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Flow chart example (large print)
by Rnib BookshareOn this page is a flowchart showing the making of a lemon cake. There is a locator dot shown, which will be at the top left of the page when the image is the right way up. The chart is on the left of the page and the labels describing the chart are to the right. The chart runs vertically from the top left of the page to the bottom, each stage being represented by various shaped boxes with text in them. Start with the sausage shaped box at the top and follow the arrows. With the diamond-shaped decision box, there will be more than one set of arrows to follow.
Flow chart example (UEB uncontracted)
by Rnib BookshareOn this page is a flowchart showing the making of a lemon cake. There is a locator dot shown, which will be at the top left of the page when the image is the right way up. The chart is on the left of the page and the labels describing the chart are to the right. The chart runs vertically from the top left of the page to the bottom, each stage being represented by various shaped boxes with text in them. Start with the sausage shaped box at the top and follow the arrows. With the diamond-shaped decision box, there will be more than one set of arrows to follow.
Flow chart example (UEB contracted)
by Rnib BookshareOn this page is a flowchart showing the making of a lemon cake. There is a locator dot shown, which will be at the top left of the page when the image is the right way up. The chart is on the left of the page and the labels describing the chart are to the right. The chart runs vertically from the top left of the page to the bottom, each stage being represented by various shaped boxes with text in them. Start with the sausage shaped box at the top and follow the arrows. With the diamond-shaped decision box, there will be more than one set of arrows to follow.
Gantt chart example (large print)
by Rnib BookshareThis page shows an example of a Gantt chart. There is a locator dot shown, which will be at the top left of the page when the image is the right way up. The short text descriptions down the left of the page relate to the row of boxes (or cells) opposite in the grid at the right. Each represents a step in the process of making a cake. Across the top of the page, the time is shown in intervals of five minutes. Below this is the grid in which some of the boxes are filled with textures. The textured cells in each row show how long each step will take and when it will start and end. So, for example, the third stage down Break open eggs, refers to the fourth cell to the right. By moving up to the scale at the top, you can see that this step will take five minutes to complete and will run from minute 15 to minute 20 in the cake-making process.
Gantt chart example (UEB uncontracted)
by Rnib BookshareThis page shows an example of a Gantt chart. There is a locator dot shown, which will be at the top left of the page when the image is the right way up. The short text descriptions down the left of the page relate to the row of boxes (or cells) opposite in the grid at the right. Each represents a step in the process of making a cake. Across the top of the page, the time is shown in intervals of five minutes. Below this is the grid in which some of the boxes are filled with textures. The textured cells in each row show how long each step will take and when it will start and end. So, for example, the third stage down Break open eggs, refers to the fourth cell to the right. By moving up to the scale at the top, you can see that this step will take five minutes to complete and will run from minute 15 to minute 20 in the cake-making process.
Gantt chart example (UEB contracted)
by Rnib BookshareThis page shows an example of a Gantt chart. There is a locator dot shown, which will be at the top left of the page when the image is the right way up. The short text descriptions down the left of the page relate to the row of boxes (or cells) opposite in the grid at the right. Each represents a step in the process of making a cake. Across the top of the page, the time is shown in intervals of five minutes. Below this is the grid in which some of the boxes are filled with textures. The textured cells in each row show how long each step will take and when it will start and end. So, for example, the third stage down Break open eggs, refers to the fourth cell to the right. By moving up to the scale at the top, you can see that this step will take five minutes to complete and will run from minute 15 to minute 20 in the cake-making process.
Chocolate cake: design proposal (large Print)
by Rnib BookshareThis page shows a key at the top left of the page, a small plan (seen from the top) view of the cake to the right, and a larger side view at the bottom. The cake is shown smaller than actual size in both views. There is a locator dot shown, which will be at the top left of the page when the image is the right way up. The key at the top left of the page consists of three rectangular patches of texture with descriptive text to the right. The top view of the cake, at the right of the page, is roughly circular with a quarter section cut out at the bottom left. The side view of the cake has a cut-away section on the left that corresponds to the section cut out from the plan view at the top right of the page. It shows the layers and fillings inside the cake. The right hand side shows the outside of the cake with its distinctive icing pattern. A descriptive label at the bottom of the page has a leader line pointing to a highlighted clear rectangle around a section of the icing. There are dimension lines showing the actual size of the cake up the page and to the right.
