Fungi are organisms that scientists once confused with plants. However, scientists have found that, at the cell level, the fungi are more like animals than they are like plants. For one thing, fungi cannot synthesize their own food like plants do, but instead they eat other organisms as do animals. Fungi come in a variety of shapes and sizes and different types. They can range from single cells to enormous chains of cells that can stretch for miles. Fungi include single-celled living things that exist individually, such as yeast, and multicellular clusters, such as molds or mushrooms. Yeast cells look round or oval under a microscope. They're too small to see as individuals, but you can see large clusters of them as a white powdery coating on fruits and leaves. Molds are described as filament-like because they form long filament-like, or thread-like, strands of cells called hyphae. These hyphae are what give mold colonies their fuzzy appearance. They also form the fleshy body, or mushroom, that some species grow. It may seem strange to think of something as big as a mushroom as a microbe. But the cells of the hyphae making up that mushroom are connected in a closer way than the cells of other multicellular living things, like you and me, are. Fungi usually grow best in environments that are slightly acidic. They can grow on substances with very low moisture. Fungi live in the soil and on your body, in your house and on plants and animals, in freshwater and seawater. A single teaspoon of topsoil contains about 120, 000 fungi. Fungi are basically stationary. But they can spread either by forming reproductive spores that are carried on wind and rain or by growing and extending their hyphae. Hyphae grow as new cells form at the tips, creating even longer chains of cells. Fungi absorb nutrients from living or dead organic matter that they grow on. They absorb simple, easily dissolved nutrients, such as sugars, through their cell walls. They give off special digestive enzymes to break down complex nutrients into simpler forms that they can absorb. Some fungi are quite useful to us. We've used several kinds to make antibiotics to fight bacterial infections. These antibiotics are based on natural compounds the fungi produce to compete against bacteria for nutrients and space. We use baker's yeast, to make bread rise and to brew beer. Fungi break down dead plants and animals and keep the world tidier. We're exploring ways to use natural fungal enemies of insect pests to get rid of these bugs.

Now I'm nowhere near qualified enough to give you a really indepth answer that's multiple paragraphs long with a bunc of professionally cited papers, but I can tell you why mitochondria are completely absent in bacteria. Mitochondria are absent in bacteria for multiple reasons. First up, Bacteria are Prokaryotes That is, bacterium contain no membrane bound nucleus and rarely contain membrane bound organelles. Simply, most don't have any large organelles with their own membranes; this means no nucleus, no mitochondria and no chloroplast. As they lack important tools to carry genetic information and perform other basic cell activitys, prokaryotes have to make up in other ways: the average prokaryote is smaller (no need for Golgi Apparutus), contains genetic information in the form of small rings of coiled DNA called a Nucleiod (no need for Nucleus) and, finally, they can all produce energy independant of any organelle. Energy is produced right in the chloroplasm. How the energy is produced depends on what type of cell they are. Autotrophic Prokaryotes generate energy on their own, usually (but not always) through photosynthesis. Heterotrophic Prokaryotes have to take in, or engulf, biological matter to produce energy, usually by engulfing smaller cells. Even if a bacteria wanted to have mitochondria, it couldn't. This is because: They’re too small Generally speaking, bacteria cells are roughly the same size as mitochondria and chloroplasts, sometimes smaller and occasionally larger. This is because mitochondria and chloroplasts are practically cells on their own right; mitochondria contain DNA Nucleoids and ribosomes, both of which are distinctly unique from their parent cells. All of these similarities are often thought too be too wild to be just coincidence. But thats another topic entirely. For a bacteria cell to contain mitochondria, it would have to be much larger. To cater for its larger size, it would require more organelles, to exchange larger amounts of material with its environment, to provide structure and support and other very vital cellular functions that would be hampered by its larger size. At this point, it is no longer a prokaryote, and in turn no longer a bacteria cell. It would instead fall into a different class, specifically the class Protista (usually). TL;DR: Bacteria are prokaryotes, which means they do not contain many or any organelles at all. Besides, bacteria are far too small to contain mitochondria. They are, after all, roughly the same size.

