Summary Biology unit 2- cells

Cell Structure

Eukaryotes
● Linear DNA
● Nucleus
● Larger ribosomes (80s)
● Undeveloped flagella
● Cell walls made of cellulose
● No plasmids
● Membrane bound organelles


Prokaryotes
● Circular DNA
● No nucleus
● Smaller ribosomes (70s)
● Fully developed flagella
● Cell walls made of murein
● Plasmids
● No membrane bound organelles


Studying cells

Light Electron

Cheap Expensive

Little electricity needed Uses an electron beam

Simple to prepare Complex to prepare

Coloured images Black and white images

Living or dead tissues can be viewed Only dead tissue can be viewed

Low magnification High magnification

Low resolution High resolution