5.4 Hormonal ntrol OCR ExamBuilder

Answer all the questions.

1. Which of the following is / are interventions in the control of blood glucose concentration?

Statement 1: Insulin injection.

Statement 2: Regular cardiovascular exercise.

Statement 3: Glucagon injection.

A 1, 2 and 3

B Only 1 and 2

C Only 2 and 3

D Only 1

Your answer

[1]

2. The following are statements about the liver:

1 stores bile in the gall bladder

2 contains sinusoids

3 receives blood from the gut and heart

Which of these statements relate to the exocrine function of the liver?

A 1, 2 and 3

B Only 1 and 2

C Only 2 and 3

D Only 1

Your answer

[1]

3. The graph below shows the change in glucose concentration in a rat's bloodstream over a short period of time.

Which of the statements, A to D, is correct?

blood glucose concentration at 15 min > blood glucose concentration at 20 min

blood glucose concentration at 9 min << blood glucose concentration at 20 min

blood glucose concentration at 0 min < blood glucose concentration at 40 min

blood glucose concentration at 5 min >> blood glucose concentration at 28 min

Your answer

[1]

4. The following terms relate to the metabolism of carbohydrates in the human body:

1 gluconeogenesis

2 glycogenesis

3 glycolysis

Which of these processes will be stimulated when glucagon is released into the bloodstream?

A 1, 2 and 3

B Only 1 and 2

C Only 2 and 3

D Only 1

Your answer

[1]

5(a). During pregnancy, the hormone human chorionic gonadotrophin (hCG) is produced by the placenta. Fig. 16.1

shows how levels of hCG change throughout pregnancy.

Describe the trends shown in Fig. 16.1.

[4]

(b). At birth, the production of another hormone, oxytocin, increases. Oxytocin causes rapid contractions of the

uterus. These contractions cause more oxytocin to be released.

What term is used to describe this kind of interaction?

[1]

(c). 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?

[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]

(d). A hydatidiform mole is a rare complication of pregnancy that can occur after implantation of the fertilised egg in

the uterus. It results in excessive production of hCG and damage to the lining of the womb, leading to

miscarriage.

Suggest how a hydatidiform mole could increase hCG above normal levels.

[3]

6(a). Birds and humans have similar pancreas tissues, with the same cell types contributing to exocrine and endocrine

roles.

(i) Fig. 21.1 shows a transverse section of pancreas tissue from a bird.

Select which letter identifies the following structures:

islet of Langerhans

[1]

acinus

[1]

(ii) Fig 21.2 shows a high-power image of cells from the pancreas.

In the space provided below draw five adjacent cells, annotating them to show visible features.

[5]

Fig 21.1

Fig 21.2

(b). Table 21.1 gives some information about the hormones produced by the different regions of the adrenal gland.

Complete the table to include the correct region, hormone and role.

Region of adrenal gland Hormone produced Role of hormone in body

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ aldosterone

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

medulla _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ Increases heart rate.

Stimulates glycogenolysis.

Table 21.1

[2]

(c). * Growth hormone (GH) is a peptide hormone that stimulates cell reproduction and regeneration in humans and

other animals. It is produced during development to increase muscle mass and increase bone size and density.

GH can also be used in farming to enhance yields from different animals.

Design an experiment to investigate the following hypothesis:

"Varying the concentration of GH injected affects the yield of meat from farmed

chickens"

You must explain how you would obtain valid data.

[9]

7(a). The rhythm and rate at which a human's heart beats can be determined by several factors.

Fig. 5.1 shows electrocardiogram traces (ECGs) from two different individuals, X and Y.

Draw an ECG trace on Fig. 5.1 (next to Z) to represent a recording from a patient with an ectopic heartbeat.

Show at least three cardiac cycles.

[2]

(b). Heart rate can be increased by the hormone adrenaline, which binds to cardiac cells.

Describe how adrenaline binds to cardiac cells.

[2]

8(a). The figure represents a cross-section of part of the pancreas.

(i) Name the group of cells that include the cell labelled C.

[1]

(ii) Identify the structure labelled D.

[1]

(b). The figure shows the concentrations of glucose and insulin in the blood of an individual before and after a meal.

(i) After the meal, the concentrations of glucose and insulin in the blood increase.

Explain why there is a delay in the increase of insulin concentration following the increase in blood glucose

concentration.

[2]

(ii) The shaded parts of the graph are over-simplified representations of the blood glucose and insulin

concentrations.

Describe and explain how these concentrations should be represented on the graph accurately.

In your answer, you should use appropriate technical terms, spelled correctly.

