A-Level Edexcel Biology AS Decimal and Standard Form

A-Level Edexcel Biology AS Decimal and Standard Form
Pearson Edexcel International Advanced Subsidiary/Advanced Level in Biology, Issue 2, February 2021Biology XBI11/YBI11

Review A-Level Edexcel Biology decimal and standard form through cell sizes, DNA mass, biomass, gas volume and population calculations.

How this is tested

  • express biological quantities such as DNA mass or cell counts in correct standard form
  • convert ordinary decimals into powers of ten while keeping the stated significant figures
  • compare magnitudes or rates using standard-form values from biological data

Question 5(b)(ii)

[Maximum number: 1]

Mycobacterium tuberculosis (Mtb) and human immunodeficiency virus (HIV) are two pathogens that infect people. When people infected with either pathogen become infected with the other pathogen the disease is worse.

In one year, it was estimated that 33.4 million people were infected with HIV. It was estimated that 30% of these people were also infected with M t b.

Calculate the number of people with both infections. Give your answer in standard form.