<p>Animated Powerpoint presentation to support a lesson on 4.1.1 phagocytosis, clonal selection and clonal expansion of B and T cells. I have prepared these in outline and more notes can be added as needed. I have provided a link to one of my videos to revise the steps of phagocytosis. The animated slides show how helper T cells are activated and undergo clonal expansion. I then show how B cells undergo activation and clonal expansion. I also show the same process for killer T cells and show a link to one of my videos which clarifies the distinction between the process of activation of helper and killer T cells (this last bit is slightly beyond A level but this extra bit of detail may help clarify some confusion arising from textbook over-simplification).</p>

<p>Includes a black mindmap, a scrambled list of answers and the completed mindmap. The mindmap describes clonal selection and clonal expansion of B and T cell populations</p>

<p>This YouTube video comes with</p> <ol> <li>a pdf summary of the video</li> <li>an unannotated version of the summary sheet that students can fill in using the video. This sheet has only the pictures from the video.</li> <li>an unannotated version with scaffolding</li> </ol> <p>Phagocytes have evolved over millions of years to be able to recognise common features of pathogens. They carry various receptors on their surface for this purpose. They are part of the first stages of a response to infection. This is described as innate immunity because it is not learned through exposure during a single lifetime. It is described as part of the cellular immune response to to distinguish it from an antibody response. However, antibodies enhance phagocytosis. Phagocytosis by macrophages also plays a key role in the initiation of an antibody response because macrophages can present antigens to helper T cells. Macrophages also release cytokines that stimulate antibody responses.</p>

<p>For this puzzle various keywords need to be matched with their definition by arranging cut-out shapes.</p>

<p>A visual summary of the Calvin cycle in pdf format with a video link (QR code) to a YouTube video showing the summary being developed</p>

<p>Why do plants produce oxygen and need light? A YouTube video including a pdf summary of the video. The summary contains a QR code link for quick access to the video.</p>

<p><a href="https://youtu.be/3U4AhlOX3Tw" target="_blank" rel="nofollow">https://youtu.be/3U4AhlOX3Tw</a></p> <p>Here’s a quick summary of how the loop of Henle functions. I have separated out the two processes that, in combination, set up a salt concentration gradient in the kidney. I start by showing that active transport of salt from the ascending limb of the loop of Henle leads to a high salt concentration in the surrounding tissue. The salt concentration gradient is set up by the fact that the descending limb is permeable to water. This means that as fresh filtrate, with a lower concentration, continuously enters the descending limb, water diffuses out of the tubule to balance the salt concentrations inside and outside the tubule. This lowers the salt concentration in the cortex, but at the same time concentrates the filtrate as it moves down the descending limb into the medulla.</p> <p>The low salt concentration in the cortex makes possible for the cells in the ascending limb to keep pumping out salt. They are pumping salt against a relatively low salt concentration gradient because the salt is continuously being cleared away (diluted) by water from fresh filtrate as it diffuses from the descending limb. If the tubule was not set up in a loop, the amount of salt that could be pumped out of the tubule would be limited by the high concentration of salt accumulating outside the ascending limb, with no means of clearing it away.</p> <p>The high salt concentration in the medulla is important because, after the loop of henle, the tubule changes direction again and loops back down into the medulla as the collecting duct. In the medulla, water again diffuses out of the tubule to balance the salt concentration in the medulla. This concentrates the urine and conserves water. This time, however, the permeability of the collecting duct walls to water is dependent on water permeability channels (aquaporins) whose abundance in the cell membranes of the cells lining the collecting duct is controlled (increased) by antidiuretic hormone (ADH).</p> <p>My video was inspired by this excellent video:</p> <p><a href="https://youtu.be/cYyJF_aSC6o" target="_blank" rel="nofollow">https://youtu.be/cYyJF_aSC6o</a></p> <p>which goes into the mechanism in more detail and gives a really clear numerical explanation.</p> <p>There are errors in the A level biology textbooks that make this all seem a lot more complicated than it really is. You can see these on twitter here</p> <p><a href="https://twitter.com/biologypictures/status/1320316042506342402?s=21" target="_blank" rel="nofollow">https://twitter.com/biologypictures/status/1320316042506342402?s=21</a></p> <p>and here</p> <p><a href="https://twitter.com/biologypictures/status/1320279380862636038?s=21" target="_blank" rel="nofollow">https://twitter.com/biologypictures/status/1320279380862636038?s=21</a></p>

