1.  Cells

2.  Earth is inhabited by different kinds of living organism, which look very different from each other but their bodies are all made up of microscopic units called cells.  Robert Hooke 1665  Cells are the building blocks of life  Unicellular  Organisms made up of only one cell, e.g. an amoeba  Multicellular  Organisms made up of many cells, e.g. humans

3. Cell Structure  This year we will study animal and plant cells.  Cells come in many different shapes and sizes, but they all have three basic features. Cell Membrane Cytoplasm Nucleus Animal cell Plant cell

4. Animal Cell Cell Membrane Cytoplasm Nucleus Jelly like material that contains all the cells internal structures. Chemical reactions like respiration occur here. Control centre of the cell. Contains DNA, the genetic blueprint of the organism. Controls what goes in and out of the cell. Substances move by diffusing across the membrane. DNA = DeoxyriboNucleic Acid

5. Plant Cell Cell Wall Chloroplast Large Vacuole Site of photosynthesis. Contain a chemical called chlorophyll that gives plants their green colour. Made of cellulose. Gives the plant structure. The cells storage organ. Holds excess water Plant cells still contain the nucleus, cell membrane and cytoplasm.

6. Do All Cells Look The Same? Cells can be different shapes and sizes and also have different functions. This is because they are specialized. The shape of a cell is related to its function. Where do you see this idea in sport? The players in a rugby team are different shapes and sizes because each player does a different job for the team. Human Cells https://clickv.ie/w/uW9d

7. Stem Cells  Before cells become specialized they are called stem cells.  These have the potential to become any type of cell.  High concentration in a developing embryo  Using these cells is controversial  Also found in adults, in bone marrow, muscle and brain but these are pre-programmed to become specific cell types.  In 2006 a technique was developed that allows us to reprogramme specialized adult cells into stem cells.  These are called iPSCs (induced pluripotent stem cells)  It is hoped that these cells can be used in regenerative medicine, organ transplants, and to treat conditions like Parkinson’s

8. Cell Division  Cells use a method called mitosis to make copies of themselves.  Each new cell is a clone of its parent cell.  Red blood cells live for about four months  White blood cells live on average live just over a year  Skin cells live about two to three weeks  Colon cells die after about four days  Brain cells typically last a lifetime and are not replaced.

9. Why Do Cells Divide?  Growth  As organisms age and absorb energy new cells are created and the organism grows in size.  Older cells are also replaced when they die  Repair  If the organism becomes injured, new cells are created to heal the injury.  Reproduction  Sex cells are made to ensure the species’ survival. In mammals these cells are sperm and egg cells.

10. The Microscope  The microscope was invented by a Dutch man named Van Leeuwenhoek in the 17 th Century.  We know have powerful electron and digital microscopes but the light microscope we use here is still basically modeled on Van Leeuwenhoek’s design.

11. The Light Microscope Using the microscope Plug it in and place the slide on the stage. Make sure the smallest lens is selected and turn on the light source. Look through the eye piece and use the coarse focus (big wheel) to raise the stage. Once you can see something through the eyepiece use the fine focus (small wheel) to zoom in. You can now select a larger lens but only use the fine focus.

12. Each specific cell is grouped with other cells similar in structure and function to form tissues and ultimately organs : Groups of tissues work together to form organs. Groups of cells work together to form tissues. Cells are the basic units of life. celltissueorgan Cells Organism

13.  Groups of organs combine to form systems, and working together these systems combine to form an organism.  Human Systems Human Systems Cells Organism