Objective– The main objective of this experiment is to find the various places of bacteria as to where they live. Bacterias are the single-celled organisms. These organisms are not visible to our naked eye as they are very tiny. Bacterias serve almost many functions within the environment and also your body like in helping the nutrients in the soil, and also in the process of digestion. Some of the bacterias are known to be harmful in nature. This experiment helps you in knowing the where the harmful microorganisms live? Requirements – 5 or more cell-culture dish Glass dish Zipped plastic bags Water Agar powder Labeling tape Cotton swabs Nitrile disposable gloves Marker Procedure – Make use of cotton swabs in order to collect the bacteria samples. To collect the bacteria, wipe the cotton swab on any surface. Find some good locations to get the samples like handles of a door, train or bus seats, etc. Make use only single cotton swab per location. Store each of the cotton swabs in labeled zipped bag. Label your cell-culture dishes with the names of the locations as to where you got the sample. Mix agar powder with water and pour this solution in a small glass dish Take another clean, new cotton swab and then wipe a clean cell-culture dish Dip this cotton swab in the dish of liquid agar. Later wipe it again on the cell-culture and then label it as “control.” Clean the small dish. You should not contaminate the agar in between samples. Now, Take the collected samples each, dip in agar solution, and swab labeled petri dish. Keep these dishes at an room temperature and then record the observations over after some few days. By this you come to know as to which of the locations have the most of bacterias. Conclusion – Agar acts as an surface for the growing up of bacteria and harmful microorganisms. It is not digested by most of the organisms, but the packets of agar for the growing up of cells have the additives which the bacteria eat and also use them to grow.

Established infectious agents continue to be a major cause of human morbidity and mortality worldwide. However, the causative agent remains unknown for a wide range of diseases; many of these are suspected to be attributable to yet undiscovered microorganisms. The advent of unbiased high-throughput sequencing and bioinformatics has enabled rapid identification and molecular characterization of known and novel infectious agents in human disease. An exciting era of microbe discovery, now under way, holds great promise for the improvement of global health via the development of antimicrobial therapies, vaccination strategies, targeted public health measures, and probiotic-based preventions and therapies. Here, we review the history of pathogen discovery, discuss improvements and clinical applications for the detection of microbially associated diseases, and explore the challenges and strategies for establishing causation in human disease.

The cytoplasm refers to the entire area of the cell outside of the nucleus. The cytoplasm has two parts, the organelles and the cytosol, a grayish gel-like liquid that fills the interior of the cell. The cytosol provides a home for the nucleus and organelles as well as a location for protein synthesis and other fundamental chemical reactions. Cytoskeleton The cytoskeleton is a protein structure that maintains cell shape and helps move organelles around the cell. There are two types of cytoskeleton proteins: microtubules and microfilaments . Microtubules are thick, hollow rods that provide a strong scaffold for the cell. The smaller microfilaments are thin rods made of a protein called actin; they are strung around the perimeter of the cell to help it withstand strain. In some organisms, the microtubules power limbs called cilia and flagella, creating movement. Contraction of the microfilaments powers muscle movement in animals and facilitates the creeping motion of creatures like amoebas. The microtubules also form protein tracks on which organelles can slide around the cell. The Organelles Floating in the cytoplasm are the many membrane-bound organelles, each with a distinct structure and an important function in the processes of the cell. Nucleus: stores the cell’s genetic material in strands of DNA and choreographs life functions by sending detailed messages to the rest of the cell. The interior of the nucleus is separated from the cytosol by a membrane called the nuclear envelope, which lets only select molecules in and out. The DNA itself is wrapped around proteins known as histones in an entangled fibrous network called chromatin. When the nucleus is about to split in two, this amorphous mass coils more tightly, forming distinct structures called chromosomes. The nucleus also houses a small, dark structure called the nucleolus , which helps manufacture ribosomes. Ribosomes: synthesize proteins for the cell. Some ribosomes are mounted on the surface of the endoplasmic reticulum (see below), and others float freely in the cytoplasm. All ribosomes have two unequally sized subunits made of proteins and a substance called RNA. All living cells, prokaryotic and eukaryotic alike, have ribosomes. Ribosomes are explained in more detail in the chapter on Cell Processes as part of the larger discussion about the way the cell manufactures proteins. Mitochondria: produces energy for the cell through a process called cellular respiration (see the chapter on Cell Processes). The mitochondria has two membranes; the inside membrane has many folds, called cristae. Many of the key cell-respiration enzymes are embedded in this second membrane. The chemical reactions of respiration take place in the compartment formed by the second membrane, a region called the mitochondrial matrix. Endoplasmic reticulum: an extensive network of flattened membrane sacs that manufactures proteins. These proteins are transferred to the Golgi apparatus, from which they will be exported from the cell. There are two types of endoplasmic reticulum: rough and smooth. Rough endoplasmic reticulum is studded by ribosomes covering its exterior. These ribosomes make the rough endoplasmic reticulum a prime location for protein synthesis. The smooth endoplasmic reticulum moves the proteins around the cell and then packages them into small containers called vesicles that travel to the Golgi apparatus. The smooth endoplasmic reticulum also functions in the synthesis of fats and lipids. Golgi apparatus: a complex of membrane-bound sacs that package proteins for export from the cell. Proteins enter the Golgi complex from the endoplasmic reticulum and proceed through the stacks, where they are modified and stored before secretion. When proteins are ready for export, pieces of the Golgi membrane bud off, forming vesicles that send them to the cell membrane. Lysosomes: small membrane-bound packages of acidic enzymes that digest compounds and worn-out cellular components that the cell no longer needs.

