What type of cells do archaebacteria have

Archaebacteria are single-celled prokaryotes originally thought to be bacteria. They are in the Archaea domain and have a unique ribosomal RNA type. The cell wall composition of these extreme organisms allows them to live in some very inhospitable places, such as hot springs and hydrothermal vents. Archaea of the methanogen species can also be found in the guts of animals and humans. These organisms are considered to be true bacteria and are classified under the Bacteria domain. Bacteria live in almost every type of environment and are often associated with disease.

Most bacteria , however, do not cause disease. Bacteria are the main microscopic organisms that compose the human microbiota. There are more bacteria in the human gut, for instance, than there are body cells. Bacteria ensure that our bodies function normally. These microbes reproduce at an alarming rate under the right conditions.

Most reproduce asexually by binary fission. Bacteria have varied and distinct bacterial cell shapes including round, spiral, and rod shapes. The protista kingdom includes a very diverse group of organisms. Some have characteristics of animals protozoa , while others resemble plants algae or fungi slime molds. These eukaryotic organisms have a nucleus that is enclosed within a membrane.

Some protists have organelles that are found in animal cells mitochondria , while others have organelles that are found in plant cells chloroplasts. Protists that are similar to plants are capable of photosynthesis. Many protists are parasitic pathogens that cause disease in animals and humans. Others exist in commensalistic or mutualistic relationships with their host.

Fungi include both unicellular yeast and molds and multicellular mushrooms organisms. Unlike plants, fungi are not capable of photosynthesis. Some fungi taste great and others can kill you! Fungi are organisms that biologists once confused with plants, however, unlike plants, fungi cannot make their own food. Most obtain their food from parts of plants that are decaying in the soil. Slime molds and algae are protists. Sometimes they are called the odds and ends kingdom because its members are so different from one another.

Protists include all microscopic organisms that are not bacteria, not animals, not plants and not fungi. Most protists are unicellular. You may be wondering why those protists are not classified in the Archaebacteria or Eubacteria kingdoms. It is because, unlike bacteria, protists are complex cells. These delicate looking diatoms are classified in the protist kingdom. The Six Kingdoms When Linnaeus developed his system of classification, there were only two kingdoms, Plants and Animals.

Animals The animal kingdom is the largest kingdom with over 1 million known species. Eubacteria Like archaebacteria, eubacteria are complex and single celled. Fungi Mushrooms, mold and mildew are all examples of organisms in the kingdom fungi. Fun Facts about Fungi Some fungi taste great and others can kill you! Protists Slime molds and algae are protists. Prokaryotes come in various shapes, but many fall into three categories: cocci spherical , bacilli rod-shaped , and spirilli spiral-shaped Figure.

Recall that prokaryotes are unicellular organisms that lack membrane-bound organelles or other internal membrane-bound structures Figure. Their chromosome—usually single—consists of a piece of circular, double-stranded DNA located in an area of the cell called the nucleoid.

Most prokaryotes have a cell wall outside the plasma membrane. Some bacterial species have a capsule outside the cell wall. The capsule enables the organism to attach to surfaces, protects it from dehydration and attack by phagocytic cells, and makes pathogens more resistant to our immune responses. Some species also have flagella singular, flagellum used for locomotion, and pili singular, pilus used for attachment to surfaces including the surfaces of other cells. Plasmids, which consist of extra-chromosomal DNA, are also present in many species of bacteria and archaea.

Recall that prokaryotes are divided into two different domains, Bacteria and Archaea, which together with Eukarya, comprise the three domains of life Figure. Characteristics of bacterial phyla are described in Figure and Figure. Major bacterial phyla include the Proteobacteria, the Chlamydias, the Spirochaetes, the photosynthetic Cyanobacteria, and the Gram-positive bacteria. The Proteobacteria are in turn subdivided into several classes, from the Alpha- to the Epsilon proteobacteria.