Chocolate cake: design proposal (UEB uncontracted)
by Rnib BookshareThis page shows a key at the top left of the page, a small plan (seen from the top) view of the cake to the right, and a larger side view at the bottom. The cake is shown smaller than actual size in both views. There is a locator dot shown, which will be at the top left of the page when the image is the right way up. The key at the top left of the page consists of three rectangular patches of texture with descriptive text to the right. The top view of the cake, at the right of the page, is roughly circular with a quarter section cut out at the bottom left. The side view of the cake has a cut-away section on the left that corresponds to the section cut out from the plan view at the top right of the page. It shows the layers and fillings inside the cake. The right hand side shows the outside of the cake with its distinctive icing pattern. A descriptive label at the bottom of the page has a leader line pointing to a highlighted clear rectangle around a section of the icing. There are dimension lines showing the actual size of the cake up the page and to the right.
Chocolate cake: design proposal (UEB contracted)
by Rnib BookshareThis page shows a key at the top left of the page, a small plan (seen from the top) view of the cake to the right, and a larger side view at the bottom. The cake is shown smaller than actual size in both views. There is a locator dot shown, which will be at the top left of the page when the image is the right way up. The key at the top left of the page consists of three rectangular patches of texture with descriptive text to the right. The top view of the cake, at the right of the page, is roughly circular with a quarter section cut out at the bottom left. The side view of the cake has a cut-away section on the left that corresponds to the section cut out from the plan view at the top right of the page. It shows the layers and fillings inside the cake. The right hand side shows the outside of the cake with its distinctive icing pattern. A descriptive label at the bottom of the page has a leader line pointing to a highlighted clear rectangle around a section of the icing. There are dimension lines showing the actual size of the cake up the page and to the right.
Periodic table overview (Large Print)
This is an overview to the periodic table with an accompanying key. It is a multi-page image set on two pages. There is a locator dot shown, which will be at the top left of the page when the image is the correct way up. The table shows element categories, groups and periods. Key to periodic table overvw - The textures/colours used on the overview to the periodic table of elements are shown in two columns. The texture/colour examples representing the element categories are labelled to the right. The same colours are also used on the full-sized periodic table mentioned above. Periodic table overvw The vertical columns show the groups (families) of elements. The groups are numbered across the top of the page. A horizontal row in the table is a period. The periods are numbered at the left of the page. In this arrangement of the periodic table, the lanthanoids and actinoids (the f-block) are separated from the other elements and are shown stretching across the bottom of the page. Full-size table A full-size version of the table is also available. It shows the element categories (in Large Print only), groups and periods, plus the atomic number, the chemical symbol and atomic weight for each element.
