This document provides possible questions and answers related to a scientific article on performance-enhancing drugs in sports. It includes 32 questions that could be asked, grouped by the paragraphs in the article they relate to. For each question, it lists the number of marks an answer would receive and provides example points that could be included in responses. The questions cover topics like the reasons athletes use performance-enhancing drugs, the classes of drugs and their effects, genetic engineering techniques, and the roles of various hormones and proteins in muscle growth and athletic performance.

1. BIO/A2 Unit 5 - Scientific Article June 2015
Possible Questions and Answers
These are some possible questions that could come up from the material in the scientific article.
There is some repetition of topics and so some questions will have similar answers.
The number of marks, in brackets after the question, indicates the detail required by the answer. Possible point s for
writing the answers are also provided.
General Question
(a) Give an ethical reason why athletes may use performance-enhancing drugs. (1)
o Athletes have a right to decide whether they take the drug or not in order to achieve the best performance
they can;
o Athletes have a right to decide if the benefit is worth the risk of their health;
o Athletes have a duty to the sponsors to perform at their best;
Paragraph 1 to 4 :
1. Mention three reasons for why athletes and sports people may take drugs (3)
• As medication for diseases ;
• To enhance performances ;
• As recreational activity
Paragraph 2 & 3 : (also mentioned in other paragraphs e.g. para 37 and 46)
2. Is it ethical to allow the use of performance-enhancing drugs in sports? What are some of the issues we have
to consider e.g. safety, costs, availability? Who is to blame if an athlete fails a drugs test? (minimum 4)
• Some of these issues are highlighted in the rest of the article. You should be able to produce
arguments for both sides of this issue.
• Why should we allow athletes to use performance-enhancing drugs and why should they be banned?
Paragraph 3:
3. List three different classes of performance-enhancing drugs and describe briefly how they act to enhance
athletic performance? (6)
Any three from:
• anabolic steroids – build muscle mass
• stimulants e.g. caffeine – increase heart rate to improve alertness
• beta-2 agonists – dilate airways, allowing more oxygen into lungs
• beta-blockers – slow down heart rate and reduce trembling
• hormones and their releasing factors – increase the effects of natural, endogenous hormones
• narcotics – allow athletes to ignore pain
diuretics – cause excess urination to eliminate drug traces in the urine
Paragraph 6:
4. How do anabolic steroids (steroid hormones) have an effect on cells? (5)
• hydrophobic/lipophilic
• cross the cell membrane
• bind to a receptor protein
• complex acts as a transcription factor
• binds to DNA/increases gene transcription
Paragraph 7:
5. Banned substances can include alcohol & caffeine above a certain level. Suggest ways how caffeine is used
as a stimulant (4)
Any 3 to 4 points
• Caffeine passes through the blood-brain barrier. , achieve their effects by imitating or altering the
release or uptake of neurotransmitters.
VIHS / Dept. of Biology / Page 1 of 10

2. • Caffeine achieves many of its effects by blocking the activity of adenosine, a neurotransmitter that
affects almost every bodily system. One of the primary actions of adenosine is to make us tired or
sleepy, caffeine, by blocking the uptake of adenosine, keeps us from feeling the effects of fatigue.
• By increasing the activity of acetylcholine, caffeine increases muscular activity and may also improve
long-term memory. By raising and adjusting serotonin levels, caffeine relieves depression, makes us
more relaxed, alert, and energetic, and relieves migraine headaches.
• The reason caffeine works so well as a stimulant for the nervous system is because it enters the
blood stream 15 minutes after it has been consumed and it takes the body 6 hours to eliminate half of
the caffeine.
• Another effect of caffeine is that it increases the level of dopamine. This neurotransmitter affects the
brain processes that control the ability to experience pleasure and pain. It is believed that the
increased levels of dopamine contribute to the addiction to caffeine.