<p><a href="https://youtu.be/KfgUoXCLm_E" target="_blank" rel="nofollow">https://youtu.be/KfgUoXCLm_E</a></p> <p>This YouTube video describes cyclic and non-cyclic photophosphorylation and NADPH production. It describes photosystems I and II and the oxygen-evolving complex. It describes how proton-motive force drives the synthesis of ATP by ATP synthase.</p> <p>There is an annotation task based on the video for students to fill in the details and make notes</p>

<p>Hand drawn, single page visual summaries (pdf format) of various biology topics. Each has a link to a YouTube video showing the ideas being developed</p> <p>you can find YouTube videos at:</p> <p><a href="https://www.youtube.com/channel/UCdpk1x4DTs8kvMpjvy-X2uw" target="_blank" rel="nofollow">https://www.youtube.com/channel/UCdpk1x4DTs8kvMpjvy-X2uw</a></p> <p>Topics so far included in pdf bundle:</p> <p>Coronavirus life cycle:<br /> Two levels of detail, the first shows how the virus replicates within host cells, highlighting how the human cell’s own machinery is doing all the work and providing the materials. <a href="https://youtu.be/SlAIc_uE3cwThe" target="_blank" rel="nofollow">https://youtu.be/SlAIc_uE3cwThe</a><br /> The second goes into more detail of the molecular biology, but still at a fairly basic level.<br /> <a href="https://youtu.be/ojPL5wZw-p0" target="_blank" rel="nofollow">https://youtu.be/ojPL5wZw-p0</a></p> <p>Antigens: This simply shows the the two main categories of antigen; those recognised by antibodies and those recognised by T cells.<br /> <a href="https://youtu.be/VFm782K3Wyg" target="_blank" rel="nofollow">https://youtu.be/VFm782K3Wyg</a></p> <p>Antibodies: How they are produced by B cells, how many we have at birth, what happens during an antibody response, what other cells do when a pathogen has been coated with antibodies.<br /> <a href="https://youtu.be/afoQPHhRu-s" target="_blank" rel="nofollow">https://youtu.be/afoQPHhRu-s</a></p> <p>Vaccines: the challenge of virus mutation <a href="https://youtu.be/9TEeBiwwkNI" target="_blank" rel="nofollow">https://youtu.be/9TEeBiwwkNI</a></p> <p>The function of helper and Killer T cells: <a href="https://youtu.be/JKPrvaqssRk" target="_blank" rel="nofollow">https://youtu.be/JKPrvaqssRk</a></p> <p>Photosynthesis: The first sheet shows why water is used and oxygen is produced<br /> <a href="https://youtu.be/aNw0QnZI0GU" target="_blank" rel="nofollow">https://youtu.be/aNw0QnZI0GU</a></p> <p>The second is on the Calvin cycle and shows how carbon dioxide is incorporated into sugar.<br /> <a href="https://youtu.be/AJKSITxUbV4" target="_blank" rel="nofollow">https://youtu.be/AJKSITxUbV4</a></p> <p>Mitosis: A summary of how nuclei divide<br /> <a href="https://youtu.be/jZ58O72SXYI" target="_blank" rel="nofollow">https://youtu.be/jZ58O72SXYI</a></p> <p>Meiosis: Highlighting the point at which crossing over and recombination occur<br /> <a href="https://youtu.be/lo7VwUCBSuY" target="_blank" rel="nofollow">https://youtu.be/lo7VwUCBSuY</a></p> <p>DNA replication: The role of DNA polymerase in DNA replication. This works as background information for understanding PCR<br /> <a href="https://youtu.be/HWP84mDZMH0" target="_blank" rel="nofollow">https://youtu.be/HWP84mDZMH0</a></p> <p>The structure of DNA and RNA: There is only a very slight difference between these two molecules. I made this one because coronavirus contains RNA as its genetic information.<br /> <a href="https://youtu.be/oZ4q2YJfRck" target="_blank" rel="nofollow">https://youtu.be/oZ4q2YJfRck</a></p> <p>Club moss life cycle showing alternation of generations<br /> <a href="https://youtu.be/tlW-I5H8yn0" target="_blank" rel="nofollow">https://youtu.be/tlW-I5H8yn0</a></p> <p>###########################<br /> Topics on the channel, not yet included in the pdf bundle:<br /> The carbon cycle: <a href="https://youtu.be/U5GxlbURZOU" target="_blank" rel="nofollow">https://youtu.be/U5GxlbURZOU</a><br /> Mitosis animation using photos from a plant root tip: <a href="https://youtu.be/X8nyHJ29BRQ" target="_blank" rel="nofollow">https://youtu.be/X8nyHJ29BRQ</a><br /> ###########################</p>