Periodic table overview (UEB Contracted)
by RnibThis is an overview to the periodic table with an accompanying key. It is a multi-page image set on two pages. There is a locator dot shown, which will be at the top left of the page when the image is the correct way up. The table shows element categories, groups and periods. Key to periodic table overvw - The textures/colours used on the overview to the periodic table of elements are shown in two columns. The texture/colour examples representing the element categories are labelled to the right. The same colours are also used on the full-sized periodic table mentioned above. Periodic table overvw The vertical columns show the groups (families) of elements. The groups are numbered across the top of the page. A horizontal row in the table is a period. The periods are numbered at the left of the page. In this arrangement of the periodic table, the lanthanoids and actinoids (the f-block) are separated from the other elements and are shown stretching across the bottom of the page. Full-size table A full-size version of the table is also available. It shows the element categories (in Large Print only), groups and periods, plus the atomic number, the chemical symbol and atomic weight for each element. Additional note: embossed .brf Periodic table is available at; https://www.rnibbookshare.org/cms/braille-teaching-resources
Periodic table overview (UEB Uncontracted)
This is an overview to the periodic table with an accompanying key. It is a multi-page image set on two pages. There is a locator dot shown, which will be at the top left of the page when the image is the correct way up. The table shows element categories, groups and periods. Key to periodic table overvw - The textures/colours used on the overview to the periodic table of elements are shown in two columns. The texture/colour examples representing the element categories are labelled to the right. The same colours are also used on the full-sized periodic table mentioned above. Periodic table overvw The vertical columns show the groups (families) of elements. The groups are numbered across the top of the page. A horizontal row in the table is a period. The periods are numbered at the left of the page. In this arrangement of the periodic table, the lanthanoids and actinoids (the f-block) are separated from the other elements and are shown stretching across the bottom of the page. Full-size table A full-size version of the table is also available. It shows the element categories (in Large Print only), groups and periods, plus the atomic number, the chemical symbol and atomic weight for each element.
Periodic table (Large Print - colour)
by RnibThis is a multi-page document showing the periodic table of chemical elements, and on the Large Print version, a key to the table. The LP key is on the first page. The table is in five parts, which can be joined together. There is a locator dot and title shown on each page. These will be at the top left of the page when it is the correct way up. This is a complex diagram and blind and partially sighted people may find it helpful to have some sighted assistance at first viewing. The table shows element categories (in large print only), groups (families) and periods, plus the atomic number, the chemical symbol and atomic weight for each element. Key to Large Print periodic table - The key to the table shows the colours used to represent the element categories, and is arranged in two columns. In each column, the colour samples are to the left with their names to the right. The categories are not shown on the tactile version of the table, as there is insufficient space in the cells for textures. It is recommended that you download the Periodic table overview from the ImageShare site, as this shows the element categories in tactile format. Periodic tabl The table comprises cells arranged in columns and rows. A cell shows the atomic number, chemical symbol and atomic weight for an element. In the Large Print version of the table, the cell colour relates to the element category as shown on the key. The vertical columns show the groups (or families) of elements. The groups are numbered across the top of the page. A horizontal row in the table is a period. The periods are numbered on the left side of the first page of the table. In this arrangement of the periodic table, the lanthanoids and actinoids (periods 6 to 7, known as the f-block) are separated from the other elements and are shown stretching across the bottom of the page. The f-block on pages 3, 4 and 5 has no periodic numbers marked on the page. Joining the page - To allow space for braille labelling, this table has been split into five sections on separate pages. Join them to each other in number order, from left to right, trimming the periodic numbers as required. Pages 1 and 5 are A4 size and in portrait orientation. Pages 2 to 4 are A3 size and in landscape orientation. Trim the pages to allow joining, using the light, vertical dashed grid lines as guides. When joining the tactile pages, care should be taken to avoid covering any part of the table.
Periodic table (UEB Contracted)
This is a multi-page document showing the periodic table of chemical elements, and on the Large Print version, a key to the table. The LP key is on the first page. The table is in five parts, which can be joined together. There is a locator dot and title shown on each page. These will be at the top left of the page when it is the correct way up. This is a complex diagram and blind and partially sighted people may find it helpful to have some sighted assistance at first viewing. The table shows element categories (in large print only), groups (families) and periods, plus the atomic number, the chemical symbol and atomic weight for each element. Key to Large Print periodic table - The key to the table shows the colours used to represent the element categories, and is arranged in two columns. In each column, the colour samples are to the left with their names to the right. The categories are not shown on the tactile version of the table, as there is insufficient space in the cells for textures. It is recommended that you download the Periodic table overview from the ImageShare site, as this shows the element categories in tactile format. Periodic tabl The table comprises cells arranged in columns and rows. A cell shows the atomic number, chemical symbol and atomic weight for an element. In the Large Print version of the table, the cell colour relates to the element category as shown on the key. The vertical columns show the groups (or families) of elements. The groups are numbered across the top of the page. A horizontal row in the table is a period. The periods are numbered on the left side of the first page of the table. In this arrangement of the periodic table, the lanthanoids and actinoids (periods 6 to 7, known as the f-block) are separated from the other elements and are shown stretching across the bottom of the page. The f-block on pages 3, 4 and 5 has no periodic numbers marked on the page. Joining the page - To allow space for braille labelling, this table has been split into five sections on separate pages. Join them to each other in number order, from left to right, trimming the periodic numbers as required. Pages 1 and 5 are A4 size and in portrait orientation. Pages 2 to 4 are A3 size and in landscape orientation. Trim the pages to allow joining, using the light, vertical dashed grid lines as guides. When joining the tactile pages, care should be taken to avoid covering any part of the table.