• Once caffeine enters the blood stream via absorption in the stomach and small intestine, it inhibits the
action of the adenylyl cyclase enzyme. How does it do this? Caffeine is structurally similar to the
chemical adenosine. The caffeine molecules compete with adenosine for binding sites on the cell
surface. Thus the enzymes are not activated to break down cAMP; meaning that ATP is not converted
to glucose. With an increase of cAMP levels the heart prompts norepinephrine (noradrenalin) and the
neurotransmitter epinephrine to increase the rate and the force of the muscle contractions.
• The sympathetic nerves located near the pacemaker tissue in the heart release norepinephrine. The
pituitary gland releases hormones that activate the adrenal glands to produce epinephrine
(adrenaline). This chain of events produces the "fight or flight" behaviour in the body. This behaviour
increases the rate and force of the heartbeat and thereby providing the brain and other tissues with
more oxygen.
EXTRA INFORMATION
6. Beta-blockers are drugs that block the action of the sympathetic nervous system on the heart. Describe how
the resting heartbeat is coordinated within the heart. What would be the effect of an athlete using beta-
blockers? (5)
• SAN node generates the impulse to the atrial wall
• causes/depolarises atria
• atria contract/atrial systole
• (depolarisation reaches) AV node
• delay (to allow atrial contraction)
• excitation passes along Purkinje fibres/bundle of His
• ventricular contraction/systole
• diastole/relaxation
• (beta-blockers) slow down heart rate; relax the athlete
7. Differentiate between Beta–blockers and Beta-agonist (2)
o β-blockers block the β-adrenergic receptors & slows the heart rate & decreases BP;
o β-agonist- they mimic the action of β-blockers, either by binding to the receptors or binding to
adrenaline hence blocking their actions;
Paragraph 12
8. Athletes often suffer injuries & analgesics may be appropriate. Explain why uses of narcotic analgesics are
banned in sports?(3)
• Analgesics are used to relieve pain & narcotic analgesics are highly addictive,
• as the competitor does not feel pain at all, his behaviour changes as a risk to himself & other
competitors during the competition.
VIHS / Dept. of Biology / Page 2 of 10

3. Paragraph 14
9. What are the functions of tendons and ligaments? How are their structures/properties related to their
functions? Why might steroid injections weaken the ligaments or muscles? (3)
• tendons – join muscle to bones / inelastic / large amounts of collagen;
• function: do not stretch/transmit force of muscle contraction to skeleton
• ligaments – join bones to bones / more elastic / collagen and elastic fibres;
• function: stretch to allow a range of bone movements
• injections might weaken the fibre – snap under tension/when pulled/stretched
Paragraph 15
10. The main reason for wishing to use diuretics is to produce more dilute urine so that, illicit substances are not
detected. Diuretics is an antihypertensive drug, explain how it reduces hypertension.(3)
• They increase the volume of urine produced by kidneys & thus rid the body of excess fluid & salts.
• This leads to a decrease in blood plasma volume & cardiac output, which lowers BP
• Lowering the BP reduces the risk of CVD
11. If you were to analyse a muscle sample from a weight-lifter or a judo competitor, what type of muscle fibres
do you think would be more prominent? Why? What are the properties of these types of fibres? (4)
• fast-twitch /glycolytic fibres
• useful for fast, powerful muscle contractions (in judo etc)
• glycolytic (if not mentioned already)
• low levels of myoglobin
• less blood capillaries
12. ‘The main reason for wishing to use diuretics is to produce more dilute urine so that illicit substances are not
detected. For this reason they are banned’. However doctors prescribe diuretics as a control measure for
hypertension. Using your own knowledge, explain how diuretics reduce the risk of CVD. (3)
• Diuretics increase the volume of urine produced by the kidneys & thus rid the body of excess fluids &
salt;This leads to a decrease in blood plasma volume & cardiac out put, which lowers BP;
• Lowering BP reduces the risk of CVD;
Paragraph 17
13. ‘Anticholinergic agents block the action of acetylcholine’. Describe how acetylcholine is involved in synaptic
transmission of nerve impulses. How might anticholinergic agents interfere with the normal function of
acetylcholine? (5)
• Neurotransmitter / released from pre-synaptic neuron/synaptic bulb/knob
• by exocytosis
• diffuses across synaptic cleft/gap
• binds to post-synaptic receptors/neuroreceptors / causes sodium channels to open
• (anticholinergics) block binding of acetylcholine to receptor
• may bind to the receptor themselves
• may bind to acetylcholine and prevent it binding
• may cause increased acetyl cholinesterase activity
Paragraph 18
14. Beta-2 agonists cause hyperpolarisation of smooth muscle cell membranes. How might they achieve this? (3)
• bind to receptor protein (on membrane surface)
• cause opening of potassium channels
• cause opening of chloride channels
Paragraph 19
15. The haematocrit is the proportion of red blood cells in a blood sample. Why might a high haematocrit be
dangerous for an athlete? (2)
• may cause increased blood clotting
• resulting in stroke/heart attack etc
VIHS / Dept. of Biology / Page 3 of 10

4. 16. Mention three ways to achieve a high haematocrit that enhances performances in endurance events.(3)
• Training at altitude in a low pO2;
• Blood doping;
• Using recombinant erythropoietin;
