Please answer all questions with the correct answer, some are multiple choice and others are written

Scaffold proteins ensure that signals are relayed ____.

	a.	methodically
	b.	simultaneously
	c.	inaccurately
	d.	efficiently
	e.	sl

What type of protein can transduce a signal in two directions?

	a.	Ras proteins
	b.	integrins
	c.	phosphorylated proteins
	d.	scaffold proteins
	e.	G proteins

What enzyme splits a membrane phospholipid into inositol trisphosphate (IP3) and diacylglycerol (DAG)?

	a.	adenylyl cyclase
	b.	protein kinase C
	c.	protein kinase A
	d.	phospholipase C
	e.	phosphodiesterase

What type of chemical compound diffuses across synapses?

	a.	neurons
	b.	nitric oxide
	c.	neurotransmitters
	d.	hormones
	e.	prostaglandins

Under which of the following situations would receptor down-regulation most likely occur?

	a.	The concentration of a hormone is too high.
	b.	The number of receptors in the plasma membrane is too low.
	c.	The number of G proteins is too high.
	d.	The concentration of a neurotransmitter is too low.
	e.	The cell is unable to manufacture cyclic AMP.

Compare and contrast local regulators, neurotransmitters, and hormones.?

In what part of the cell does a polar signaling molecule bind its receptor? A nonpolar signaling molecule. Explain your reasoning.?

The hydrolysis of GTP to GDP deactivates the ____.

	a.	protein kinase pathway
	b.	ligand-gated channel
	c.	G protein
	d.	Ras protein
	e.	cAMP

The outer part of a G protein receptor binds to a(n) ____, and its inner part binds to a(n) ____.

	a.	ion channel; G protein
	b.	signaling molecule; tyrosine kinase
	c.	G protein; ion channel
	d.	signaling molecule; G protein
	e.	G protein; tyrosine kinase

Adenylyl cyclase catalyzes the reaction in which:

	a.	GTP is converted to GDP.
	b.	ATP is converted to cAMP.
	c.	a protein is phosphorylated.
	d.	PIP₂ is split.
	e.	calcium ions bind calmodulin.

Typically, the gate of an ion channel remains closed until a(n) ____ binds to the receptor.

	a.	target cell
	b.	ligand
	c.	G protein
	d.	first messenger
	e.	enzyme

What happens when Ras proteins become stuck in their â€œonâ€ state?

	a.	Additional ions are catalyzed.
	b.	There is unregulated cell division.
	c.	Ligand-gated channels close off the membrane.
	d.	Cellar responses are slowed.
	e.	There is an increase in protein synthesis.

The main signaling cascade for cell division and differentiation is the ____ cascade.

	a.	phospholipase C
	b.	cAMP
	c.	phosphoinositol
	d.	calcium-calmodulin
	e.	MAP kinase

How is paracrine signaling different from other types of signaling?

	a.	The signaling molecules are transferred by electrical signals.
	b.	The signaling molecule diffused through interstitial fluid, acting on nearby cells.
	c.	The signaling molecule are hormones.
	d.	The signaling molecules are displayed on the cell surface.
	e.	The signaling molecules release neurotransmitters.

A receptor on the cell surface usually has several domains. What is the function of the external domain?

	a.	It attaches the receptor to the DNA.
	b.	It is the docking site for a signaling molecule.
	c.	It function is as an enzyme.
	d.	It holds the receptor within the membrane.
	e.	It transmits the signal to the inside of the cell

What type of cells must receive, relay, and respond to the information signaled?

	a.	GABA
	b.	integrins
	c.	local regulators
	d.	neurotransmitters
	e.	target cells

What is meant by signal amplification? Provide two examples.?

What activates protein kinase C?

	a.	cAMP
	b.	IP₃
	c.	calcium ions
	d.	DAG
	e.	PIP₂

Which is a major group of enzyme-linked receptors?

	a.	adenylyl cyclases
	b.	phospholipases
	c.	tyrosine kinases
	d.	G proteins
	e.	ion channels

Which MAP protein kinase is the last to be activated in the MAP kinase pathway?

	a.	Mek
	b.	Raf
	c.	Ras
	d.	ERK
	e.	tyrosine

Phosphodiesterase catalyzes the conversion of:

	a.	cAMP to AMP.
	b.	GDP to GTP.
	c.	a protein to a phosphorylated protein.
	d.	IP₃ to PIP₂.
	e.	calcium to calcium-calmodulin.

During enzyme-linked reception, signal molecules bind to two tyrosine kinase receptors. The receptor proteins move closer together in the plasma membrane and pair, forming a(n) ____.

	a.	protein kinase cascade
	b.	dimer
	c.	polypeptide chain
	d.	pathway
	e.	gate

In the phospholipase C signal transduction pathway, which two second messengers are produced?

	a.	IP₃ and DAG
	b.	phospholipase C and protein kinase A
	c.	PIP₂ and IP₃
	d.	cAMP and IP₃
	e.	phospholipase C and G protein

Many intracellular receptors are transcription factors; when activated, they activate or repress specific _____ .

	a.	ribosomes
	b.	enyzmes
	c.	neurons
	d.	genes
	e.	kinases

Which local regulator is stored in cells of the immune system and released during an allergic reaction?

	a.	histamine
	b.	a growth factor
	c.	a prostaglandin
	d.	a neurotransmitter
	e.	nitric oxide

Which MAP kinase was found to be a signaling molecule for oocyte maturation in mice?

	a.	Raf 1 and Raf 2
	b.	Ras 1 and ERK 2
	c.	Mek and Raf
	d.	Mek and ERK2
	e.	ERK 1 and ERK 2

Phospholipase C catalyzes the reaction in which:

	a.	calcium ions are released from the ER.
	b.	IP₃ is converted to DAG.
	c.	DAG is converted to PIP₂.
	d.	PIP₂ is split.
	e.	a protein kinase is activated.

