AQA AS BIOLOGY Paper 2 BEST RATING May 2023

AQA AS BIOLOGY Paper 2 Thursday 25 May 2023 Morning Time allowed: 1 hour 30 minutes Materials For this paper you must have: • a ruler with millimetre measurements • a scientific calculator. Instructions • Use black ink or black ball-point pen. • Fill in the boxes at the top of this page. • Answer all questions. • You must answer the questions in the spaces provided. Do not write outside the box around each page or on blank pages. • If you need extra space for your answer(s), use the lined pages at the end of this book. Write the question number against your answer(s). • Show all your working. • Do all rough work in this book. Cross through any work you do not want to be marked. Information • The marks for the questions are shown in brackets. • The maximum mark for this paper is 75. Answer all questions in the spaces provided. box . Which statement about the function of ribosomes is correct? Tick () one box. [1 mark] Site of transcription, catalyse the joining of amino acids by hydrolysis reactions Site of transcription, catalyse the joining of nucleotides by condensation reactions Site of translation, catalyse the joining of amino acids by condensation reactions Site of translation, catalyse the joining of nucleotides by hydrolysis reactions 0 1 . 2 Name two biological molecules that can be coded for by a gene. Do not include a polypeptide or protein in your answer. [1 mark] 1 2 . Scientists investigated the structure of the endoplasmic reticulum. Table 1 shows some of the scientists’ results. Table 1 Type of endoplasmic reticulum Percentage of endoplasmic reticulum made of phospholipids Rough 46.8 Smooth 52.5 Use the data in Table 1 to suggest how the structure of rough endoplasmic reticulum is different from the structure of smooth endoplasmic reticulum and how this is related to their functions. box [3 marks] Turn over for the next question Turn over ► . Figure 1 shows an ATP synthase enzyme in the inner mitochondrial membrane. Figure 1 box Complete the passage with the appropriate terms. [2 marks] ATP synthase comprises several polypeptides, so is said to have a structure. It catalyses the synthesis of an ATP molecule by a reaction; this involves the of a water molecule. The ATP synthase in Figure 1 is in a mitochondrion so would catalyse reactions during . Turn over for the next question box Turn over ► Galacto-oligosaccharides (GOS) are polymers of galactose. box . Explain why GOS are described as polysaccharides. [2 marks] 0 3 . 2 Give two differences between the structures of GOS and lactose. [2 marks] 1 2 . Explain why amylase produced in the human digestive system does not digest GOS. [2 marks] . Prebiotics are foods used to promote good health in humans. Prebiotics stimulate the growth of ‘healthy’ bacterial populations in the human digestive system. The bacteria in these ‘healthy’ populations produce enzymes that hydrolyse GOS. box Suggest how GOS can work as a prebiotic. [3 marks] Turn over for the next question *07* Turn over ► . This question is about the flow of blood into and through the heart. Add the numbers 1 to 6 to Table 2 to give the order of structures through which blood will pass as it enters the heart and flows through the left ventricle. box Use each number only once. Number 4 has been done for you. [2 marks] Table 2 Aorta Pulmonary vein Left atrioventricular valve Left semi-lunar valve Right atrioventricular valve Vena cava Left atrium Left ventricle 4 Right atrium Right ventricle Pulmonary artery Right semi-lunar valve Question 4 continues on the next page DO NOT WRITE ON THIS PAGE ANSWER IN THE SPACES PROVIDED box Turn over ► . Scientists investigated the heart activity of humans at rest, during medium-intensity exercise and during high-intensity exercise. Figure 2 shows the scientists’ results. Figure 2 box