[4]

(c). The published Glycaemic Index value (GI) of a carbohydrate-containing food, rates the food on a scale from 0 to

100 according to how much it raises blood glucose concentration after it is eaten.

To determine the GI value of a test food:

10 healthy people fast overnight

the test food containing 50 g of carbohydrate is eaten

blood samples are taken every 15 minutes for the next two hours and blood glucose concentrations are

measured

a value known as the iAUC is obtained from these measurements

the GI value is calculated by dividing the iAUC for the test food by the iAUC for glucose and multiplying by

100

the mean of the GI values from all 10 people is the published GI value for that food

(i) Why is it necessary for the people to fast overnight before the start of the test?

[1]

(ii) The iAUC for glucose is used to calculate the GI value of the test food. For this calculation to be valid, a

number of variables must be controlled when determining the iAUC for glucose.

Suggest two variables and how they may be controlled.

[2]

(iii) Why does the procedure use the mean of the GI values to obtain the published GI value for the food?

[1]

9. 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]

10(a). A doctor arranged for a 59-year-old patient to have a series of blood tests. One of these tests was to determine

the patient’s ‘fasting blood glucose’ concentration.

The result of this test indicates whether or not the patient’s blood glucose concentration is being regulated

within the normal range.

The validity of the result relies on the patient not having eaten for at least eight hours before the test.

The patient confirmed to the doctor that he had not eaten since the previous evening.

(i) What condition was being tested for in this 59-year-old patient?

[1]

(ii) Why was it important that the patient had not eaten for at least eight hours before the test?

[1]

(iii) The result of the patient’s fasting blood glucose test was 7.0 mmol dm

−3

The upper limit for ‘normal’ blood glucose concentration is considered to be 5.9 mmol dm

−3

Calculate the percentage by which this patient’s blood glucose concentration is higher than the upper limit for

normal concentration.

Show your working. Give your answer to one decimal place.

Answer = _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ % [2]

(b). The patient was sent for a further blood test, known as the haemoglobin A1C (HbA1C) test.

Glucose combines with haemoglobin in the bloodstream to form a 'glycosylated haemoglobin' molecule,

HbA1C.

The concentration of HbA1C is directly proportional to the mean concentration of glucose in the blood over

an eight to twelve week period.

Suggest why a single HbA1C test cannot indicate accurately the mean blood glucose concentration for a period

longer than twelve weeks.

[2]

(c).

The result of the patient’s fasting blood glucose test showed a blood glucose concentration higher than the

normal range even though the patient had not eaten food for at least eight hours before providing a blood

sample.

The result of the patient’s HbA1C test indicated that his mean blood glucose concentration had been within the

normal range for the previous eight to twelve weeks.

Suggest an explanation for the patient’s high value for the fasting blood glucose test.

[1]

(d). Another patient shows severe symptoms of unregulated blood glucose concentration. Under certain

circumstances this condition may need to be treated with glucagon injections.

(i) Under what circumstances might this patient need to be given a glucagon injection?

[1]

(ii) Describe how glucagon is involved in the regulation of blood glucose concentration in a person who is able to

regulate their blood glucose concentration correctly.

In your answer, you should use appropriate technical terms, spelled correctly.

[5]

11(a). 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]

(b). Insulin is secreted from the beta cells of the pancreas in response to increased blood glucose concentration.

Fig. 2.1 is a diagram representing the sequence of events leading to the secretion of insulin from the beta cell.

(i) With reference to Fig. 2.1, describe the events occurring at the stages labelled 1 to 4.

[4]

(ii) After the initial release of insulin from the beta cell, insulin secretion continues even when there is no further

glucose intake.

Suggest and explain why the cell continues to secrete insulin.

[2]

12(a). Stem cell therapy is a potential future treatment for diabetes mellitus.

Stem cells were extracted from the bone marrow of 131 patients with diabetes mellitus. Each patient received an

implantation of their own stem cells.

Following the stem cell treatment:

53 patients showed no change

78 patients showed an improvement in their condition.

Suggest three additional pieces of information that would be needed to assess the effectiveness of the stem cell

therapy.

[3]

(b). In the future, it might be possible to differentiate stem cells in a laboratory (in vitro) before they are implanted into

the pancreas of a patient with diabetes.

(i) Name the type of differentiated cell that scientists would produce from stem cells in order to treat diabetes

mellitus.

[1]

(ii) Which type of diabetes mellitus is most likely to be improved by stem cell therapy?

Explain your answer.

[2]

(c). The blood glucose concentration of a diabetes patient was measured on five separate occasions.

The five measured values (in mmol dm

−3

) were 8.7, 8.7, 9.0, 9.0 and 10.9.

(i) Using the formula below, calculate the standard deviation of the patient's blood glucose concentration.

n = number of samples

x = each value in the data set

= mean

Answer _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ [3]

(ii) Explain why standard deviation is better than range for measuring the dispersion of these data.

[2]

(iii) Scientists compared the blood glucose concentrations of two diabetes patients:

a patient who had received stem cell therapy

a patient who had received no stem cell therapy.

Describe two aspects of the experimental design that the scientists would need to consider in order to

produce a valid comparison of the two patients.

[2]

END OF QUESTION PAPER

Mark Scheme

1 D 1

Total 1

2 D 1

Total 1

3 B 1

Total 1

4 D 1

Total 1

5 a any 4 from:

no production of hCG, until 4 weeks / AW

(1)

rapid increase / high gradient, until 8

weeks (1)

idea that rate of decline, is less than

increase after 8 weeks (1)

levels peak at 8 weeks (1)

levels fluctuate / not constant, after 19

weeks (1)

idea that levels remain similar after 19

weeks (1)

use of comparative figures to illustrate any

point with units (1)

4 All points with dates underlined must have

exact wording to achieve mark

ALLOW hCG production starts at 4 weeks

/ is undetectable until 4 weeks

ALLOW ‘fluctuation’ / AW

DO NOT ALLOW ‘plateau’

b positive feedback 1

c i (hCG is a) peptide hormone / hCG is not a

lipid-based hormone (1)

(hCG) binds to cell surface receptor (1)

idea that cell signalling is involved in action

of hCG (1)

(hCG) uses cAMP / second messenger, to

bring about response in cell (1)

ii DNA / deoxyribonucleic acid 1 ALLOW transcription(al) factor / repressor

protein

DO NOT ALLOW RNA / histone / DNA

polymerase

Question Answer/Indicative content Marks

Guidance

Mark Scheme

d idea that (hydatidiform mole) cells produce

more hCG than normal (1)

(due to) expression / up regulation, of

genes (1)

synthesising more, hCG / protein(s) (1)

idea that other tissues could be stimulated

to produce more hCG than normal (1)

3 Cannot be inferred from other mark points

ALLOW stimulates, mitosis in /

proliferation of, cells that secrete hCG

ALLOW idea that hydatidiform mole

inhibits / competes with another molecule

that would otherwise regulate the

production of hCG

Total 12

Question Answer/Indicative content Marks

Guidance

Mark Scheme

6 a i A

ii five cells drawn adjacent to each other

AND

clear continuous lines (1)

correct proportions (1)

uses ≥50% of area provided (1)

annotations:

label lines drawn with a ruler to correct

feature (1)

cell membrane

AND

nucleus

AND

cytoplasm labelled (1)

comparative colour of any of above

mentioned (1)

5 DO NOT ALLOW cells separated by gaps

DO NOT ALLOW more than five cells

DO NOT ALLOW ragged lines / any

shading

ALLOW if it is clear which cells the

candidate has attempted to draw

IGNORE any annotations not mentioned

here

DO NOT ALLOW arrow heads

ALLOW implied comparison from different

colours

NOTE:

= 3 marks (MP2, 3 and 6)

b One mark per correct row 2

ALLOW epinephrine / noradrenaline /

norepinephrine

Question Answer/Indicative content Marks

Guidance

Mark Scheme

c * Read through the whole answer from

start to finish, concentrating on features

that make it a stronger or weaker answer

using the indicative scientific content as

guidance. The indicative scientific content

indicates the expected parameters for

candidates' answers, but be prepared to

recognise and credit unexpected

approaches where they show relevance.

Using a ‘best-fit’ approach based on the

science content of the answer, first decide

which set of level descriptors, Level 1,

Level 2 or Level 3, best describes the

overall quality of the answer using the

guidelines described in the level

descriptors in the mark scheme.

Once the level is located, award the higher,

middle or lower mark.

The higher mark should be awarded

where the level descriptor has been

evidenced and all aspects of the

communication statement (in italics) have

been met.

The middle mark should be awarded

where the level descriptor has been

evidenced but aspects of the

communication statement (in italics) are

missing.

The lower mark should be awarded where

the level descriptor has been evidenced

but the communication statement (in

italics) has not been met.

In summary:

The science content determines the

level.

The communication statement

determines the mark within a level.