Periodic table (UEB Uncontracted)
by RnibThis is a multi-page document showing the periodic table of chemical elements, and on the Large Print version, a key to the table. The LP key is on the first page. The table is in five parts, which can be joined together. There is a locator dot and title shown on each page. These will be at the top left of the page when it is the correct way up. This is a complex diagram and blind and partially sighted people may find it helpful to have some sighted assistance at first viewing. The table shows element categories (in large print only), groups (families) and periods, plus the atomic number, the chemical symbol and atomic weight for each element. Key to Large Print periodic table - The key to the table shows the colours used to represent the element categories, and is arranged in two columns. In each column, the colour samples are to the left with their names to the right. The categories are not shown on the tactile version of the table, as there is insufficient space in the cells for textures. It is recommended that you download the Periodic table overview from the ImageShare site, as this shows the element categories in tactile format. Periodic tabl The table comprises cells arranged in columns and rows. A cell shows the atomic number, chemical symbol and atomic weight for an element. In the Large Print version of the table, the cell colour relates to the element category as shown on the key. The vertical columns show the groups (or families) of elements. The groups are numbered across the top of the page. A horizontal row in the table is a period. The periods are numbered on the left side of the first page of the table. In this arrangement of the periodic table, the lanthanoids and actinoids (periods 6 to 7, known as the f-block) are separated from the other elements and are shown stretching across the bottom of the page. The f-block on pages 3, 4 and 5 has no periodic numbers marked on the page. Joining the page - To allow space for braille labelling, this table has been split into five sections on separate pages. Join them to each other in number order, from left to right, trimming the periodic numbers as required. Pages 1 and 5 are A4 size and in portrait orientation. Pages 2 to 4 are A3 size and in landscape orientation. Trim the pages to allow joining, using the light, vertical dashed grid lines as guides. When joining the tactile pages, care should be taken to avoid covering any part of the table. Additional note: embossed .brf Periodic table is available at; https://www.rnibbookshare.org/cms/braille-teaching-resources
Distillation Apparatus (UEB Uncontracted)
by Rnib BookshareThis page shows six items of laboratory equipment used for separating liquids with different boiling points. They are seen from the side in cross section. Each image is labelled. There is a locator dot and title shown, which will be at the top left of the page when it is the correct way up.Condensers - On the left of the page, from left to right, are an Allihn condenser, a coil condenser and a Graham condenser. Each of them has a small tube inside a larger tube. In the Allihn and Graham condensers, the larger, outside tube carries a coolant, usually water or antifreeze. The coolant flows from the bottom left to the top left of the image. Arrows show the direction of flow. Hot vapour is passed through the smaller, inner tube. It cools and condenses to a liquid that is collected at the bottom. The inner tube of the Allihn condenser has a series of bulbs along its length, to increase its surface area and speed up the exchange of heat. The inner tube of the Graham condenser is coiled, also to increase its surface area. The coil condenser is a variant of the Graham condenser except the small coiled, inner tube carries the coolant and the hot vapour condenses in the larger, outside tube.Alembic Retort: This image in the top left of the page shows an alembic retort. It was used as part of an alembic still by the Ancient Greeks. The retort is being heated by a Bunsen burner down the page.Cold finger:This image is to the left of the Bunsen burner. Coolant (often water) flows into the cold finger in the top right of the image and out of the top left. The direction of flow is shown by arrows. The cold finger provides a cold surface and can be use as a simple condenser or in a sublimation apparatus.
