Bio344-Exam#2 (Q's & A's)

Question 1

What enzyme does cAMP activate?

Answer 1

protein kinase A

Question 2

How can glucose transporters be inserted rapidly into the cell membrane after the cell detects insulin?

Answer 2

Glucose transporters are present in recycling endosomes which can fuse with the plasma membrane rapidly.

Question 3

How do enzymes end up in the late endosome?

Answer 3

from the ER they go to the Golgi then the late endosome

Question 4

How does a protein get directed to a specific cellular address?

Answer 4

The correct target has a receptor that binds the signal sequence of the protein.

Question 5

Where is the signal recognition particle receptor located in the cell?

Answer 5

the ER membrane

Question 6

What signal can activate a Jak-Stat pathway?

Answer 6

Interferon

Question 7

What is autocrine signaling?

Answer 7

Occurs when a cell releases a signal and expresses a receptor for that signal at the same time.

Question 8

Which of the following is true of the mitochondrial signal sequence?

Answer 8

it forms an alpha helix with one charged side while the other side is non-polar.

Question 9

How do proteins get transported from the cytosol to the endoplasmic reticulum?

Answer 9

Transmembrane transport

Question 10

What is a difference between an early endosome and a late endosome?

Answer 10

Endocytosed receptors are recycled from the early endosome and not the late endosome.

Question 11

How can a mutation in dynamin lead to paralysis in fruit flies?

Answer 11

New synaptic vesicles can no longer be made because phospholipids are not recycled from the cell membrane

Question 12

The Jak-STAT pathway is an example of…

Answer 12

enzyme linked receptor signaling pathway

Question 13

Which is a difference between the cis and trans face of the Golgi apparatus?

Answer 13

Enzymatic reactions that occur in the cis face are different from those present in the trans face.

Question 14

What does a kinase do?

Answer 14

it adds phosphate groups to proteins

Question 15

Why are the Golgi in goblet cells in the small intestine not homogeneously distributed throughout the cell?

Answer 15

These cells release mucus which is only released from one end of the cell.

Question 16

What are start and stop transfer sequences?

Answer 16

They are membrane spanning regions that determine how a protein is inserted into the ER membrane.

Question 17

What happens to cargo after it has arrived at an early endosome?

Answer 17

it is sent to the late endosome

Question 18

Where does the signaling molecule nitric oxide come from?

Answer 18

It is generated from arginine by an enzyme

Question 19

Where are sugars first added to proteins?

Answer 19

Endoplasmic reticulum.

Question 20

What is a difference between the early endosome and the late endosome?

Answer 20

The late endosome has proton transporters in its membrane while the early endosome does not

Question 21

What is a function of a protein coat in vesicular transport?

Answer 21

It aids in bending the membrane and forming the transport vesicle.

Question 22

Why does invagination happen in multivesicular bodies that form between early and late endosomes?

Answer 22

So that membrane proteins can be degraded completely.

Question 23

What does a G-protein linked receptor do when it binds a signal?

Answer 23

It replaces the GDP of a G protein with GTP.

Question 24

What molecule provides the energy to actively transport proteins from the cytosol into the nucleus?

Answer 24

Ran-GTP

Question 25

Which receptor binds antibodies?

Answer 25

the Fc receptor

Question 26

What enzyme makes cAMP?

Answer 26

adenylyl cyclase

Question 27

Why is a phospholipid exchange protein needed to transfer phospholipids to the mitochondria?

Answer 27

Because there is no vesicular traffic to mitochondria to deliver phospholipids.

Question 28

What is the content of secretory vesicles that wait near the plasma membranes of beta cells in the pancreas?

Answer 28

insulin

Question 29

What kind of protein coat is present on vesicles transporting cargo from the cell membrane to an early endosome?

Answer 29

Clathrin

Question 30

What is a low density lipoprotein particle?

Answer 30

It is a protein that delivers cholesteryl esters to cells

Question 31

What is likely to happen to a receptor, such as the LDL receptor, once it has delivered its cargo?

Answer 31

It is recycled back to the cell membrane.

Question 32

What kind of N-linked oligosaccharides are generated in the Golgi apparatus?

Answer 32

complex oligosaccharides

Question 33

What is a function of the Golgi Apparatus?

Answer 33

This is where the original oligosaccharide precursor is modified

Question 34

How do cells take up the correct substrates in endocytosis?

Answer 34

A receptor, specific for the substrate, will concentrate it into endocytic vesicles.

Question 35

What type of filament is used to move multivesicular tubular clusters?

Answer 35

microtubules

Question 36

What is a domain present on a nuclear receptor that binds steroid hormones?

Answer 36

A DNA binding domain

Question 37

Where is there a reservoir of calcium inside the cell?

Answer 37

Endoplasmic Reticulum

Question 38

Which below is an important class of cell surface receptors?

Answer 38

G-protein linked receptors

Question 39

What is a difference between a G-protein linked receptor and an enzyme linked receptor?

Answer 39

The enzyme linked receptor phosphorylates itself and can phosphorylate other proteins; the G protein linked receptor cannot.

Question 40

What would be the consequence of a mutant low-density lipoprotein particle receptor that does not bind to adaptin?

Answer 40

More LDL particles in the blood stream.

Question 41

Where are phospholipids made in the cell?

Answer 41

In the cytosolic layer of the smooth ER membrane.

Question 42

How are proteins often activated in signaling pathways?

Answer 42

they are phosphorylated.

Question 43

How do cargo vesicles fuse with the membrane of the target compartment?

Answer 43

SNARE proteins bring the membranes of the vesicle and target compartment close together so they can fuse.

Question 44

What does a mast cell do?

Answer 44

It releases histamines

Question 45

What kind of protein coat is present on vesicles transporting proteins from the ER to the Golgi?

Answer 45

COP II

Question 46

What signal tag is required to send a protein to the lysosome?

Answer 46

Mannose 6 phosphate

Question 47

Which organelle is responsible for carbohydrate synthesis?

Answer 47

Golgi apparatus

Question 48

Where are G-proteins located inside the cell?

Answer 48

on the cytoplasmic face of the plasma membrane

Question 49

What is the form of intercellular signaling that involves hormones called?

Answer 49

endocrine signaling

Question 50

Insulin binds to:

Answer 50

an enzyme linked receptor