ScienceBiologyMB Chapter 47
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MB Chapter 47

Iver Campbell avatar Iver Campbell
24 July 2022
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question
When comparing endocrine system feedback inhibition to an analogous thermostat, which would best represent the furnace? sensory input the effector the central nervous system cell-to-cell signals
answer
the effector. This acts to restore the balance via alternate inputs.
question
Hormones exert what type of cell-to-cell signaling?
answer
endocrine
question
Negative feedback is defined as _____.
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the product of a process inhibits its production
question
Why might different cells be able to respond to T3 in very different ways?
answer
They have different receptors. The hormone could spark very different processes depending on which receptor is triggered.
question
How would the phenotype of a doubly homozygous individual (ob/ob db/db) compare to a singly homozygous individual (ob/ob)?
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They would both be obese. A deficiency in either signal or both signal and receptor results in an obese individual.
question
Which of the following would be most improved following a shot of epinephrine?
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improved escape from predators. Epinephrine is also known as adrenaline.
question
Metamorphosis in frogs is stimulated by which of the following hormones?
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thyroid hormone
question
High levels of which of the following two hormones will result in development of a male mammal?
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testosterone and Müllerian-inhibiting hormone
question
Ob/ob mice lack which of the following?
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leptin
question
Which type of hormone is lipid soluble?
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Steroids.
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Which molecules determine the tissue specificity of hormones?
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Receptors. Hormones bind to receptors on target cells and trigger a cellular response.
question
True or false? Lipid-insoluble hormones affect their target cells by binding to receptors inside the cell.
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False. Lipid-insoluble hormones cannot cross the plasma membrane and get into the cell, so they must bind to receptors on the cell surface and transduce their signals through signal transduction pathways.
question
Which of the following statements about lipid-soluble hormones is true?
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They act by affecting the transcription of genes. Lipid-soluble hormones act by affecting the transcription of genes.
question
Which of the following is a structure that allows hormone-receptor complexes to bind to specific DNA sequences?
answer
Zinc finger. A zinc finger is a distinctive DNA-binding domain on some hormone receptors that is exposed when hormone-receptor complexes are formed.
question
What is the role of cAMP in the signal transduction pathway activated by epinephrine?
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It binds to and activates protein kinase A, which then phosphorylates other enzymes. cAMP binds to and activates protein kinase A, which then phosphorylates other enzymes in the signal transduction pathway.
question
True or false? For a signal transduction pathway to be activated, hormones must be present in the bloodstream at very high concentrations.
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False. Only low concentrations of hormones are needed in the bloodstream to activate a signal transduction pathway, which works by producing second messengers inside the cell that amplify the hormonal signal.
question
Receptors for nonsteroid hormones are located in _____.
answer
association with a cell's plasma membrane.Since nonsteroid hormones do not cross a cell's plasma membrane, their receptors are located in association with the plasma membrane.
question
Which of these is a nonsteroid hormone? estrogen testosterone both estrogen and testosterone oxytocin epinephrine and oxytocin
answer
epinephrine and oxytocin. Both epinephrine and oxytocin are nonsteroid hormones.
question
How do nonsteroid hormones differ from steroid hormones?
answer
nonsteroid hormones act via signal transduction pathways; steroid hormones do not act via signal transduction pathways. Since they do not enter the cell, nonsteroid hormones act via signal transduction pathways.
question
What accounts for the fact that the hormone estrogen only affects the uterus, hypothalamus, and mammary glands?
answer
Only the uterus, hypothalamus, and mammary glands have estrogen receptors.
question
At what stage of development does the brain essentially reach its adult size?
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middle childhood
question
Due to proximity, adrenal glands are often damaged during surgery on what organ?
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kidney
question
Your body doesn't produce the correct amount of DHEA. Which of the following stages of development will be impacted? menarche gonadarche thelarche adrenarche
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adrenarche
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Which of the following do the adrenal glands depend on to release DHEA? thyroid hypothalamus thalamus pituitary
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pituitary
question
Describe the rate of skeletal development in middle childhood compared to adolescence.
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Skeletal development in middle childhood is slower than in early childhood.
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Why are hormones better suited for regulating homeostasis rather than electrical signals alone?
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Hormones are long lived and can spread throughout the body. Maintenance of homeostasis requires inputs from tissues and organs throughout the body.
question
How can a cell respond to more than one hormone?
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It has different receptors for each hormone. This allows a cell to respond to multiple signals.