Bio 111 Exam 3 UPDATED ACTUAL
Questions and CORRECT Answers
In a controlled experiment, researchers manipulate one variable at a time.
What was the experimental variable in this study? - CORRECT ANSWER the genotype of
the transplanted tissue
Why did the researchers use more than one hamster for each procedure? - CORRECT
ANSWER to assess whether the differences in cycle period before and after transplant
were greater than the variation in cycle period from animal to animal
What traits of the individual hamsters would likely have been controlled across the treatment
groups? - CORRECT ANSWER age and sex
For the wild-type hamsters that received τ SCN transplants, what would have been an
appropriate control? - CORRECT ANSWER transplant the SCN from one wild-type
hamster to another wild-type hamster
What general trends does the graph reveal about the period of the circadian rhythm in transplant
recipients? - CORRECT ANSWER It was similar to that of the donor, whether the
recipient was wild-type or τ mutant.
What can you conclude about the role of the SCN in determining the period of the circadian
rhythm? - CORRECT ANSWER The SCN determines the period of the circadian rhythm.
In 20% of the hamsters, there was no restoration of rhythmic activity following the SCN
transplant.
Can you be confident of your conclusion about the role of the SCN based on data from 80% of
the hamsters? Why or why not? - CORRECT ANSWER Yes. The data from 80% of the
hamsters are very consistent. In the other 20%, the transplanted SCN may not have established
functional connections with the recipient's brain.
, Suppose researchers identified a mutation that caused hamsters to have no rhythmic activity.
Also suppose you transplanted the SCN of wild-type hamsters into hamsters with this mutation.
What result would you expect from this experiment, assuming that the SCN determines the
period of the circadian rhythm? - CORRECT ANSWER The recipients would have
rhythmic activity with a period of about 24 hours.
What result would you expect if you transplanted the SCN of τ hamsters into no-rhythmic-
activity mutants? - CORRECT ANSWER The recipients would have rhythmic activity
with a period of about 20 hours
Carbon dioxide enters the blood at the _____. - CORRECT ANSWER capillaries of the
head, forelimbs, abdominal organs, and hind limbs
The _____ has(have) the thinnest walls. - CORRECT ANSWER capillaries
Blood pressure is highest in the _____. - CORRECT ANSWER aorta
Blood returns to the heart via the _____. - CORRECT ANSWER pulmonary veins
From the pulmonary veins, blood flows to the _____. - CORRECT ANSWER left atrium
From the anterior vena cava, blood flows to the _____. - CORRECT ANSWER right
atrium
From the capillaries of the abdominal organs and hind limbs, blood flows to the _____. -
CORRECT ANSWER posterior vena cava
Most carbon dioxide is carried from the body tissues to the lungs _____. - CORRECT
ANSWER as bicarbonate ions (HCO3 -)
Questions and CORRECT Answers
In a controlled experiment, researchers manipulate one variable at a time.
What was the experimental variable in this study? - CORRECT ANSWER the genotype of
the transplanted tissue
Why did the researchers use more than one hamster for each procedure? - CORRECT
ANSWER to assess whether the differences in cycle period before and after transplant
were greater than the variation in cycle period from animal to animal
What traits of the individual hamsters would likely have been controlled across the treatment
groups? - CORRECT ANSWER age and sex
For the wild-type hamsters that received τ SCN transplants, what would have been an
appropriate control? - CORRECT ANSWER transplant the SCN from one wild-type
hamster to another wild-type hamster
What general trends does the graph reveal about the period of the circadian rhythm in transplant
recipients? - CORRECT ANSWER It was similar to that of the donor, whether the
recipient was wild-type or τ mutant.
What can you conclude about the role of the SCN in determining the period of the circadian
rhythm? - CORRECT ANSWER The SCN determines the period of the circadian rhythm.
In 20% of the hamsters, there was no restoration of rhythmic activity following the SCN
transplant.
Can you be confident of your conclusion about the role of the SCN based on data from 80% of
the hamsters? Why or why not? - CORRECT ANSWER Yes. The data from 80% of the
hamsters are very consistent. In the other 20%, the transplanted SCN may not have established
functional connections with the recipient's brain.
, Suppose researchers identified a mutation that caused hamsters to have no rhythmic activity.
Also suppose you transplanted the SCN of wild-type hamsters into hamsters with this mutation.
What result would you expect from this experiment, assuming that the SCN determines the
period of the circadian rhythm? - CORRECT ANSWER The recipients would have
rhythmic activity with a period of about 24 hours.
What result would you expect if you transplanted the SCN of τ hamsters into no-rhythmic-
activity mutants? - CORRECT ANSWER The recipients would have rhythmic activity
with a period of about 20 hours
Carbon dioxide enters the blood at the _____. - CORRECT ANSWER capillaries of the
head, forelimbs, abdominal organs, and hind limbs
The _____ has(have) the thinnest walls. - CORRECT ANSWER capillaries
Blood pressure is highest in the _____. - CORRECT ANSWER aorta
Blood returns to the heart via the _____. - CORRECT ANSWER pulmonary veins
From the pulmonary veins, blood flows to the _____. - CORRECT ANSWER left atrium
From the anterior vena cava, blood flows to the _____. - CORRECT ANSWER right
atrium
From the capillaries of the abdominal organs and hind limbs, blood flows to the _____. -
CORRECT ANSWER posterior vena cava
Most carbon dioxide is carried from the body tissues to the lungs _____. - CORRECT
ANSWER as bicarbonate ions (HCO3 -)
