Question A1
A1
A1. A study was made to look at the effect of breastfeeding on infant health. The infants studied were all healthy at birth. They were classified as never breastfed, partially breastfed or only breastfed, based on their feeding status in the first three months of life. The frequency of health care use was assessed for each of these groups, for three illnesses (lower respiratory infection, middle ear infection and gastroenteritis). The table below indicates the frequency of initial and follow-up visits to the doctor, prescription of medication and hospitalizations during the first year of life. Follow-up visits and medication were seldom needed for gastroenteritis.
0 marks
Question A1(c)
A1(c)
Suggest how the composition of breast milk and artificial milk may have contributed to these results.
Mediumstructured2 marks
Answer
breast milk contains maternal antibodies / lack of antibodies in artificial milk; antibodies provide protection against some viral and bacterial infections / passive immunity; breast milk has white blood cells/macrophages to fight infection; breast milk has nutrients in correct proportions so easier to digest/less likely to cause gastroenteritis;
Question A1
A1
A1. Nuts are nutritionally important because they are energy rich and their lipids may reduce the risk of cardiovascular disease. Despite these advantages, some people avoid eating nuts because they fear gaining weight from them. The role of mastication (chewing) of nuts was explored in relation to the absorption of lipids by the body and to the sense of fullness after eating nuts. Energy and total lipid content in the fecal matter (feces) of 13 people were measured over a four-day period. After not eating for eight hours, participants were initially given 55 g of raw whole almonds (in 5 g portions) to be chewed 10, 25 or 40 times before swallowing. For the remainder of the four-day period, participants were fed three controlled meals each day without any nuts. [Acknowledgment: Cassady, B.A., Hollis, J.H., Fulford, A.D., Considine, R.V. and Mattes, R.D. 'Mastication of almonds: effects of lipid bioaccessibility, appetite, and hormone response.' American Journal of Clinical Nutrition, 2009; 89 (3): 794-800, ©American Society for Nutrition.]
0 marks
Question A1(a)
A1(a)
The amount of energy lost in fecal matter after 10 chews is 3890 kJ . State the amount of lipids lost in fecal matter after 10 chews, giving the units.
Easystructured1 marks
Answer
A1. (a) 42 g (accept answers in the range of 41 g to 43 g )
Question A1(b)
A1(b)
Using the data, analyse the effects of mastication on loss of energy in fecal matter.
Mediumstructured2 marks
Answer
chewing reduces loss of energy in feces/quotes data \(\left\{\begin{array}{l}\text { (accept analysis made quoting } \\ \text { numerical data) }\end{array}\right.\) increasing from 10 to 25 chews gives larger reduction than 25 to 40 chews / OWTTE;
Question A1(c)
A1(c)
Deduce how mastication affects the absorption of lipids by the body.
Mediumstructured1 marks
Answer
a. more chewing releases more lipids (for absorption); b. chewing breaks cell walls/increases surface area (for digestion);
Question A1(d)
A1(d)
Evaluate the importance of the given information for individuals concerned with weight control.
Mediumstructured3 marks
Answer
a. lots of chewing could result in weight gain because less energy/lipids lost; b. nuts are only a part of a person's diet / depends on how many nuts are eaten; c. despite possible weight gain, nut lipids are good for the cardiovascular system / OWTTE; d. data restricted to chewing / no data given about sense of fullness after eating nuts; e. eating nuts may satisfy hunger/lead to greater sense of fullness sooner than eating other food; f. small sample size in study;
Question 1
1
Cells in the alveolus wall produce a surfactant. Its function is to prevent alveoli collapse at the end of expiration. Surfactants are used in the treatment of respiratory system disease in premature babies. The table shows some of the components of different surfactant preparations.
structured0 marks
Question 1(d)
1(d)
Phospholipids found in the surfactants form a surface film on the moist lining of the alveoli. Outline how the hydrophilic and hydrophobic parts of the phospholipids in the surfactants are aligned on the alveolar surface.
Mediumstructured1 marks
Answer
hydrophilic groups facing the surface/are in the moist lining/water and hydrophobic tails facing outwards/are in the air Award [0] for a description of a phospholipid bilayer. The orientation of both hydrophilic and hydrophobic parts must be included.