Distillation Apparatus (UEB Contracted)
by Rnib BookshareThis page shows six items of laboratory equipment used for separating liquids with different boiling points. They are seen from the side in cross section. Each image is labelled. There is a locator dot and title shown, which will be at the top left of the page when it is the correct way up.Condensers - On the left of the page, from left to right, are an Allihn condenser, a coil condenser and a Graham condenser. Each of them has a small tube inside a larger tube. In the Allihn and Graham condensers, the larger, outside tube carries a coolant, usually water or antifreeze. The coolant flows from the bottom left to the top left of the image. Arrows show the direction of flow. Hot vapour is passed through the smaller, inner tube. It cools and condenses to a liquid that is collected at the bottom. The inner tube of the Allihn condenser has a series of bulbs along its length, to increase its surface area and speed up the exchange of heat. The inner tube of the Graham condenser is coiled, also to increase its surface area. The coil condenser is a variant of the Graham condenser except the small coiled, inner tube carries the coolant and the hot vapour condenses in the larger, outside tube.Alembic Retort: This image in the top left of the page shows an alembic retort. It was used as part of an alembic still by the Ancient Greeks. The retort is being heated by a Bunsen burner down the page.Cold finger:This image is to the left of the Bunsen burner. Coolant (often water) flows into the cold finger in the top right of the image and out of the top left. The direction of flow is shown by arrows. The cold finger provides a cold surface and can be use as a simple condenser or in a sublimation apparatus.
Laboratory balance (Weighing Scales) (Large Print)
by Rnib BookshareThis page shows a laboratory balance seen from the side in cross section. There is a locator dot and title shown, which will be at the top left of the page when it is the correct way up. The laboratory balance is a device for measuring the mass of an object using a known mass as a reference. At the top centre of the image is the beam, stretching out to the left and right of the page. The beam is a lever that rests on a point at its centre called a fulcrum. At each end of the beam are adjusting screws. Down the page from the fulcrum is a supporting pillar and down again is the base of the balance, running across the bottom of the page. There are two scale pans up the page from the balances base. There is one is hanging from each end of the beam. The one on the left of the page has an unknown weight of a substance. Weights are added to the pan on the right until the balance beam is level; there is a large and small weight on the pan. When the beam is level, the known mass of the weights on the right pan equals the unknown mass on the left pan.
Laboratory balance (Weighing Scales) (UEB Contracted)
by Rnib BookshareThis page shows a laboratory balance seen from the side in cross section. There is a locator dot and title shown, which will be at the top left of the page when it is the correct way up. The laboratory balance is a device for measuring the mass of an object using a known mass as a reference. At the top centre of the image is the beam, stretching out to the left and right of the page. The beam is a lever that rests on a point at its centre called a fulcrum. At each end of the beam are adjusting screws. Down the page from the fulcrum is a supporting pillar and down again is the base of the balance, running across the bottom of the page. There are two scale pans up the page from the balances base. There is one is hanging from each end of the beam. The one on the left of the page has an unknown weight of a substance. Weights are added to the pan on the right until the balance beam is level; there is a large and small weight on the pan. When the beam is level, the known mass of the weights on the right pan equals the unknown mass on the left pan.
Laboratory balance (Weighing Scales) (UEB Uncontracted)
by Rnib BookshareThis page shows a laboratory balance seen from the side in cross section. There is a locator dot and title shown, which will be at the top left of the page when it is the correct way up. The laboratory balance is a device for measuring the mass of an object using a known mass as a reference. At the top centre of the image is the beam, stretching out to the left and right of the page. The beam is a lever that rests on a point at its centre called a fulcrum. At each end of the beam are adjusting screws. Down the page from the fulcrum is a supporting pillar and down again is the base of the balance, running across the bottom of the page. There are two scale pans up the page from the balances base. There is one is hanging from each end of the beam. The one on the left of the page has an unknown weight of a substance. Weights are added to the pan on the right until the balance beam is level; there is a large and small weight on the pan. When the beam is level, the known mass of the weights on the right pan equals the unknown mass on the left pan.
