Cell Structure and Function

Nucleoid:

region of the cytoplasm that is not enclosed in a membraneous sac.

Lipid bilayer:

continous, oily boundary that keeps water-soluble substances from getting across it.

Wavelenght:

the distance from the peak of one wave to the wave behind it.

Electron Microscopes:

use magnetic lenses to bend and difract beams of electrons.

Transmission Electron Microscopes:

electrons pass through a specimen to make an internal image of their details.

Scanning Electron Microscopes:
 the passing of beams of electrons back and forth on the surface of a specimen.

Organelles:
bounded sacs.

Secretory Pathway:

moves new polypeptide chains from some ribosomes through ER and Golgi bodies.

Endocytic Pathway:

moves ions and molecules into the cytoplasm.

Vesicles:

tiny sacs that move substances.

Nuclear Envelope:

double membrane system in which two lipid layers are pressed against each other.

Chromatin:

cell's collection of DNA and proteins.

Chromosomes:

double stranded DNA molecules.

Peroxisones:

hold enzymes that digest fatty acids, amino acids and hydrogen peroxide.

Cell Junctions:

structures where cells send or receive materials.

Basal Body:

finished array.

Pseudopods:

false feet.