Eukaryotic vs Prokaryotic SEM 2,000 Eukaryotic vs Prokaryotic

What are the major criteria for the divisions of this tree? This slide show how the prokaryotes are organized. But what unites the group? Archaea and bacteria are quite similar in size and shape, although a few archaea have very strange or unusual shapes, such as the flat and square-shaped cells of Haloquadratum walsbyi. Despite this visual similarity to bacteria, archaea possess genes and several metabolic pathways that are more closely related to those of eukaryotes, notably the enzymes involved in transcription and translation. Other aspects of archaean biochemistry are unique, such as their reliance on ether lipids in their cell membranes. Archaea use a much greater variety of sources of energy than eukaryotes: ranging from familiar organic compounds such as sugars, to ammonia, metal ions or even hydrogen gas. Salt-tolerant archaea (theHaloarchaea) use sunlight as an energy source, and other species of archaea fix carbon; however, unlike plants and cyanobacteria, no species of archaea is known to do both. Archaea reproduce asexually by binary fission, fragmentation, or budding; unlike bacteria and eukaryotes, no known species form spores. Initially, archaea were viewed as extremophiles that lived in harsh environments, such as hot springs and salt lakes, but they have since been found in a broad range of habitats, including soils, oceans, marshlands and the human colon and navel

Note - Size, scale, internal organization of each Comparison of Cell Types Prokaryotic cell Nucleoid region Nucleus Eukar yotic cell Organelles Colorized TEM 15,000  Note - Size, scale, internal organization of each

Prokaryotic Cell Structure Lacking well defined nuclei or organelles Variety of shapes and sizes Will often secrete chemicals into the environment to help modify their environment favorably for them. No chloroplasts, mitochodria, or nucleas…but certain form can carry out photosynthesis and oxidative phosphorylation but rely on membrane NOT specializes organelles.

Variety of Shapes and Sizes Prokaryotic Pneuomonia diplococcus, Strep Throat streptococcus, Botchulism- Bacillus, Lyme’s Disease

Compartmentalization Many small enclosed environments to create environments for unique chemical reactions. Note the continuous flow of membranous compartments Endomembrane system- internal system of membrane bound compartments What is meant

Animal Cell

Plant Cell

Cells are limited in size because of surface area to volume ratio Scale of Life Cells are limited in size because of surface area to volume ratio What is the biggest cell in the human body?