Edexcel GCSE Biology Paper 1 Higher November 2021 question paper 1BI0/1H

1 (a) Figure 1 shows a diagram of the human eye.

(i) Which row in the table gives the function of structure X and structure Y?

(ii) Describe the changes that occur in the eye when a bright light is directed into the eye.

(b) Eye tests can detect some brain tumours.

(i) State one other way that brain tumours can be detected.

(ii) Describe why a brain tumour is difficult to treat.

2 (a) Figure 2 shows part of a reflex arc in the spinal cord. sensory neurone

relay neurone

Figure 2

(i) Describe how an impulse passes from the relay neurone to the motor neurone.

(ii) Explain the function of a reflex arc.

(b) A scientist investigated the reaction times of five students using a computer program. The computer screen showed a blue square at the start. As soon as the blue square turned yellow, each student had to press a key on the keyboard as fast as possible. Figure 3 shows the results for the five students.

Figure 3

(i) Which is the median result for these students?

(ii) The scientist wanted to investigate if the colours of the squares used on the computer program affected reaction time. The computer program started with blue squares that turned into yellow squares. Describe how the scientist could compare the reaction times of these students when they respond to red squares turning into yellow squares.

3 (a) Name the organisation which defines health as a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity.

(b) Tuberculosis (TB) is a communicable disease.

(i) State two ways that communicable diseases are different from non-communicable diseases.

(ii) Explain one way that the spread of tuberculosis (TB) can be reduced or prevented.

Complete the table to show the student’s data.

(c) Explain why people with AIDS are more susceptible to TB.

4 Streptococcus mutans is one species of bacteria which causes tooth decay. A scientist tested the effectiveness of toothpaste at killing this species of bacteria. The scientist spread the bacteria Streptococcus mutans across an agar jelly plate.

(a) (i) Which word describes the techniques used to prevent contamination of the agar jelly plate?

(ii) Give two precautions needed to prevent contamination of the agar jelly plate.

(b) The scientist placed a filter paper disc soaked in toothpaste mixed with saliva (disc A) on one half of the agar jelly plate. A filter paper disc soaked in only saliva (disc B) was placed on the other half of the agar jelly plate. The agar jelly plate was kept at 37°C for 24 hours. Figure 5 shows the results.

(i) The diameter of the zone of inhibition around disc A is 9 mm. Calculate the area of this zone of inhibition using the equation πr². Use a value of 3.14 for π. Give your answer to 1 decimal place.

(ii) Give a reason why disc B, soaked in only saliva, was included in this test.

(iii) Suggest two reasons why this test does not prove that toothpaste kills all bacteria on teeth.

(c) Before a new toothpaste can be sold, the toothpaste has to be tested on cultured human cells. Cultured human cells were placed into four identical flasks. Saliva was added to each flask and a different brand of toothpaste was added to each of three flasks. The human cells were left for two hours and the percentage of cells that were healthy was recorded. Figure 6 shows the results.

Explain the conclusion that can be made from this data.

5 (a) Figure 7 shows cells from an onion root tip as seen using a light microscope.

(Source: © Rattiya Thongdumhyu/Shutterstock)

Figure 7

(i) Identify the stages of mitosis shown in cell Q and cell R.

(ii) Describe two processes that occur in cells during prophase.

(iii) State the term used to describe the process which occurs after mitosis, when the cell divides into two.

(iv) The diameter of one cell in Figure 7 is 0.075 mm. Which is this diameter in µm?

(b) A student placed a prepared slide on the stage of a light microscope. Describe how to adjust the microscope to view the slide at a magnification of ×400.

(c) Arthritis is a condition that occurs when cells in joints get damaged or destroyed. Stem cell therapy can be used to treat arthritis. Discuss the benefits and risks of using stem cell therapy to treat arthritis.

6 (a) Figure 8 shows how alcohol consumption increases the risk of developing liver cancer. Someone who does not drink alcohol has a 1.0 risk of developing liver cancer.

alcohol consumed in grams per day

Figure 8

(i) One unit of alcohol contains 8 grams of alcohol. Calculate the risk of developing liver cancer for someone who consumes 4 units of alcohol a day.