Level 3 (7–9 marks)

A full and detailed method is provided

which would allow valid comparisons and

data to be collected. There is a detailed

9 Indicative scientific points may

include…

Independent variable – concentration

of GH injected

Dependent variable – rate of growth

Control variables – animal species,

foodstuff, (named) conditions

Trial populations over several months

Control group to ensure validity of

conclusions

Method for assessing growth – e.g. %

mass change or growth rate to allow

comparability

Different species of chickens should be

investigated

Ensure food is consistent across all

trial groups

Sample size needs to be large enough

to reduce effect of anomalies

Ethical concerns – chickens should be

reared in humane conditions

Consideration of potential negative

effects on chickens, e.g. larger muscle

mass, so may be unable to move as

easily

Question Answer/Indicative content Marks

Guidance

Mark Scheme

explanation of the variables to be changed

and measured, and how this could

realistically be attempted in the scenario

provided, along with detailed information

about which variables need to be

controlled. There is an appreciation of

ethical concerns involved OR an

appreciation of the sample size required to

obtain repeatable data and to rule out

anomalies.

There is a well-developed line of reasoning

which is clear and logically structured. The

method is detailed and clearly argued.

Level 2 (4–6 marks)

A detailed method is provided which would

allow valid comparisons and data to be

collected. There is an explanation of the

variables to be changed and measured,

and how this could be attempted in the

scenario provided, along with information

about which variables need to be

controlled. There is mention of the sample

size required to obtain representative data.

There is a line of reasoning presented with

some structure. The method has some

detail.

Level 1 (1–3 marks)

A limited method is provided which may

allow valid comparisons and data to be

collected. There is some explanation of the

variables to be changed and measured,

and how this could be attempted, along

with limited information about which

variables need to be controlled. Possible

consideration of the sample size required

for representative data is included.

There is a logical structure to the answer.

The explanation, though basic, is clear.

0 marks

No response or no response worthy of

credit.

Total 9

Question Answer/Indicative content Marks

Guidance

Mark Scheme

7 a three cardiac cycles drawn (1)

second cardiac cycle closer to the first

cycle than the third cycle (1)

abnormal QRS in second cycle (e.g.

extended peak or lack of T phase) (1)

2 e.g. 2 marks for

b (binds to) receptor in, cell surface / plasma,

membrane (1)

glycoprotein (1)

Total 4

Question Answer/Indicative content Marks

Guidance

Mark Scheme

8 a i

islet(s) of Langerhan(s);

1 Mark the first answer. If the answer is

correct and an additional answer is given

that is incorrect or contradicts the correct

answer then = 0 marks

ACCEPT α and β / alpha and beta, cells

DO NOT CREDIT a / b / A / B , cells

DO NOT CREDIT acinar cells

Examiner's Comments

Most candidates correctly identified the

islets of Langerhans. Some candidates,

however, mentioned only alpha or beta

cells (although had both been mentioned

the mark would have been awarded).

erythrocyte / red blood cell;

1 Mark the first answer. If the answer is

correct and an additional answer is given

that is incorrect or contradicts the correct

answer then = 0 marks

IGNORE RBC

IGNORE ref to blood vessel

Examiner's Comments

Erythrocytes were commonly seen,

although some candidates identified a

blood vessel instead.

Question Answer/Indicative content Marks

Guidance

Mark Scheme

b i

1 increase (in blood sugar) is detected (by

α cells);

2 idea that takes time for depolarisation (in

α cells);

3 time needed for αcells to, produce /

release, insulin;

2 max DO NOT CREDIT ‘B’ or ‘b’ cell on first

occasion then apply ecf

A description of a sequence of events

provides a timeline

2 time for making sure that there is enough

ATP / ion channels open / to pump out K

for Ca

to enter

3 DO NOT CREDIT ref to α cell(s)

Examiner's Comments

Poor communicators were not able to

convey the idea of a timeline as the

account was muddled. Some excellent

accounts were seen, however, although

many went into excessive descriptions

about the mechanism of secretion of

insulin that the mark tariff did not warrant.

Some otherwise good answers failed to

mention that insulin was secreted by the

beta cells or that they were also

responsible for detecting the increased

glucose levels.

1 there should be no straight line(s) (on the

graph)

line(s) (should), rise and fall / fluctuate;

2 glucose and insulin levels fluctuate;

3 insulin levels (should) rise (and fall) after

those of glucose;

4 (glucose) level, maintained around /

returned to, the norm(al) / a set point / a

set value;

5 ref to negative feedback / homeostasis;

3 max DO NOT CREDIT in the context of eating a

meal

2 Must be a statement that implies both

levels change

4 CREDIT ‘within narrow limits’ / ‘relatively

constant’

IGNORE optimum

CREDIT maintained at, 80 – 120 mg

100cm

–3

/ 4 – 6 mmol dm

–3

for the glucose

value

Question Answer/Indicative content Marks

Guidance

Mark Scheme

ii QWC; 1 Award if 3 of the following terms have been

used in a correct context with correct

spelling:

set (point / value) norm(al)

negative feedback homeostasis

Examiner's Comments

This was challenging for many candidates.