An example of a typical prokaryote is the bacterial cell. Bacterial cells can be shaped like rods, spheres, or corkscrews. All prokaryotes are bounded by a plasma membrane. Overlying this plasma membrane is a cell wall, and in some bacteria, a capsule consisting of a jelly-like material overlies the cell wall. Many bacteria that cause illness in animals have capsules. The capsule provides an extra layer of protection for the bacteria, and often pathogenic bacteria with capsules cause much more severe than those without capsules. Within the cytoplasm of prokaryotes is a nucleoid, a region where the genetic material (DNA) resides. This nucleoid is not a true nucleus because it is not bounded by a membrane. Also within the cytoplasm are numerous ribosomes. These ribosomes are not attached to any structure and are thus called "free" ribosomes. Attached to the cell wall of some bacteria are, whip-like structures that provide for movement. Some bacteria also have pili, which are short, finger-like projections that assist the bacteria in attaching to tissues. Bacteria cannot cause disease if they cannot attach to tissues. Bacteria that cause, for instance, attach to the tissues of the lung. Bacterial pili greatly facilitates this attachment to tissues, and thus, like capsules, bacteria with pili are often more virulent than those without.

Bacteria usually live in colonies and reproduce quickly. There are 10, 000 known species of bacteria. There are probably many more waiting to be discovered. Bacteria are divided into three groups. Cocci bacteria are round. They can be found alone, in pairs, in clumps or in long strands. Bacilli bacteria have a straight shape. Spiral bacteria look like corkscrew pasta. Bacteria can reproduce about once every 20 minutes. Some bacteria are harmful. These bacteria can cause serious diseases, such as tuberculosis, typhoid fever and even tooth plaque. Bacteria Vocabulary Flagella: tiny hairs that can move Colony: group Decay : rotting Learn More About Bacteria Check out this video about bacteria: An animated video all about a bacterium talking about itself. Bacteria Q&A Question: Do antibiotics kill bacteria? Answer: Antibiotics can kill bacteria and keep us healthy. Some vaccines also fight bacteria. One of the best things you can do is wash your hands with soap and water. Wash hands when you get home from school, before you eat and after you use the restroom. —————————- Question: Do bacteria live in the soil? Answer: Some bacteria live in the soil. They help break down dead matter so plants can use it. They are called soil builders and they’re good for your garden.

All living cells have certain features in common. They all are enclosed by a plasma membrane with cytoplasm held inside. They all contain nucleic acids, ribosomes and membrane transport mechanisms. Even though all of these things are in common between prokaryotes and eukaryotes, there are differences. Eukaryotes have their multiple chromosomes stored in a special structure called the nucleus. Prokayotes do not, the single chromosome floats around in the cytoplasm. Both cell types contain ribosomes yet the structure of each one is actually somewhat different. There are other differences between prokaryotes and eukaryotes in that each one has specific structures the other does not. Cell structures unique to eukaryotic cells were listed in the earlier cell biology lesson. Here we'll discuss some of the cell structures unique to prokaryotes. The most basic thing to discuss about a bacterial cell is its shape. Bacteria come in all sorts of shapes. Round ones are called Cocci. Then there are Bacilli which are rod shaped cells. A cell that is sort of round and not quite a rod (something like an oval) would be called a Coccobacillus . If a rod shaped cell has a bit of a curve to it, like a comma, it's called a Vibrio. Then there are cells with a corkscrew or even a spring shape which are referred to as a Spirillum or Spirochete. Making things even more interesting, these cells often times cluster together into specific patterns that can be seen using a microscope. A pair of cocci are called Diplococci. Sometimes cocci will form chains, the Streptococci do this. Other times cocci may form clusters which is a characteristic of Staphylococci . Bacilli may not form any particular pattern but when they do it often looks like a line of them linked together to form a chain. The cells depicted here seem to have white centers in some of them. These are endospores, we'll discuss them a bit later.