_{.............................................................} risk of developing liver cancer

(ii) Describe how cancer develops in the liver.

(b) Haemochromatosis is a disease that occurs when iron accumulates in the liver. A person with haemochromatosis is treated by having 0.5 dm³ of their blood removed each week. This lowers the level of iron in their blood.

(i) Give two safety precautions needed when blood is removed from this person.

(ii) Haemochromatosis can be inherited. Haemochromatosis occurs when a person inherits two copies of a recessive allele. Figure 9 shows the inheritance of haemochromatosis in a family.

Figure 9

State and explain the genotype of female Z.

7 Hipparion is an extinct genus of horse that lived between approximately 20 million and 0.8 million years ago. Figure 10 shows the skeletons of a Hipparion and a modern horse.

Hipparion modern horse (Sources: © Morphart Creation/Shutterstock and © Hein Nouwens/Shutterstock)

Figure 10

(a) (i) Give one method that can be used to date a fossil of a Hipparion.

(ii) Give one reason why scientists have concluded that the modern horse has evolved from Hipparion.

(b) Describe how racehorses alive today have been selectively bred to run faster.

* (c) Discuss the advantages and disadvantages of sexual reproduction and asexual reproduction.

8 Chymosin is an enzyme that causes milk to curdle. When milk curdles the proteins in the milk clump together and become solid.

(a) As part of an investigation, milk was heated in test tubes to different temperatures using a Bunsen burner. Two drops of chymosin solution were added to each test tube and the time taken for the milk to curdle was recorded. Figure 11 shows the results.

Figure 11

(i) Which variables need to be kept constant in this investigation?

(ii) Explain why the time taken for the milk to curdle decreases from 30°C to 40°C.

(iii) Explain what the expected result would be if two drops of chymosin were added to the milk at 70°C in the test tube.

(iv) As part of this investigation, test tubes containing only milk were heated to each temperature and no chymosin solution was added. State why these test tubes containing only milk were used.

(v) Describe two improvements that could be made to the method of this investigation so that the optimum temperature for chymosin can be found.

(b) Chymosin can be produced by genetically modified bacteria. Figure 12 shows a bacterial cell.

Figure 12

Explain how to genetically modify a bacterial cell to produce chymosin.

9 (a) Figure 13 shows a sperm cell.

Figure 13

Describe how structure A and structure B enable fertilisation.

structure A

structure B

(b) Figure 14 shows a human egg cell, magnified ×700.

(Source: © Pascal Goetgheluck / Science Photo Library)

Figure 14

Calculate the actual width of the region indicated by the line on Figure 14. Give your answer in millimetres, in standard form.

* (c) A student investigated the movement of water. Hens’ eggs were placed in vinegar for two days to dissolve the shell. This makes the eggs permeable to water. The eggs were then weighed and placed in different solutions. After 24 hours the eggs were weighed again. Figure 15 shows the results.

Figure 15

Evaluate the results of this investigation. You should include calculations using the data in Figure 15.

10 (a) One gene can have several different alleles. Explain why these alleles can produce proteins with different structures.

(b) Monoclonal antibodies are proteins. Figure 16 shows the process of monoclonal antibody production.

mouse hybridoma

Figure 16

(i) Which type of cell is added to the B lymphocytes to produce the hybridoma?

(ii) A person with blood group A has the A antigen on the surface of their red blood cells. Monoclonal antibodies can be used to detect the A antigen on red blood cells to determine the blood group of a person. Explain why monoclonal antibodies, used to detect blood group A, would not react with the blood of a person with blood group B.

(c) The allele for blood group A and the allele for blood group B are codominant. Gregor Mendel investigated the inheritance of alleles using flowering plants. He showed that the allele for red flowers (I) is codominant with the allele for He showed that the allele for red flowers (I^R) is codominant with the allele for white flowers (I^W). A heterozygous plant produces pink flowers.

(i) Give the genotype for a plant producing white flowers.

(ii) Explain the outcome if two plants that produce pink flowers are crossed. You should complete the Punnett square as part of your answer.

(TOTAL FOR PAPER = 100 MARKS)