BIOL 118 Lecture Notes - Lecture 4: Signal Transduction, Cell Membrane, G Protein

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blackjackal192

18 Feb 2017

School

Binghamton University

Department

Biology

Course

BIOL 118

Professor

Dr.Mc Gee

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Document Summary

Less= less responsive: receptors can be blocked, drugs created to block hormones from binding to receptors. Signal processing: transmitting the signal into the cell, two basic processes, steroid hormones. Bunch of shit you missed here*****************: steroid hormones bind to receptors inside the cell, non-steroid hormones, use a signal transduction pathway. Converts the extracellular hormone signal to an intercellular signal: signal transduction occurs at the plasma membrane. Involves, g-proteins or enzyme linked receptors: signal transduction pathway. Signal is transduced from extracellular signal to intracellular signal. Signal response, activate or inactivate genes or proteins: 3 major signal transduction mechanisms. All three amplify the signal: g proteins. Intracellular peripheral membrane proteins (associated with the signal receptors) Activate enzymes that produce second messengers (small non- protein signaling molecules, diffuse rapidly, spread the message throughout the cell) Inactive, binds, induces receptor to change conformation, exchanges.

Related Questions

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

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The junction specialized for the transmission between a neuron and another cell is called a (1) _____ ______. Usually, the signal being sent to the receiving cell is carried by chemical messengers called (2) _____. (3) _____ is an example of this type of chemical messenger, which diffuses across the synaptic cleft, combines with protein receptor molecules on the muscle cell membrane, and soon thereafter is rapidly broken down by enzymes. At an (4) ____ synapse, the membrane potential is driven toward the threshold value and increases the likelihood that depolarization and an action potential will occur. At an (5) ____ synapse, the membrane potential is driven away form the threshold value, and the receiving neuron becomes hyperpolarized and is less likely to achieve an action potential. A specific transmitter substance can have either excitatory or inhibitory effects depending on which type of protein channel it opens up in the (6) ____ membrane. (7) ____ are neuromodulators that inhibit perceptions of pain and may have roles in memory and learning, emotional states, temperature regulation, and sexual behavior. (8) ____ ________ at the cellular level is the moment-by-moment tallying of all excitatory and inhibitory signals acting on a neuron. Incoming information is (9) ____ by the cell bodies, and the charge differences across the membranes are either enhanced or inhibited. Some narrow-diameter neurons are wrapped in lipid-rich (10) _______ produced by specialized neuroglial called Schwann cells; each of these is separated from the next by a(n) (11) ________ ________ - a small gap where the axon is exposed to extracellular fluid. A (12) ____ is an involuntary sequence of events elicited by a stimulus. During a (13) _______ ________, a muscle contracts involuntary whenever conditions cause a stretch in length; many of these help you maintain an upright posture despite small shifts in balance. Imbalances can occur at chemical synapses; a neurotoxin produced by Clostridium tetani blocks the release of GABA and glycine, thus freeing the motor neurons from (14) _____ control, which may cause tetanus â a prolonged, spastic paralysis that can lead to death. A. Excitatory H. Stretch reflex B. Inhibitory I. Summed C. Myelin J. Neurotransmitters D. Chemical synapse K. Postsynaptic E. Synaptic integration L. Endorphins F. Exposed node M. Acetylcholine (ACh)

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________30. If you are investigating the inner structure of a new cell and see that it has a significantly larger amount of RER than other cells. You would conclude the cell does a great deal of____?
A. ATP synthesis

B. protein synthesis
C. DNA synthesis
D. active transport
E. polysaccharide hydrolysis

________31. If a cell comes in contact with a toxic substance such as H2O2, it could survive as long as it has a ___ to digest it.
A. DNA
B. peroxisome

C. mitochondria
D. phospholipids
E. intermediate filaments

________32. Some cells have structures to help them withstand osmotic pressure. For example,
A. Plant cells due to their walls
B. Animal cells due to the sodium/potassium pumps

C. Bacterial cell due to their swimming

D. Viruses due to their protein coats

________33. Evolution occurs only as a cell ____.

A. They undergo mitosis
B. Change in their gene pool
C. They move from one habitat to another

D. They begin to eat different foods

________34. Ribosomes are produced in the

A. nucleoli.
B. chromatin.
C. nuclear envelopes.

D. Golgi complex. E. cisternae.

________35. Algae are often green, but there are red and brown species also. What accounts for this difference in color?
A. The chlorophyll of chloroplasts
B. The pigments in other plastids

C. The presence of a mitochondria
D. The accumulation of cellular wastes

________36. The chloroplast and other like prokaryotes have which of the following that helps with photosynthesis?
A. They live in water based environments
B. They have chloroplasts in their cytoplasm

C. Change color in the dark vs. the sun
D. They have photoreceptor proteins in their membranes or mesosomes.

________37. Located in the membrane, we see a set of proteins called receptors that only connect with or bind to specific substances. This is called __.
A. ligand specificity.
B. hormone selectivity.

C. cell tonicity.
D. water saturation. E. signal resolution.

________38. Of the following statements, we could say that ___ is false.
A. All organisms are composed of cells and cell products.
B. An organism's structure and all of its functions are due to the activities of cells.
C. The cellular organelles are the simplest structural and functional unit of life.
D. Cells come from preexisting cells.
E. Cells are made from nonliving components including the nucleus, cell membrane and cytoplasm.

________39. If it is really true that our cells are the smallest anatomical unit that meets all of the properties of life, then which of the following could imply otherwise?
A. vacuoles
B. centrioles

C. Golgi apparatus
D. mitochondria
E. endoplasmic reticulum

________40. Oxygen is an absolute need for animal and plant cells alike due to the ___.

A. RER
B. Mitochondria
C. Lysosomes

D. DNA

________41. In a plasma membrane, we expect to see the carb/protein structures to extend into the ___, but the secondary messengers to move within the __.
A. extracellular fluid; cytosol
B. cytosol; extracellular fluid

C. intracellular fluid; cytosol

D. cytosol; intracellular fluid

E. extracellular fluid; plasma

________42. Bacteria are found in all of the following habitats:

A. Caves
B. Oceans
C. Animals

D. Everywhere on Earth

________43. Two solutions are separated by a selectively permeable membrane. Solution A has a higher concentration of an impermeable solute compared to solution B. Which of the following do you expect would happen?
A. solute will move from solution A to solution B

B. solute will move from solution B to solution A

C. water will more from solution A to solution B

D. water will move from solution B to solution A E. no movement of solute or water will occur

________44. In the kidney, we notice that almost all of the cells involved in the production of urine have high concentrations of the Na+/K+ pump. Which typically works to push Na+ ___ its concentration gradient by using ___.
A. up; active transport

B. up; facilitated transport
C. up; cotransport
D. down; active transport
E. down; facilitated transport

________45. In the charts of a patient recently admitted to the hospital noted that he was taking a medication called lithium and high doses of calcium supplements. Given this, we would expect the patientâs liver to have a higher than normal amount of __ to purify out the lithium and calcium.

A. lysosomes.
B. centrosomes.
C. mitochondria.
D. peroxisomes.
E. rough endoplasmic reticulum.

________46. We have long observed that our neural cells in the brain cannot replicate or replace themselves due to the lack of ____.
A. produce ATP.
B. divide.

C. produce enzymes.
D. secrete material across their plasma membrane E. conduct electrical signals.

________47. An organismâs structure and function is ultimately due to the structure and function of itâs __.
A. Organs
B. Tissues

C. Cells

D. Nuclei

BIOL 118 Lecture Notes - Lecture 4: Signal Transduction, Cell Membrane, G Protein

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