Mock Exam Set 1 - Paper 2

[Maximum mark: 15]

Tuberculosis (TB) is an airborne infection caused by the bacterium Mycobacterium tuberculosis, and it infects about 10 million people each year. The research was carried out in Peru to see if diabetes increases TB infection. 112 TB patients were investigated, 17 of which had diabetes and 33 had pre-diabetes. During the research, smear microscopy tests were carried out to investigate the bacterial load of each patient, and the results of these are shown below. The smear results are rated negative (no bacteria detected), scanty/1+ (very low bacterial load), 2+ (medium bacterial load), and 3+ (high bacterial load).

[Source: Adapted from Lopez K, Arriaga MB, Aliaga JG, Barreda NN, Sanabria OM, Huang C-C, et al. (2021) Dysglycemia is associated with Mycobacterium tuberculosis lineages in tuberculosis patients of North Lima—Peru. PLoS ONE 16(1): e0243184. Retrieved October 25 2022, from https://doi.org/10.1371/journal.pone.0243184 Copyright under CC0 4.0]

1. Calculate the difference between the percentage of incidences of 3+ smears in patients who only have TB and those patients who are diabetic. [1]
   

2. Describe the pattern shown in this graph. [2]
   

3. Deduce from these results whether there is a link between diabetes and TB infections, and discuss the evidence supporting your conclusion. [3]
   

Smoking can also cause an increase in TB. Research into the combined effect of smoking and diabetes was carried out in Taiwan. Groups of patients were split into diabetic smokers, diabetic non-smokers, non-diabetic smokers and non-diabetic non-smokers in 3 regions of Taiwan. The results of 972 TB patients are shown below, 581 with diabetes and 628 without diabetes. 649 of them were non-smokers and 323 were smokers. Clinical records were used to record the gender, age and result of the pre-treatment smear (negative, scanty, 1+, 2+, 3+, 4+). The results are shown below.

[Source: Adapted from: Bai K-J, Lee J-J, Chien S-T, Suk C-W, Chiang C-Y (2016) The Influence of Smoking on Pulmonary Tuberculosis in Diabetic and Non-Diabetic Patients. PLoS ONE 11(6): e0156677. Retrieved October 25 2022, from https://doi.org/10.1371/journal.pone.0156677. Copyright under CC0 4.0]

4. Compare and contrast the results from the first research with the data for the non-smoking groups in the graph provided above. [2]
   

5. Suggest the importance of knowing the mean precent (%) of the population that has diabetes and mean % of the population that are smokers in Taiwan, when investigating if diabetes and smoking increase the risk of TB infection. [2]
   

6. Evaluate the evidence provided by the data in the two graphs and table to support the hypothesis that diabetics who smoke have an increased risk of TB infection. [3]
   

7. From 2000 to 2008, there has been an overall increase in the cases of type II diabetes in Taiwan.

   1. Distinguish between type I and type II diabetes. [1]
      

   2. State one factor that may cause this increase in the incidence of type II diabetes. [1]
      

[Maximum mark: 10]

Pictured below are Robert Remak’s original drawings of cells from a chick embryo.

[Source: Wilson, Edmund B. (1897). The Cell in Development and Inheritance. New York: Macmillan, IV, p46. Retrieved January 4, 2023, from https://archive.org/details/cellindevelopmenwils2. Copyright under Public Domain.]

1. Outline how Remak’s observations supported Louis Pasteur’s findings on spontaneous generation. [3]
   

2. State which characteristic of life is carried out by Euglena in each of the following:

   1. flagella [1]
      

   2. eyespot [1]
      

3. Retinal degeneration can be treated with adult or embryonic stem cells. Compare the advantages and disadvantages of the use of adult and embryonic stem cells. [3]
   

4. Predict the effects of the removal of saprotrophs from an ecosystem. [2]
   

[Maximum mark: 5]

The image shows the observed surface temperature change in the Northern Hemisphere from 1979 to 2019.

[Source: Adapted from Buis, A. (2022, April 22). Making Sense of "Climate Sensitivity." National Aeronautics and Space Administration Goddard Institute for Space Studies. Retrieved January 4, 2023, from https://www.giss.nasa.gov/research/features/202009_sensitivity/. Copyright under Public Domain.]

1. State the name and source of the greenhouse gas primarily associated with the observed temperature increases. [2]
   

   Name:

   Source:

2. Outline the process through which greenhouse gases increase Earth’s global temperatures. [2]
   

3. The bar-tailed godwit (Limosa lapponica) nests and breeds on Arctic coasts and tundra and overwinters in the Southern Hemisphere. Predict how the increase in surface temperatures in the Northern Hemisphere may affect the survival of such a migratory bird. [1]
   

[Maximum mark: 4]

Sickle cell anaemia is caused by the allele Hb$^S$. The normal allele is Hb$^A$.

[ © Revision Village 2022]

1. If individual 7 had a child with an affected female, identify the possible genotypes of the child. Justify your answer. [2]
   

2. Distinguish between sex-linked inheritance and autosomal inheritance in humans. [3]
   

[Maximum mark: 16]

Biotechnology, including methods of genetic modification, has produced many benefits for society despite ongoing technical challenges.

1. Describe how Meselson and Stahl obtained evidence for the semi-conservative replication of DNA. [3]
   

2. Outline how a plasmid can be used to introduce a new gene to bacteria, including the role of restriction endonucleases and DNA ligase. [4]
   

3. Explain methods for the cloning of embryonic and adult animals and the technical challenges related to these methods. [8]
   

[Maximum mark: 16]

Sydney Smith, an English author, once said “I am convinced digestion is the great secret to life.”

1. Distinguish between the structure of cellulose, starch and glycogen. [4]
   

2. Outline how insulin and glucagon control blood sugar. [3]
   

3. Explain the steps through which the nutrients in a meal ultimately enter the bloodstream. [8]