rajpurkar/squad huggingface dataset:
Title: Bacteria

Once regarded as plants constituting the class Schizomycetes, bacteria are now classified as prokaryotes. Unlike cells of animals and other eukaryotes, bacterial cells do not contain a nucleus and rarely harbour membrane-bound organelles. Although the term bacteria traditionally included all prokaryotes, the scientific classification changed after the discovery in the 1990s that prokaryotes consist of two very different groups of organisms that evolved from an ancient common ancestor. These evolutionary domains are called Bacteria and Archaea.

Question: What living organisms are bacteria being reffered as?
Answer: prokaryotes

Question: What vital part is missing in bacteria to eukaryotes?
Answer: nucleus

Question: When did the scientific classification change?
Answer: 1990s

Question: What are two main groups prokaryotes can be divided into?
Answer: Bacteria and Archaea
Title: Bacteria

The ancestors of modern bacteria were unicellular microorganisms that were the first forms of life to appear on Earth, about 4 billion years ago. For about 3 billion years, most organisms were microscopic, and bacteria and archaea were the dominant forms of life. In 2008, fossils of macroorganisms were discovered and named as the Francevillian biota. Although bacterial fossils exist, such as stromatolites, their lack of distinctive morphology prevents them from being used to examine the history of bacterial evolution, or to date the time of origin of a particular bacterial species. However, gene sequences can be used to reconstruct the bacterial phylogeny, and these studies indicate that bacteria diverged first from the archaeal/eukaryotic lineage. Bacteria were also involved in the second great evolutionary divergence, that of the archaea and eukaryotes. Here, eukaryotes resulted from the entering of ancient bacteria into endosymbiotic associations with the ancestors of eukaryotic cells, which were themselves possibly related to the Archaea. This involved the engulfment by proto-eukaryotic cells of alphaproteobacterial symbionts to form either mitochondria or hydrogenosomes, which are still found in all known Eukarya (sometimes in highly reduced form, e.g. in ancient "amitochondrial" protozoa). Later on, some eukaryotes that already contained mitochondria also engulfed cyanobacterial-like organisms. This led to the formation of chloroplasts in algae and plants. There are also some algae that originated from even later endosymbiotic events. Here, eukaryotes engulfed a eukaryotic algae that developed into a "second-generation" plastid. This is known as secondary endosymbiosis.

Question: When did the first antecedents of bacteria appear on Earth?
Answer: 4 billion years ago

Question: Why were bacteria and archaea dominant forms of life?
Answer: most organisms were microscopic

Question: What are Stromatolites?
Answer: bacterial fossils

Question: What pre-historic group did bacteria evolve from?
Answer: archaeal/eukaryotic lineage

Question: How did chloroplast appear in first vegetation?
Answer: mitochondria also engulfed cyanobacterial-like organisms
Title: Bacteria

Bacteria display a wide diversity of shapes and sizes, called morphologies. Bacterial cells are about one-tenth the size of eukaryotic cells and are typically 0.5–5.0 micrometres in length. However, a few species are visible to the unaided eye — for example, Thiomargarita namibiensis is up to half a millimetre long and Epulopiscium fishelsoni reaches 0.7 mm. Among the smallest bacteria are members of the genus Mycoplasma, which measure only 0.3 micrometres, as small as the largest viruses. Some bacteria may be even smaller, but these ultramicrobacteria are not well-studied.

Question: Are bacteria cells smaller than eukaryotic cells?
Answer: one-tenth the size

Question: What is the common name for shapes and forms of bacteria?
Answer: morphologies

Question: How big is Epulopiscium bacteria?
Answer: 0.7 mm

Question: What are one of the smallest bacteria?
Answer: genus Mycoplasma

Question: Is ultramicrobacteria is well examined?
Answer: not well-studied
Title: Bacteria

Most bacterial species are either spherical, called cocci (sing. coccus, from Greek kókkos, grain, seed), or rod-shaped, called bacilli (sing. bacillus, from Latin baculus, stick). Elongation is associated with swimming. Some bacteria, called vibrio, are shaped like slightly curved rods or comma-shaped; others can be spiral-shaped, called spirilla, or tightly coiled, called spirochaetes. A small number of species even have tetrahedral or cuboidal shapes. More recently, some bacteria were discovered deep under Earth's crust that grow as branching filamentous types with a star-shaped cross-section. The large surface area to volume ratio of this morphology may give these bacteria an advantage in nutrient-poor environments. This wide variety of shapes is determined by the bacterial cell wall and cytoskeleton, and is important because it can influence the ability of bacteria to acquire nutrients, attach to surfaces, swim through liquids and escape predators.

Question: What shape does usually cocci type of bacteria can be?
Answer: spherical

Question: What type of bacteria usually takes rod-shaped form?
Answer: bacilli

Question: What shape Spirochaetes are?
Answer: tightly coiled

Question: What shape was newly discovered bacteria from deep under Earth?
Answer: branching filamentous types with a star-shaped cross-section

Question: Can shape of bacteria be beneficial to their survival?
Answer: can influence the ability of bacteria to acquire nutrients
Title: Bacteria

Many bacterial species exist simply as single cells, others associate in characteristic patterns: Neisseria form diploids (pairs), Streptococcus form chains, and Staphylococcus group together in "bunch of grapes" clusters. Bacteria can also be elongated to form filaments, for example the Actinobacteria. Filamentous bacteria are often surrounded by a sheath that contains many individual cells. Certain types, such as species of the genus Nocardia, even form complex, branched filaments, similar in appearance to fungal mycelia.

