Additional Science B2 Edexcel

TOPIC 1 INSIDE LIVING CELLS

DNA

Fermentation

Using microorganisms

Making proteins

Protein synthesis

Aerobic respiration

Measuring the effects of exercise

Improving measurements

Anaerobic respiration and exercise

Which diet? How much exercise?

DNA in the nucleus controls the whole cell and therefore the whole organism. Students will appreciate that our understanding of how cells work owes a lot to our search for cures for cancer.

Energy for the cell is provided by the chemical reaction called respiration, which is driven by proteins. Proteins are important components of the cell and their production is determined by the genes: genes contain codes that determine the sequence of amino acids in proteins.

In this topic, there are opportunities to measure body functions and investigate how they are affected by physical activities. The data can be interpreted in relation to theories about respiration and oxygen debt. Students can practise measuring accurately and understand that they need to consider safety when collecting data.

There is an opportunity to consider the industrial use and benefits of technological developments, including the cultivation of microorganisms in fermenters. How scientific ideas develop can be demonstrated by the DNA story, from data collection to the leap of imagination.

Guidance for students

Have you ever wondered?

What processes in cells keep you alive?
Why are plants and animals so different?
How does my body know which enzymes to produce?
Why does my heart beat faster when I exercise?
Why do I get cramp?

Learning objectives

• The chemical reactions essential for life take place inside cells.
• Respiring cells require a supply of glucose and oxygen, producing carbon dioxide as a waste
• product.
• Genes are the template for protein synthesis inside cells.
• The digestive, circulatory and respiratory systems provide cells with the basic materials they
• need to carry out their functions.

Glossary

You will be expected to be able to recall, explain, describe and use appropriately the following words and phrases:

adenine cramp guanine ribosome aerobic cultivated insulin RNA amino acid cytosine lactic acid strand anaerobic diffusion microorganism thymine aseptic DNA organelle triplet code bases double helix polypeptide capillary fermentation protein coding glucose respiration fermenter plasmid ventilation mRNA (messenger RNA) tRNA (transfer RNA)

rRNA (ribosomal RNA)

transcription translation

Students will be assessed on their ability to:

• describe a DNA molecule as two strands coiled to form a double helix, the strands linked by a series of paired bases (adenine with thymine and cytosine with guanine) B2 1.1 • explain that DNA controls the joining together of amino acids to make a specific protein in a cell and that the order of bases in a section of DNA decides the order of amino acids in the protein B2 1.2 • explain that sections of DNA coding for specific proteins can be transferred into microorganisms which are then cultivated in fermenters to produce useful substances, including human insulin B2 1.3 • explain that microorganisms use an external food source to obtain energy, changing some substances in the medium and recall that this process is fermentation…