Edexcel IGCSE Biology Biology Paper 1 November 2023 question paper 4BI1/1B

This food web comes from a woodland ecosystem.

Which organism is the producer?

Which organism is a secondary consumer?

Which organism is both a secondary and a tertiary consumer?

A farmer is using a pesticide in fields next to the woodland. The pesticide is reducing the numbers of greenfly and caterpillars in the woodland.

Explain what effect this may have on the blackbirds in the woodland.

Describe a different method the farmer could use to reduce the number of greenfly on his crops.

A student investigates the effect of different concentrations of sucrose on potato tissue. The student first makes a series of sucrose solutions using this dilution table.

Complete the table by writing the volume of distilled water for test tube 2.

This is the student’s method. Step 1 cut six equal-size cylinders of potato each 5 cm in length Step 2 dry the cut surfaces using filter paper Step 3 measure the mass of each cylinder Step 4 place one cylinder of potato in each of the six test tubes containing

• 20 cm³ of 1 molar (1.0 mole per litre) sucrose solution

• 20 cm³ of 0.8 molar sucrose solution

• 20 cm³ of 0.6 molar sucrose solution

• 20 cm³ of 0.4 molar sucrose solution

• 20 cm³ of 0.2 molar sucrose solution

Step 5 put a bung in each test tube and leave the test tubes for one hour Step 6 remove the cylinders from each test tube Step 7 dry the cylinders with filter paper Step 8 measure the mass of each cylinder again

Explain the reason for step 7 in the student’s method.

The table shows the student’s results.

Calculate the percentage change in mass for the 0.4 mole per litre sucrose solution.

percentage change =_........

Comment on the effect of the different concentrations of sucrose on the potato tissue.

3 (a) A student investigates the differences between inhaled and exhaled air using this apparatus.

They use solution X to compare the concentration of carbon dioxide in inhaled and exhaled air. Give the name of solution X.

Explain the changes that will take place in solution X in test tube A and in test tube B.

Other than concentration of carbon dioxide, state one other difference between exhaled air and inhaled air.

Another student investigated the effect of the duration of exercise on their breathing rate. These are their results.

Give the independent variable in this investigation.

Plot a line graph to show the effect of duration of exercise on breathing rate. Join the points with straight lines.

Describe the effect of duration of exercise on breathing rate.

Give one way the student could improve the reliability of their investigation.

The diagram shows two samples of blood seen using a high power microscope. One sample is of normal blood and the other sample is from a patient with a blood condition.

Erythrocytes Neutrophil Lymphocyte Monocyte Platelets

State two differences between the normal blood sample and the sample from the patient with the blood condition.

The line P–Q shown on the diagram has an actual length of 25 µm. [1000 µm = 1 mm] Calculate the magnification of the diagram.

magnification = _........

In a healthy person 1 cm³ of blood contains 5.0×10⁹ red blood cells. An adult has 5.0 litres (5.0 dm³) of blood in their body. Calculate the number of red blood cells in the body of a healthy adult. Give your answer in standard form. [1 dm³ = 1000 cm³]

Using the information from the diagram and your own knowledge, comment on the likely effect of the blood condition on the patient.

Guinea pigs have either long hair or short hair. The hair length is controlled by one gene with two alleles. The photograph shows a guinea pig with long hair and a guinea pig with short hair.

(Source: © Kallayanee Naloka/Shutterstock)

State what is meant by the term allele.

A breeder did the following crosses. Cross 1 a male long-haired guinea pig with a female short-haired guinea pig, this produces five offspring all with short hair Cross 2 a male short-haired guinea pig with a female long-haired guinea pig, this produces four offspring all with short hair Cross 3 a male short-haired offspring from cross 1 with a female short-haired offspring from cross 2, this produces some offspring with long hair and some offspring with short hair

Draw a genetic diagram to show the parents, gametes and all possible genotypes and phenotypes of the offspring from cross 3.

Calculate the probability that the first offspring born from cross 3 is a male with short hair.

Some short-haired guinea pigs are homozygous and some short-haired guinea pigs are heterozygous. Explain how a breeder could use a cross to determine the genotype of a short‑haired guinea pig.

Guinea pigs stay completely still and do not move when they sense danger. Describe how this behaviour has evolved by natural selection.

The diagram shows a human reflex arc with some structures labelled. It is the withdrawal reflex, which allows a person to remove their hand from a hot object quickly.

Which structure is the sensory receptor?

Which structure is the cell body of the relay neurone?

Which structure is the motor neurone?

Which structure is the effector?

A nerve impulse travels at 50 metres per second.

Calculate the time taken for an impulse to travel 180 cm.

The length of the nerve pathway in the withdrawal reflex arc is 180 cm. The time a person takes to remove their hand away from a hot object is called the response time. Explain why the actual response time is different from the time taken for a nerve impulse to travel 180 cm.

Biologists classify organisms into different groups. Two of these groups are bacteria and fungi.

Complete the passage about bacteria by writing a suitable word or words in each blank space.

Bacteria are small_........ celled organisms. They have a cell membrane and a cell_........ , made of peptidoglycan. Some bacteria are able to use the energy from the Sun to carry out _........ but other bacteria are_........ and feed on dead and decaying organisms. Bacterial cells do not have a nucleus but most of their genetic material is contained in a circular_........ of DNA. They also have small circles of DNA called_........ in their cytoplasm. Some bacteria are used by humans in food production. An example is using

Other bacteria, such as Pneumococcus, cause disease and so are called

A microscopic single-celled fungus, yeast, is used in the production of bread. Describe how yeast is used to produce bread.

The diagrams show the female reproductive system and the male reproductive system with some structures labelled.

Which structure produces gametes?

Which structure is the site of fertilisation?

In which structure does the placenta usually develop?

Some males have an operation called a vasectomy. This means that they do not release sperm. This involves cutting and sealing the sperm ducts (vas deferens) inside the man’s scrotum.

On the diagram draw two lines to show where the cuts are made.

Explain why this operation can be used as a permanent way of preventing pregnancy.

Female sterilisation is another operation that can be used as a permanent way of preventing pregnancy. This involves cutting and sealing the fallopian tubes (oviducts). Scientists compared female and male sterilisation, looking at the outcomes of the operations. This is their data.

The scientists concluded that male sterilisation should be recommended for most couples considering a permanent way of preventing pregnancy. Discuss this conclusion using data from the table.

Farmers and scientists have worked together for the last 50 years to develop crop plants and farm animals with desired characteristics.

Explain why selective breeding with crop plants is easier and quicker than selective breeding with farm animals.

Selective breeding in cattle has been used to improve features such as higher milk yield, longer life and increased muscle mass. Describe how selective breeding can be used to improve milk yield in dairy cattle.

Scientists and farmers are also selecting animals based on behaviour and temperament.

Suggest why an animal with a calmer temperament may be more suitable for the farmer on a dairy farm.

Cattle behaviour is also affected by the hormone adrenaline. When cattle are more stressed, they have higher levels of adrenaline. The effect of adrenaline on the cattle nervous system is similar to the effect of adrenaline in humans. Describe the production of adrenaline and its effects on the body.

Stress in cattle can also affect their reproductive system, leading to damage to the placenta. Describe the role of the placenta in reproduction.

Plants absorb light energy for photosynthesis. Some colours of light result in a higher rate of photosynthesis than other colours of light. Devise an investigation to discover which colour of light results in a higher rate of photosynthesis. Include experimental details in your answer and write in full sentences.