Bacteria and Archaea are prokaryotes, the two domains of prokaryotic life.
There are many types of bacteria:
Some but not all bacteria are pathogens: a disease causing agent
Some bacteria are purely beneficial and help with symbiosis: the relationship in which two different organisms live together, often interdependently.
The other domain of prokaryotic life, tend to live in extreme environments
Grouped according to where they live (pg 371):
Archaea in hydrothermal vents:
The sea floor is an anaerobic environment, no oxygen
Evolutionary theory of the origin of eukaryotic cells from prokaryotic organisms.
That prokaryotes ate a mitochondria and kept it around, some ate a chloroplast and became plants (pg. 391)
Endosymbiotic theory deals with the origins of mitochondria and chloroplasts, two eukaryotic organelles that have bacteria characteristics. Mitochondria and chloroplasts are believed to have developed from symbiotic bacteria, specifically alpha-proteobacteria and cyanobacteria, respectively.
Mitochondria: an organelle found in large numbers in most cells, in which the biochemical processes of respiration and energy production occur. It has a double membrane, the inner layer being folded inward to form layers (cristae).
Mitochondria origin: The endosymbiotic hypothesis for the origin of mitochondria (and chloroplasts) suggests that mitochondria are descended from specialized bacteria (probably purple nonsulfur bacteria) that somehow survived endocytosis by another species of prokaryote or some other cell type, and became incorporated into the cytoplasm.
SO Mitochondria and Chloroplasts were bacteria billions of years ago.
They have their own DNA
Mitochondria and chloroplasts have striking similarities to bacteria cells.
Mitochondrial DNA (mtDNA or mDNA): is the DNA located in mitochondria, cellular organelles within eukaryotic cells that convert chemical energy from food into a form that cells can use, adenosine triphosphate (ATP).
Mitochondrial DNA is double-stranded like cellular DNA in prokaryotes. However it is circular and similar in size and structure to the single DNA loops found in prokaryotes like bacteria.
Mitochondria and Chloroplasts can no longer live outside the eukaryotic cell, and cells cannot live without mitochondria or chloroplasts because that is how they get ATP.
Over millions of years of evolution, mitochondria and chloroplasts have become more specialized and today they cannot live outside the cell.
They are now interdependent/codependent
Cells would only be able to obtain energy from anaerobic respiration (in the absence of oxygen)
So mitochondria helped get archaea out of the hydrothermal vents
Evidence obtained so far indicates that the Bacteria and Archaea diverged from a common ancestor about 3.7 billion years ago, and somewhat later the Archaea diverged from the lineage that would become the Eukarya.
Around 2 billion years ago, archaea and bacteria found a way to share genes or merge some of their material and a third kingdom of life, eukaryotes, was born.
Mitochondria know both aerobic and anaerobic respiration: When oxygen is present, the mitochondria will undergo aerobic respiration which leads to the Krebs cycle.
so plants, protists, fungi, and animals
A multi cellular eukaryote that has cell walls, carries out photosynthesis, and is adapted to living on land
Types of plants:
Vascular plant: plant with tissues that transport water and nutrients through the plants body. Xylem and Phloem.
The six main groups are: invertebrates, mammals, birds, amphibians, reptiles and fish.
Invertebrate: no spine
Arthropod: an invertebrate having a segmented body, a hard exoskeleton, and jointed appendages
Exoskeleton: a hard external skeleton, usually made of chitin protein
Endoskeleton: a solid internal skeleton, found in many animals
Insect: a six-legged arthropod with three body segments, head, thorax and abdomen
Mammal: an animal with mammary glands and fur
Birds: a warm-blooded egg-laying vertebrate distinguished by the possession of feathers, wings, and a beak and (typically) by being able to fly.
Amphibians: a cold-blooded vertebrate animal of a class that comprises the frogs, toads, newts, and salamanders. They are distinguished by having an aquatic gill-breathing larval stage followed (typically) by a terrestrial lung-breathing adult stage.
Reptiles: a cold-blooded vertebrate animal of a class that includes snakes, lizards, crocodiles, turtles, and tortoises. They are distinguished by having a dry scaly skin and typically laying soft-shelled eggs on land.
Fish: a limbless cold-blooded vertebrate animal with gills and fins and living wholly in water.
Author: Jazmin Gannon
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