1. A Canadian Senate committee has proposed the legalization of marijuana. Give three biological reasons for
agreeing with this proposal or three biological reasons for opposing this proposal.
Students must choose one position only. One mark each for any three reasons below.
Agree:
Oppose:
(1) treatment of chronic pain
(1) causes anxiety, depression, etc.,
(2) elevates mood
(2) causes lung cancer, sinusitis, or bronchitis
(3) controls muscle movement
(3) reduces amount of O2 going to the heart
(4) blocks frustration/confusion
(4) can cause long term effects such as
(5) treats nausea from chemotherapy
impaired speech, memory loss, understanding
(6) relieves arthritis pain complex
ideas, impaired vision, infertility
(7) anti-epiletic
(5) reduced immunity
(8) less addictive than a pain killer
2. If a person experienced memory loss after a concussion, which part of the brain was most likely injured?
Explain how you know this.
cerebrum (1 mark)
It is the region responsible for memory and decision-making (1 mark)
3. A child shows abnormal growth of bone tissue causing extra long legs and arms.
What is the probable cause of this condition and give two ways it can be treated?
Excess production of human growth hormone is the cause. (1 mark)
½ mark each for any two treatments below:
(1) surgery to remove tumor
(2) irradiation of gland tissue
(3) hormone blocking drug
4. In what three ways does the response of a nerve differ from the response of a hormone?
1 mark for any three differences below:
(1) a nerve response is fast while a hormone response is slow
(2) a nerve response has a short duration while a hormone response has a long duration
(3) a nerve response is electrical while a hormone response is chemical
(4) a nerve response has a direct pathway while a hormone response has a general circulation
5. A stimulus is received by a neuron. The membrane surrounding the neuron continues to be depolarized.
Why might this occur and what is the result?
Drugs/medication that would interfere with the Na+/K+ pump.
Result being no repolarization.
6. The graph below shows the potential difference between the inside and the outside of a motor neuron.
Did an action potential pass down the neuron?
Why or why not?
No. The stimulus has not reached the threshold level. 1 mark
7. Neurotransmitter levels in the brain have been linked to clinical depression. What is the biological
basis for this relationship?
Certain neurotransmitters are responsible for excitatory response and mood elevation (e.g. glutamate, GABA,
dopamine and serotonin). Reduction in levels of these neurotransmitters would reduce transmission across the
synapse reducing alertness and response time. Similar behaviour can be mimicked with depressants such as
alcohol and opiates.
8. Explain how the nervous and endocrine systems work together when the body responds to a dangerous
situation.
Receptor picks up stimulus (1 mark)
Sympathetic nervous system reaction (1 mark)
Adrenal gland secretes aadrenaline and its response (1 mark)
9. State two reasons why “designer drugs” are more dangerous than prescription drugs.
Any of the following reasons can be used.
Designer drugs are prepared by untrained and unlicensed chemists, thus there is no quality control.
Abuse of designer drugs is even more dangerous.
Dosage monitoring is poor to none.
These drugs may contain toxic impurities.
We are unaware of how addictive they may be.
10. The diagram below shows a nerve pathway in the human body that does not involve the brain.
(need diagram)
i) Draw arrowheads on lines A and B in the diagram to show the direction of travel of the nerve pathway and
name the response.
Response name: Reflex arc
11. After a snowmobile accident a person cannot move his legs and loses the ability to feel pain in his legs.
Give two possible reasons for the loss of these abilities.
Possible answers:
- Spinal cord injury
- Brain damage
- Nerve damage in the leg
- Poor blood flow due to a blood clot that may form
12. Describe one advantage and one disadvantage of a reflex arc response as compared to a normal response
from the brain.
Advantage:
- quick
- removal from danger
- automatic
Disadvantage:
- may react inappropriately for the situation
- over-reaction
13. A researcher surgically removes the Islets cells from a rat’s pancreas to observe the effects.
i) Describe two symptoms the rat should start exhibiting after the surgery.
- thirsty
- tiredness
- frequent urination
- inability to store sugar
- loss/deterioration of vision
ii) Explain one way the researcher could treat these symptoms.
- give insulin
- surgery
- diet and exercise
14. Shortly after being struck in the back of the head, a person staggers. What part of the brain was damaged?
Give two reasons to support your answer.
Cerebellum - motor coordination and balance
15. What four symptoms would confirm the diagnosis obtained from a positive result on a Benedict’s Solution
test?
