Name: _______________________________________________ 	

  	
  	
Topic 1 Lifestyle, Health and Risk	

 	
Date:	

  	
  	
Time:  26 minutes	
  	
Total marks available:  26	
  	
Total marks achieved: ______ 	

  	

  	

  	

  	

  	

  	

  	
Longer answer focus  	

	

Questions

Q1.  Lipids and carbohydrates are found in both plants and animals.
The carbohydrate content of vegetables ranges from 3 to 35%. However, meat contains little to no carbohydrate. Milk is the only food source from animals that contains a significant amount of carbohydrate.
Although plant material contains a higher proportion of carbohydrate than animal tissues, it has been claimed that carbohydrates are more important to animals than they are to plants.
Assess the relative importance of carbohydrates to plants and animals.
(9)
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 (Total for question = 9 marks)
 Q2.  Cardiovascular disease (CVD) is a major cause of death and disability in the UK.
It has been suggested that magnesium ions are involved in regulating the ratio of HDL to LDL in the blood.
(i)  Describe the role of LDLs in the development of atherosclerosis.										(3)
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(ii)  Explain how atherosclerosis can result in damage to heart muscle.									(3)
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(Total for question = 6 marks)

 Q3.  LDL cholesterol found in plasma binds to receptor proteins and is taken into cells by endocytosis.
A gene found on chromosome 19 is responsible for making LDL receptor proteins in human cell membranes.
* Familial hypercholesterolaemia (FH) is an inherited condition.
The recessive allele (f) makes normal LDL receptor proteins. 
The dominant allele (F) makes LDL receptor proteins that do not function. 
Explain why people who inherit the dominant allele have an increased risk of dying early. 
(6)
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  (Total for question = 6 marks)
Q4.  During the cardiac cycle, muscles in the walls of the atria and ventricles contract and 
relax.
The graph below shows the changes in pressure that occur in the left side of the 
mammalian heart during one cardiac cycle.

* During this cardiac cycle, the changes in pressure that occur in the left atrium and 
in the left ventricle are different.
Using the information in the graph and your own knowledge, explain these differences.
(5)
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Examiner's Report

Q1.
 
This question is a nine mark extended response item. The candidates were asked to assess the relative importance of carbohydrates to plants and animals.
Whilst there were a number of very good answers offered by candidates, the majority were limited by one or more of the following:

·	Only considering one or two roles of carbohydrates in plants and animals such as answers limited to energy storage or respiration and cellulose
·	Significantly confusing responses such as considering carbohydrates as polysaccharides only, or that animals require glucose for respiration but plants require it for photosynthesis
·	Either no comment on the relative importance or a very simplistic one.
It was noted that a number of candidates used additional lined paper when there was space available in the question paper. This was particularly evident in this question where much of the second page was not used.
There was limited focus on carbohydrates in this answer so it was deemed to sit in level 1. It also showed a rather simple assessment of the relative importance.

Results Plus: Examiner Comments
The lack of much content places this response at the lower end of the level so was awarded 1 mark.

Results Plus: Examiner Tip
When tackling this type of question, take particular note of the command word so that the answer fully reflects the question. In this case, an assessment of relative importance of carbohydrates to plants and animals was required.

This response demonstrates isolated elements of biology in the context of the question, most notably respiration in both plants and animals, cellulose in plants and a reference to amylose and amylopectin as forms of starch.
The candidate has also made an assessment of the relative importance by stating that carbohydrates are more important to animals than plants but the evidence is limited.

Results Plus: Examiner Comments
Whilst this response was also considered to be at level 1, it is of a higher order than the previous one and was awarded 3 marks.

 

Q2.
 
(i)
Many candidates could provide a reasonable description of the role of LDL in the development of atherosclerosis.
Many candidates gained all three marks. Marking point three was the most frequently missed.
Candidates frequently referred to endothelium without linking it to the artery and did not gain the mark. Some candidates did not link LDLs to cholesterol and if they did they made no mention of this being in the blood and therefore did not gain marking point 1.

Results Plus: Examiner Comments
This response demonstrates good understanding of the biology and is clearly expressed. All three available marks awarded.

