 35

A variety of proteins forming alpha-helix dimers

Question 36

What is the function of intermediate filaments?

Answer 36

- Support nuclear envelope (lamins)

Question 37

What are microvilli supported by?

Answer 37

Actin filaments

Question 38

What is the function of microvilli?

Answer 38

Engage in protrusions or extensions in movement, phagocytosis, absorption

Question 39

What are the two great steps in eukaryotic cell evolution?

Answer 39

Compartmentalisation and mitochondria

Question 40

What is the evolutionary benefit of compartmentalisation?

Answer 40

Specialised reactions can be separated, concentrated and optimised

Question 41

How did mitochondria originate?

Answer 41

An archaea cell engulfed a bacterium that provided ATP

Question 42

What change followed mitochondrial evolution?

Answer 42

Membrane invagination formed ER and nuclear envolope

Question 43

What do mitochondria contain?

Answer 43

Two membranes, their own DNA and enzymes for ATP productionW

Question 44

What is inside the mitochondrial matrix?

Answer 44

Enzymes for citric acid cycle and fatty acid oxidation

Question 45

What is found in the inner mitochondrial membrane?

Answer 45

Enzymes for oxidative phosphorylation