- thirst - frequent urination - sweating
- poor circulation - fatigue - high & low blood sugars
- vision problems - high blood pressure - disorientation
- headaches
- also ½ marks if “diabetes” is mentioned.
16. Due to a mutation, the sodium binding site on a sodium potassium pump has changed such that it now binds
with chloride ions (Cl-). Sodium ions (Na+) remain inside the membrane. What happens to nerve transmission?
Give two reasons to justify your answer.
If the sodium binding site now binds with chloride ions and sodium ions remain inside the membrane, then
nerve transmission will stop. Reploarization will not occur because sodium is not being pumped out, the outside
of the membrane will be more negative or the inside of the membrane will be less negative.
(1½ mark) Nerve transmission stops.
(1½ mark) Repolarization does not occur because: (any two of the following)
- sodium is not being pumped out
- outside would be more negative
- inside would be less negative
17. Which endocrine gland is most likely damaged in a female whose menstrual cycle has stopped and
metabolism has slowed? Explain.
If a female’s menstrual cycle has stopped and metabolism has slowed then the
pituitary gland (or anterior pituitary gland) is most likely damaged because it
releases hormones that control these symptoms.
(1 mark) Pituitary Gland (or Anterior Pituitary Gland)
(1 mark) gland which releases hormones that control these symptoms
18. The graph below shows the membrane potential of the inside of a neuron.
(need graph)
(i) Indicate on the graph, with an X, when the neuron was stimulated. Justify your choice.
(ii) Extend the graph above to show what the membrane potential would look like from time C to D, assuming
there is no further stimulus.
1 mark - indicating the position of X
1½ marks - The reversal of polarity (depolarization) begins at A and continues to B. The change in polarity is
caused by the sodium ions moving across the membrane causing the inside to become more positive than negative.
19. When humans consume excessive amounts of alcohol they lose their ability to reason, walk straight, and
breathe normally. List two parts of the brain that are affected by alcohol consumption. Justify your choices.
Answer: Any two of the following:
Cerebrum
Receives input from sense organs,
processes the information and then
produces an output. Alcohol slows
this processing ability making
decisions more difficult to make.
Cerebellum
Medulla Oblongota
Controls skeletal muscle
Breathing centre of the brain.
coordination. Alcohol slows
Alcohol acts as a depressant
the coordination of the
and slows breathing rate
contracting and relaxing of
making it more difficult to
individual muscles in walking breathe
making it difficult to walk
straight
1 mark – identifying any two of the three parts above as parts of the brain that are affected by alcohol consumption
1 mark – describing how each part identified is affected by alcohol consumption based on the fact that humans lose
their ability to reason, walk straight, and breathe normally
20. Describe two differences between nerve responses and endocrine responses.
Answer:
Nerve Response
-Nerve responses are fast.
-Nerve responses require ions &
neurotransmitters.
-Nerve responses require the nervous
system to create responses.
-Nerve responses require a threshold to occur.
-Nerve responses are of a short duration.
-Nerve responses are direct from nervous
system to an effector.
Endocrine Response
-Endocrine responses are slower in
comparison to nerve responses.
-Endocrine responses require hormones.
-Endocrine responses require the circulatory system.
-Endocrine responses do not require any threshold value.
-Endocrine responses are longer lasting.
-Endocrine responses are indirect in that a second
messenger may have to be used or one gland has to
stimulate another gland to produce a response.
1 mark for each difference. If students made reference to one response but not the other, 0.5 marks were given.
For example, stating that “nerve responses require the use of the nervous system” but not following with the
other difference.
21. A person exhibits increased appetite, muscle weakness, increased metabolic rate, excessive heat production,
sweating and warm skin. What is the probable cause of this condition and give two ways it can be treated?
Excess secretion of thyroxin from the thyroid gland (hyperthyroidism) /Graves’ Disease
Methods of treatment
1. Surgically remove part of the thyroid gland.
2. Use anti-thyroid drugs to suppress the production of thyroxin.
3. Use radioactive iodine to help destroy an overactive area of the thyroid gland.
4. Injection of thyroid hormones.
5. Reduce iodinated salt in the diet.
22. Following a meal, blood glucose levels are monitored in two people over a period of 4 hours and the results
are graphed below. Which person has diabetes mellitus? Explain.
