Proteins

Delve into the world of structural biology and take a look at protein structure and function.

  • Credit: Paul Wilkinson

Introduction

We have developed a series of clips to explore the Life Fantastic with your students. The pages are intended for use as a prompt to help you prepare when exploring these topics in lessons. Teachers have told us that the videos and questions best suit being used as a topic introduction.

On this page you will find an overview of the topic covered by the clips, a brief summary of each clip, related questions and how the topic links to the curriculum.  This is one of eight available resources on developmental biology. For more topics see the teaching resources list.

Overview

The structures and functions of myosin, haemoglobin and myoglobin are described, and why their structures are suitable for their roles in the body are explained. The clips provide a useful basis on which to consider macromolecules and their construction in general, here with the repeating units of proteins, the amino acids. 

Topics in the videos

  • Understand that the shape of a protein is critical for its role within the body
  • Understand that the shape of a protein is determined by the sequence of amino acids that make it up
  • Describe the structure of three macromolecules
  • Consider the similarity of proteins between one organism and another and the evidence for evolution

The material in this resource is supported by video clips from the CHRISTMAS LECTURES 2013.

Curriculum links

This resource is suitable for Key Stage 4 and AS/A2 level. Full curriculum links are given at the bottom of the page.

Clip 1 - Protein structure

The clip starts with a question: what makes a neuron different from a heart cell? The answer is proteins; the type of proteins a cell produces determines what that cell does. Alison Woollard explains that proteins are one of the biological macromolecules, made up of repeating units of amino acids. The sequence of these amino acids determines the shape and structure of the protein and each protein has a structure perfectly suited to its role. Myosin, for example, has a long tail and bending head that allows it to flex and straighten – this drives muscle contraction. Alison’s second protein, haemoglobin, is seen live in a volunteer’s arm and neck with the VeinViewer scanner. Alison uses the device to see the haemoglobin and the blood within the volunteer’s blood vessels in real time. This amazing demonstration also reveals the arrangement of the blood vessels in the volunteer’s arm, a technique that may be used in the medical practice of the future.

Running Time: 4 min 19 sec

Summary questions

  • What makes a neuron different from a heart cell? (The type of proteins the cell produces, 0:17)
  • What is the basic unit of a protein? (Amino acid, 0:42)
  • Proteins are a polymer of amino acids. How many different amino acids are there? (20, 0:44)
  • Where can you find myosin? What is its job? (In muscle, 1:15; Creates the force required for movement, 1:38)
  • What is the role of haemoglobin? Where can you find it in the body? (Oxygen carrying molecule and within the blood, 1:48)
  • What is cooperative binding? (Described at 2:05)

Background and discussion questions

  • Haemoglobin carries oxygen around the body but it also carries another gas to the lungs. What is the name of that gas?
  • Enzymes are also proteins. Can you name any?
  • Can you draw the structure of an amino acid? What group makes one amino acid different from another?
  • Alison talks about cooperative binding in haemoglobin. Can you describe what this means with the aid of a dissociation curve?

Clip 2 - Myoglobin

Prof Stephen Curry of Imperial College London introduces myoglobin, an oxygen-storing protein that was the first protein structure to be seen by humans. The early model may be crude and rather ugly looking but it represents the beginning of structural biology – a discipline which looks at the 3D shape of molecules to discover more about their function.  Prof Stephen Curry explains how the method they used to determine myosin’s structure in 1958, called X-ray crystallography, has revolutionised the way that we study biology, allowing scientists to look in tremendous detail at biological molecules.

Running Time: 4 min 31 secs

Summary questions

  • What does myoglobin do? (Extract oxygen from blood, store it in muscles, 0:25; binding site for single oxygen molecule, 2:48)
  • What is the level of protein structure shown in the myoglobin model at 0:47 – primary, secondary or tertiary? (Tertiary)
  • How did scientists find the structure of myoglobin? (Firing x-rays at crystals, 1:26)
  • What is that technique called? (X-ray crystallography, 1:49)
  • How many protein chains is haemoglobin made of? (Four, 3:36)

Discussion questions

  • How can protein shapes be used as evidence for evolution?
  • What other molecule structures have been found using X-ray crystallography?

To extend this resource for A-level students, watch the Royal Institution’s short animation on crystallography, Celebrating Crystallography. This animation journeys through the 100 year history of crystallography – from the pioneering work of William and Lawrence Bragg in 1913 to the surface of Mars. To date 28 Nobel Prizes have been awarded to projects related to the field and X-ray crystallography remains the foremost technique in determining the structures of a huge range of complex molecules.

Curriculum links

KS4

The resource illustrates the diversity of protein shape and structure given by different sequences of amino acids and explains that protein structure is strongly related to protein function. This corresponds to the requirements in:

  • AQA GCSE Biology 4401/ Additional Science 4408 Unit 2: Biology 2 B2.5.1 ‘Proteins’;
  • Edexcel GCSE Biology 2BI01/ Additional Science 2SA01 Unit B2 Topic 1 ‘The building blocks of cells’ 1.24.

Haemoglobin is considered in more depth and provides a platform for the teaching of the role of haemoglobin within the blood as referred to in:

  • AQA GCSE Biology 4401 Unit 3: Biology 3 B3.2.1 ‘The Blood System’ and B3.2.2 ‘The Blood’.

AS/A2

The resource examines protein structure in detail, using the examples of myosin, haemoglobin and myoglobin. Haemoglobin is discussed in reference to its role in the in the body and the role of the vasculature is highlighted. This conforms to:

  • AQA GCE Biology AS 1411 Unit 1 BIOL1 ‘Biology of disease’ section 3.1.2 and Unit 2 BIOL2 ‘The variety of living organisms’ section 3.2.4;
  • OCR GCE Biology AS Unit F212 Module 1 ‘Biological molecules’ section 2.1.1.

The similarity in myoglobin and haemoglobin structure between animals as discussed in the second clip gives an example of a protein comparison used to inform evolutionary relationships, a topic corresponding to:

  • AQA GCE Biology AS 1411 Unit 2 BIOL2 ‘The variety of living organisms’ section 3.2.9.

Related content

Celebrating Crystallography

Use these resources on TED-Ed

TED-Ed: Protein structure

TED-Ed: Myoglobin

Watch the full lectures

View the full CHRISTMAS LECTURES, Life Fantastic, along with behind the scenes footage, and related content, at the Ri Channel (www.richannel.org).