The white blood cells that first ingest the TB bacteria are macrophages, which kill invading particles (be they cells or bits of cells, or even dead parts of your own cells) by ingesting them into a vacuole and then breaking them down. The TB gets ingested fine, but once inside the cell, it stops the cell from breaking it down. That means that you now have a white blood cells infected with a TB bacterium. In order to create the granuloma, the TB bacterium needs to bring other white blood cells to the scene. The best way to do this is to rupture the cell that it's currently in, because bits of broken up cell are a great way to get the immune system rushing over. A recent paper in PloS (reference below) shows that in order to do this, the TB must break out of the vacuole holding it following ingestion, and then kill the host cell once it's in the cytoplasm: This model is not a fully accepted one within the TB community, and there's still some conflict as to whether the bacterium actually breaks out of the vacuole it gets ingested into (as shown above) or whether it stays within the vacuole and wrecks havoc from there. The paper explores this using a technique called FRET. FRET works by using two fluorescent probes which, when they get close to each other, light up. If the two probes are far apart, no fluorescence is seen, but if they're in close proximity they light up like a fairy light and can be detected. One half of the probe was attached to a protein found in the white blood cell cytoplasm, while the other was attached to a sugar found on the bacterial cell surface. What they found was not only does the bacterial sugar end up very close to the cytoplasmic protein, it does it relatively quickly. Within 24 h to 48 h after infection fluorescence could be detected in almost all the infected blood cells. A bit of tinkering around with knocking out bacterial protein activity also discovered a set of proteins that were vital for this process to occur: ESX-1.

Bacteria and archaea are the only prokaryotes. All other life forms are Eukaryotes (you-carry-oats), creatures whose cells have nuclei. (Note: viruses are not considered true cells, so they don't fit into either of these categories.) What Difference Does It Make? Does a bacterium’s cell wall, shape, way of moving, and environment really matter? Yes! The more we know about bacteria, the more we are able to figure out how to make microbes work for us or stop dangerous ones from causing serious harm. And, for those of us who like to ponder more philosophical questions like the origins of the Earth, there may be some clues there as well. How Long They’ve Been Around Like dinosaurs, bacteria left behind fossils. The big difference is that it takes a microscope to see them. And they are older. Bacteria and their microbial cousins the archaea were the earliest forms of life on Earth. And may have played a role in shaping our planet into one that could support the larger life forms we know today by developing photosynthesis. Cyanobacteria fossils date back more than 3 billion years. These photosynthetic bacteria paved the way for today's algae and plants. Cyanobacteria grow in the water, where they produce much of the oxygen that we breathe. Once considered a form of algae, they are also known as blue-green algae. Bacteria are among the earliest forms of life that appeared on Earth billions of years ago. Scientists think that they helped shape and change the young planet's environment, eventually creating atmospheric oxygen that enabled other, more complex life forms to develop. Many believe that more complex cells developed as once free-living bacteria took up residence in other cells, eventually becoming the organelles in modern complex cells. The mitochondria (mite-oh-con-dree-uh) that make energy for your body cells is one example of such an organelle. There are thousands of species of bacteria, but all of them are basically one of three different shapes. Some are rod- or stick-shaped and called bacilli (buh-sill-eye) . Others are shaped like little balls and called cocci (cox-eye). Others still are helical or spiral in shape, like the Borrelia pictured at the top of this page. Some bacterial cells exist as individuals while others cluster together to form pairs, chains, squares or other groupings. Bacillus anthracis causes anthrax, a deadly disease in cattle and a potential bioweapon against humans Cyanobacteria (formerly known as blue-green algae) live in water, where they produce large amounts of the oxygen we breathe. Escherichia coli (a.k.a. E. coli) lives in the gut, where it helps digest food and produces Vitamin K. The "bad" strain of E. coli O157:H7 causes severe foodborne sickness. Some bacteria are photosynthetic (foe-toe-sin-theh-tick) —they can make their own food from sunlight, just like plants. Also like plants, they give off oxygen. Other bacteria absorb food from the material they live on or in. Some of these bacteria can live off unusual "foods" such as iron or sulfur. The microbes that live in your gut absorb nutrients from the digested food you've eaten. Some bacteria have hair- or whip-like appendages called flagella used to ‘swim’ around. Others produce thick coats of slime and ‘glide’ about. Some stick out thin, rigid spikes called fimbriae to help hold them to surfaces. Some contain little particles of minerals that orient with the planet’s magnetic fields to help the bacteria figure out whether they’re swimming up or down. Bacteria can be found virtually everywhere. They are in the air, the soil, and water, and in and on plants and animals, including us. A single teaspoon of topsoil contains about a billion bacterial cells (and about 120, 000 fungal cells and some 25, 000 algal cells). The human mouth is home to more than 500 species of bacteria.