(need graph)
The student would have to state the following:
1. Person A
2. Person A’s blood glucose level is higher and remains higher than Person B over the four hour period.
3. Person A’s blood glucose does not return to a lower level after four hours in comparison to Person B. 3.0 %
The student chose Person A and then stated that Person A’s blood glucose was very high after eating and stayed
high for the whole time period. It did not return to normal. 2.5%
The student chose Person A and stated that person A had high blood glucose. 2%
Person A had diabetes. People with diabetes have higher levels of glucose in their blood after eating. There was
no reference to the graph or to Person A on the graph. 1.5%
The student chose Person A only or they spoke about the lack of insulin causing the problem. 1%
23.State one way prescription drugs can be beneficial to society and one way they can be harmful to society.
Beneficial
- Return to homeostasis using antibiotics drugs.
- Return to homeostasis or function better in society using drugs to treat
neurological disorders.
Harmful
- Abuse of narcotic prescription drugs.
- Increased crime for purchase of illegal drugs.
- Increased hospital admissions from overdoses/long term drug use.
- Resistance in bacteria by overuse of antibiotics.
1.5% Student chose one benefit or harm correctly but the other answer had vague references.
1%Student chose one benefit or harm correctly but had no other answer.
0.5%Student gave a vague answer relating to one of the benefits or harm to society.
24. Some cell phones have ring tones with high frequencies that can be heard by adolescents but not by older
adults.
i) Explain two biological reasons for this difference.

-Damage occurring to the cilia of the cochlea due to exposure to sound over many years, thus various
frequencies are not picked up (nerve deafness).
-Damage occurring to the ossicles or ear drum due to aging over time which does not allow sound to get
effectively to the choclea (conduction deafness).
0.5% for damage to cilia.
0.5% for stating that the frequencies were not being picked up.
0.5% for damage to the eardrum/ossicles.
0.5% for stating that the physical vibrations were not transmitted as well to the
cochlea.
ii) Most newer cell phones can be used as a personal listening device. Explain why the use of personal listening
devices, played at high volumes for prolonged periods, should be discouraged in adolescents?
Loud music from personal listening devices damages cilia in the cochlea or damage is done to the
eardrum/ossicles causing loss of hearing (conduction or nerve deafness).
0.5% for cause of damage due to loud sounds. Named the structures of the ear damaged.
0.5% for saying that the loud sounds caused hearing problems or deafness
25. The abuse of steroid hormones, such as testosterone, by athletes can lead to problems with homeostasis.
Explain how this abuse can have a negative impact on the body.
The abuse of steroids cause:
1. Decrease in sperm production
2. Shrinkage of the testicles
3. Prostate enlargement
4. Aggressive behaviour
5. Acne
6. Liver damage
7. Heart attacks due to over worked heart muscle
8. Changes in the menstrual cycle
9. Hair growth in females
10. Deeper voice in females
1% per cause listed above (any two for 2%).
Note: 0.5% for reference to negative feedback cycle
26. Describe two reasons for supporting or two reasons for opposing prescribing HGH to a normal adult who is
short in stature.
Answer with Marking Scheme and Explanation:
The individual should be given HGH because it will promote normal high and and thus reduce the stigma of
being below average high. The HGH will also help to ensure that the individual passes through puberty and
develops as a normal adult from a reproductive point of view.
Or
The individual should not be given HGH because it may promote acromegaly which promotes deformities that
are not desirable. The HGH may also function similar to prolactin which could cause over development of the
mammary glad and lead to lactogenesis.
Common Errors and Misconceptions:
Throughout this course students will deal with issues that have two sides. It is important that teachers discuss
both sides and question students on them. A common error with this type question is that students may only
know one reason for and one reason against and give both these reasons and expect full marks. They have not
recognized that this question is an either/ or question. Also, there are very many hormones in this unit and
students often get confused and overwhelmed by the amount.
27. John has a job working in a kitchen as a cook’s helper. He had to be rushed to the hospital because he
unknowingly placed his hand on a hot stove and did not pull it away. Identify three neurological reasons why
John did not withdraw his hand immediately.
Answer with Marking Scheme and Explanation:
John may be unable to withdraw the hand immediately because he may have damaged the receptor in the skin
of his hand at some previous time. He may be on a legal or illegal drug which prevents either the release or
block the absorption of neurotransmitters. He may have unknowingly been exposed to chemicals such
as concentrated pesticides which have done damage to the reflex arc. John may have damaged the association
neuron, this would prevent the impulse from being passed from the sensory neuron to the master neuron.
Common Errors and Misconceptions:
A common error with this type question would be to describe the actual functioning of the reflex
arc and not directly answer the question.
Student have to be aware that this question relates to problem with transmission, not the action.