AQA GCSE BIOLOGY PAPER 2H HIGHER TIER VERSION 1

AQA GCSE BIOLOGY PAPER 2H HIGHER TIER VERSION 1 GCSE Monday 1 June 2020 Afternoon Time allowed: 1 hour 15 minutes Materials For this paper you must have: • a ruler • a scientific calculator. Instructions • Use black ink or black ball-point pen. • Pencil should only be used for drawing. • Fill in the boxes at the top of this page. • Answer all questions in the spaces provided. • 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). • Do all rough work in this book. Cross through any work you do not want to be marked. • In all calculations, show clearly how you work out your answer. Information • The maximum mark for this paper is 70. • The marks for questions are shown in brackets. • You are expected to use a calculator where appropriate. • You are reminded of the need for good English and clear presentation in your answers. *jun20 464 2h01* IB/M/Jun20/E9 8464/B/2H This question is about DNA and genes. box . Which diagram represents a DNA molecule? Tick () one box. . Describe the structure of a DNA molecule. [1 mark] [1 mark] 0 1 . 3 A gene is a small section of DNA on a chromosome. Complete the sentences. [2 marks] A gene codes for a particular sequence of . This sequence makes a specific . . What is meant by the term genome? [1 mark] box . The complete human genome is now known. Which important scientific advance was made using knowledge of the human genome? Tick () one box. [1 mark] Discovering antibiotic resistant bacteria Finding more foods to eat from tropical forests Tracing how aboriginal people spread across Australia Working out when the last ice age ended Question 1 continues on the next page Turn over ► box . All the snails are different. What scientific term describes differences in characteristics between individuals of a species? [1 mark] . A change in DNA has caused snail P to be very different from the other five snails. Suggest why there might be an increasing number of snails similar to snail P in each future generation. [2 marks] Turn over for the next question DO NOT WRITE ON THIS PAGE ANSWER IN THE SPACES PROVIDED box Turn over ► box . A student investigated whether using the right hand or the left hand had an effect on reaction time. The student only tested right-handed people. Describe a method for the student’s investigation. box Include details of the test you would use for reaction time. [4 marks] Question 2 continues on the next page *07* Turn over ► A different student carried out an investigation to see if playing tennis improved reaction time. The student used two groups of six people. Table 1 shows the results. Table 1 box Person Reaction time in seconds People who play tennis People who do not play tennis 1 0.2 0.3 2 0.4 0.4 3 0.3 0.6 4 0.4 0.5 5 0.2 0.3 6 0.3 0.2 Mean X 0.4 . Calculate mean value X in Table 1. [2 marks] X = seconds . What is the dependent variable in the student’s investigation? [1 mark] *0* The student concluded: box ‘Playing tennis improves reaction time.’ . Give one piece of evidence which supports the conclusion. [1 mark] . Give one piece of evidence which does not support the conclusion. [1 mark] Turn over for the next question Turn over ► There is a need to grow enough food for all the people in the world. Growing enough food affects habitats and biodiversity. box . What is meant by the term biodiversity? [1 mark] Peat bogs are being destroyed because peat is used by humans. Destroying peat bogs also reduces biodiversity. . Give one use of peat taken from peat bogs. [1 mark] . Explain why the use of peat is harmful to the environment. Do not refer to biodiversity in your answer. [2 marks] box . Most of the world’s production of antibiotics is used in farming. Antibiotics are given to animals to prevent the spread of disease. Explain how the widespread use of antibiotics in farming is a threat to human life. [4 marks] Turn over ► . In sexual reproduction, cells divide by meiosis to form gametes. Which two statements are true for cell division by meiosis? Tick () two boxes. [2 marks] box Daughter cells have two sets of chromosomes. Four daughter cells are formed. The daughter cells are genetically identical. The DNA replicates twice. The parent cell divides twice. box . Label the endocrine glands on Figure 3. [3 marks] Question 4 continues on the next page Turn over ► . Complete Table 2. [3 marks] box Table 2 Hormone Name of gland which releases hormone Target organ of hormone Luteinising hormone (LH) Pituitary gland Adrenal gland Glucagon Millions of geranium plants are sold each year in garden centres. Geraniums can be reproduced asexually or sexually. Figure 4 shows a potted geranium plant. Figure 4 Turn over for the next question box Turn over ► This question is about inheritance. Humans have 23 pairs of chromosomes in each body cell. One pair of chromosomes determines sex. box . Complete Figure 5. [2 marks] Male Figure 5 Female . In some families all children are the same sex. Give the reason why. [1 mark] Cystic fibrosis (CF) is an inherited disorder. box . A man and a woman do not have CF. The man and the woman have a child who has CF. Draw a Punnett square diagram to find the probability that their next child will have CF. Use the symbols: T = dominant allele t = recessive allele Draw a ring around the genotype of any children with CF. [4 marks] Probability = Question 5 continues on the next page *17* Turn over ► Embryo screening for CF can be done by two methods. Method 1 • The woman becomes pregnant by sexual intercourse. • After 10 weeks of pregnancy a fine needle is inserted into the uterus. • A sample of the fluid surrounding the embryo is taken. • The DNA of the embryo is tested for CF. The screening is done free by specialist hospitals for couples who are at risk of having a child with CF. There is a small risk of miscarriage. Method 2 • The couple use In Vitro Fertilisation (IVF) to produce a small number of embryos. • Each embryo is tested for CF. • One or two embryos without CF are implanted in the woman’s uterus. In 2017 the success rate for having a baby by IVF for women under 35 years was 30% IVF is a stressful, invasive procedure. In most UK areas the free public health service does not provide IVF for all women asking for it. box *1* box . Suggest one advantage of Method 2. [1 mark] Turn over for the next question Turn over ► Scientists believe that the first life on Earth was primitive anaerobic bacteria which first appeared billions of years ago. box . Which domain of the three-domain classification system do these primitive anaerobic bacteria belong to? [1 mark] Scientists have identified five periods of mass extinction since the fossil record began. Figure 6 shows the timeline of the five mass extinction events. Figure 6 . Ammonites were organisms that first appeared in the oceans 415 million years ago. Ammonites disappeared in the 5th mass extinction. Draw a horizontal line on Figure 6 to show the time period that ammonites existed on Earth. Label the line ‘ammonites’. [1 mark] . Another type of organism that existed in the oceans was called trilobites. Trilobites existed from 544 million years ago until 278 million years ago. How many more years did ammonites exist than trilobites? [2 marks] box years . There was an increase in the percentage of species which became extinct in the third mass extinction compared to the first mass extinction. Calculate the percentage increase. [3 marks] Turn over for the next question Turn over ► Human activities affect the environment. . Describe the reasons why deforestation takes place and the effects deforestation has on the environment. box [6 marks] Forests have been called: box ‘The lungs of the planet.’ . Describe one way forests being called ‘The lungs of the planet’ can be considered to be a correct statement. [1 mark] . Trees do not have lungs. Describe one other way forests being called ‘The lungs of the planet’ is an incorrect statement. [1 mark] END OF QUESTIONS There are no questions printed on this page DO NOT WRITE ON THIS PAGE ANSWER IN THE SPACES PROVIDED box Question number Additional page, if required. Write the question numbers in the left-hand margin. *27* There are no questions printed on this page DO NOT WRITE ON THIS PAGE ANSWER IN THE SPACES PROVIDED box Copyright information For confidentiality purposes, all acknowledgements of third-party copyright material are published in a separate booklet. This booklet is published after each live examination series and is available for free download from . Permission to reproduce all copyright material has been applied for. In some cases, efforts to contact copyright-holders may have been unsuccessful and AQA will be happy to rectify any omissions of acknowledgements. If you have any queries please contact the Copyright Team. Copyright © 2020 AQA and its licensors. All rights reserved. *2* *206g 464/ /2H*