Some just referred to axis labels and

scales but others attempted to describe the

way in which the lines should have been

portrayed. It was all too tempting for many

candidates to refer to what was happening

before, during and after a meal and they

then launched into details of insulin and

glucagon and their effects on the cells.

Few conveyed the idea that the fluctuation

of the blood glucose and insulin

concentrations were out of phase. The

Quality of Written Communication mark

(QWC) was rarely awarded.

c i to ensure that the (blood) glucose, is at its,

base (level) / low (level) / normal (level);

1 ACCEPT ‘sugar’ instead of ‘glucose’

ACCEPT to make sure that the glucose

(level) is not, raised / high

ACCEPT to make sure that the rise in

blood glucose is only due to the (tested)

food eaten

DO NOT CREDIT ref to no, sugar /

carbohydrate

Examiner's Comments

Most candidates appreciated that a base

blood glucose concentration was required.

Some did not get the mark as they referred

to glucose being broken down, the need to

remove all the glucose from the blood or

that the participants needed the same

blood glucose concentration at the

beginning of the test.

Question Answer/Indicative content Marks

Guidance

Mark Scheme

1 50 g of glucose must be used;

2 the data for glucose should be obtained

for the same (ten) people (to eliminate

differences between individuals);

3 same age / same age range (as people

in original test);

4 same gender balance (as in original test);

5 have the same level of activity (during

the test);

6 be at the same temperature;

7 don't eat or drink anything else (during

the test);

8 same, body mass / BMI;

2 max IGNORE ref to volume of blood taken or

where in the body it is taken from

IGNORE same number of people

1 CREDIT ref to same mass as test

carbohydrate

IGNORE amount

7 CREDIT ‘only drinks water’ (during the

test)

8 ACCEPT same weight

IGNORE same build

Examiner's Comments

This question referred to finding the iAUC

for glucose but many candidates

interpreted it as referring to the different

foodstuffs. The question also asked them

to indicate how the variables could be

controlled but a significant number just

stated the variables. Some felt that the

blood samples should have the same

volume or be taken from the same part of

the body. Consequently, this question

proved to be quite a good discriminator.

Question Answer/Indicative content Marks

Guidance

Mark Scheme

iii

1 (absorption / effect on blood glucose),

variable from person to person;

2 it reduces the effect of, outliers /

anomalous values;

1 max IGNORE ref to accuracy / precision /

reliability / validity

Examiner's Comments

A common misapprehension was that by

calculating a mean it would identify or

eliminate any anomalous results rather

than reducing the effect of an atypical

result or the risk of using a single

unrepresentative result. Some vague

answers and those quoting reliable,

accurate or precise did not score without a

more specific answer that related to the

question.

Total 12

Question Answer/Indicative content Marks

Guidance

Mark Scheme

9 i

False / F

True / T

True / T;;

2 All 3 answers correct = 2 marks

Any 2 answers correct = 1 mark

1 or 0 answers correct = 0 marks

Mark incorrect cells first

1 ✗ = 1 max

2 ✗ = 0 marks

Examiner's Comments

Candidates frequently scored 1 mark for

this question. The most common error was

to decide that the final statement was false.

1 idea that

(hormonal) stimulation of individual muscle

cells would result in uncoordinated

response

(hormonal) stimulation of SAN results in

coordinated action of the cardiac muscle;

2 idea that

(hormonal) stimulation of individual muscle

cells will not result in a change in heart rate

(hormonal) stimulation of SAN results in a

change in heart rate;

3 (as) (hormone) receptors only present

on the SAN / individual cells do not have

(hormone) receptors;

2 max hormone binds to / hormone acts on =

stimulation

e.g. coordinated action = both atria

contract together

Examiner's Comments

Candidates who simply described the role

of the SAN in coordinating and regulating

the rate of heart beat did not score as this

did not answer the question. Answers

needed to link this to the effect that

hormones would have on either the SAN or

individual cardiac muscle cells.

