Edexcel GCSE Combined Science Paper 1: Biology 1 Higher November 2020 question paper 1SC0/1BH

The human immunodeficiency virus (HIV) can cause AIDS.

Which type of cell is destroyed by the HIV virus?

Describe how the specific immune system defends the body against disease.

Figure 1 shows the number of people per million of the population in five European countries who were diagnosed with measles in one year.

The population of Belgium in that year was 11.18 million.

Calculate the number of people in Belgium diagnosed with measles.

Give your answer to three significant figures.

_........ people

Countries do not report the total number of people diagnosed with measles. Countries report the number of people diagnosed with measles per million of the population.

Give one reason why this is better.

Give one reason why the number of people per million diagnosed with measles is different in these countries.

Figure 2 shows a banana plantation.

After the bananas have been harvested, the old plants are cut down.

The suckers then develop into mature plants producing the next crop of bananas.

The tip of each sucker contains a group of cells called a meristem.

Describe the function of a meristem in the growth of a plant.

A student took a sample of cells from a meristem to view under a light microscope.

Describe how the student would prepare a microscope slide using these cells.

Figure 3 is a drawing of a eukaryotic cell.

Structure Z is found in plant leaf cells.

Name structure Z.

Give one function of the mitochondrion.

Describe how a prokaryotic cell is different from the cell in Figure 3.

Figure 4 shows a great tit on a bird feeder.

Scientists have found that great tits living now have longer beaks than great tits living 50 years ago.

Genetic analysis shows changes in the sequence of the bird’s DNA.

Give the complementary strand sequence for this DNA template.

Which statement correctly describes a DNA molecule?

State the term used to describe a change in the sequence of DNA bases.

Scientists think that great tits living now have longer beaks because of the increased use of bird feeders during the last 50 years.

Explain how natural selection could have caused an increase in beak length because of the use of bird feeders.

Birds are classified in the domain Eukarya.

Why are the cells from birds described as eukaryotic?

Give one reason why the three domain classification system was proposed.

A student mixed 10 cm3³ of starch solution with 5 cm³ of amylase solution and kept the tube in a water bath at 25 °C.

The student tested the solution for starch and for glucose every 30 seconds.

Figure 5 shows the results.

Give one reason for the result at 150 seconds.

Another student repeated the investigation with the same volumes of solutions and at the same temperature of 25 °C.

Give two other variables that would need to be controlled in the investigation.

Both students also included a tube containing 10 cm³ of starch solution with 5 cm³ of distilled water instead of 5 cm³ of amylase solution.

They tested the solution for starch and for glucose every 30 seconds.

Give one reason why this tube was included in their investigations.

Amylase has an optimum pH of 6.8.

Devise a method the students could use to confirm the optimum pH for amylase.

Amylase is produced by salivary glands and the pancreas.

Explain why amylase is not produced in the stomach.

The reaction time of five people was tested using a computer.

These people were then given 100 cm³ of a liquid to drink.

Their reaction times were recorded 10 minutes after drinking the liquid.

Figure 6 shows the results.

Calculate the mean difference in reaction time.

Give your answer in milliseconds.

_........ ms

The drinks manufacturer wants to advertise the effect of the drink on reaction time.

The manufacture needs to confirm the effect on reaction time by improving the investigation.

Give two improvements the manufacturer would need to make to this investigation.

Figure 7 shows a neurone.

Name the type of neurone shown in Figure 7.

Which row identifies structure P and structure Q ?

*(c) Some painkillers prevent neurotransmitters binding to receptors in a synapse.

Explain how a signal is transmitted at a synapse and how the painkillers reduce the pain felt by the person.

Cancer Research UK found that many people do not realise that obesity is linked to an increased risk of developing cancer.

In the body, fat tissue sends signals that cause other cells to divide.

Describe how this could cause cancer to develop.

Cell division occurs during the cell cycle.

During which stage of the cell cycle is DNA replicated?

Obesity is linked to 1 in 20 cases of all types of cancer.

Approximately 13% of cases of bowel cancer are caused by obesity.

Determine how the impact of obesity on bowel cancer compares to the impact of obesity on all types of cancer.

Two men have the same mass of 80 kg.

One man’s BMI is categorised as normal weight, the other man’s BMI is categorised as obese.

Explain why the men have different BMI values.

Obesity can also cause cardiovascular disease to develop.

Describe the different treatments available for cardiovascular disease.