1. FAT IN ORGANISMS IMAGES

2. BIGPICTUREEDUCATION.COM This illustration shows the pore-forming proteins that exist in the cell membrane. These integral membrane proteins (usually as subunits made of multiple proteins) pass through the lipid bilayer of the cell membrane. They allow ions to travel in and out of cells, down a concentration gradient. CC BY NC Credit: Maurizio De Angelis/Wellcome Images CC BY NC Ion channels in the cell membrane

3. Model of a section of the lipid bilayer that makes up the cell membrane. A number of different types of proteins are embedded into the bilayer – some span the bilayer, while others are exposed to just one side of the membrane. Some proteins, called glycoproteins, contain carbohydrate side chains. These side chains are added after the protein is produced. CC BY NC Credit: John Wildgoose/Wellcome Images CC BY NC Model of the lipid bilayer

4. Computer graphic showing a cross-section through a lipid bilayer, the basic structure of all biological membranes. Phospholipids organise into two layers, with their hydrophobic tails (shown in green) facing each other in order to protect them from exposure to water. Their polar, hydrophilic heads (shown in yellow) face the outside, where they can interact with water molecules on either side of the bilayer. Lipid bilayers form a continuous barrier around a cell or organelle, providing structure and protection and controlling what enters and exits. CC BY NC Credit: Maurizio De Angelis/Wellcome Images CC BY NC BIGPICTUREEDUCATION.COM Phospholipid bilayer

5. A scanning electron micrograph of a lobule of adipose tissue, clearly showing individual adipocytes (fat cells). In adipocytes, fat is stored as chemically unreactive triglycerides, formed by three fatty acid molecules bonding to a glycerol molecule. The fat in adipocytes can be respired to release energy. The first step is hydrolysis, which is carried out by enzymes called lipases. CC BY NC Credit: David Gregory & Debbie Marshall/Wellcome Images CC BY NC BIGPICTUREEDUCATION.COM Fat cells

6. A light micrograph of a stained section of adipose tissue. Adipocytes (fat cells) are perfectly adapted to their function for fat storage, having large fat reservoirs (white bubbles) that store unreactive triglycerides and take up most of the cytoplasm. CC BY NC Credit: Spike Walker/Wellcome Images CC BY NC BIGPICTUREEDUCATION.COM Adipose tissue

7. Phase-contrast micrograph of fat cells derived from mesenchymal stem cells. The lipid globules within the cells are stained red. CC BY NC Credit: Stephen Elliman/Wellcome Images BIGPICTUREEDUCATION.COM Fat cells derived from mesenchymal stem cells

8. Exclusive Confocal micrograph of mouse adipose (fat) tissue. The adipose cells (red) are surrounded by a network of blood vessels (green). Adipose tissue provides thermal insulation and is also an energy store. CC BY NC Credit: Daniela Malide, NIH, Bethesda, USA/Wellcome Images CC BY NC BIGPICTUREEDUCATION.COM Mouse adipose tissue

9. A computer graphic of the influenza virus. The viral RNA is contained within the capsid, which is itself surrounded by the lipid envelope on the outside. On the outside of the lipid envelope are two surface proteins: haemagglutinin (blue), a lectin that binds the virus to its target cell, and a neuraminidase (green), which helps the newly replicated virus exit the host cell. CC BY NC Credit: Anna Tanczos/Wellcome Images CC BY NC BIGPICTUREEDUCATION.COM Flu virus

10. This computed tomography (CT) scan was produced with a 3D volume-rendering technique in which the skeleton has been made opaque and the soft tissues (fat tissue) semi- translucent. The skull, ribs, vertebrae and bones of the flippers are clearly visible. Conventional CT uses a single X-ray source to scan the animal in a series of virtual slices. These are then digitally reconstructed to produce the 3D image. CC BY NC Credit: Anders Persson/Wellcome Images CC BY NC BIGPICTUREEDUCATION.COM Computed tomography image of a seal

11. Digital artwork showing the sagittal section of the female breast, showing nipple, areola, lactiferous duct and sinuses, lobules and fat layer. Credit:Wellcome Images BIGPICTUREEDUCATION.COM Female breast

12. 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