Question Answer/Indicative content Marks

Guidance

Mark Scheme

iii

1 adrenaline / first messenger / it, binds to

receptor(s) on cell surface membrane (of

SAN cell(s));

2 activates adenyl(yl) cyclase;

3 ATP converted to, cyclic AMP / cAMP

cyclic AMP / cAMP / second messenger,

synthesised;

4 results in depolarisation (of SAN cell

membrane);

2 max IGNORE ref to synthesis of glucose

1 CREDIT ‘plasma membrane’ or

‘plasmalemma’ for ‘cell surface membrane’

2 CREDIT ref to adenylate cyclase

3 DO NOT CREDIT in context of ‘wave of

depolarisation’

Examiner's Comments

Many knew this well, but a lack of precision

in expression meant that marks were not

awarded. They were expected to refer to

receptors on the cell surface membrane,

activation of adenylyl cyclase and the

formation of cAMP. The terms ‘activation’,

‘production’ and ‘synthesis’ seemed to be

used interchangeably, so not always

appropriately.

Total 6

Question Answer/Indicative content Marks

Guidance

Mark Scheme

10 a i 1 Mark the first answer. If the answer is

correct and an additional answer is given

that is incorrect or contradicts the correct

answer then = 0 marks

i diabetes (mellitus); 1 ACCEPT hyperglycaemia

IGNORE Type 1 or Type 2

DO NOT CREDIT hypoglycaemia

Examiner's Comments

Almost all candidates recognised that the

condition being tested for was diabetes

(mellitus).

ii idea that time needed, to restore normal

(blood) glucose concentration / for insulin

to act (fully);

1 Examiner's Comments

Few candidates were awarded this mark

as most were unable to grasp the idea that

time would be needed to for insulin to act

and reduce the concentration back to

normal levels. Most candidates stated that

a meal eaten within this time period would

affect the blood glucose concentration and

give an invalid result, which did not really

indicate why it was important to leave an

eight hour period before performing the

test.

Question Answer/Indicative content Marks

Guidance

Mark Scheme

iii 18.6; 2 Correct answer = 2 marks, even if no

working shown.

If answer is incorrect, then ALLOW 1

mark for seeing: 1.1 ÷ 5.9 or (7.0 – 5.9) ÷

5.9 or 118.6 or 118.64

If the answer is not correctly rounded to

1dp, then

ALLOW 1 mark for seeing a correct

unrounded answer e.g. 18.64

Examiner's Comments

Most candidates were able to calculate the

percentage by which the patient’s blood

glucose concentration was higher than the

upper limit for normal concentration,

achieving both marks. However, some

rounded up incorrectly, or gave an

incomplete answer of 118.6%. The

common error was to divide 1.1 by 7.0

instead of 5.9.

Question Answer/Indicative content Marks

Guidance

Mark Scheme

1 HbA1C / glycosylated Hb, contained

within, red blood cell(s) / erythrocyte(s);

red blood cells / erythrocyte(s), have

limited life span / live for 8 to 12 weeks

red blood cells / erythrocyte(s), break down

after, 12 weeks / 3 months;

3 HbA1C / glycosylated Hb, broken

down, in liver / by hepatocytes / by Kupffer

cells;

2 max CREDIT RBC / rbc for ‘red blood cell’

throughout

3 IGNORE ref to recycling

Examiner's Comments

Some candidates were able to gain a mark

for understanding that red blood cells

would only last for a maximum of 12 weeks

after which they would be replaced.

Candidates failed to gain credit for being

too vague, for example stating ’blood cells‘

rather than RBC's, and several referred to

‘haemoglobin’ rather than glycosylated

haemoglobin. Those candidates who did

mention HBA1C being broken down failed

to state that it was broken down in the liver.

Many candidates commented that eating

habits would vary during this period, with

different amounts of glucose being

consumed on different days, or varying

amounts of exercise, which might cause

the mean concentration to alter. Others

stated that a single test would not allow a

mean to be calculated or anomalous

results to be identified.

Question Answer/Indicative content Marks

Guidance

Mark Scheme

patient might have had a drink containing

sugar;

AVP;

1 max DO NOT CREDIT ref to having eaten (as

patient had confirmed that he had not

eaten)

CREDIT ref to a specific sugar-containing

drink

e.g.

patient was nervous and secreted

adrenaline

other medication interferes with

glucose levels

patient's haemoglobin does not bind

effectively with glucose (e.g. anaemia /

sickle cell)

Examiner's Comments

Few candidates made reference to the

patient having consumed a sugary drink,

although some mentioned that the patient

may have been nervous before the test so

secreted adrenaline. Many attempted to

answer the question by suggesting that the

body would carry out a physiological

response to a low blood glucose

concentration by stimulating the secretion

of glucagon which would then increase the

blood glucose level. Others suggested that

insulin may not have been able to reduce

the concentration following a meal,

although they had been told in the stem of

the question that the patient’s mean blood

glucose concentration had been within the

normal range for the previous 8 to 12

weeks.