17. The production of recombinant human erythropoietin is currently being investigated using transgenic sheep.
The human erythropoietin will be secreted into the sheep’s milk and purified. Explain how such an animal
could be produced. (5)
• isolate gene for human erythropoietin / using restriction enzymes
• place into a vector / virus/liposomes/microinjection/plasmid
• insert gene into zygote/fertilised egg of sheep
• use of promoter to ensure gene expression
• use of marker gene to select cells containing vector
• embryo implanted into uterus of surrogate ewe/adult female sheep
Paragraph 21
18. With reference to the structure of skeletal muscle, in what way could anabolic steroids affect muscle so as to
“promote muscle growth”? (3)
• idea of increasing synthesis of muscle proteins e.g. myosin, actin, tropomyosin, troponin
• by changing gene expression
19. Describe how anabolic steroids could lead to changes in protein synthesis (4)
• hormones are hydrophobic/lipophilic
• diffuse through cell membrane
• bind to steroid hormone receptors in cytoplasm
• steroid: receptor complex diffuses into the nucleus
• binds DNA
• acts as a transcription factor
• changes gene expression
20. What is atherosclerosis? What could be the consequences of developing this condition? (3)
• hardening of the artery walls / due to accumulation of fats/cholesterol
• following damage to the endothelium/lining of the artery
• presence of macrophages /foam cells
• inflammation/ formation of an atheroma or plaque
• narrowing of the lumen of the artery / increased blood pressure
• risk of blood clotting
Paragraph 24
21. SERMs are drug molecules that bind to the oestrogen steroid hormone receptor. What effects would this have
in the cell? (2)
• block the effects of oestrogen/stop oestrogen binding to the receptor
• stop transcription of oestrogen-sensitive genes
Paragraph 26
22. Describe how peptide hormones act on target cells (4)
• hormones bind to a receptor on the cell surface membrane
• (receptor is an) integral or transmembrane protein
• hormone binding causes the receptor to become activated
• causes production of a second messenger in the cytoplasm/changes to molecules in the cytoplasm
• leads to activation of transcription factors in the nucleus
• causes transcription of target genes
VIHS / Dept. of Biology / Page 4 of 10

5. 23. In 1989 the medical commission of International Olympic Committee (IOC) introduced the new doping class of
peptide hormones & analogues. Peptide hormones act as DNA transcription factors to switch on particular
genes, Explain how?(4)
• peptide hormones bind on the surface membrane of target cells
• activate the secondary messenger which in turn causes a series of enzyme controlled kinase/
(adenyl cyclase )cascade events to occur
• in which transcription factor is formed & transcription factor enters the nucleus to switch on specific
genes (required for the intended protein)
• Transcription of DNA to mRNA & the mRNA gets translated into protein which can fold into a tertiary
structure to become an enzyme of any protein with a specific function.
