Edexcel IGCSE Biology Biology Paper 1 November 2021 question paper 4BI1/1B

The table lists values that can be obtained in practical investigations.

Complete the table by naming pieces of laboratory apparatus that can be used to help obtain these values.

The first one has been done for you.

The diagram shows a red blood cell viewed through a microscope.

The actual width of this red blood cell is 8 µm.

The magnification of this red blood cell can be calculated using this formula.

Calculate the magnification of this red blood cell.

The diagram shows the human heart with four blood vessels labelled A, B, C and D.

Which blood vessel brings oxygenated blood to the heart?

Which blood vessel contains blood at the highest pressure?

Draw a label line on the diagram to show the position of a semi-lunar valve.

Describe the function of the semi-lunar valves.

In the heart of a foetus, the two upper chambers (atria) are linked by a hole so that blood can pass between them.

Explain why this hole is normally closed before the baby is born.

Sometimes the hole does not close.

Explain what effect this will have on the baby.

A student investigates factors that affect photosynthesis.

In his first experiment, the student uses this method to investigate the effect of light on photosynthesis.

• place a plant in the dark for 24 hours

• cover part of leaf X with black paper

• place the plant in the light for 24 hours

The diagram shows the plant in the light.

Describe how the student tests leaf X to show the effect of light on photosynthesis.

In his second experiment, the student uses a water plant to investigate the effect of carbon dioxide concentration on the rate of photosynthesis.

He does the experiment at two different light intensities.

The table shows the student’s results.

Explain the student’s results.

Describe how the student could change the light intensity in this investigation.

Give the dependent variable in this investigation.

Give one way in which the student could control the biotic variable in this investigation.

The diagram shows a yeast cell.

Which row of the table is correct for this yeast cell?

Which type of organism is a yeast cell?

Biofuel is made from ethanol.

Scientists use genetically modified (GM) yeast to produce biofuel.

The GM yeast contains an enzyme that digests plant cell walls to produce glucose.

The yeast uses the glucose in respiration to produce ethanol.

Which of these equations shows the respiration in the yeast?

Name an enzyme used by scientists to genetically modify the yeast.

The GM yeast is a recombinant strain.

State what is meant by the term recombinant.

Suggest why biofuel produced using glucose from plants could reduce global warming.

The graph shows the mass of ethanol produced by GM yeast and by normal yeast over a period of 3 days.

Calculate the percentage increase in the mass of ethanol produced by GM yeast compared to normal yeast after 1 day.

Give two reasons why the rate of ethanol production decreases after 1 day.

Weeds are plants that compete with crop plants.

A scientist investigates the use of two different ways of reducing the population of weeds.

This is her method.

• use chemical control in one field by spraying herbicides, a type of pesticide, that kill the weeds

• use biological control in another field by releasing insects that eat the weeds

• measure the mean (average) number of weeds in each field once a month from February to August

The table shows the scientist’s results.

Describe a method to measure the mean number of weeds per m² in each field.

The scientist concludes that biological control is a better way of controlling weeds than chemical control.

Discuss this conclusion.

Use data from the table and your own knowledge to support your answer.

A student studies the organisms in a pond community.

Which of these is the correct description of a community?

The table shows the number of organisms per m² at different trophic levels in a pond community.

It also shows the total biomass of these organisms per m².

Trophic level	Number of individuals per m2	Total biomass in g per m2
secondary consumers	100	1.0
primary consumers	1.5 104	2.5
producers	7.2 1010	17.5

Calculate the mean mass in g of a single primary consumer.

Give your answer in standard form.

Use the grid to draw a pyramid of biomass for the pond community.

The number of secondary consumers is low because energy transfer is not 100% efficient.

Explain why egestion is one reason why energy transfer is not 100% efficient.

Give two other reasons why energy transfer is not 100% efficient.

Inherited conditions may be caused by a dominant allele (D) or by a recessive allele (d).

The diagram shows a family pedigree for an inherited condition.

The shaded circle shows a female with the condition.

Complete the table by giving the genotype of each individual.

One has been done for you.

The parents have a third child.

Calculate the probability that this third child is female and has the condition.

The graphs show changes in the concentrations of the hormones testosterone and oestrogen in child R and in child S between the ages of 11 to 15.

Explain how the changes in hormone concentrations affect the development of each child.

The table gives the percentage composition by mass of human breast milk, and of cow’s milk.

Discuss whether cow’s milk is a suitable alternative to breast milk for young babies.

Use data from the table and your own knowledge to support your answer.

Human breast milk may contain insufficient vitamin D for a growing child.

Give two ways that additional vitamin D could be provided for the child.

Describe how a sample of cow’s milk could be tested for protein.

The scientist, Richard Doll, collected data about deaths from cancer in the 1950s.

The table shows data for four groups.

Plot a bar chart to show the number of deaths from lung cancer and from other cancers for each of the four groups.

Calculate the difference in the percentage of all deaths caused by lung cancer in heavy smokers compared to the percentage of all deaths caused by lung cancer in light smokers.

This table gives no information about the age of the people who died.

Suggest why age may affect the likelihood of dying from lung cancer.

Explain one effect, other than lung cancer, that smoking has on health.

Humans can control their internal environment.

State the term used to describe the control of an organism’s internal environment.

Coordination uses hormones and nerves.

Some responses are simple reflex arcs.

Describe the structure and functioning of the withdrawal reflex of a finger from a hot object.

Humans use their skin to regulate their body temperature. The diagram shows a section through the skin with two structures labelled A and B.

Changes take place in the skin when a person moves from a warm environment to a cold environment.

Explain the changes that take place in structure A as a person enters a cold environment.

Explain the changes that take place in structure B as the person enters a cold environment.

Modern humans have less body hair than their ancestors.

Explain how this evolutionary change was brought about by natural selection.

Pollution of air or water can affect ecosystems.

Explain the biological consequences of air pollution by sulfur dioxide.

State how sulfur dioxide pollution can be reduced.

Some scientists have suggested that adding hydrogencarbonate solution to soil, instead of adding water, can increase plant growth.

Design an investigation to discover the effect that adding hydrogencarbonate solution has on the growth of seedlings.

Include experimental details in your answer and write in full sentences.