Question 1
1
Obesity (excessive weight) is recognized as a global health problem and has been correlated with a large number of health issues, diseases and deaths. The increased consumption of fructose, now widely used as a sweetener, has been associated with the increase in obesity. In a study, mice were divided into four groups. Each group was given the same amount of food and either a soft drink with a different sweetener or water.
14 marks
Question 1(f)
1(f)
Determine which sugar is primarily used in the production of ribose.
Mediumstructured1 marks
Answer
fructose
Question 1
1
Obesity (excessive weight) is recognized as a global health problem and has been correlated with a large number of health issues, diseases and deaths. The increased consumption of fructose, now widely used as a sweetener, has been associated with the increase in obesity. In a study, mice were divided into four groups. Each group was given the same amount of food and either a soft drink with a different sweetener or water.
15 marks
Question 1(a)
1(a)
Describe the overall trend in body fat accumulation for the four groups of mice.
Mediumdata_response1 marks
Answer
positive/direct relationship / correlation (in all four groups) / (all four groups) accumulated fat over time
Question 1(b)
1(b)
Compare the body fat accumulation between the four groups.
Mediumdata_response2 marks
Answer
body fat accumulation increased over time for all four groups; fructose caused the (significantly) greatest accumulation of fat and (both water the least; needed) sucrose and artificial sweetener/diet soft drink had the same increase; sucrose, artificial sweetener and water did not start accumulating fat until after 20 days while fructose increased from the beginning;
Question 1(f)
1(f)
Determine which sugar is primarily used in the production of ribose.
Mediumdata_response1 marks
Answer
fructose
Question 1
1
During an investigation, 773 participants who had lost body mass through a low-energy diet were randomly assigned a diet (with no energy restriction) for the next 26 weeks to maintain their mass. These maintenance diets were one of the four combinations of high or low protein with either high or low glycemic index. A control group followed the recommended daily intake. High glycemic index foods enable a quicker release of glucose into the bloodstream than foods with a low glycemic index. Key: HP - high protein HGI - high glycemic index LP - low protein LGI - low glycemic index
6 marks
Question 1(d)
1(d)
Explain the possible health consequences of diets rich in carbohydrates.
Mediumstructured2 marks
Answer
excess carbohydrates converted/stored as fat/lipids; source of obesity / gain in weight; may increase risk of diabetes / other related health risk factor; other nutrients may be deficient;
Question 1
1
Low protein diets are a widespread problem in the developing world. A low protein diet in a pregnant mother could affect a developing fetus. Other mammals are used as a biomedical model for energy metabolism and malnutrition in humans. In an experiment to study the effect of protein levels in the diet, pregnant mammals were fed diets with different ratios of protein to carbohydrate: - low protein : high carbohydrate (LP), - adequate protein: adequate carbohydrate (AP), - high protein : low carbohydrate (HP). The table shows the average birth mass of the offspring and the body mass gain of the mother during the pregnancy. The concentration of several substances in the plasma of the mothers was also recorded. LDL (low density lipoprotein) is considered "bad cholesterol" and HDL (high density lipoprotein) is considered "good cholesterol".
0 marks
Question 1(a)
1(a)
Identify the substance that varies the most in the plasma of the mothers.
Mediumstructured1 marks
Answer
urea
Question 1(c)
1(c)
Distinguish between LDL cholesterol and HDL cholesterol in relation to the diet.
Mediumstructured1 marks
Answer
LDL cholesterol increases and HDL cholesterol decreases as (proportion of) protein increases/carbohydrate decreases / OWTTE
Question 1
1
Which molecule is a polysaccharide? Cellulose Fructose Maltose Sucrose
Easymcq1 marks
Answer
A
Question 1
1
Which molecule is a sugar? A. B. C. D.
Easymcq1 marks
Answer
A
Question 1
1
Lipase was extracted from the fungus Aspergillus niger and used to hydrolyse one of its substrates. This was repeated for an immobilized form of lipase. The graph shows how the enzyme activity varied at different pH and temperature levels.
0 marks
Question 1(a)
1(a)
State the effect immobilization of lipase has on its optimum temperature.
Mediumstructured1 marks
Answer
it is increased