Quarter 2 Test Flashcards
How big are most cells?
1 mircometer to 1,000 mircometer
What unit of measure is used to measure a cell?
Micrometer
cell membrane name three things
• Every cell has a boundary that separates the inside from the outside
It’s a protective covering that encloses the entire cell.
Any material coming into or out of the cell must pass through the cell membrane
Contains the cytoplasm
cytoplasm name two things
Located inside the cell membrane is a gelatin-like material
Most of the work of the cell is carried out in the cytoplasm.
Scientists separate cells into two broad categories based on what key difference;
the location of the genetic material cells need to reproduce and function.
eukaryotic cell
the genetic material is in a structure called the nucleus, a structure enclosed by its own membrane.
organelle .
Is used to describe any part of a cell that is enclosed by membrane
•prokaryotic cell
there is no separate compartments for the genetic material. Instead, it is in the cytoplasm. There are no organelles
Most unicellular organisms are
prokaryotic cells.
Almost all multicellular organisms are.
eukaryotic
The invention of the light microscope led to what?
the discovery of cell and to the development of cell theory.
In light microscopes, lenses are used to do what?
bend light and make objects appear bigger than they are and can magnify objects up to 1000 times.
Cell samples are treated with dyes to do what?
make structures in the cells easier to see. They also use video cameras and computer processing to observe the movements of cell part and materials within cells.
One important advantage of light microscopes is what?
That scientists can observe living cells with them.
Two other types of microscopes that are important in the study of cells are
The scanning electron microscope (SEM) and the transmission electron microscope (TEM)
Why do we need to use a SEM And TEM microscope?
The light microscope can be used to see objects that are larger than 0.2 micrometers.
the SEM and TEM can be used for looking at the details of the cell
both the SEM and TEM, see tiny particles called
electrons, not light, are used to produce images.
The advantage of the SEM and Tem microscopes is what?
is that they can magnify objects up to a million times.
The disadvantage of the SEM and TEM
they cannot be used to study living specimens.
What must happen to the cell To be viewed with a SEM,
A cell sample is coated in a heavy metal, such as gold. Then a beam of electrons is run back and forth over the surface of the cell. The electrons bounce off the coating and are read by a detector that produces a 3-dimensional image of the surface.
How can a cell be viewed with a TEM
A cell is sliced extremely thin. Electrons pass through a section. Images produced by a TEM appear 2-dimensional.
