Deck 4: Cell Signaling and Endocrine Regulation

Question 1

Neural signaling is different from other types of long-distance signaling because

A)it involves the release of chemical signals.
B)it involves the use of receptors.
C)the signal is contained within a single cell as it travels the long distance.
D)it relies on the blood to carry the signal from one cell to the next.

Answer 1

C

Question 2

In the thyroid hormones,T₃ and T₄,the 3 and 4 refer to the

A)relative half-life (3 or 4 hours).
B)number of tyrosine molecules linked together.
C)number of iodines which are found on the hormone.
D)number of enzymes required to synthesize the hormone.

Answer 2

C

Question 3

Which of the following statements provides inaccurate information?

A)In paracrine communication,the target cell receives chemical messenger from signal cell via diffusion.
B)A neurotransmitter is a chemical messenger that had been converted from an electrical signal.
C)Endocrine messengers are hormones.
D)Allelochemicals are chemical messengers released into the external environment by individuals of the opposite sex but of the same species.

Answer 3

D

Question 4

Which of the following compounds are endocrine disruptors?

A)tributyltin,polychlorinated biphenyls,tyramine,and anabolic steroids
B)polychlorinated biphynels and tyramine
C)anabolic steroids,tributyltin,and polychlorinated biphenyls
D)anabolic steroids,polychlorinated biphenyls,and tyramine

Question 5

The portion of the transmembrane receptor that binds to hydrophilic messengers is termed the

A)receptor-binding domain.
B)transmembrane domain.
C)ligand-binding domain.
D)intracellular domain.

Question 6

Eicosanoids are NOT effective as hormones because

A)they are hydrophobic and cannot dissolve easily in the blood.
B)they have a very short half-life and would degrade before reaching the target cell.
C)the signaling cell cannot regulate when they diffuse through the membrane.
D)all of the above

Question 7

It is possible for cells to communicate directly (via a connection of the cytoplasm)with each other by using

A)gap junctions.
B)paracrine signaling.
C)endocrine signaling.
D)autocrine signaling.

Question 8

The biogenic amine,__________,is important for invertebrates as a neurotransmitter.

A)epinephrine
B)norepinephrine
C)thyroid hormone
D)octopamine

Question 9

Why do steroids take so long to generate change when they bind to intracellular receptors?

A)The intracellular receptors have very slow kinetics.
B)The bound receptors affect gene transcription rates.
C)The steroid receptor complex activates signal transduction pathways.
D)The steroid receptor complex must then exit the cell to exert its effects.

Question 10

Antagonists are compounds that

A)prevent synthesis of new receptors.
B)prevent synthesis of hormones.
C)bind to a receptor,activating it.
D)bind to a receptor,but do not activate it.

Question 11

Peptide hormones (chains of 50 or fewer amino acids)are first synthesized as

A)the hormone itself.
B)prehormones.
C)prohormones.
D)preprohormones.

Question 12

A chemical is termed a neurohormone when it is

A)released by a neuron,but travels in the blood like a hormone.
B)released by an endocrine gland,but binds to receptors on a neuron.
C)released by neurons and endocrine glands.
D)known to be involved with communication,but scientists have not concluded which system uses it.

Question 13

When indirect signaling is used,the target cell responds to the signal when that chemical

A)binds to an enzyme.
B)binds to a receptor.
C)binds to a gene.
D)binds to the nuclear membrane.

Question 14

Gap junctions are formed by

A)groups of 8-12 connexons making a pore in one cell.
B)groups of 4-6 innexins or connexins forming a pore in one cell.
C)connexons from adjacent cells connecting with each other to form a cytoplasmic bridge.
D)both A and C
E) both B and C

Question 15

Exocrine secretions are used to communicate between different animals and

A)to digest foodstuffs.
B)to aid in locomotion.
C)in trapping prey.
D)all of the above

Question 16

The vertebrate hormones involved in water and electrolyte balance in the body are called

A)mineralocorticoids.
B)glucocorticoids.
C)ecdysteroids.
D)reproductive hormones.

Question 17

__________ is a generalized carrier protein that plays a major role in vertebrate blood.

A)Globulin
B)Albumin
C)Hemoglobin
D)Cholesterol

Question 18

Which of the following statements is true of any communication system?

