BIOL 3060 Lecture Notes - Lecture 4: Pinocytosis, Phagocytosis, 5,6,7,8
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QUESTION 1
Which of the following is an example of an extracellular signal molecule?
a. | IP3 | |
b. | cAMP | |
c. | Insulin | |
d. | Diacylglycerol |
2 points
QUESTION 2
Nuclear hormone receptors _____
a. | Bind to water soluble ligands | |
b. | Activate second messengers | |
c. | Regulate transcription in response to ligand binding | |
d. | Are normally located on the plasma membrane |
2 points
QUESTION 3
Which of the following does not occur when a receptor tyrosine kinase is bound by ligand?
a. | Phosphorylation of the RTK | |
b. | Cytoplasmic proteins bind the phosphorylated RTK | |
c. | Dimerization of the RTK | |
d. | The RTK binds to DNA to regulate transcription |
2 points
QUESTION 4
Which of these is a logical signal-transduction pathway?
a. | An intracellular receptor activates phospholipase C, which cleaves a membrane protein to form IP3, which then activates the opening of an ER channel protein, which releases cyclic AMP into the cytoplasm, where it binds to an intracellular enzyme that carries out a response. | |
b. | A G-protein-linked receptor activates G protein, which activates phospholipase C, which cleaves a membrane lipid to form IP3, which binds to a calcium channel on the ER, which opens to release calcium ions into the cytoplasm, which bind to an intracellular enzyme that carries out a response. | |
c. | An ion-channel receptor opens, allowing a steroid hormone to enter the cell; the steroid hormone then activates protein kinases that convert GTP to GDP, which binds to an intracellular enzyme that carries out a response. | |
d. | A tyrosine-kinase receptor activates adenylyl cyclase, which activates phospholipase C, which converts ATP into cyclic AMP, which binds to an intracellular enzyme that carries out a response. |
2 points
QUESTION 5
Which of the following is an example of signal amplification?
a. | activation of an enzyme molecule | |
b. | activation of a specific gene by a growth factor | |
c. | Breakdown of many cAMP molecules | |
d. | activation of 100 molecules by a single signal binding event |
2 points
QUESTION 6
Consider a signal transduction pathway that utilizes cAMP as a second messenger to activate PKA (Protein Kinase A). Which of the following situations will result in the cellular response?
The G protein releases GDP and binds to GTP | ||
The target protein (adenylyl cyclase) is inactive | ||
The regulatory subunits of PKA (Protein Kinase A) are bound to the catalytic subunits | ||
The appropriate G protein is bound to GDP |
2 points
QUESTION 7
Which of the following is found in only some signal transduction pathways? [In other words, which is not found in all signal transduction pathways?]
Receptor protein | ||
Extracellular signal molecule | ||
Intracellular signaling molecule | ||
Cellular response | ||
Effector protein |
2 points
QUESTION 8
The enzyme that specifically catalyzes the conversion of ATP to cAMP is:
Adenylyl phosphatase | ||
Adenylyl kinase | ||
Adenylyl dehydrogenase | ||
Adenylyl cyclase |
2 points
QUESTION 9
If an animal cell suddenly lost the ability to produce GTP, what might happen to its signaling system?
It would use ATP instead of GTP to activate and inactivate the G protein on the cytoplasmic side of the plasma membrane. | ||
It would not be able to activate and inactivate the G protein on the cytoplasmic side of the plasma membrane. | ||
It would employ a transduction pathway directly from an external messenger. | ||
It would be able to carry out reception and transduction but would not be able to respond to a signal. |
2 points
QUESTION 10
A hormone signal is sent from the brain to other parts of the body via the bloodstream. Why do only certain cells respond to this signal?
Hormones do not last long enough in the bloodstream to stimulate a cellular response | ||
Only cells that have a specific transcription factor gene will be able to respond to the signal | ||
Only cells in the immediate vicinity of the cell sending the signal will respond | ||
Only cells that have a receptor for the specific signal will be able to respond to it |
I have this questions for my homework i need help with them look please it is important i need help so please give me the correct answers for each question and also please be clear to understand and aslo be correct it is very important becuase i need them so i really need the right answers. please help me and on Questions 6 and 9 please help me with it hope you can help me with the correct answers please
Question 5
At a constant temperature, if you increase the number of unsaturated fatty acid chains in the phospholipid, the membrane will become......
less fluid |
more fluid |
fluidity will be unchanged |
Question 6
Bacteria in a hot spring at 80 degrees celsius would be expected to have ______________ in their cell membrane
high proportions of saturated phospholipids |
high proportions of unsaturated phospholipids |
an equal ratio of saturated to unsaturated phospholipid |
Question 7
Membrane proteins have an important role in membrane fluidity
True |
False |
Question 8
The HIV virus can't attach to cells that have a mutation in the CCR5 gene and so such individuals are resistant to HIV. What population of people have a higher incidence of the mutant CCR5 gene and why?
europeans because their ancestors survived the bubonic plague |
North Americans because their ancestors survived small pox |
europeans because they have a longer evolutionary past with HIV |
Africans because they have a longer evolutionary past with HIV |
Question 9
Nematode trapping fungi have ______________ molecules called ______________ that recognize specific carbohydrates on the surface of the nematode worms. This is how a fungus can recognize that its prey, the nematode worm, has wriggled into the loop. Write two words on lowercase separated by a space with no other syntax
Question 10
Diffusion requires energy
True |
False |
Question 11
The net direction of molecule movement when molecules diffuse is
down their concentration gradient |
random directions |
Question 12
In osmosis, water molecules from a solution of higher solute concentration cross a semi-permeable membrane into a solution of lower solute concentration?
True |
False |
Question 13
Which best defines osmosis?
In osmosis, water from a solution of lower solute concentration move across a semi-permeable membrane into a solution of higher solute concentration? |
In osmosis, water from a solution of higher solute concentration move across a semi-permeable membrane into a solution of lower solute concentration? |
Question 14
Animal cells placed into a hypotonic solution would most likely?
lyse (burst) |
shrink |
remain unchanged in size |
Question 15
Glucose and amino acids move into cells via carrier proteins, the same protein can move glucose or amino acids
True |
False |
Question 16
ATP powered pumps move substances into and out of cells by diffusion?
True |
False |
Question 17
For every 3 Na ions moved out, 2 K ions are moved into a cell by one cycle of the sodium-potassium pump.
True |
False |
Question 18
Bulk transport of fluid and any of the substances within that fluid is called
pinocytosis |
phagocytosis |
receptor-mediated endocytosis |
exocytosis |