Eukaryotic mitochondria are thought to be the descendants of alphaproteobacteria, while eukaryotic chloroplasts are derived from cyanobacteria. Archaeal phyla are described in Figure. Other bacterial phyla. Chlamydia, Spirochetes, Cyanobacteria, and Gram-positive bacteria are described in this table.

Note that bacterial shape is not phylum-dependent; bacteria within a phylum may be cocci, rod-shaped, or spiral. Archaea are separated into four phyla: the Korarchaeota, Euryarchaeota, Crenarchaeota, and Nanoarchaeota. Its selectively permeable nature keeps ions, proteins, and other molecules within the cell and prevents them from diffusing into the extracellular environment, while other molecules may move through the membrane.

Recall that the general structure of a cell membrane is a phospholipid bilayer composed of two layers of lipid molecules. In archaeal cell membranes, isoprene phytanyl chains linked to glycerol replace the fatty acids linked to glycerol in bacterial membranes. Some archaeal membranes are lipid monolayers instead of bilayers Figure. The cytoplasm of prokaryotic cells has a high concentration of dissolved solutes. Therefore, the osmotic pressure within the cell is relatively high.

The cell wall is a protective layer that surrounds some cells and gives them shape and rigidity. It is located outside the cell membrane and prevents osmotic lysis bursting due to increasing volume.

The chemical composition of the cell wall varies between Archaea and Bacteria, and also varies between bacterial species. Bacterial cell walls contain peptidoglycan , composed of polysaccharide chains that are cross-linked by unusual peptides containing both L- and D-amino acids including D-glutamic acid and D-alanine.

Proteins normally have only L-amino acids; as a consequence, many of our antibiotics work by mimicking D-amino acids and therefore have specific effects on bacterial cell-wall development. There are more than different forms of peptidoglycan. S-layer surface layer proteins are also present on the outside of cell walls of both Archaea and Bacteria. Bacteria are divided into two major groups: Gram positive and Gram negative , based on their reaction to Gram staining.

Note that all Gram-positive bacteria belong to one phylum; bacteria in the other phyla Proteobacteria, Chlamydias, Spirochetes, Cyanobacteria, and others are Gram-negative. The Gram staining method is named after its inventor, Danish scientist Hans Christian Gram — The different bacterial responses to the staining procedure are ultimately due to cell wall structure. Gram-positive organisms typically lack the outer membrane found in Gram-negative organisms Figure.

Up to 90 percent of the cell-wall in Gram-positive bacteria is composed of peptidoglycan, and most of the rest is composed of acidic substances called teichoic acids.

Teichoic acids may be covalently linked to lipids in the plasma membrane to form lipoteichoic acids. Lipoteichoic acids anchor the cell wall to the cell membrane. Gram-negative bacteria have a relatively thin cell wall composed of a few layers of peptidoglycan only 10 percent of the total cell wall , surrounded by an outer envelope containing lipopolysaccharides LPS and lipoproteins. This outer envelope is sometimes referred to as a second lipid bilayer. The chemistry of this outer envelope is very different, however, from that of the typical lipid bilayer that forms plasma membranes.

Which of the following statements is true? There are four different types of archaean cell walls. One type is composed of pseudopeptidoglycan , which is similar to peptidoglycan in morphology but contains different sugars in the polysaccharide chain.

The other three types of cell walls are composed of polysaccharides, glycoproteins, or pure protein. Other differences between Bacteria and Archaea are seen in Figure. Note that features related to DNA replication, transcription and translation in Archaea are similar to those seen in eukaryotes.

Reproduction in prokaryotes is asexual and usually takes place by binary fission. Recall that the DNA of a prokaryote is a single, circular chromosome. Prokaryotes do not undergo mitosis; instead, the chromosome is replicated and the two resulting copies separate from one another, due to the growth of the cell.

The prokaryote, now enlarged, is pinched inward at its equator and the two resulting cells, which are clones , separate. Binary fission does not provide an opportunity for genetic recombination or genetic diversity, but prokaryotes can share genes by three other mechanisms.

In transformation , the prokaryote takes in DNA shed by other prokaryotes into its environment.