24. Human Chorionic Gonadotropin (hCG), is a peptide hormone. Transcription factors bind to promoter region
forming transcription initiation complex, switching on a gene. Illustrate using a flow chart, how a peptide
hormone could induce production of testosterone in a female. (4)
Paragraph 29
25. Proteins such as recombinant human growth hormone can be made in large quantities using bacteria and
simple genetic engineering techniques. Describe you would produce this recombinant protein in bacteria (5)
• isolate the human gene/DNA for human growth hormone from human cells/DNA
• using restriction enzymes/endonucleases
• add to a plasmid/vector / using DNA ligase
• add recombinant plasmid to bacterial cells/transform bacterial cells with the recombinant plasmid
• grow bacterial cells (in a fermenter)
• purify protein from bacterial cells/split open cells and extract the growth hormone
Paragraph 30
26. What is “homeostasis”? If GH has the opposite action to insulin, with respect to glucose homeostasis,
describe how the body can use these hormones in glucose homeostasis. (4)
• homeostasis = maintenance of a constant internal environment
• if blood glucose increases: insulin released from pancreas (beta cells)/Islets of Langerhans
• causes conversion of glucose to glycogen in liver and muscle
• if blood glucose decreases: GH released (from anterior pituitary gland)
• causes conversion of glycogen to glucose in the liver/muscle
Peptide hormone binds to surface
membrane receptors
ATP converted to cAMP by
adenyl cyclase
cAMP the second messenger
activates the cascade of events of
to activate transcription factors
VIHS / Dept. of Biology / Page 5 of 10

6. 27. Using the knowledge of negative feedback mechanism, describe and explain the role of insulin in blood
glucose regulation. (3)
• Stimulates the uptake of glucose by cells;
• Helps liver cells convert glucose to glycogen & store;
• Thereby reducing the high level of blood glucose;
Paragraph 31
28. Describe how gene doping for insulin growth factor 1 could be carried out on human athletes. (4)
• isolate the human insulin growth factor 1 gene/DNA
• using restriction enzymes/endonucleases
• use a vector/virus/injection
• introduce DNA into athlete’s cells/body
29. The potential for gene doping would be to inject ‘normal’ genes into the body to increase the functioning of a
‘normal’ cell. Explain briefly how a ‘normal’ cell would transform into a cancerous cell. (3)
• Mutation/ changes in bases of DNA;
• Oncogenes stimulated;
• Tumor suppressor gene deactivated;
Paragraph 39
30. Briefly elicit the functions of World Anti-Doping Agency, WADA. (1)
• Coordinating and monitoring the global fight against doping in sports
31. A mutation in the EPOR gene is thought to cause increased cell division in the blood cells that will
differentiate to form red blood cells. Describe the sequence of events that occurs when cells divide in this
manner. How this cell division is usually controlled? (5)
• DNA is replicated/copied
• DNA/chromatin condenses/chromosomes become visible
• nuclear envelope and nucleolus disappear
• centrioles divide and migrate to opposite sides/poles of the cell
• spindle fibres/microtubules are produced
• microtubules attach to chromosomes/centromeres
• chromosomes line up on the equator of the cell
• sister chromatids are pulled apart (as microtubules contract/shorten)
• nuclear envelope reforms
• chromosomes decondense/chromatin forms
• controlled by cyclins and cyclin-dependent kinases
• form checkpoints for the cell cycle
32. Describe how a mutation in EPOR gene could lead to production of more RBCs than normal in the body. (3)
• Mutation causes changes in bases coding for EPOR gene;
• Change in mRNA codon leading to change in protein formed ;
• More RBC are made as a change in the function of cell;
Paragraph 41
33. What is a “fast-twitch muscle fibre”? Why would the lack of a protein from fast-twitch muscle fibres be a
disadvantage for sprinters? (4)
• glycolytic fibre / function anaerobically/ fatigue quickly
• poor blood supply/ low levels of myoglobin
• few mitochondria/ rich glycogen stores
• high levels of creatine phosphate
• many myofibrils
• fast twitch muscle fibres are useful for powerful contractions over short periods of time
VIHS / Dept. of Biology / Page 6 of 10

7. 34. For instance ,1 in 5 Europeans cannot produce the alpha- actinin -3 protein found in fast twitch muscle fibres
Differentiate between fast twitch and slow twitch muscle fibres.(3)
35. Thin lower legs which weigh less helps save energy in distance sports. Describe the role of ETC in
generating energy required during endurance sports.(5)
• The role of electron transport system is to produce a proton gradient across a membrane.