Question Answer/Indicative content Marks

Guidance

Mark Scheme

d i 1 if blood glucose falls, extremely /

dangerously / too / very, low;

2 if patient, cannot produce (enough)

glucagon / produces little glucagon;

3 idea that glucose source cannot be taken

by mouth;

1 max 1 CREDIT hypoglycaemic / hypoglycaemia

IGNORE ‘below normal’ alone

2 CREDIT ref to dysfunctional, α cells /

glucagon receptors

3 CREDIT a suitable reason (e.g. fitting or

in a coma)

Examiner's Comments

Most candidates gained a mark in this

section for stating that the circumstance

under which the patient would need to be

given a glucagon injection would be a very

low blood glucose level. Some also

commented that the alpha cells may not be

functioning properly, resulting in an

inadequate secretion of glucagon. It was

insufficient to refer to ‘low blood glucose’ or

‘below normal blood glucose

concentration’.

Question Answer/Indicative content Marks

Guidance

Mark Scheme

ii when blood glucose concentration

decreases

1 (glucagon) released by the, alpha / α,

cells in, islets of Langerhans / pancreas;

2 promotes / AW, conversion of glycogen

to glucose / glycogenolysis, in, liver /

muscle / effector, cells;

3 ref gluconeogenesis / described;

4 ref conversion of triglycerides to (free)

fatty acids / lipolysis / increased use of fatty

acids in respiration;

5 negative feedback, reduces / inhibits,

the secretion of glucagon;

6 glucagon, reduces / inhibits, insulin

secretion;

4 max IGNORE ref to insulin or events following

an increase in blood glucose concentration

1 DO NOT CREDIT ‘alpha cells are

produced’

2 Any description must correspond

correctly to term

DO NOT CREDIT if glucagon converts

glycogen directly

3 Any description must correspond

correctly to term

IGNORE imprecise ref to glucagon doing

the conversion

4 Any description must correspond

correctly to term

IGNORE imprecise ref to glucagon doing

the conversion

5 DO NOT CREDIT stopping glucagon

secretion

6 DO NOT CREDIT stopping insulin

secretion

Question Answer/Indicative content Marks

Guidance

Mark Scheme

ii QWC – technical terms used appropriately

and spelled correctly;

1 Use of three terms from:

alpha, islet,

pancreas, glycogen,

glycogenolysis, effector,

gluconeogenesis, negative feedback

Please insert a QWC symbol next to the

pencil icon, followed by

a tick (✓) if QWC has been awarded

or a cross (×) if QWC has not been

awarded You should use the green dot

to identify the QWC terms that you are

crediting.

Examiner's Comments

The role of glucagon in the regulation of

blood glucose concentration produced

variable responses. Better candidates

achieved all marks available for a good

description of the secretion of glucagon

from the alpha cells of the islets of

Langerhans in the pancreas and its

subsequent effects on liver or muscle cells.

Most appreciated that glucagon would

stimulate glycogenolysis and

gluconeogenesis, or described the

processes, although some failed to gain

the second marking point for either failing

to identify the effector cells or stating that

glucagon itself would convert glycogen into

glucose. Some contradicted their answers

by referring to the breakdown of glycogen

to glucose as glycolysis. While many also

recognised that more fatty acids would be

used in respiration, some simply that fats

or lipids would be used. There were

comparatively few references to glucagon

reducing insulin secretion (most stated that

insulin secretion was stopped) and hardly

any to negative feedback reducing

glucagon secretion once blood glucose

levels had been restored to normal.

Most candidates were awarded the QWC

mark for three technical terms spelled

correctly and used in an appropriate

context.

Question Answer/Indicative content Marks

Guidance

Mark Scheme

Total 13

Question Answer/Indicative content Marks

Guidance

Mark Scheme

11 a

endocrine;

hormone;

cortex / cortical;

target / effector;

4 Mark the first answer on each prompt

line. If the answer is correct and an

additional answer is given that is incorrect

or contradicts the correct answer then = 0

marks

Examiner's Comments

Many candidates were able to complete

the passage using suitable terms.

Common errors were to confuse endocrine

with exocrine and cortex with medulla.

Very occasionally, neutrotransmitter was

used in place of hormone.

b i

1 glucose, respired / phosphorylated /

metabolised, to produce ATP;

2 ATP, blocks / closes, potassium ion

channel(s)

and

potassium ions / K

build up (inside cell) / cannot leave;

3 (voltage-gated) calcium ion / Ca

channels open

and

calcium ions / Ca

, enter (cell by

diffusion);

4 (more) calcium ions / Ca

, resulting

in, movement of vesicles to membrane

/ exocytosis / described;

4 IGNORE the numbered prompt lines, but

the events must be in the correct

sequence.

