The smallest and most common microorganisms that are unicellular organisms and lack a nucleus
For many years, what were prokaryotes called?
What are the two groups of prokaryotes?
Eubacteria and Archaebacteria
Which type of kingdom of prokaryotes is larger?
What does Eubacteria?
A wide range of organisms with different lifestyles
Where do Eubacteria live? Examples.
Almost everywhere. Fresh water, salt water, on land, and on and within the human body
How do Archaebacteria resemble eubacteria?
Equally small, lack nuclei, and have cell walls
How are Archaebacteria different from Eubacteria?
Lack the pepidoglycan and have different membrane lipids
What do DNA sequences in key archaebacterial genes suggest?
That archaebacteria may be the ancestors of eukaryotes
What are the 3 Archaebacteria groups, what they mean, where do they live and give examples.
Methonagens, produce methane gas and live in oxygen-free environments (thick mud and digestive tracts of animals)
Hlaophiles "salt lovers" live in extremely salty environments, 10X saltier than sea water (Great Salt Lake and the Dead Sea)
Thermoacidophiles "lover of hot acidic environments" thrive in hot and acidic environments (Yellowstone sulfur hot springs)
What can Prokaryotes be identified by?
Shape, chemical nature of their cell walls, the way they move, and the way they obtain energy
What can you identify all bacteria by?
Rod-shaped prokaryotes called bacilli
Spherical prkaryotes called cocci
Spiral and corkscrew-shaped prokaryotes called spirilla
Where are two different types of cell walls found?
What is used to tell Eubacteria from Archaebacteria apart?
Staining method called Gram staining
With Gram staining, how do you know its Eubacteria?
When it retains the dark color of the violet stain
Why does Eubacteria retain the violet stain color?
Because it has thick peptidoglycan walls that bond to the stain so it doesn't wash away
What happens when you test an Archaebacteria?
The violet stain washes away leaving it a pink or light red color
Why does Archaebacteria not retain the violet stain color?
Because it does not have peptidoglycan in its cell walls to bond with the stain so instead it just washes away
List the four ways prokaryotes can move?
Some don't move at all
Some are propelled by flagella, whiplike structures
Other prokaryotes lash, snake, or spiral forward
Others glide slowly along a layer of slimelike material they secrete (produce)
What are heterotrophs?
Organisms that get their energy from consuming organic molecules made by other organisms
What are the two types of heterotrophs? Explain.
Chemoheterotrophs: must take in organic molecules for both enery and a supply of carbon (most animals, humans)
Photoheterorophs: photosynthetic but also need to take in organic compounds as a carbon source
What are autotrophs?
Organisms that make thier own food from organic molecules
What are the two types of autotrophs? Explain.
Photoautotrophs: use light energy to convert carbon dioxide and water to carbon compounds and oxygen
Chemoautotrophs: make organic carbon molecules from carbon dioxide, use energy directly form chemical reactions involving ammonia, hydrogen sulfide, nitrites, sulfur, or iron. Some live deep in darkness of ocean getting energy from hydrogen sulfide gas that flows from hydrothermal vents