1. GENERAL PROTEIN IMAGES

2. This computer graphic shows a nuclear pore in a eukaryotic cell. Nuclear pores are large protein complexes that span the nuclear membrane. They allow molecules – including proteins, lipids and other molecules such as mRNA – to move between the nucleus and the cytoplasm. Credit: Dr M Towler and J Aitken, University of Dundee, Wellcome Images The nuclear pore

3. A model of a bacterial ribosome showing the RNA and protein components in the form of ribbon models. In the large (50S) subunit, the 23S RNA is shown in cyan, the 5S RNA in green and the associated proteins in purple. In the small (30S) subunit, the 16S RNA is shown in yellow and the proteins in orange. The three solid elements in the centre of the ribosome, coloured green, red and reddish brown, are the tRNAs in the A, P and E sites respectively. The anticodon loops of the tRNAs are buried in a cleft in the small subunit where they interact with mRNA. The other ends of the tRNAs, which carry the peptide and amino acid, are buried in the peptidyl transferase centre of the large subunit, where peptide bond formation occurs. Credit: MRC Lab of Molecular Biology, Wellcome Images BIGPICTUREEDUCATION.COM Molecular model of a ribosome

4. A movie showing the process of translation. It highlights the 30S and 50S bacterial ribosomal subunits, the mRNA, tRNAs, initiation and elongation factors, and the emerging polypeptide chain. During this process, the genetic code is read from the mRNA and transferred via the tRNAs into the correct sequence of amino acids in the encoded polypeptide. Credit: MRC Lab of Molecular Biology, Wellcome Images BIGPICTUREEDUCATION.COM Translation

5. This colour-enhanced image of part of a kidney cell shows many mitochondria in red, a portion of the nucleus in blue and the cytoplasm in green. The cytoplasm is densely packed with the membranes of the endoplasmic reticulum. Credit: Dr David Furness, Wellcome Images BIGPICTUREEDUCATION.COM Rough endoplasmic reticulum in the retina of a fruit fly

6. A colour-enhanced electron micrograph of part of a pancreas cell showing the nucleus in blue, mitochondria in orange, a lysosome in red and rough endoplasmic reticulum in green. A nuclear pore is also visible in the nuclear membrane towards the bottom right. The horizontal field width of the sample is 2.9 micrometres. Credit: University of Edinburgh, Wellcome Images BIGPICTUREEDUCATION.COM Organelles in a pancreas cell

7. A colour-enhanced image of mitochondria (shown in red), rough endoplasmic reticulum and smooth endoplasmic reticulum. Mitochondria are the energy factories within the cell. Rough endoplasmic reticulum is called this because it has ribosomes (dark blue) attached to its outer surface. Smooth endoplasmic reticulum has no ribosomes attached and is seen towards the bottom of the image. The horizontal field width of the sample is 2.9 micrometres. Credit: University of Edinburgh, Wellcome Images BIGPICTUREEDUCATION.COM Organelles within a liver cell

8. A colour-enhanced image showing the stacked membrane discs of the Golgi complex. The Golgi is the area within a cell where many carbohydrates are synthesised, which can then be used to modify proteins that pass through the Golgi on the way to other parts of the cell. Credit: Dr David Furness, Wellcome Images BIGPICTUREEDUCATION.COM Golgi complex

9. A model of a section of the lipid bilayer that makes up the cell membrane. Several different types of protein are embedded into the bilayer; some span the bilayer, whereas others are only exposed to one side of the membrane. Some proteins carry carbohydrate side chains that are needed for them to function properly. These side chains are added after the protein is produced. Credit: John Wildgoose, Wellcome Images BIGPICTUREEDUCATION.COM Model of the lipid bilayer of the cell membrane

10. This illustration shows the pore-forming proteins that exist in the cell membrane. These integral membrane proteins (usually comprising multiple proteins that form a subunit) pass through the lipid bilayer of the cell membrane and allow ions to travel in and out of cells, usually via an electrochemical gradient. Credit: Maurizio De Angelis, Wellcome Images BIGPICTUREEDUCATION.COM Ion channels

11. A scanning probe image, which shows part of the outer protein coat of the gas vesicle of the alga Anabaena flos-aquae. The cylindrical structure is composed of hoops (ribs) joined side by side. These are the near-vertical bands in the image spaced by 4.57 nm. Within the ribs, a repetitive U-shaped fine structure is visible. This is the beta-sheet motif with an inter-chain repeat distance of 1.12 nm along the rib, and an intra-chain spacing of 0.45 nm. Credit: T J McMaster, Wellcome Images BIGPICTUREEDUCATION.COM Scanning probe image of beta-pleated sheet

12. This diagram shows the hierarchy of a protein structure. It shows the secondary structure, super-secondary structure, motif, alpha-helix, beta-strand, alpha-hairpin, beta-hairpin and four- helical bundle against a white background. Credit: T Blundell and N Campillo, Wellcome Images BIGPICTUREEDUCATION.COM A hierarchical organisation of a protein structure

13. A colour-enhanced image of prion proteins from an animal infected with scrapie, a fatal degenerative disease that affects the nervous systems of sheep and goats. The orange prion protein particles are associated with lipoprotein ‘rafts’ (red) through glycosylphosphatidylinositol linkages. The rafts are specialised microdomains of the membrane rich in cholesterol and sphingolipids. Credit: R Dourmashkin, Wellcome Images BIGPICTUREEDUCATION.COM Prion particles

14. X-ray diffraction pattern An X-ray diffraction pattern of the enzyme glutamate dehydrogenase. Credit: Patrick Baker, Wellcome Images BIGPICTUREEDUCATION.COM

15. Reusing our images Images and illustrations All images, unless otherwise indicated, are from Wellcome Images. Contemporary images are free to use for educational purposes (they have a Creative Commons Attribution, Non-commercial, No derivatives licence). Please make sure you credit them as we have done on the site; the format is ‘Creator’s name, Wellcome Images’.Creative Commons Attribution, Non-commercial, No derivatives licence Historical images have a Creative Commons Attribution 4.0 licence: they’re free to use in any way as long as they’re credited to ‘Wellcome Library, London’.Creative Commons Attribution 4.0 licence Flickr images that we have used have a Creative Commons Attribution 4.0 licence, meaning we – and you – are free to use in any way as long as the original owner is credited.Creative Commons Attribution 4.0 licence Cartoon illustrations are © Glen McBeth. We commission Glen to produce these illustrations for ‘Big Picture’. He is happy for teachers and students to use his illustrations in a classroom setting, but for other uses, permission must be sought. We source other images from photo libraries such as Science Photo Library, Corbis and iStock and will acknowledge in an image’s credit if this is the case. We do not hold the rights to these images, so if you would like to reproduce them, you will need to contact the photo library directly. If you’re unsure about whether you can use or republish a piece of content, just get in touch with us at bigpicture@wellcome.ac.uk.bigpicture@wellcome.ac.uk