1 During pregnancy, the hormone human chorionic gonadotrophin (hCG) is produced by the placenta. Fig. 16.1
shows how levels of hCG change throughout pregnancy.
Studies on the effects of hCG in humans have revealed the following information:
Many different tissues are affected by hCG.
Susceptible cells have glycoprotein receptors on their cell surface.
These receptors are complementary to the shape of hCG molecules.
(i) What can be concluded from this information?
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, [3]
(ii) Another hormone produced during pregnancy is oestrogen. Oestrogen is lipid soluble.
Which molecule does oestrogen interact with when it changes cell activity?
[1]
2 Within the mammalian body, different systems of communication are used to coordinate and control activities.
Complete the following passage by using the most suitable term in each case.
The pancreas and the adrenal glands are both examples of _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ glands. Adrenaline is
a _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ that is secreted by the adrenal glands. These glands also secrete steroids such
as corticosteroids from cells in the _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ region. The chemicals secreted by these glands
are transported by the blood to their _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ cells and tissues.
[4]
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, 3 Heart rate is controlled by nervous and hormonal mechanisms.
(i) For each of the following statements, indicate whether the statement is true or false.
Statement True or False
Heart rate is accelerated by stimulation from the vagus nerve.
Stimulation by the sympathetic and parasympathetic nerves have opposite effects
on the heart rate.
The vagus nerve releases acetylcholine.
[2]
(ii) Hormonal control of heart rate is achieved by hormones acting on the sino-atrial node (SAN).
Using your knowledge of the way in which heart action is coordinated, suggest why it can be deduced that
hormones act on the SAN rather than on individual cardiac muscle cells.
[2]
(iii) Suggest how adrenaline brings about a response inside the cells of the SAN.
[2]
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shows how levels of hCG change throughout pregnancy.
Studies on the effects of hCG in humans have revealed the following information:
Many different tissues are affected by hCG.
Susceptible cells have glycoprotein receptors on their cell surface.
These receptors are complementary to the shape of hCG molecules.
(i) What can be concluded from this information?
© OCR 2023. You may photocopy this page. 1 of 25 Created in ExamBuilder
, [3]
(ii) Another hormone produced during pregnancy is oestrogen. Oestrogen is lipid soluble.
Which molecule does oestrogen interact with when it changes cell activity?
[1]
2 Within the mammalian body, different systems of communication are used to coordinate and control activities.
Complete the following passage by using the most suitable term in each case.
The pancreas and the adrenal glands are both examples of _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ glands. Adrenaline is
a _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ that is secreted by the adrenal glands. These glands also secrete steroids such
as corticosteroids from cells in the _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ region. The chemicals secreted by these glands
are transported by the blood to their _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ cells and tissues.
[4]
© OCR 2023. You may photocopy this page. 2 of 25 Created in ExamBuilder
, 3 Heart rate is controlled by nervous and hormonal mechanisms.
(i) For each of the following statements, indicate whether the statement is true or false.
Statement True or False
Heart rate is accelerated by stimulation from the vagus nerve.
Stimulation by the sympathetic and parasympathetic nerves have opposite effects
on the heart rate.
The vagus nerve releases acetylcholine.
[2]
(ii) Hormonal control of heart rate is achieved by hormones acting on the sino-atrial node (SAN).
Using your knowledge of the way in which heart action is coordinated, suggest why it can be deduced that
hormones act on the SAN rather than on individual cardiac muscle cells.
[2]
(iii) Suggest how adrenaline brings about a response inside the cells of the SAN.
[2]
© OCR 2023. You may photocopy this page. 3 of 25 Created in ExamBuilder
