Deck 33: Sensory Systems

Question 1

What type of stimulus is necessary for hearing and touch?

A) visual
B) mechanical
C) auditory
D) olfactory
E) None of the answers is correct.

Answer 1

B

Question 2

Salty tastes are detected through _________________.

Answer 2

sodium ion channels

Question 3

Which ions signal a sour taste as they pass through ion channels?

A) hydrogen
B) sodium
C) potassium
D) chloride
E) ammonium

Answer 3

A

Question 4

What ion stimulates guanylate cyclase?

A) sodium
B) potassium
C) calcium
D) magnesium
E) hydrogen

Question 5

What visual pigment is found in rods?

A) chlorophyll
B) phycocyanin
C) carotene
D) rhodopsin
E) anthrocyanin

Question 6

The sense of vision is due to the absorption of light by _________________cells in the eye.

Question 7

Odor and some taste sensations are dependent on the stimulus of specific 7TM receptors causing triggering of _________________ stimulation.

Question 8

In terms of sequence structure,OR family proteins are 20% identical to the ________________.

Question 9

Rhodopsin,the photoreceptor molecule in rods,consists of the protein ______________ linked to 11-cis retinal.

Question 10

The daily rhythms of activity and restfulness are known as _____ rhythms.

A) biennial
B) diurnal
C) circadian
D) arcadian
E) None of the answers is correct.

Question 11

Specific odors are detected and transmitted to the olfactory bulb by ____________________.

Question 12

The _________________ family of receptors is involved in odor and some taste sensations.

Question 13

Which of the following animals has the most highly developed color perception?

A) dog
B) human
C) iguana
D) honeybee
E) chicken

Question 14

Which G-protein subunit is expressed in taste buds?

A) transducin
B) Rho
C) $\alpha$ _olf
D) gustducin
E) GNAL

Question 15

_________________ are structural motifs found in many proteins,and they consist of a hairpin loop followed by a helix-turn-helix.

Question 16

What type of receptor detects pain?

A) nociceptor
B) baroreceptor
C) chemoreceptor
D) osmoreceptor
E) proprioceptor

Question 17

What condition is characterized by the inability to smell certain compounds?

A) dysosmia
B) specific anosmia
C) ageusia
D) parosmia
E) Kallmann syndrome

Question 18

Capsaicin is a chemical found in _______________.

Question 19

Which of the following is a tastant category?

A) acidic
B) oily
C) fruity
D) creamy
E) umami

Question 20

Mutant mice lacking the VR1 receptor are less responsive to the taste of capsaicin and can endure noxious levels of _______________.

Question 21

What clues indicate that protein receptors are important in detection of smells?

Question 22

How many active olfactory genes are found in rats and humans? Explain the discrepancy.

Question 23

Because the major clue to the mechanism of hearing is speed,sounds are detected through

A) 7TM receptors.
B) amiloride-sensitive ion channels.
C) chemical receptors.
D) mechanosensory ion channels.
E) None of the answers is correct.

Question 24

How is the stimulus by light terminated so that the initial state is restored?

A) Activated rhodopsin is blocked from activating transducin when metarhodopsin II (R*) is phosphorylated and the inhibitor arrestin binds the R*.
B) The level of cGMP is raised to reopen the gated ion channels.
C) The GTP bound to the G protein is hydrolyzed, allowing the transducin and the phosphodiesterase to return to their original states.
D) All of the above.
E) None of the answers is correct.

Question 25

What is the end point for the taste transduction pathways regardless of the diverse nature of the detection process?

Question 26

How is olfactory detection maximized?

Question 27

What structural features are important in the light-detecting function of the chromophore 11-cis-retinal?

A) It is a polyene with alternating single and double bonds forming an unsaturated electron network.
B) It is easily ionized to carry a charge.
C) It has several linked cyclic rings.
D) It is very water soluble.
E) It is highly colored.

Question 28

Which of the following taste sensations is not detected by 7TM receptors?

A) umami (delicious)
B) sweet
C) salty
D) bitter
E) All of the answers are correct.

Question 29

How were initial matches made to link specific odors to receptors?

A) overexpression of genes in rats
B) binding of odors to receptor molecules
C) studying the effect of odors on rats
D) sequence comparison to other known proteins
E) isolation and characterization of OR proteins

Question 30

Detection of touch includes several stimuli,and two of the key components include

A) pressure and sharpness.
B) temperature and sound.
C) pressure and duration.
D) temperature and taste.
E) pressure and temperature.

Question 31

What protein has been identified as a potential transduction channel for detecting sound from fruit fly experiments?

A) ankyrin repeats
B) helix-turn-helix protein
C) NompC (No mechanoreceptor potential)
D) hear2
E) bundl

Question 32

Which photoreceptors are most closely related in humans?

A) green and blue
B) green and red
C) red and rhodopsin
D) rhodopsin and green
E) blue and red

Question 33

How were most OR proteins and ligands identified?

Question 34

How is expression of OR proteins controlled?

A) Expression is controlled by stimuli from the environment.
B) Expression is activated by feedback mechanisms from the olfactory sensory system.
C) Each olfactory neuron produces only one OR receptor protein.
D) All neurons produce the OR proteins, as there is no reason to increase or decrease expression.
E) Each neuron produces a subset of related OR proteins, under control of a common stimulus.

Question 35

How were genes identified for bitter tastants?

A) A specific taste was genetically linked to a chromosome region and the DNA sequence examined for a sequence similar to 7TM receptors.
B) Knockout mice were used to determine the exact sequence.
C) A hybridization analysis of all genes expressed in taste buds with 7TM probes was obtained.
D) Protein purification and characterization of a family of proteins were conducted.
E) Taste tests were conducted with humans deficient in 7TM receptors.

Question 36

What biochemical conditions indicated the role of G proteins in olfactory systems?

A) Rat cilia were found to be ATP deficient.
B) The levels of ATP and cAMP were critical.
C) The receptors required GDP for activity were present.
D) cAMP and GTP participated in the process.
E) The receptors were localized in membranes.

Question 37

In which sensory systems do 7TM receptors play a role?

A) hearing
B) olfaction
C) vision
D) hearing and olfaction
E) olfaction and vision

Question 38

Most odorants are

A) mixtures of ions.
B) small, volatile, organic molecules.
C) complex salts.
D) small globular proteins.
E) large organic molecules.

Question 39

What characteristics were sought in cDNA libraries to identify the G proteins involved in olfactory systems?

Question 40

What is the immediate effect of a photon on the structure of 11-cis retinal?

A) The molecule is polarized.
B) The molecule is released from the protein rhodopsin.
C) The molecule is converted to the all-trans-retinal.
D) The molecule is converted from an aldehyde to an alcohol (retinol).
E) The structure is not changed but accepts electrons.

Question 41

What evidence is there that sweet receptors are heterodimeric?

Question 42

What is the reason for color-blindness in humans?

Question 43

How are the molecular mechanisms for salty taste sensations and nonpainful touch sensations similar?

Question 44

Describe the steps leading to the detection of light.

Question 45

Name another stimulus (besides the basic senses)that appears to be detected by humans.

Question 46

What clues about signaling can be gained by studying the structural motifs of proteins,such as the ankyrin repeats found in NompC?

Question 47

How is sound converted to a biochemical signal?

Question 48

How do taste and odor detection vary?

Question 49

Many of the receptors involved in transmission of stimuli contain multiple transmembrane domains.Why?