Diet & Health (Edexcel A (SNAB) AS Biology)

Exam Questions

57 mins5 questions
1a
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1 mark

Lipids are classed as more energy-rich storage compounds than carbohydrates. 

Which of A - D explains why? 

  A Lipids contain energy-rich ester bonds whereas carbohydrates contain glycosidic bonds which are less energetic
  B Lipids contain a lower proportion of oxygen than carbohydrates
  C Lipids can be stored as fat droplets and held in specialised tissue under the skin and around the major organs
  D Lipids contain C=C double bonds which increases their energy content

1b
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3 marks

The ester bond plays an important role in the biochemistry of lipids. 

Describe the role of the ester bond within lipids and the mode of ester bonds' formation and breakage. You may use a suitable illustration in your answer.

1c
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4 marks

Lipids have many roles within an animal's body. The following list shows four of those roles. 

  1. energy storage
  2. insulation
  3. cellular structure
  4. protection

For each of roles 1 - 4, give one example of how lipids play the roles listed.

Role
Example
1  energy storage  
2  insulation  
3  cellular structure  
4  protection  

1d
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4 marks

Compare and contrast the structures of saturated and unsaturated fatty acids.

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2a
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4 marks

There are several risk factors for cardiovascular disease, some of which are listed in the table below.

(i)

Identify these by placing a tick (✔) in the appropriate boxes in the table.

The first row has been completed for you.

Factor Risk factor?
Exposure to air pollution
A person's height  
Smoking   
High salt in the diet  
Stress  
A person's gender  
A person's age  

(2)

Another risk factor for cardiovascular disease, not listed in the table above, is the misuse of alcohol.

(ii)

Describe how the misuse of alcohol can result in an increased risk of CVD.

(2)

2b
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2 marks

A group of researchers attempted to assess the risk of young adults (aged 18 - 45 years) with high blood pressure from developing cardiovascular disease in later life.

Risk was measured as relative risk compared to a healthy individual of that age group. 

The results are shown in the graphs below.

charts-2

Determine the systolic and diastolic blood pressures that would result in a doubling of the relative risk of developing coronary heart disease. 

2c
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3 marks

Explain why increased blood pressure causes an increase in the risk of cardiovascular disease.

2d
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2 marks

The drug Frusol™ (furosemide) is a diuretic and is widely prescribed to patients with high blood pressure.

A diuretic increases urine production. 

Explain how a diuretic may reduce blood pressure and relieve the symptoms.

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3a
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2 marks
The sugar ribose (C5H10O5) has the following structure.

Structure of Ribose

In the table below, place a tick () against each statement that applies to ribose.

Statement:
Ribose...

Applies to ribose?
 Contains a 2:1 ratio of hydrogen to oxygen atoms  
 Is found in polysaccharides  
 Plays a role in cell nuclei  
 Is insoluble  
 Is a monosaccharide  
 Is a pentose sugar  

3b
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4 marks

Compare and contrast the structures of alpha and beta glucose.

3c
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4 marks

The table below lists some properties of glucose (C6H12O6). 

Property Value for glucose
 Molar mass Small (180g)
 Ability to polymerise High
 Solubility in water at 25°C High (909 gdm-3)
 Energy content High (2805 kJmol-1)

For each property listed, state why the properties of glucose make it a good molecule for its roles.

3d
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2 marks

State two features of a glycosidic bond that forms between two monosaccharides in a condensation reaction.

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4a3 marks

The table below contains statements that could apply to three polysaccharides. 

Complete the table with a tick () in each box if the statement applies correctly. 

Statement Glycogen Cellulose Starch
Contains 1-6 links      
Contains α-glucose      
Contains hydrogen bonds      

4b2 marks

Explain the name of the type of reaction that forms the carbohydrates in part (a) from their monomers.

4c4 marks

State two features of starch and explain how these features allow starch to act as a storage substance.

4d
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1 mark

Two molecules of a disaccharide are condensed together to form a larger sugar molecule.

The chemical formula of the disaccharide is C12H22O11.

Determine the formula of the resulting larger sugar molecule.

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5a
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6 marks

The Basic Metabolic Rate (BMR) of a human is the rate at which that person uses food energy to sustain life at rest.

BMR can be divided among various organs and systems as shown in the graphs below.

Q7TTtvoA_5a-oxygen-consumption---sq

-wDMz38G_5a-percent-of-bmr---sq

(i)
Calculate the percentage difference in the oxygen consumption of the liver & spleen at rest as compared to that of the brain.

Express your answer to an appropriate number of significant figures. 

(3)

(ii)
Using the pie chart, predict the changes in the metabolic rates of the various organs in the table below if a person goes from a resting state into a period of vigorous exercise.

State your predictions by completing the missing boxes in the table below. 

(3)

Organ Percent of BMR (at rest) Percent of metabolic rate under vigorous exercise
Liver & spleen 27%  
Brain 19% 23%
Skeletal muscle 18%  
Kidneys 10% 5%
Heart 7% 12%
Other 19% 13%
Totals 100% 100%

5b
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2 marks

Around 25% of the total BMR at rest is used to release energy into the nervous system.

Use your knowledge of the nervous system to explain what this energy is principally released for.

5c
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4 marks

The table below gives some data about two adult males.

One is a professional athlete and the other is an office worker. 

  Professional athlete Office worker
 Age 29 31
 Mass /kg 85 77
 Daily exercise / kcal 3 000 450
 Daily BMR / kcal per day 1 500 2 000
 Daily energy consumption from food 3 500 2 070

A dietician looked at this data and concluded that both men would lose weight over a period of two weeks if they each sustained these levels of energy input and output. 

Evaluate this statement.

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