A)Neurons are always involved.
B)The endocrine system is always involved.
C)A signal must always be sent and received.
D)Signals can be sent only in electrical form.

Question 19

When chemical signals are sent between two animals,__________ communication is being used.

A)neural
B)endocrine
C)autocrine
D)exocrine

Question 20

Which of the following choices is not a basic feature of cellular communication?

A)The signal must be produced.
B)The signal can be produced only by a eukaryote.
C)The signal must be transported to a target cell.
D)The target cell must respond to the signal.

Question 21

Which of the following statements is correct?

A)Ligand-gated ion channels change the ion permeability of the membrane,which results in a response by the target cell.
B)Intracellular receptors interact with hydrophilic chemical messengers.
C)Receptor enzymes activate extracellular enzymes.
D)G protein-coupled receptors interact with hydrophobic chemical messengers.

Question 22

The posterior pituitary is

A)one of the most important endocrine organs.
B)an organ producing (not just secreting)neurohormones.
C)just a physical extension of the hypothalamus.
D)a very small thin sheet in adult mammals.

Question 23

What is the correct relationship between receptor tyrosine kinases and Ras proteins?

A)Phosphorylated Ras proteins activate the tyrosine kinase.
B)Phosphorylated Ras proteins pair with a tyrosine kinase to activate other proteins.
C)Tyrosine kinase dimers phosphorylate the Ras proteins directly.
D)Tyrosine kinase dimers use GAPs and GNRPs to regulate Ras proteins.

Question 24

Which of the following is NOT a second messenger utilized by G proteins?

A)Ca²⁺
B)Na⁺
C)cyclic GMP
D)phosphatidyl inositol

Question 25

The hypothalamic-pituitary portal system transports blood and neurohormones between the

A)hypothalamus and the heart.
B)hypothalamus and the pituitary gland (after returning to the heart).
C)hypothalamus and the posterior pituitary.
D)hypothalamus and the anterior pituitary.

Question 26

Phospholipase C cuts membrane phospholipids into

A)PIP₂ and DAG.
B)PIP₂ and IP₃.
C)Ca²⁺ and DAG.
D)DAG and IP₃.

Question 27

Which domain of intracellular receptors binds to responsive elements in the nucleus?

A)DNA-binding domain
B)transactivation domain
C)ligand-binding domain
D)membrane-binding domain

Question 28

Once a ligand binds to a receptor-enzyme,

A)the catalytic domain interacts with extracellular components.
B)the catalytic domain interacts with intracellular components.
C)the ligand-binding domain is phosphorylated.
D)the ligand-binding domain is dephosphorylated.

Question 29

The organ that is connected to the hypothalamus by neurons is the

A)anterior pituitary.
B)posterior pituitary.
C)adenohypophysis.
D)thyroid.

Question 30

In a feedback loop,the portion that brings the variable back to its normal value is the

A)effector.
B)set point.
C)integrating center.
D)sensor.

Question 31

The response of a cell to a particular chemical messenger is determined by the

A)ligand-binding domain.
B)transmembrane domain.
C)functional domains.
D)chemical messenger itself.

Question 32

Tropic or trophic hormones

A)are found in tropical organisms.
B)have the ability to cause other hormones to be released.
C)are secreted only from the hypothalamus.
D)both B and C

Question 33

In a __________ feedback loop,both the endocrine and nervous systems can be involved.

A)first order
B)second order
C)third order
D)both B and C

Question 34

A receptor that binds to a ligand at very low concentrations has a

A)high dissociation constant.
B)low Kₐ.
C)high affinity for the ligand.
D)low affinity for the ligand.

Question 35

Insulin is produced by

A)Islets of Langerhans in the pancreas.
B)walls of the intestines.
C)acinar cells of the pancreas.
D)red blood cells to help maintain glucose levels.

Question 36

Insulin release is NOT stimulated by

A)CCK.
B)stretch of the gut.
C)low blood glucose levels.
D)high blood glucose levels.

Question 37

The signal transduction cascade acts as the __________ of a transducer.

A)receiver
B)transducer
C)amplifier
D)responder

Question 38

Up-regulation of receptors

A)results in increased sensitivity to its ligand.
B)results in decreased sensitivity to its ligand.
C)occurs when a ligand has been present at high levels.
D)both B and C

Question 39

The G-protein-coupled receptors are a diverse family with this common feature.

