Edexcel IGCSE Biology Biology Paper 1 January 2020 question paper 4BI1/1B

The diagram shows a forest food web.

How many producers are shown in this food web?

How many secondary consumers are shown in this food web?

The coyote uses some of its senses to catch deer.

Name the sense that uses receptor cells in the retina.

A coyote runs 530 metres in 30.0 seconds trying to catch a deer.

Calculate the speed of this coyote in metres per second.

The coyote will not catch the deer if too much lactic acid builds up in its muscles.

Explain why lactic acid builds up in the coyote’s muscles when it runs.

Organisms can be classified into groups based on their features.

State three differences between eukaryotic and prokaryotic organisms.

Give an example of a disease caused by a protoctist.

name of protoctist_........

Squirrels are animals that live in woodland. They feed on nuts produced by the trees.

The diagram shows a squirrel eating a nut.

Describe a method you could use to show that the nut contains fat.

The table lists substances found in two types of nut, A and B.

The mass of each substance is given in milligram per gram of nut.

Explain the role of fibre in the squirrel’s diet.

Explain which nut is better at helping the squirrel make red blood cells.

Nut A has a mass of 28.0 grams.

Calculate the total mass of carbohydrate in this nut.

Enzymes are biological molecules that act as catalysts in metabolic reactions.

State what is meant by the term catalyst.

State what is meant by the term metabolic.

A teacher investigates the effect of enzyme concentration on the rate of a reaction.

He uses the enzyme catalase, which is found in potato.

He changes the enzyme concentration by adding different numbers of potato discs.

Catalase breaks down hydrogen peroxide solution into water and oxygen.

This is his method.

● cut same-sized discs from a potato

● put 5 cm³ of hydrogen peroxide solution into each of five test tubes

● add a different number of potato discs to the hydrogen peroxide

● measure the volume of oxygen gas produced in three minutes

The teacher repeats each test four times for each concentration.

He then calculates the mean rate of oxygen production for each concentration.

The table shows his results.

Plot a line graph to show the effect of enzyme concentration on the mean rate of oxygen production.

Use a ruler to join the points with straight lines.

Explain the effect of increasing enzyme concentration on the rate of oxygen production.

Name a piece of apparatus suitable for measuring the volume of oxygen produced.

Explain why it is important for the teacher to keep the volume and concentration of the hydrogen peroxide constant.

Name another variable the teacher should keep constant in his investigation.

Farmers can increase their crop yield by growing crops in a temperature controlled glasshouse.

Explain how increasing the temperature can result in an increase in crop yield.

Farmers sometimes use a type of heater that burns gas or oil to raise the temperature of their glasshouse to improve crop yield.

Explain why they use this type of heater to improve crop yield.

Some farmers also add chemical fertilisers to their crops in a glasshouse.

Different minerals are added to chemical fertilisers. Explain one mineral that should be added to these fertilisers.

Discuss why some farmers limit the amount of chemical fertilisers they add to their crops.

The human liver produces bile.

Explain the role of bile in digestion.

These are the three main blood vessels attached to the liver.

● hepatic artery

● hepatic vein

● hepatic portal vein

How many of these blood vessels transport deoxygenated blood from the liver?

A scientist investigates the glucose concentration in a person’s hepatic portal vein and hepatic vein after the person has eaten a meal.

This is the scientist’s method.

● give a person a meal to eat

● after one hour take a blood sample from the hepatic portal vein and a blood sample from the hepatic vein

● measure the glucose concentration in both samples

● after five hours take another blood sample from each of the two veins

● measure the glucose concentration in both samples

The table shows the scientist’s results.

After one hour, the concentration of glucose in the hepatic portal vein is higher than the concentration of glucose in the hepatic vein.

Explain this difference in concentration.

After five hours, the concentration of glucose in the hepatic vein is higher than the concentration of glucose in the hepatic portal vein.

Explain this difference in concentration.

The diagram shows a male fruit fly with long wings and a female fruit fly with long wings.

Wing length in these flies is controlled by a gene with two alleles.

The dominant allele (L) produces long wings and the recessive allele (l) produces short wings.

A male and a female fruit fly mate.

The table shows the number of male and female offspring with long wings and short wings.

Which of these describes the genotypes of the parent fruit flies?

Genetic diagrams are used to show how sex is inherited.

Complete the genetic diagram to show that equal numbers of male and female offspring are produced.

Explain why the results of the cross might not produce exactly equal numbers of male and female offspring.

Fruit flies feed on decomposing fruit.

The smell of the fruit attracts the fruit flies.

Design an investigation to find out if the smell of decomposing apples attracts fruit flies more than the smell of decomposing bananas.

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

The diagram shows a section through a leaf with different parts labelled P to U.

Which part of the leaf transports amino acids?

Which part absorbs the most sunlight?

Which part transports the products of photosynthesis?

Which part reduces the amount of water escaping?

Explain how the structure and position of cells in parts R and T help the leaf to photosynthesise.

The diagram of the leaf section is magnified 100 times.

Determine the actual thickness of the leaf.

The photograph shows water lilies, plants that float on the surface of ponds.

Suggest why the leaves of the water lily only have stomata on their upper surface.

Phagocytes and lymphocytes are white blood cells involved in the immune response.

Explain the role of lymphocytes in the immune response.

Phagocytes ingest bacteria.

Explain what happens to bacteria after they have been ingested by phagocytes.

A scientist uses this method to investigate how vitamin C affects ingestion of bacteria by phagocytes.

● add different concentrations of vitamin C solution to three test tubes

● add distilled water to a fourth test tube

● add phagocytes to each tube

● leave the tubes for one day

● add 10 cm³ of a culture of non‑pathogenic bacteria to each tube

● keep each tube at 35C for two hours

● measure the number of bacteria ingested

The graph shows the scientist’s results.

concentration of vitamin C in arbitrary units

Which of these is the rate of ingestion of bacteria in the control?

State the independent variable in this investigation.

State two biotic variables the scientist should control.

The scientist concludes that vitamin C in a person’s diet will protect people from pathogens.

Comment on this conclusion.

The diagram shows some of the structures involved in fertilisation in a flowering plant.

Name the parts labelled A, B and C.

On the diagram, draw the path the pollen tube takes after the pollen grain has germinated.

Describe what happens to the structures in part C after fertilisation.

A scientist investigates the effect of four different storage conditions on the germination of grass seeds.

She stores 500 seeds in each storage condition for two months.

She then counts the number of seeds that germinate when planted.

The table shows her results.

Calculate the percentage increase in the number of seeds that germinate in wet and cold conditions compared to the number of seeds that germinate in wet and warm conditions.

Suggest why fewer seeds germinate when they are stored in wet and warm conditions than in the other conditions.

Give one observation that shows a seed has germinated.