AQA AS BIOLOGY Paper 2 2

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AS BIOLOGY Paper 2 2 *02* IB/M/Jun22/7401/2 Do not write outside the Answer all questions in the spaces provided. box 0 1 . 1 What is a gene? [1 mark] 0 1 . 2 Describe how the production ... of messenger RNA (mRNA) in a eukaryote cell is different from the production of mRNA in a prokaryote cell. [2 marks] 0 1 . 3 Scientists produced a short, single-stranded, artificial nucleic acid, called PNA. The PNA binds to a small section of DNA. The scientists introduced PNA into cells and discovered that these cells produced less mRNA than cells that did not contain PNA. Suggest how PNA affected the transcription of the section of DNA. [2 marks] 3 *03* Turn over ► IB/M/Jun22/7401/2 Do not write outside the 0 1 box . 4 Describe the role of ATP in the process of translation in protein synthesis. [2 marks] Turn over for the next question 7 4 *04* IB/M/Jun22/7401/2 Do not write outside the 0 2 box . 1 What term is used to describe the different structures of α-glucose and β-glucose? [1 mark] 0 2 . 2 A student investigated the difference in the reducing sugar content of two fruit juices. He performed a biochemical test on each fruit juice using Benedict’s solution. He then used a colorimeter with each test result. Describe how the results from the colorimeter can identify the fruit juice containing the higher sugar content. [1 mark] 0 2 . 3 The student controlled variables in the test using Benedict’s solution. Give two variables the student controlled. [2 marks] 1 2 5 *05* Turn over ► IB/M/Jun22/7401/2 Do not write outside the 0 2 box . 4 Apples consist of flesh tissue which surrounds core tissue where the seeds are located. A student has an apple with a mass of 180 g The ratio of flesh tissue to core tissue in this apple is 5:1 8% of the whole apple is sugar. Calculate the mass of sugar in the flesh tissue. Show your working. [2 marks] Answer g 0 2 . 5 Iodine solution stains fresh apple tissue black. When iodine solution is added to apples stored for a week, the stain is less black. The water potential of apple juice decreases when apples are stored. Suggest why the water potential of apple juice decreases when apples are stored. [2 marks] Turn over for the next question 8 6 *06* IB/M/Jun22/7401/2 Do not write outside the 0 3 box Figure 1 is an image of part of a cell lining the ileum. Figure 1 0 3 . 1 Describe and explain two ways that structures shown in Figure 1 increase the rate of absorption by this cell. [2 marks] 1 2 7 *07* Turn over ► IB/M/Jun22/7401/2 Do not write outside the box 0 3 . 2 An ileum cell without microvilli has 7.85 µm2 of cell surface in contact with digested substances. A scientist found an ileum cell with 1000 microvilli. The microvilli cover the entire cell surface in contact with digested substances. Microvilli are 0.1 μm in diameter and 1 μm in length. The surface area of a microvillus is calculated using this equation 2 πrl + πr 2 where π is 3.14, r is the radius, l is the length. Calculate the ratio of the area of the ileum cell surface with microvilli to the area of ileum cell surface without microvilli. Show your working. [2 marks] Ratio :1 Question 3 continues on the next page 8 *08* IB/M/Jun22/7401/2 Do not write outside the 0 3 box . 3 The protein ZO-1 is found on the surface of ileum cells. A scientist used an anti-ZO-1 monoclonal antibody to identify ileum cells in a sample of intestine observed using an optical microscope. Suggest how the monoclonal antibody helped the scientist to identify ileum cells in the sample of intestine. [3 marks] 7 9 *09* Turn over ► IB/M/Jun22/7401/2 Do not write outside the 0 4 box . 1 Describe how the process of meiosis results in haploid cells. Do not include descriptions of how genetic variation is produced in meiosis. [4 marks] Question 4 continues on the next page 10 *10* IB/M/Jun22/7401/2 Do not write outside the 0 4 box . 2 Figure 2 shows the arrangement of chromosomes in a cell during the first meiotic division. Figure 2 A scientist observed 300 cells. All of the cells were at exactly the same stage of meiosis as the cell shown in Figure 2. Use your knowledge of the independent segregation of homologous chromosomes to calculate how many of these cells are expected to have an identical arrangement of chromosomes to those shown in Figure 2. Assume no crossing over occurs. [2 marks] Answer 0 4 . 3 Draw a diagram to show the chromosomes in one gamete produced by meiosis from the cell shown in Figure 2. [1 mark] 11 *11* Turn over ► IB/M/Jun22/7401/2 Do not write outside the 0 4 box . 4 Figure 3 shows the life cycle of a fungus. The life cycle includes sexual reproduction. Figure 3 What is the name of the process shown by arrow A in Figure 3? Tick () one box. [1 mark] Binary fission Fertilisation Meiosis Mitosis Turn over for the next question 8 12 *12* IB/M/Jun22/7401/2 Do not write outside the 0 5 box . 1 Describe how organisms are grouped in a phylogenetic classification system. [2 marks] Table 1 shows some of the taxa in the phylogenetic classification of a rhinoceros species. Table 1 Taxon name Scientific name Class Mammalia Order Perissodactyla Family Rhinocerotidae Genus Rhinoceros Species unicornis Figure 4 shows the relationship between the taxa in the classification of two rhinoceros species: Rhinoceros unicornis and Dicerorhinus sumatrensis. Figure 4 13 *13* Turn over ► IB/M/Jun22/7401/2 Do not write outside the 0 5 box . 2 Use information in Table 1 to give the scientific name of the taxon labelled B in Figure 4. [1 mark] 0 5 . 3 Draw an oval on Figure 4 to show the species Rhinoceros sondaicus. [1 mark] Question 5 continues on the next page 14 *14* IB/M/Jun22/7401/2 Do not write outside the Scientists investigated a phylogenetic relationship between individuals of five species box of rhinoceros. The scientists: • determined the DNA base sequence of the cyt b gene of each rhinoceros • compared each cyt b DNA base sequence with that [Show More]

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