In the cAMP signal transduction pathway, a protein kinase is activated. What happens next/

	a.	cAMP is converted to ATP.
	b.	G protein is activated.
	c.	GDP is replaced by GTP.
	d.	Adenylyl cyclase is activated.
	e.	The protein kinase activates a cellular response.

What is calmodulin?

	a.	a calcium-binding protein
	b.	a protein kinase
	c.	a hormone
	d.	a phospholipase
	e.	a phosphatase

Which list describes the correct sequence of events involved in cell signaling?

	a.	reception, signal transmission, response, signal transduction
	b.	signal transmission, reception, signal transduction, response
	c.	signal transmission, signal transduction, reception, response
	d.	signal transduction, reception, signal transmission, response
	e.	response, signal transduction, signal transmission, reception

Where are calcium ions stored before a signaling pathway releases them into the cytosol?

	a.	endoplasmic reticulum
	b.	ribosome
	c.	plasma membrane
	d.	lysosome
	e.	nucleus

Which is an example of a second messenger?

	a.	cyclic AMP
	b.	an ion channel
	c.	insulin
	d.	protein kinase A
	e.	GABA

How many times do G proteinâ€“linked receptors loop back and forth through the plasma membrane?

	a.	once
	b.	twice
	c.	three
	d.	seven
	e.	eleven

What is the process in which one activated receptor can give rise to thousands of
final products?

	a.	signal transcription
	b.	signal amplification
	c.	signal transduction
	d.	signal termination
	e.	signal transmission

During signal transduction involving G protein and cAMP, what do protein kinases add to target proteins?

	a.	calmodulin
	b.	substrates
	c.	calcium ions
	d.	phosphate groups
	e.	enzyme

How are hormones produced by endocrine glands typically transported to target cells?

	a.	in the blood
	b.	across a synapse
	c.	through the air
	d.	via direct contact
	e.	in interstitial fluid

Most intracellular receptors are what type of protein?

	a.	enzymes
	b.	neurotransmitters
	c.	DNA
	d.	steroids
	e.	transcription factors

Suppose that acetylcholine binds its receptor on the surface of a muscle cell. What happens next?

	a.	A neurotransmitter crosses the synapse.
	b.	G protein is activated.
	c.	Tyrosine is phosphorylated.
	d.	A sodium gate opens.
	e.	Tyrosine kinase is activated.

What is typically the result of receptor up-regulation?

	a.	The number of genes that code for a receptor increases.
	b.	The number of receptors decreases.
	c.	A hormone’s signal is amplified.
	d.	The sensitivity of a cell to a hormone decreases.
	e.	The concentration of hormone molecules in the blood increases.

What can happen when GABA binds to its receptor?

	a.	Neural signaling is inhibited.
	b.	New signals are transmitted.
	c.	Sodium ions enter the cell.
	d.	Enzyme-linked receptors are activated.
	e.	Muscle contraction is stimulated.

Biological membranes are one dimensional fluids.
__________________

True

False

What is required for facilitated diffusion to take place?

	a.	energy from ATP
	b.	a transmembrane protein
	c.	the transport of large food particles
	d.	the transport of small nonpolar molecules
	e.	movement down a concentration gradient

If the concentration of solutes in a cell is less than the concentration of solutes in the surrounding fluid, then the extracellular fluid is said to be:

	a.	hypotonic.
	b.	isotonic.
	c.	hypertonic.
	d.	amphipathic.
	e.	stable.

In the accompanying figure, what is the form of cellular junction?

	a.	desmosomes
	b.	plasmodesmata
	c.	tight junctions
	d.	adhering junctions
	e.	gap junctions

Since sodium-potassium pumps transport sodium ions out of a cell and potassium ions into a cell, what type of carrier proteins are they?

	a.	antiporters
	b.	ABC transporter
	c.	ion pumps
	d.	symporters
	e.	uniporters

In a lipid bilayer, __________ fatty acid tails face each other within the bilayer and form a region that excludes water.

	a.	hydrophilic
	b.	hypotonic
	c.	hydrophobic
	d.	hypertonic
	e.	hyperosmotic

Peripheral proteins are linked to either surface of the plasma membrane by:

	a.	associating with glycoproteins on the inner membrane surface.
	b.	associating with fatty acids through hydrophobic interactions.
	c.	bonding to integral proteins through noncovalent interactions.
	d.	embedding in one side of the membrane and, thus, not extending through to the other side.
	e.	covalent disulfide bonds.

The term “fluid mosaic model” refers to the:

	a.	method of substance transport across the membrane.
	b.	movement of lipids and integral proteins within the lipid bilayer.
	c.	diffusion of lipid-soluble substances through the lipid bilayer.
	d.	movement of surface proteins through the membrane.
	e.	solubility of water in the membrane.

Compare and contrast simple diffusion, osmosis, and facilitated diffusion.?

During phagocytosis, what may fuse with the vacuole to further degrade the ingested material?

	a.	lysosome
	b.	phosphate
	c.	receptor
	d.	desmosome
	e.	ligand

What happens during the cotransport of glucose and sodium ions?