Edexcel GCSE Combined Science Paper 1: Biology 1 Foundation June 2019 question paper 1SC0/1BF

A student investigated mitosis in the root tip of a garlic plant.

Explain why the student used the tip of the root.

The student squashed the root tip on a microscope slide to spread out the cells.

The slide was placed on the stage of a microscope.

Describe how to use the microscope to obtain a clear image of the cells.

The student could not see the chromosomes inside the cells.

State what can be added to the root tip squash to make the chromosomes visible.

Figure 1 shows a root cell in a stage of mitosis.

Which stage of mitosis is shown in Figure 1?

Describe what is happening in Figure 1.

Chlamydia is caused by a pathogen.

Chlamydia is transmitted by

The type of pathogen that causes chlamydia is a

Figure 2 shows the number of cases of chlamydia in the United Kingdom per 100 000 people between 1996 and 2013.

Describe the trend in the number of cases of chlamydia between 1996 and 2013.

State the number of cases of chlamydia per 100 000 in 2013.

The population of the United Kingdom in 2013 was 64 000 000.

Calculate the number of people with chlamydia in 2013.

Figure 3 shows the activity of the enzymes pepsin and trypsin at different pH

Describe the trend in the graph for the enzyme trypsin.

Use data from the graph to support your answer.

State the optimum pH for the enzyme pepsin.

Pepsin only works effectively in the stomach.

Describe the conditions in the stomach that allow pepsin to work effectively.

At high pH values the active site of the enzyme pepsin changes shape.

When the active site of the enzyme changes shape, the enzyme is

State what is produced when proteins are digested.

A karyogram is a picture of the chromosomes found in the nucleus of a single cell.

Figure 4 shows a human karyogram.

State two reasons why this karyogram cannot be from a gamete (sex cell).

State the gender shown by this karyogram.

Complete the Punnett square to show how gender is inherited.

State the probability that a child will be male.

Figure 5 shows two sperm cells.

Name structure Z.

Sperm B has a larger middle section than sperm A.

Explain why sperm B will be more likely to fertilise an egg than sperm A if they were both released at the same time.

James Watson and Francis Crick built a model that showed that DNA has a double helix structure.

Which statement about DNA is correct?

Figure 6 shows the percentage of each base in human DNA.

Describe how this data provides evidence for base pairing in DNA.

A scientist obtained a mass of 0.0062 nanograms of DNA from a diploid human cell.

Calculate the mass of DNA the scientist should obtain from a haploid human cell.

Give your answer in picograms.

(1 nanogram = 1000 picograms)

_........ picograms

A student used the method shown in Figure 7 to compare the mass of DNA extracted from strawberry fruit cells and from kiwi fruit cells.

State why ethanol is used.

State two variables the student needs to control when using this method to compare the mass of DNA from these two fruits.

The student repeated the experiment.

Give one reason why.

Mitosis and meiosis are processes that produce new cells.

Compare the outcomes of mitosis and meiosis.

Clostridium tetani is a bacterium that can be found in soil.

It causes the infection tetanus.

Children are vaccinated against tetanus.

Explain why these children do not get tetanus if the bacteria enter their body through a cut in the skin.

Colistin is an antibiotic used to treat infections in the bloodstream.

Some bacteria are resistant to Colistin.

Explain how these bacteria have become resistant to Colistin.

*(c) Figure 8 shows three stone tools found in different layers of rock.

Explain how information from Figure 8 provides evidence for human evolution.