Molecules Unit 2-A Flashcards
what is the smallest unit of a living thing?
a cell is the smallest living unit
organism
a living thing- either made of one cell (bacteria) or many cells (human)
cells are building blocks of all organisms
microscopy
photographs of cells taken with a microscope are called micrographs
visible light passes through the lens system to enable user to see specimen
electron microscope
use a beam of electrons instead of light
- allows for higher magnification
- higher resolving power
why cant living cells be viewed through an electron microscope?
living cells cannot be examined through an electron microscope due to the preparation of electron microscopes killing live specimen
unified cell theory
all living things are composed of one more cells, the cells are the basic unit of life and new cells arise from existing cells
micrometer
1 millionth of a meter
nanometers
1 billionth of a meter
- lipids
- proteins
picometer
trillionth of a meter
-carbon atom
surface area
where a cell exchanges materials with its environment
-cell products, waste, nutrients, and gasses must pass through surface area
volume of a cell
living portion that demands transport of materials through surface area (cell membrane)
volume grows faster than surface area
skin cells stay small
example: skin cells of mouse are about the same size as elephant
plant cells decrease functional volume
vacuole holds dead material
the key is to increase surface area while keeping volume small
examples
- fish gills have finger like projections
- flat worms can exert gasses
small intestine
easy passing of materials passing in and out of cells
-size of full tennis court
