National 5 Biology Cell Structure Mr G Davidson

Cellular Structure Cells are the living units from which all organisms are made. Simple organisms have only one cell and are unicellular, e.g. bacteria. Other organisms have many cells working together and are multicellular, e.g. humans. Monday, September 17, 2018 Mr G Davidson

Animal Cell Structure Cell membrane Ribosome Nucleus Mitochondrion Cytoplasm Monday, September 17, 2018 Mr G Davidson

Animal Cell Structure Cell Structure Function Nucleus Cytoplasm Controls cell activities and passes on information to the next generation Cytoplasm Site of all biochemical reactions Cell membrane Controls what enters and leaves the cell Mitochondrion Site of aerobic respiration Ribosomes Site of protein synthesis Monday, September 17, 2018 Mr G Davidson

Plant Cell Structure Nucleus Ribosome Cell wall Cell membrane Mitochondrion Sap vacuole Chloroplast Cytoplasm Monday, September 17, 2018 Mr G Davidson

Plant Cell Structure Cell Structure Function Chloroplast Cell wall As well as the same structures found in animal cells, the following structures are also found in plant cells only. Cell Structure Function Chloroplast Contains chlorophyll which traps light energy to be used in photosynthesis Cell wall Made of cellulose and supports the structure of the cell Vacuole Stores water and solutes as a solution called “cell sap” Monday, September 17, 2018 Mr G Davidson

Fungal Cell Cell membrane Mitochondrion Cell wall Nucleus Cytoplasm Vacuole Cytoplasm Monday, 17 September 2018 G Davidson

Fungal Cell Structure An example of a unicellular fungus is yeast. It has structures in common with both animal and plant cells. These structures carry out the same functions. Monday, 17 September 2018 G Davidson

Bacterial Cell Monday, 17 September 2018 G Davidson

Bacterial Cell Structure Bacterial cells can be all different shapes. The structures within the bacterial cell are much the same as animal cells. The main difference is a lack of a nucleus. Bacterial cells have plasmids which are circular rings of DNA as well as a large circular DNA. The cell wall is different from a plant cell wall in that it is kind of slimy. Monday, September 17, 2018 Mr G Davidson

Cell Sizes Cells cannot be seen without the aid of a microscope. They are so small that we used units called micrometres(μm) or microns to measure them. There are 1000 microns in 1 millimetre. Monday, 17 September 2018 G Davidson

Cell Sizes We can estimate the sizes of cells by knowing the diameter of the field of view. e.g. if the field of view is 2mm which is 2000μm, and there are 8 cells stretching from one side to the other, then each cell must be 250μm. (2000/8) Monday, 17 September 2018 G Davidson

Cell sizes Field of View This field of view is 1mm. Estimate the size of each cell. Answer – 62.5μm Monday, 17 September 2018 G Davidson

Cell Sizes We can magnify the size of the cells using the lenses on the microscope. Total magnification = eyepiece x objective e.g. if the objective lens is x20 and the eyepiece is x10, then the total magnification will be x200. If we increase the magnification of the microscope the number of cells we see in the field of view decreases. Monday, 17 September 2018 G Davidson