Biology Flashcards
(23 cards)
The functions of life living things carry out (8):
1) Organization: Structurally composed of one or more cell.
2) Metabolism: All the chemical reactions that occur inside the cell/organism.
3) Growth: Increase in size of the organism.
4) Response: The ability to respond to environmental stimuli (Natural disasters)
5) Reproduction: The ability of an organism to create new organisms.
6) Homeostasis: Maintaining a constant internal environment.
7) Nutrition: Take in nutrients and dispose waste.
8) Adaptation: The ability of an organism to change over a period of time in response to the environment.
in the heirarchy of biological organization, what is the most simplest collection of matter that can live?
A cell (simplest collection of matter that can live)
The cell theory (3):
1) All organisms are composed of one or more cells
2) Cells are the functional units of life
3) Cells are produced by the divisions of other pre-existing cells.
Robert Hooke (1665)
- Was the first person to describe a cell
- dead cork cells
Antonie Van Leewanhoek (1674)
- Observed the first living cells
- Called them animalcules
- (Blood, spem, pond water and teeth scrapings)
Botanist Matthias Schleiden (1838)
Stated that plants are composed of cells.
- (all organisms are composed of cells)
- Created cell theory
Zoologist Theodore Schwaan (1839)
Stated that animals were made up of cells.
-(all organisms are composed of cells)
Robert Brown (1885)
Discovered the nucleus in plant cells.
Frencesco Redi (1668)
Disproved the ‘Theory of Spontaneous Generation’ or ‘Ageneration’
- Maggots were only developed in rotting meat if flies came in contact with it.
- Sealed/ open jar, maggots and flies theory
Louis Pasteur (1859)
Also proved that spontaneous generation of life does not occur now.
-If nutrient broth was kept in seal swan-necked flask (no air) it remained unchanged and no fungi or other organisms appeared.
Rudolph Virchow (1855)
observed cells dividing and stated that new cells were formed by the division of pre-existing cells (biogenesis)
3 important perimeters of microscopy:
1) Magnification: The ratio of an object’s image to its actual size.
2) Resolution: The measure of clarity of the image.
3) Contrast: Accentuates the difference between parts of the object (Difference between light and shade)
Light Microscope
Light goes through the specimen and through one (single) or two (compound) glass lenses.
The lenses refract (bend) the light to make the image of the specimen magnified for the eye.
Dissecting Microscope
Is used at low magnification
Large working distance between the stage and objective lenses are required.
Dissecting microscope has two eye pieces, one for each eye which produces a 3-D view of the specimen.
Florescent Microscope
subjects the specimen to UV light which makes the florescent molecules emit light of different wavelengths.
Confocal Microscope
the out of focus light in specimens that are thicker than the focal plane is eliminated, improving resolution.
Multiple images of taken at different layers through a specimen’s thickness can be combined to create 3-D images.
Transmission Electron Microscope:
Electrons are passed through a thin section of the specimen which creates clear images of the interior of the specimen.
Scanning Electron Microscope:
Electrons are reflected off a specimen which is covered by electron dense material.
Produces clear 3-D images of the surfaces of the specimen.
Magnification
How large the object appears compared to its actual size.
Field of View (FOV)
A measurement of the actual diameter of the circular area visible through a lens.
-Allows estimation of actual size of the objects viewed under the microscope.
Actual Size
actual size of an object viewed under the microscope can be estimated using the field of view.
Drawing Magnification
is how much larger the biological drawing is than the actual size of the object.
- Drawing magnification is usually indicated in brackets after the title of a biological drawing or picture.
Scale
Is the difference between the size of the biological drawing of the object and the size of the actual object.
-Scale is usually indicated on the biological drawing using a scale bar.
