Edexcel a level biology question paper 2 june 2023 salters Nuffield + mark scheme

Please check the examination details below before entering your candidate information Candidate surname Other names Centre Number Candidate Number Pearson Edexcel Level 3 GCE Friday 16 June 2023 Morning (Time: 2 hours) Paper reference 9BN0/02 Total Marks Biology A (Salters Nuffield) Advanced PAPER 2: Energy, Exercise and Coordination You must have: Scientific calculator, pencil, ruler Instructions • Use black ink or ball-point pen. • Fill in the boxes at the top of this page with your name, centre number and candidate number. • Answer all questions. • Show your working in any calculation questions and include units in your answer where appropriate. • Answer the questions in the spaces provided – there may be more space than you need. Information • The total mark for this paper is 100. • The marks for each question are shown in brackets – use this as a guide as to how much time to spend on each question. • You may use a scientific calculator. • In questions marked with an asterisk (*), marks will be awarded for your ability to structure your answer logically showing how the points that you make are related or follow on from each other where appropriate. Advice • Read each question carefully before you start to answer it. • Try to answer every question. • Check your answers if you have time at the end.*P71907A0232* DO NOT WRITE IN THIS AREA DO NOT WRITE IN THIS AREA DO NOT WRITE IN THIS AREA 2  Answer ALL questions. Write your answers in the spaces provided. Some questions must be answered with a cross in a box . If you change your mind about an answer, put a line through the box and then mark your new answer with a cross . 1 During growth, cells divide by mitosis. Many organisms also carry out meiosis to enable sexual reproduction. (a) (i) In which stage of cell division do spindle fibres attach to the centromeres? (1) A anaphase B interphase C metaphase D telophase (ii) In which stage of the cell division does the nuclear membrane start to break down? (1) A interphase B metaphase C prophase D telophase (iii) In which stage of cell division are chromatids first visible when using a light microscope? (1) A interphase B metaphase C prophase D telophase *P71907A0332* Turn over 3 DO NOT WRITE IN THIS AREA DO NOT WRITE IN THIS AREA DO NOT WRITE IN THIS AREA (b) Meiosis is involved in the production of sperm cells. Crossing over during meiosis can result in genetic variation. Explain how crossing over can lead to genetic variation. 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(Total for Question 1 = 6 marks)*P71907A0432* DO NOT WRITE IN THIS AREA DO NOT WRITE IN THIS AREA DO NOT WRITE IN THIS AREA 4  2 It has been estimated that up to 90% of the cells present in a human are prokaryotic. This is due to prokaryotes being present on the skin surface and within the human body. (a) Which one of the following statements comparing prokaryotic DNA with human DNA is correct? (1) A prokaryotic DNA is linear and human DNA is circular B prokaryotic DNA is located in a membrane-bound nucleus C the base thymine is replaced by uracil in the prokaryotic DNA D the sugar in both eukaryotic and prokaryotic DNA is deoxyribose (b) The lac operon is found in some prokaryotes. (i) Describe what is meant by the term operon. 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(ii) Describe the effect of lactose on the lac operon. 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(Total for Question 2 = 6 marks) *P71907A0532* Turn over 5 DO NOT WRITE IN THIS AREA DO NOT WRITE IN THIS AREA DO NOT WRITE IN THIS AREA BLANK PAGE*P71907A0632* DO NOT WRITE IN THIS AREA DO NOT WRITE IN THIS AREA DO NOT WRITE IN THIS AREA 6  3 Damage to the anterior cruciate ligament (ACL) is the most common major knee injury in football. (a) Which of the following describes the structure and function of a ligament? (1) A elastic and attaches bone to bone