A)They are activated when a kinase molecule phosphorylates them.
B)They are activated when GTP is released from the G protein.
C)They are activated when GTP binds to the G protein.
D)They are activated when the α subunit binds to the β and γ subunits.

Question 40

Which of the following is different between stimulatory and inhibitory G proteins in the cyclic AMP pathway?

A)α subunit
B)β subunit
C)γ subunit
D)all of the above

Question 41

In the nervous system,chemical messages cross a __________,a short distance between the signal and target cells.

Question 42

When two or more hormones are __________,then the response of all the hormones when applied at the same time is greater than the sum of the responses to each hormone applied individually.

A)antagonistic
B)additive
C)synergistic
D)agonistic

Question 43

The protein __________ binds four calcium molecules and then interacts with other proteins in the cell,including CaM kinases.

Question 44

The communication and interspecies relationship between the Hawaiian bobtail squid,Euprymna scolopes,and the bacteria,Vibrio fischeri,is one of _____________.

Question 45

__________ are a group of steroid hormones found in all vertebrates.

A)Estrogens
B)Androgens
C)Glucocorticoids
D)All of the above

Question 46

A signal of one type may be changed to another type of signal using a __________.

Question 47

What endocrine gland secretes ACTH?

A)anterior pituitary
B)posterior pituitary
C)hypothalamus
D)adrenal medulla

Question 48

The term__________ refers to any molecule that binds specifically to a protein.

Question 49

When all available receptors have ligand bound to them,we say the receptors are __________.

Question 50

Epinephrine and norepinephrine are secreted by the

A)adrenal cortex.
B)chromaffin cells.
C)heart.
D)kidneys.

Question 51

A G protein with no known ligand or function is termed an __________.

Question 52

When ligand-gated __________ open,ions move in or out of the cell,affecting the membrane potential.

Question 53

__________ is a biogenic amine used in immune responses and allergic reactions.

Question 54

__________ is the major hormone secreted by the pineal gland and is involved with circadian and seasonal cycles.

Question 55

Nitric oxide is one of three gaseous chemical messengers and is produced by the enzyme __________.

Question 56

A signaling cell's message may affect itself as well,in a process known as __________ signaling.

Question 57

The three main classes of chemicals that act as hormones are __________,amines,and steroids.

Question 58

The term __________ is used for chains more than fifty amino acids long,while the term peptide is reserved for shorter chains.

Question 59

Chemical messengers used by the endocrine system are referred to as __________.

Question 60

__________ is a hormone that is frequently involved with reproductive processes that is also part of a positive feedback loop.

Question 61

There are multiple ways in which two cells in an organism can communicate with each other: gap junctions,paracrine and autocrine signals,endocrine signals,and neural signals.Discuss the advantages and drawbacks for each of these types of signals.

Question 62

Define hormones and briefly summarize their function.Provide an example to support your answer.

Question 63

If steroid hormones must be bound to protein carriers to travel through the blood,how are they able to bind to intracellular receptors? (The protein carriers cannot diffuse through the membrane. )

Question 64

Insulin and __________ are two hormones,produced by the pancreas,with antagonistic control of plasma glucose levels.

Question 65

What are endocrine disruptors and how do they affect wildlife populations? Provide two examples to support your answer.

Question 66

Compare and contrast positive and negative feedback loops.

Question 67

In a __________ feedback loop,the endocrine cell acts as the sensor and integrating center.

Question 68

The chemical properties of messengers affect how they are able to communicate with the target cell.Hydrophobic and hydrophilic messengers have many differences in the way they function.Discuss these differences and how they relate to the hydrophobicity/philicity.

Question 69

Under stressful or dangerous situations,organisms enter into the "flight-or-fight" response.This response has both neural and endocrine components.Discuss the functions of each component and how they interact with each other.

Question 70

Hormones are chemicals that are released into the blood and travel all over the body where they can have effects on their target cells.Discuss the mechanisms that allow only the target cells to respond and how target cells may have very different responses to the same hormone.

Question 71

Once a ligand has bound to a receptor,it will continue to generate its response.In order to stop that response,the ligand must be removed or inactivated in some way.Describe the different ways this may be accomplished,along with features of each method.

Question 72

There is a tremendous variety of signal transduction pathways with a wide range of functions.However,all these pathways have some things in common.Discuss some of these common features.