Meiosis phase one (Large Print)
by Rnib BookshareThese pages show late interphase before meiosis, and five stages of meiosis phase one. There is a locator dot shown on each page, which will be at the top left of the page when the image is the correct way up. Meiosis is cell replication where a cell divides to produce four non-identical gametes, each with only one set of chromosomes instead of the usual two sets found in all other cells.Late interphase before meiosis. This page shows a cell immediately before meiosis starts. The cell is a large rounded shape in the centre of the page. Its nucleus fills the bottom of the cell and two centrioles are in the top of the cell. The twenty three pairs of chromosomes in the nucleus have replicated to form a mass of chromatids (double chromosomes) which are tightly coiled. Note the size of the nucleus and the centrioles in relation to the overall size of the cell are greatly enlarged for clarity. Only some of the chromatin is shown, also for clarity. Meiosis - stage one, early prophase I. This page shows the start of meiosis. The cell is in the centre of the page. In the top of the cell the centrioles to the left and right have the mitotic spindle growing between them. The nucleus shows two chromatids - the double chromosomes. The ends of the chromosomes of the chromatids are crossed in two places, to the top and bottom of the pair. In reality in humans there would be twenty three pairs of chromatids.Meiosis - stage one, late prophase I. This page shows chromatids after crossover. The cell is in the centre of the page. In the top of the cell the centrioles to the left and right have the mitotic spindle growing between them. The nucleus shows two chromatids - the double chromosomes. The ends of the chromosomes of the chromatids have swapped DNA coding where they were crossed. The ends to the top centre of the chromatids have swapped and the ends of the other pair of chromosomes to the bottom centre have also swapped.Meiosis - stage two, metaphase I. This page shows the completed mitotic spindle with a centriole to the left and right. The nuclear envelope has disappeared. The chromatids have attached themselves side by side to the centre of the spindle on the central microtubule by their centromeres in the centre of the image. For clarity other chromatids are not shown so the microtubule to the top and bottom of the image appears empty. In reality there would be many more pairs of chromatids and microtubules.Meiosis - stage three, anaphase I. This page shows the centromeres have separated. The microtubules of the spindle are retracting to the left and right. Each chromatid of the pair of chromosomes are migrating to opposite ends of the spindle to the left and right.Meiosis - stage four, telophase I. This page shows centrioles to the left and to the right. One chromatid is in the left and one chromatid is in the right of the cell. To the top and bottom centre of the cell the plasma membrane is pinching in and starting to divide the cytoplasm.
Mitosis (Large Print)
by Rnib BookshareThis image shows the four stages of mitosis over two pages. Page One has two images: 1. A cell has 4 chromosomes, two pairs. 2. Chromosomes are copied. Page Two has two images: 3. Chromosomes form one line down the centre of the cell. 4. One copy of each chromosome moves to the opposite pole of the cell.