Results Plus: Examiner Tip
Don't take short cuts. To get a mark, candidates had refer to the endothelium layer of the artery. Just using the term 'endothelium' or 'endothelium of blood vessels' was not sufficiently clear.

Results Plus: Examiner Comments
In this response the candidate has not provided the detail required to gain more than one mark. LDL has not been linked to cholesterol in the blood (MP1), 'walls of blood vessels' was not accepted for endothelial lining of arteries and the candidate was not describing cholesterol deposition (MP2). There was just enough of the idea of atheroma/plaques forming to award MP3.

Results Plus: Examiner Tip
Learn enough biology to ensure you can provide appropriate detail in your answers.

(ii)
This question was about atherosclerosis and damage to heart muscle. Candidates needed to answer in this context. Many candidates did not gain MP1 because they simply described arteries and not coronary arteries. Marking point 2 had to be in the context of heart muscle or cells.
Candidates made simple statements such as 'less oxygen reached the heart' and did not gain this marking point.
On this occasion we accepted statements such as 'arteries narrow'. However, this is only because they are part of a more substatial answer. We would prefer responses that are clearly describing a smaller or narrower lumen. Candidates should be making it clear that it is the lumen of the arteries that is reduced.
For marking point 3 candidates needed to be clear about the effect on either aerobic or anaerobic respiration. Responses such as 'heart muscle cannot respire' did not gain this mark.

Results Plus: Examiner Comments
Lines 1 to 4 lacked sufficient detail and gained no credit. 

Lines 5 to 8 allow all three available marks to be awarded.

Results Plus: Examiner Tip
Save yourself time by thinking carefully about your answer before you start writing.

Results Plus: Examiner Comments
In this response the candidate gained one mark. The first sentence describes a decrease in the lumen of the artery. However, it does not make it clear this is the coronary artery so MP1 was not awarded. Line three 'reduces the volume of blood that arrives to the heart' would not gain MP2. However, the candidate then states 'and causes heart muscle tissue to be starved of oxygen'; having now mentioned heart muscle, MP2 can be awarded.

Results Plus: Examiner Tip
When describing processes make sure your description is not ambiguous. Terms such as 'heart', 'heart muscle' and 'heart cells' are not always interchangeable.

 

Q3.
No Examiner's Report available for this question

Q4.
 
Unfortunately once again, many candidates merely gave an account of the cardiac cycle in detail with no regard to the pressure changes or the question asked. This showed a lack of attention to the rubric of the question, especially with respect to explaining rather than describing.
Those candidates who did approach this correctly usually explained the difference between the maximum pressures with respect to the relative distances needed to push the blood, so gaining two marks. Some also appreciated that the ventricular wall was more muscular to enable this to occur, and so gained three marks in total. However, many who did appreciate the importance of the chamber walls merely referred to their thicknesses without reference to the muscle.
Occasionally, candidates did manipulate the maximum pressure values of the atrium and ventricle and calculate the difference to gain another mark.
Other candidates recognised that the atrium must contract before the ventricle and described the effect of the bicuspid valve opening so that ventricular pressure increased during atrial systole.
A significant number of candidates think that the volume of the ventricle is significantly larger than the volume of the atrium.
This response gained all five marks available.

Results Plus: Examiner Comments
Full marks were earned by this response for the following points:

•        >the pressure increase happened in the atrium before the ventricle
•        the maximum pressure is much lower in the atrium than the ventricle
•        the distance the atrium has to push the blood is much shorter than the ventricle
•        the muscle of the ventricle is much thicker than the atrium
•        the difference in maximum pressures has been correctly calculated.

This response gained no marks.

Results Plus: Examiner Comments
This is a typical example of an confused account of the events of the cardiac cycle many candidates wrote. There are no clear comparisons made between the pressure changes in the atrium and the ventricle and no explanation for the reason for those differences. The one pressure comparison made is at a point in time and does not describe what the pressure difference is.

Results Plus: Examiner Tip
Read the question carefully and make sure you know what the command word 'explain' means.

 

Mark Scheme

Q1.

 

Q2.

 

Q3.

Q4.