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# IBDP Biology SL Paper 1B- Data-Based Questions.

### Question

A study was conducted to look at the short-term effects of a change in diet on the risk of disease in young adults. The table shows data on the habitual diet of the participants as well as the study diet followed for two weeks.

(a) Comment on the total energy content of the two diets.      [1]

(b) Distinguish between the two diets.  [2]

Total blood plasma cholesterol levels were measured before the study began and once a week after starting the study diet. Mean results are shown in the bar chart, including the standard deviation.

(c) Calculate, showing your working, the percentage change in mean cholesterol level after one week on the study diet.   [2]

(d) (i) Compare the data for plasma insulin levels before and after the study diet. [2]

(ii) State which cells secrete insulin.[1]

(iii) Outline the reason for plasma insulin levels changing in the first 30 minutes of the test.[1]

Ans:

a.

a.energy is not changed (between the two diets);
b.study diet slightly lower in energy than habitual diet (but means/SD overlap);

b.

a.they differ in percent of saturated and unsaturated fats (but not total fat);
b.percent of saturated fats is higher in study diet / lower in habitual diet;
c.(mono/poly) unsaturated fats decreased in study diet compared to habitual diet/more in habitual diet
OR
polyunsaturated fats in study diet only half of what they were in habitual diet;
d.(slightly) less carbohydrate in study;

c

((165–150) ÷ 150) x 100;
(=) 10 (%);

d.i.

a.both show same pattern of rise, level and then decrease / show same trend;
b.both show same/similar levels of insulin (at all times) due to overlapping error bars;
c.both rise for 30/45 minutes;

d.ii.

β cells of pancreas/islets (of Langerhans);

d.iii.

as blood glucose rises, insulin rises/increases to reduce the level/OWTTE;

### Question

Ebola virus disease (EVD) is the disease in humans and other primates that is caused by the Ebola virus. Fruit bats are the reservoir for the virus and are able to spread the disease without being affected. Humans can become infected by contact with fruit bats or with people infected by the virus, their body fluids or equipment used to treat them.

The table shows data for four African countries that were affected by the 2014–2015 Ebola outbreak.

1. Identify the country with

1. the largest number of Ebola cases. [1]

2. the largest number of deaths. [1]

2. Analysis of the data suggests that the number of deaths from EVD is not related to the total population size. State one piece of evidence from the data that would support this analysis. [1]

3. Based on the mode of transmission of the Ebola virus, suggest a possible reason for the relationship between population density and the number of Ebola cases in these four countries. [1]

The graphs show the progress of the EVD epidemic in Guinea and Liberia for the period April 2014 to May 2015.

[Source: Ebola Situation Report 2 March 2016 and data from International Journal of Infectious Diseases, 38, Ligui Wang et al, Epidemiological features and trends of Ebola virus disease in West Africa, 52-53., Copyright 2015, with permission from Elsevier]

4. Based on the data, compare and contrast the progress of the epidemic in Liberia and Guinea. [3]

5. Suggest two possible reasons for the drop in the daily numbers of newly infected cases after October 2014 in Liberia. [2]

An antiviral drug, T-705, was tested in order to establish whether it has potential to treat EVD. The graph shows the data from an in vitro trial of T-705 on cells that had been infected with Ebola virus five days previously. Virus concentration and live cells are shown as percentage of the control.

6. Based on these data, outline the evidence that T-705 has potential to be used as a treatment for EVD. [2]

7. District administrators combatting the 2014 Ebola epidemic in West Africa were assisted by international organizations such as the World Health Organization, who provided data on the progress of the epidemic. Suggest one other way in which international organizations can assist with combatting an epidemic of Ebola. [1]

Ans:

1. a i Sierra Leone

1. a ii Liberia

1. b country with biggest population/Mali has lowest number of deaths OR
country with smallest population/Liberia has biggest number of deaths  OWTTE

1. c greater density means more frequent contact with infected people/animals  Need both greater density and frequency of contact

1. d

a. overall pattern similar in both/both show a rise and a fall in the infections

b. both countries show an increase during 2014 OR neither country shows an increase in 2015

c.both show a sudden drop at one point OR sudden drop earlier «Oct–Nov 14» in Liberia than in Guinea «Dec 14, Jan 15»

d. Guinea fluctuates whereas Liberia rises to a peak and then decreases/no fluctuations

e. epidemic starts earlier «in April 14» in Guinea than in Liberia «in June 14»

f. epidemic peaks earlier «Sept 14» in Liberia than in Guinea «Dec 14»

g.epidemic lasts longer in Guinea than it does in Liberia OR last case recorded in Liberia Feb 15 while cases continue «at least» until May 15 in Guinea

h.numbers of cases in Guinea generally lower than in Liberia OR number of cases higher in Liberia than in Guinea

1. e

a. improved medical care/support/supplies/equipment/training of staff/hygiene/distribution of vaccine  OWTTE

b. improved understanding of how to avoid infection «amongst public»/greater awareness in society/better education

c. rise in number of deaths means fewer infectious individuals

d. impact of disease control measures/control policies/quarantine/isolation  e. drop in the number of fruit bats

f. maybe seasonal changes/weather changes

g. people may have left the area

h. international aid arrives

1. f

a. cells not killed/few cells killed «even at high concentrations»

b. «T-705» effective/viruses reduced/viruses killed at 100 μM OR «T-705» very effective/viruses much reduced/nearly all viruses killed at 1000 μM

c. virus concentration decreases as T-705 concentration increases

d. drug has «high» potential for treatment «at high enough concentration»

g raise awareness/provide information for local population/supply health workers/equipment/ train local staff/share expertise/provide financial support/provide vaccine/travel ban alert to affected country

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