1 IGNORE ‘glucose is broken down to

form ATP’

2 ion must be indicated at least once

If symbol used, must have correct

charge

IGNORE ref to ‘depolarisation’ (as not

indicated on fig.)

3 ion must be indicated at least once

If symbol used, must have correct

charge

IGNORE ref to polarisation

4 if ion had been mentioned in stage 3,

then allow ‘calcium’ alone for this mp

ACCEPT ecf for this mp if mp 3 not

awarded because Na

stated instead of

IGNORE ‘secretion’ as given in

question

Examiner's Comments

Well prepared candidates were able to

interpret the stimulus material in Figure 2.1

and provide good accounts of the events

taking place at the various stages leading

to the secretion of insulin from the beta

Question Answer/Indicative content Marks

Guidance

Mark Scheme

cell. Most recognized that glucose would

be respired to produce ATP, although

some stated that glucose would be

converted to ATP which was not credited.

While many went on to describe how ATP

would block the potassium ion channels, a

significant number neglected to add that

this would cause an accumulation of

potassium ions within the beta cell as they

were no longer able to leave. Most

understood that the depolarisation of the

cell would cause the calcium ion channels

to open, leading to an influx of calcium ions

and then linked this influx to the movement

of vesicles containing neurotransmitter

towards the cell surface membrane and

subsequent fusion to it. However, some

made the mistake of stating that the

vesicles, rather than insulin, would leave

the cell by exocytosis. Candidates who did

not fully express the mark points tended to

be repeating a learned sequence rather

than interpreting the information in the

diagram.

Question Answer/Indicative content Marks

Guidance

Mark Scheme

1 (continues to be secreted) as long as

blood / plasma, glucose

(concentration), remains high / is

higher than normal;

2 (sufficient) ATP is still present and so

channels remain closed;

3 (exocytosis) still being triggered by,

calcium ions / Ca

;

2 max IGNORE ref to what happens once the

glucose level returns to normal and

secretion stops (as Q asks about the

continued secretion of insulin)

3 CREDIT Ca

, still present / remain

high

CREDIT exocytosis continues until

can be removed from cell

Examiner's Comments

This question proved challenging.

Candidates who did gain marks usually

recognised that calcium ions were still

present in the cell (triggering secretion of

insulin). Several candidates knew that the

calcium ion channels remained open but

did not develop the idea further. Many

mentioned that ATP was still present,

others stated that potassium ion channels

were closed, but few mentioned both

conditions. Many of those who mentioned

high glucose levels referred to levels in the

cell rather than in the blood or to trying to

reduce the glucose to zero. Some

candidates answered in terms of the time

taken for insulin to reach the target cells,

rather than in terms of the levels of blood

glucose and its effect on the cells. Many

candidates did not note the reference to

continuing insulin secretion, and referred to

what would happen when glucose levels

returned to normal (when little or no insulin

secretion would take place) and negative

feedback.

Total 10

Question Answer/Indicative content Marks

Guidance

Mark Scheme

12 a the type of diabetes (being treated) ✓

age (of patients) ✓

gender (of patients)✓

idea of how the improvement was

measured ✓

idea of when the improvement was

measured ✓

ACCEPT extent of improvement / AW

b i (pancreatic) beta / Β, cells ✓ 1

ii type I because:

(type I) results from a shortage of beta

cells (in the pancreas)✓

idea that stem cell therapy might increase

insulin production ✓

idea that type II diabetes usually results

from insulin resistance (rather than a lack

of insulin)✓

2 max

c i 0.93 ✓✓✓ 3 ACCEPT calculator value of 0.928977933

and any correct rounding

Apply ECF throughout

Max 2 if answer is incorrect

AWARD 1 mark for calculating the mean

(9.26)

AWARD 1 mark for 5 correct subtractions

(0.56, 0.56, 0.26, 0.26, 1.64)

AWARD 1 mark for summation (Σ = 3.452)

AWARD 1 mark for dividing by 4 (/n-1)

ii standard deviation is:

less affected by the, 10.9 value / outlier /

anomaly ✓

idea of takes into account every value in

the data ✓

2 ora throughout

Question Answer/Indicative content Marks

Guidance

Mark Scheme

iii idea of blood glucose measured using the

same method ✓

blood glucose measured the same number

of times of day / after eating ✓

idea of taking into account the patients’

medical history / age / sex ✓

idea of correct use of statistical test ✓

2 max ALLOW blood glucose measured the

same number of times

ACCEPT measurement of baseline blood

glucose levels (prior to therapy)

e.g. unpaired t–test

Total 13

Question Answer/Indicative content Marks

Guidance