Download S10 Notes- The Technology of Cell Research

S10 The Technology of Cell Research: Microscopes, Gene Sequencing, Cell Cultures, Stem
Cells
What we can see with different microscopes
Types of microscopes: Microscopes differ in what they use for energy to view small things and
what sizes of objects we can see clearly with them.
 Highlight the energy source used in each microscope below.
1. Simple microscope: a microscope composed of only one lens (magnifying glass). Specimen is
illuminated by visible light.
2. Compound light microscope: uses 2 or more lenses, specimen is illuminated by visible light
3. Electron microscopes: a microscope that views objects too small to be seen with a light
microscope. Illuminates specimens with a beam of electrons. Makes an electron micrograph
(a photograph of the image from an electron microscope). Can magnify up to 1.2 million times!
There are 2 main types of electron microscopes:
Transmission electron microscope (TEM): electrons are transmitted through a specimen to
produce a 2D image
Scanning electron microscope (SEM): a beam of electrons sweeps over an object to create a 3D
image.
4. Confocal laser scanning microscope (CLSM): uses a laser to obtain an image of a specimen.
5. Scanning Tunneling Microscope: a probe with a flow of electrons follows the surface
contours of a specimen and a computer creates a 3-D image of molecules such as DNA!
 Cell Technologies: Choose 2 of the 4 following technologies that you would like to know
about: gene sequencing, culturing cells in the laboratory, genetic engineering, or stem cell
research. Using the information and clips listed below as a starting point, learn about these
techniques and report your learning. Watch this clip for background knowledge:
What is a Gene – Stated Clearly https://www.youtube.com/watch?v=5MQdXjRPHmQ
Gene Sequencing
Genes are sections of long molecules called DNA (deoxyribonucleic acid), that make up our
chromosomes. Changes in our genes can result in diseases.
DNA is composed of 4 bases adenine (A), thymine (T), guanine (G) and cytosine (C). The order of
these bases is different in every gene. Mapping the order of a gene’s bases (called gene
sequencing) can help us understand which genes are responsible for different diseases.
The Human Genome Project was a huge international project that successfully sequenced the
entire human genome. This was a crucial step in being able to understand the genetic basis of
various diseases, including cancers, and aid in their diagnosis and treatment. Watch
https://www.youtube.com/watch?v=TwXXgEz9o4w “The Story of You: what is the human
genome?
https://www.youtube.com/watch?v=gkQJ26DAxfs ethics of the human genome
Culturing Cells in the Laboratory
Cells from different cancers have been cultured (grown) in the laboratory for research. A famous
cell line, HeLa cells, were grown from a woman named Henrietta Lacks, who had cervical cancer
in 1951. Tissue cultures are very important for cell research because they are identical, can be
grown in large numbers and survive for a very long time outside of the body. A great deal about
how our cells work has been learned from these cells. Watch:
https://www.youtube.com/watch?v=22lGbAVWhro HeLa cells
http://www.teachersdomain.org/asset/biot09_vid_tissueeng/ using cultured cells to help
people with liver disease.
Genetic Engineering
Watch these videos on genetic engineering and Genetically modified foods.
https://www.youtube.com/watch?v=3IsQ92KiBwM What is genetic engineering?
https://www.youtube.com/watch?v=JMPE5wlB3Zk What is genetically modified food?
Stem Cell Research
Explore https://www.youtube.com/watch?v=K7D6iA7bZG0 What can stem cells do?
https://www.youtube.com/watch?v=evH0I7Coc54 What are stem cells? Ted-Ed
Estimating Cell and Organelle Size
Strategy #1: use the scale on the micrograph and a ruler to estimate size.
Strategy #2: use the Field of View (FOV), estimate the number of times the cell will fit in this FOV
and use this to estimate size.
 What is the cell size of the following the mitochondria and the animal cell. Report your
actual size in mm, um (micrometers (1000 x mm)) and nm (1000 x micrometers). The
scale on the micrograph of the mitochondria is 0.4 nm. The FOV with the animal cell is 2
mm.
Assignment: Answer the following questions:
1. What is the difference between a simple microscope and a compound microscope?
2. Compare how images are produced when using an electron microscope versus a light
microscope.
3. Describe how and why staining techniques are used to study cells.
4. Explain how stem cells differ from other kinds of cells.
5. What is a gene sequence?
6. Why is it valuable to know a gene’s sequence?