Microscopic scale examples
We define the microscopic scale as the range of sizes of objects that can be detected using microscopes. This diagram shows a selection of objects on the microscopic scale, all of which are featured on the Science Learning Hub. To use this interactive, move your mouse or finger over any of the labelled images and select to obtain more information. Links within the text take you to resources that tell you more about the example objects featured within the scale and the scientists who study them. Download this image as a PDF.
Transcript
GnRH neurons (length of dendrite)
In the transgenic mice used by Dr Rebecca Campbell’s team, GnRH neurons in the brain give off a green fluorescent glow. The yellow/red-coloured neuron has also been filled with neurobiotin (which glows red) to show how long its dendrites are.
The length of the dendrites is unusual – more than 2 mm, so the cells are 100 times longer than they are wide! Knowing this has helped Rebecca solve a puzzle on how GnRH neurons make connections in the brain.
Image: Dr Rebecca Campbell
Dinoflagellate fossils
The presence of these two fossil dinoflagellates in a rock can help date it to the late Cretaceous. The fossils are only about 200 µm long.
These microfossils helped scientists use fossil correlation to date dinosaurs that once lived in New Zealand.
Micrograph by Poul Schioler, Image: GNS Science
Antarctic phytoplankton (average size)
Antarctic phytoplankton, Fragilaria kerguelensis (large group), Nitzschia sp. (single small cell on the left) and partial cell of Thalassiosira sp.
Plankton are microscopic organisms that drift in either saltwater or freshwater. Phytoplankton range in size from extremely small – less than 0.001 mm – to substantially bigger (on a phytoplankton scale) – about 0.5 mm in length.
Image: National Institute of Water and Atmospheric Research (NIWA)
Queen bee ovariole (width)
This is a queen bee ovariole imaged on a confocal microscope. This type of image helps scientists understand how the ovary works in a bee and how it responds to environmental signals that repress or activate it. The red staining is DNA. The green is a stain for cortical actin, which marks the boundaries of cells in most cases. The section with the prominent red-stained nuclei is the nurse cell cluster. These cells are making RNA and protein and transporting them into the adjacent cells.
Professor Peter Dearden and his colleagues work with model organisms, like honey bees, to learn more about genes. Switching genes on and off provides insight on how an organism’s phenotype is affected. Using model organisms allows scientists to gain a better understanding of human development and disease. Learn more about this work in The genotype/phenotype connection.
Image: Peter Dearden
Dendritic cells (diameter)
Dendritic cells are a bit like spies sitting in among other cells. If they detect pathogens (foreign substances) within the body, they will ingest some, and molecules of the pathogens, called antigens, appear on the surface of the dendritic cell. The dendritic cell then leaves the site of infection and moves to the nearest lymph node. It stays there for about a week, displaying the antigens to the T and B cells that move through the lymph node.
Dendritic cells are a key part of the immune system.
Image: Prof Gareth Jones, Wellcome Images
Kaolinite crystals in clay
Kaolinite is the principal mineral present in kaolin clays. It has a flat plate-like structure. This scanning electron microscope image of a sample of kaolinite at a magnification of 1,500 times clearly shows this.
Kaolinite’s layered structure – with tight packing between the layers like the pages of a closed book – means that kaolinite clay does not shrink when dry or swell when wet.
Image: Schlumberger, Houston Texas
Bacteria
Bacteria cells are single-celled organisms – they can live by themselves. This image is of a Campylobacter bacteria – a common cause of diarrhoea and dysentery.
Bacteria are situated on extreme ends when it comes to numbers. They are really tiny – measured in micrometres (between 10-6 m and 10-7 m), but are really abundant – there are approximately 5 nonillion (5x1030) bacteria on Earth, with around 40 million bacteria in a single gram of soil!
Image: Public domain – U.S. Government
Primary cilium (width)
The primary cilium is a small organelle that acts like an antenna, co-ordinating information about the cell’s surroundings. At just 200 nm wide, the primary cilium is only just big enough to be viewed through an optical microscope, but its structure can be studied in detail by using a transmission electron microscope (TEM).
Associate Professor Tony Poole uses TEM microscopes to unlock the mystery of how the primary cilium works. Tony’s story is an excellent example of the changing nature of scientific knowledge and how new information can change the way we think about things.
Micrographs image Tony Poole
Octapod nanoparticle
Transmission electron microscope image of an octapod. You can see the regular arrangement of atoms making up the octapod.
Scientists need to use a transmission electron microscope, which has really high resolution, to view nanoparticles because they are at the nanoscale – a nanometre is a billionth of a metre!
Image: Dr Richard Tilley
