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Science 10
Bio, Chem, Physics and Climate Review (Whole Course)
| Question | Answer |
|---|---|
| Who were Hans and Zacharias Janssen? | Dutch lens makers who invented the microscope (1595) using a two-lens system of an eyepiece (ocular lens) and an objective lens They created the first compound microscope with a magnifying power of 20x |
| Who was Robert Hooke? | A famous British Scientist who used a three-lens system (eyepiece, objective and field lenses) to observe cells (20-50x). He discovered plant cells when he saw the cell walls in cork tissue, and coined the term cells. |
| Who was Antoni Van Leeuwenhoek? | He was a Dutch businessman and scientist who made observations using a single-lens microscope. He was the first person to see the movement of single cells, which he called animalcules. His lenses were so high quality he could magnify to 250x |
| How do you calculate total magnification? | Ocular magnification x objective magnification |
| How do you calculate field diameter? | M1D1=M2D2 or (Magnification low power)(field of view low power) = (Magnification high power)(field of view high power) |
| How do you calculate scale? | diagram size/actual size |
| What was spontaneous generation? | The theory that living things could come from non-living organisms |
| Who was Francesco Redi? | A man who questioned spontaneous generation and did an experiment with meat in glass jars where some jars were covered and some were not, so that he could see if maggots appeared. (The maggots appeared in the open jar but not the covered) |
| Who was John Needham? | Argued for spontaneous generation. He boiled broth in a flask to kill microbes, and then sealed the flask. He then observed that microscopic creatures still appeared, so he said that a vital force was needed for spontaneous generation |
| Who was L. Spallanzani? | Stated that micro-organisms in the air were responsible for the growth, so repeated Needham's experiment but put the broth in a vacuum (no air). No growth occurred |
| Who was Louis Pasteur? | He disproved spontaneous generation by creating a beaker with an S-shaped neck. This allowed the vital force (air) access to the broth but not the micro-organisms. No growth occurred, so the theory was false. |
| What is the Cell Theory? | Had 3 basic principles: 1. All life has cells 2. Life occurs in cells 3. Life comes from cells |
| Who were Schleiden and Schwann? | Schleiden and Schwann proposed the first two points of the cell theory. Schleiden was studying plants and proved they were all made up of cells, Schwann did the same for animals |
| Who was R. Virchow? | He said that cells could only come from pre-existing cells (the last point in the cell theory) |
| Who was Robert Brown? | He proposed the idea of the nucleus and it's importance. |
| What is the different between prokaryotes and eukaryotes? | Prokaryotes are simple cells without a nucleus (ex. bacteria). Eukaryotes have nuclei and more complex organelles (ex. skin cells). Eukaryotes have specialization |
| What are the two important values in microscopy? | Magnification (how much larger it appears) and resolution (a measure of clarity - the minimum distance two points can be separated and still be distinguished) |
| What is the resolution of the human eye and a light microscope? | Human eye - 0.1mm Light microscope - 0.2um |
| What is contrast? | the ability to see differences between structure due to differences in their capacity to absorb light |
| What is stain? | A method used in observing cells that provides contrast for observing individual cells structures. It kills the cells |
| What is a genome? | A genome is all the DNA is an organism, including it's genes |
| What do genes carry? | Genes carry information for making the proteins required by all organisms. These proteins determine many things in an organism, such as looks, metabolism, and immune system. |
| What is DNA? | DNA is the chemical name for the molecule that carries genetic instructions in all living things. It is a double helix shape |
| What is DNA formed with? | DNA has a backbone of alternating sugar and phosphate groups. Attached to each sugar is one of four bases - adenine, cytosine, guanine or thymine (ATCG). A and T bond, C and G bond. The order of these bases make us who we are. |
| What is a gene? | A long section of DNA that codes for a protein (every 3 pairs codes for one amino acid) |
| What is X-ray chrystallography? | Using x-rays, special sensors that analyze x-ray scattering, and computer technology to study the structure of molecules |
| What are GFP's? | Green Fluorescent Proteins glow bright green when exposed to light. Scientists attach them to different parts they want to study, almost like a tiny lamp. They are used to study diseases by comparing healthy tissue to infected tissue (proteins clump) |
| What was the human genome project? | A project with the goal of identifying all 20500 genes in human DNA and determine the sequence of 3 billion chemical base pairs that make up DNA. |
| What factors limit resolving power? | Wave length |
| What is Light Microscopy? | A microscope that creates images by focusing light, passing it through specimen, and onto an objective lens that magnifies the specimen. Their resolution is limited by the wavelength of visible light. |
| What is Fluorescence Microscopy? | Provides information about molecules on the cells surface, which glow under UV light |
| What is a Confocal Microscope? | A microscope that uses a laser to concentrate light onto a specimen in thin sections, which are then combined to to produce a 3D image on a computer. Cells viewed with this technique can remain living. |
| What is an Electron Microscope? | A microscope that focuses a beam of electrons rather than visible light. As electron beams are smaller than visible lightwaves, the resolution is much greater (up to 0.2nm) |
| What is a Scanning Electron Microscope? | Gives information about the surface of specimens. Specimens are fixed and covered with and electron dense material, which reflect electrons. The reflected electrons are picked up by a sensor to provide an image of the surface. |
| What is a Transmission Electron Microscope? | A beam of electrons is passed through a thin slice of a fixed and stained tissue in plastic. Electrons that pass through the specimen fall on a fluorescent screen or photo film to make black and white images of the the specimen. |
| What are advantages to a light microscope? | Easy to use and to get, and faster to use. |
| What are disadvantages to a light microscope? | Cannot see more that 0.2um resolution |
Created by:
Kate007
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