<p>A YouTube video summarising the malaria parasite life cycle</p>

<p>This Powerpoint contains videos showing the 3 dimensional structure of various molecules, including fuels. You can click on the images to start the videos or use as a 2D image. Students need to guess which structure is which.</p>

<p>A YouTube video summarising the life cycle of a club moss, providing an example of alternation of generations. The resource includes a pdf summary of the YouTube video with a QR code for quick access to the video.</p>

<p>This is a pdf summary sheet with a linked YouTube video. It summarises the role of two important kinds of T cell: helper T cells and Killer T cells. The sheet has a link and QR code so students can access the video version of this resource.</p> <p>Description of the YouTube video:<br /> T-cells play a central role in our response to infections. They act in two different ways, summarised in this video.</p> <p>There is one strategy for identifying cells that have become infected or are abnormal. These are the Killer or cytotoxic T cells. These cells recognise infected cells through receptor molecules called T-cell receptors. What they recognise are short pieces of foreign antigen presented a bit like a picture in a frame on a presentation molecule called MHC class I on the surface of the infected cell. The MHC class I act like windows to the inside of the cell, whilst at the same time acting as a mark of quality to other cells. They say: “this is good quality information”</p> <p>Pieces of pathogen that have been eaten by immune cells like macrophages are presented to a different kind of T-cell, called a T helper cell. This distinction is important because it would not be helpful for killer T cells to start killing cells that are doing a good job in eating pathogens. Instead the role of the T helper cell is to stimulate other immune cells such as B cells. B cells are instructed by T helper cells to make more antibodies. They are in effect saying to the B cell “great job-keep doing what you are doing!”. The way T helper cells recognise macrophages that have eaten pathogens is again through their T cell receptors. However, the T cell receptors of T helper cells recognise pieces of foreign antigen that are presented on MHC class II molecules, again a bit like a picture in a very specific frame that tells the the T cells that this is reliable information.</p>

<p>A video summarising the basic life cycle of coronavirus. The resource includes a pdf summary of the video with a QR code for quick access to the video from the summary.</p>

<p>A visual summary of meiosis summarizing a link (QR code) for access to a YouTube video showing the summary being developed.</p> <p>Here is the link to a video presentation of this visual summary:</p> <p><a href="https://youtu.be/lo7VwUCBSuY" target="_blank" rel="nofollow">https://youtu.be/lo7VwUCBSuY</a></p>

<p>A YouTube video summarising DNA replication. The resource includes a pdf summary sheet with a QR code for quick access to the video</p>

<p>A YouTube video summary of mitosis with a pdf summary sheet of the video. The summary sheet includes a QR code for quick access to the video.</p>

<p>A YouTube video summarising the basic molecular biology of the coronavirus life cycle. The resource includes a pdf summary of the video with a QR code for quick access to the video.</p>

<p>A YouTube video summary of nucleic acid structure showing the difference between DNA and RNA. The resource includes an annotation task using pictures from the video and a pdf summary of the video. Both sheets have a a QR code for quick access to the video.</p>

<p>This YouTube video describes why not all antibodies are protective against disease. The video helps to explain why a positive antibody test against a pathogen does not necessarily mean you are immune to the disease. This is because naturally acquired antibodies are often made against antigens exposed to the immune system after the pathogen has already died; a case of shutting the gate after the horse has bolted.</p>

<p>A visual summary of the two main ways we use to build immunity to infectious agents through cellular and humoral immunity.</p> <p>This resource is a YouTube video</p>