Mitosis (UEB Contracted)
by Rnib BookshareThese pages show interphase before mitosis, four stages of mitosis and daughter cells as a product of mitosis. There is a locator dot shown on each page, which will be at the top left of the page when the image is the correct way up. Mitosis is cell replication where a cell divides to produce two identical daughter cells. Late interphase - This page shows a cell immediately before mitosis starts. The cell is a large rounded shape in the centre of the page. Its nucleus fills the bottom of the cell and two centrioles are in the top of the cell. The twenty three pairs of chromosomes in the nucleus have replicated to form a mass of chromatids (double chromosomes) which are tightly coiled. Note the size of the nucleus and the centrioles in relation to the overall size of the cell are greatly enlarged for clarity. Only some of the chromatin is shown, also for clarity. Mitosis - stage one, Prophas - This page shows the start of mitosis. The cell is in the centre of the page. In the top of the cell the centrioles to the left and right have the mitotic spindle growing between them. The nucleus shows three chromatids, the double chromosomes. In reality in humans there would be twenty three chromatids. Mitosis - stage two, Metaphase - This page shows the completed mitotic spindle with a centriole to the left and right. The nuclear envelope has disappeared. The chromatids have attached themselves to the centre of the spindle by their centromeres in the centre of the image. Mitosis - stage three, Anaphase - This page shows the centromeres have separated. The microtubules of the spindle are retracting to the left and right. Each chromatid has split into single sister chromosomes and are migrating to opposite ends of the spindle to the left and right. Mitosis - stage four, Telophase - This page shows the spindle to left and to the right, nearly gone. The chromosomes have collected together and a new nuclear envelope has formed around them. To the top and bottom centre of the cell the plasma membrane is pinching in and starting to divide the cytoplasm. Identical daughter cells The cell has divided to form two genetically identical cells. Each has a nucleus to the left centre of the cell.
Miscellaneous laboratory equipment 1 (Large Print)
by RnibThis page shows eight items of laboratory equipment. All are seen from the side in cross section, except the micro-chambered test slide in the top left corner of the page, which is viewed from the top. There is a locator dot and title shown, which will be at the top left of the page when it is the correct way up. The items are arranged in three columns with each item labelled down the page.
Meiosis phase one (UEB Uncontracted)
by Rnib BookshareThese pages show late interphase before meiosis, and five stages of meiosis phase one. There is a locator dot shown on each page, which will be at the top left of the page when the image is the correct way up. Meiosis is cell replication where a cell divides to produce four non-identical gametes, each with only one set of chromosomes instead of the usual two sets found in all other cells.Late interphase before meiosis. This page shows a cell immediately before meiosis starts. The cell is a large rounded shape in the centre of the page. Its nucleus fills the bottom of the cell and two centrioles are in the top of the cell. The twenty three pairs of chromosomes in the nucleus have replicated to form a mass of chromatids (double chromosomes) which are tightly coiled. Note the size of the nucleus and the centrioles in relation to the overall size of the cell are greatly enlarged for clarity. Only some of the chromatin is shown, also for clarity. Meiosis - stage one, early prophase I. This page shows the start of meiosis. The cell is in the centre of the page. In the top of the cell the centrioles to the left and right have the mitotic spindle growing between them. The nucleus shows two chromatids - the double chromosomes. The ends of the chromosomes of the chromatids are crossed in two places, to the top and bottom of the pair. In reality in humans there would be twenty three pairs of chromatids.Meiosis - stage one, late prophase I. This page shows chromatids after crossover. The cell is in the centre of the page. In the top of the cell the centrioles to the left and right have the mitotic spindle growing between them. The nucleus shows two chromatids - the double chromosomes. The ends of the chromosomes of the chromatids have swapped DNA coding where they were crossed. The ends to the top centre of the chromatids have swapped and the ends of the other pair of chromosomes to the bottom centre have also swapped.Meiosis - stage two, metaphase I. This page shows the completed mitotic spindle with a centriole to the left and right. The nuclear envelope has disappeared. The chromatids have attached themselves side by side to the centre of the spindle on the central microtubule by their centromeres in the centre of the image. For clarity other chromatids are not shown so the microtubule to the top and bottom of the image appears empty. In reality there would be many more pairs of chromatids and microtubules.Meiosis - stage three, anaphase I. This page shows the centromeres have separated. The microtubules of the spindle are retracting to the left and right. Each chromatid of the pair of chromosomes are migrating to opposite ends of the spindle to the left and right.Meiosis - stage four, telophase I. This page shows centrioles to the left and to the right. One chromatid is in the left and one chromatid is in the right of the cell. To the top and bottom centre of the cell the plasma membrane is pinching in and starting to divide the cytoplasm.