High energy electrons are donated to 2 of the 4 complexes in the electron transport system.
• The electrons are then transferred from one protein or complex to the next, and in each transfer, some of the
electron's energy is released.
• The released energy is used to pump protons across the membrane unidirectional, against their concentration
and electrical gradients.
• Once on the other side of the membrane, the protons cannot diffuse back across the membrane because they
are charged - so they accumulate on one side.
• This creates an electrochemical proton gradient across the membrane, which is a form of potential energy,
• Within the inner membrane is a complex known as the ATP synthase complex.
• This complex acts as a channel in which protons flow back into the mitochondrion.
• it is this stored energy that is actually used to synthesize ATP from ADP and iP. This process is called
chemiosmosis
• So the ETC's main role is producing ATP for energy.
36. In 1989 there were 1,723,913 children born in Europe. 1 in 5 European cannot produce alpha-actin-3 protein
found in fast twitch muscle. Calculate the number of children born with this condition. Show your working. (2)
1/5 * 1,723,913 = 344782.6
Answer: 344783
37. He has a mutation in a gene called EPOR that means he produces up to 50% more red blood cells than
normal. Explain what is meant by the term mutation in a gene.(2)
• Any change in the normal sequence of bases in a gene by addition, deletion or substitution of bases,
which results in the mRNA transcribed to be different,
• and leads to translation of a different protein with different function.
38. ‘The East African runners who dominate distance events have also been shown to have at least one genetic
advantage: their lower legs are thinner and weigh on average 400 grams less than those of Danish athletes,
which translates into a massive 8 percent energy saving. Other people have distinct genetic disadvantages.
Using your own knowledge of natural selection, describe the events that lead to this genetic advantage of
East African runners. (4)
• Variation (in energy saving ability in muscles) present originally; [must be explicit, not just implied]
• (Variation) due to mutation; [CONTEXT . not caused by environment]
• Better adapted alleles are selected due to selection pressures
• Not advantageous alleles are eliminated;
• Pass on (relevant) allele / gene to offspring;
• Increasing frequency of appropriate allele in east African runners than Danish athletes;
VIHS / Dept. of Biology / Page 7 of 10

8. Paragraph 47
39. Describe how it would be possible to use gene therapy to introduce a desirable allele of a gene for a muscle
protein into one of the muscle cell. (4)
• isolate the human gene/DNA for the muscle protein
• using restriction enzymes/endonucleases
• use a vector/virus/injection
• introduce DNA into athlete’s cells/body
40. Describe how the muscle proteins work together to achieve contraction of the muscle. (9)
• calcium ions bind to troponin
• bind causes troponin to change shape
• change in shape cause it to pull tropomyosin away from myosin-binding sites on actin fibres
• myosin (heads) bind to actin/(actomyosin) cross-bridge formed
• ADP and Pi are released from myosin head
• myosin head changes position, pulling past the actin fibre
• ATP binds myosin and allows release from actin fibre
• ATP hydrolysed by myosin ATPase, producing ADP and Pi
• returns myosin head to its original position
41. In the not too distant future , gene therapy could be used to boost the strength of muscles .Explain the
meaning of the term gene therapy.(2)
• Gene therapy is an technique that uses genes to treat or prevent disease. In this technique doctors
treat a disorder by inserting a gene into a patient’s cells instead of using drugs or surgery.
• Several approaches to gene therapy, includes
 Replacing a mutated gene that causes disease with a healthy copy of the gene.
 Introducing a new gene into the body to help fight a disease.
 Inactivating, or “knocking out,” a mutated gene that is functioning improperly.
42. * Using information from paragraph 47 and your own knowledge, describe how tools and techniques of gene
therapy could be used to boost the strength of muscles in sprinters. (5)
• Gene therapy involves
• Isolating the gene;
• Purifying and cutting the gene using restriction enzymes;
• Amplifying the gene using PCR;
• Separating the gene fragments using electrophoresis;
• Make recombinant desired gene using ligase and endonuclease;
• Introduction of recombinant gene into a host using vector like virus, plasmid, liposome;
• Introduction into host by tools like electroporating / shot gun / virus DNA;
• Gene should be integrated into the non-coding regions of DNA;
• Gene is transcribed & translated & protein is made;
Paragraph 50
43. What is the role of creatine in a muscle cell? Why would an athlete want to achieve higher creatine levels in
their muscles? (3)
• stored as creatine phosphate
• allows production of ATP from ADP
• creatine transfers phosphate group to ADP
• high levels of creatine will allow more creatine phosphate to be formed
• allowing more ATP production
VIHS / Dept. of Biology / Page 8 of 10

9. Paragraph 52
44. Dehydration resulting from exercise makes matters even worse. Describe how too much exercise could
results in dehydration of the body.(3)
• During exercise, a lot of heat is generated in the body,
• as a result of increased metabolic activity , which is detected by the thermo-receptors in the body ,
• sent to thermoregulatory centre -the hypothalamus which stimulates the sweat glands to secrete
sweat to cool the body by evaporation of sweat.
• This cooling process results in decrease of body fluids causing dehydration of the body .
45. There is only one reason athletes consume lots of creatine or if they rich enough train at high altitude to
enhance performances. Explain why the governing bodies of sports allow the use of creatine to enhance the
performance.(1)
o Because creatine is found normally in the body & levels of creatine can be increased by natural ways
(hard training/at high altitude)
EXTRA INFORMATION
DRUGS IN SPORTS
VIHS / Dept. of Biology / Page 9 of 10

10. Performance enhancers, Examples of prohibited performance enhancers for which athletes have been banned
Name Effects Unwanted effects
Anabolic androgenic steroids Increased muscle growth; increases red Decrease in endogenous sex hormones;
blood cell production acne; temporary infertility rarely, increased
aggression; ventricular hypertrophy; liver
damage ,virilisation in females; testicular
atrophy and gynaecomastia in males;
increased risk of prostate cancer
Human recombinant erythropoietin (EPO) increased red blood cell production can increase blood viscosity to dangerous
,darbepoitin (increases performances in endurance levels in very high doses , increasing risk of
sports) stroke or heart attack
Some stimulants (Mesocarb, Bromantan , Increased alertness and reaction time; Cardiovascular stress, increased risk of
Etilefrine , Ephedrine , Amphetamine , Increased stamina ; increased confidence psychosis(amphetamine); cardiac arrhythmia
Cocaine, Adrenaline (new in 2006) insomnia, bradycardia, tachycardia, anorexia
Enhancement of oxygen transfer – increased red blood cell count Risks identical to EPO or hypoxic training
Blood doping, perfluorochemicals
Cannabinoids such as THC None known – likely to decrease None Known
performance
Examples of legal performance- enhancers
Name Effects Unwanted effects
Creatine Improves time to exhaustion in anaerobic may lead to muscle cramping
exercise .Faster recovery from training
Caffeine Assists mobilization of fat stores, during Insomnia , tachycardia , gastrointestinal
exercise, improving time to exhaustion; complaints, increased blood pressure (high
assists alertness and concentration , doses); withdrawal symptoms include
especially on repetitive motor tasks headache and fatigue
Hypoxic /altitude training increases endogenous EPO boosting the Excessive use can increase blood
production of red blood cells viscosity to dangerous levels in some
individuals
Some stimulants –pseudoephedrine, Increases alertness and concentration Carcinogenic( cigarettes); increased
narcotine,buproprion , pipradrol stroke risk , insomnia , tachycardia, anorexia
(Pipradrol, pseudoephedrine)
LASIK eye surgery Improves eyesight some risk of vision damage during surgery
Note: Supplement to this article is uploaded on dhasvehi. Please go through it. All the Best
VIHS / Dept. of Biology / Page 10 of 10