Question: What is the usual form for Neiserria bacteria?
Answer: diploids (pairs)

Question: What type of bacteria is surrounded by a capsule?
Answer: Filamentous bacteria

Question: What well known bacteria structure chains?
Answer: Streptococcus

Question: What does typically Staphylococcus look like?
Answer: clusters

Question: Formation of what can be related to fungal mycelia?
Answer: branched filaments
Title: Bacteria

Bacteria often attach to surfaces and form dense aggregations called biofilms or bacterial mats. These films can range from a few micrometers in thickness to up to half a meter in depth, and may contain multiple species of bacteria, protists and archaea. Bacteria living in biofilms display a complex arrangement of cells and extracellular components, forming secondary structures, such as microcolonies, through which there are networks of channels to enable better diffusion of nutrients. In natural environments, such as soil or the surfaces of plants, the majority of bacteria are bound to surfaces in biofilms. Biofilms are also important in medicine, as these structures are often present during chronic bacterial infections or in infections of implanted medical devices, and bacteria protected within biofilms are much harder to kill than individual isolated bacteria.

Question: What does bacteria use to adhere to surfaces?
Answer: biofilms

Question: How extent can biofilm be?
Answer: up to half a meter in depth

Question: What is part of secondary structure in the complex formation of bacteria?
Answer: microcolonies,

Question: What is the purpose of networks of channels in microcolonies?
Answer: to enable better diffusion of nutrients

Question: Which bacteria is more difficult to eradicate?
Answer: bacteria protected within biofilms
Title: Bacteria

Even more complex morphological changes are sometimes possible. For example, when starved of amino acids, Myxobacteria detect surrounding cells in a process known as quorum sensing, migrate toward each other, and aggregate to form fruiting bodies up to 500 micrometres long and containing approximately 100,000 bacterial cells. In these fruiting bodies, the bacteria perform separate tasks; this type of cooperation is a simple type of multicellular organisation. For example, about one in 10 cells migrate to the top of these fruiting bodies and differentiate into a specialised dormant state called myxospores, which are more resistant to drying and other adverse environmental conditions than are ordinary cells.

Question: What is the vital nutriment for Myxobacteria?
Answer: amino acids

Question: Why do cells of Myxobacteria migrate towards each other?
Answer: aggregate to form fruiting bodies

Question: How hard to treat bacteria cells in a passive state?
Answer: more resistant

Question: What bacteria do in fruiting bodies?
Answer: multicellular organisation
Title: Bacteria

The bacterial cell is surrounded by a cell membrane (also known as a lipid, cytoplasmic or plasma membrane). This membrane encloses the contents of the cell and acts as a barrier to hold nutrients, proteins and other essential components of the cytoplasm within the cell. As they are prokaryotes, bacteria do not usually have membrane-bound organelles in their cytoplasm, and thus contain few large intracellular structures. They lack a true nucleus, mitochondria, chloroplasts and the other organelles present in eukaryotic cells. Bacteria were once seen as simple bags of cytoplasm, but structures such as the prokaryotic cytoskeleton and the localization of proteins to specific locations within the cytoplasm that give bacteria some complexity have been discovered. These subcellular levels of organization have been called "bacterial hyperstructures".

Question: What is a cell membrane?
Answer: lipid

Question: What does membrane accomplish?
Answer: barrier to hold nutrients, proteins and other essential components

Question: Do bacteria have membrabe-bound organelles in their cytoplasm?
Answer: do not

Question: Absence of what make bacteria belong to prokaryotes?
Answer: true nucleus, mitochondria, chloroplasts and the other organelles

Question: What bacteria was observed as before prokaryotic cytoskeleton was discovered?
Answer: simple bags of cytoplasm
Title: Bacteria

Many important biochemical reactions, such as energy generation, use concentration gradients across membranes. The general lack of internal membranes in bacteria means reactions such as electron transport occur across the cell membrane between the cytoplasm and the periplasmic space. However, in many photosynthetic bacteria the plasma membrane is highly folded and fills most of the cell with layers of light-gathering membrane. These light-gathering complexes may even form lipid-enclosed structures called chlorosomes in green sulfur bacteria. Other proteins import nutrients across the cell membrane, or expel undesired molecules from the cytoplasm.

Question: What is crucial for biochemical reactions?
Answer: concentration gradients across membranes

Question: What kind of membrane do bacteria cells are filled with?
Answer: light-gathering membrane

Question: How does electron transit occur in bacteria?
Answer: between the cytoplasm and the periplasmic space

Question: Can membrane of bacteria create lipid structure?
Answer: light-gathering complexes may even form lipid-enclosed structures
Title: Bacteria

Bacteria do not have a membrane-bound nucleus, and their genetic material is typically a single circular DNA chromosome located in the cytoplasm in an irregularly shaped body called the nucleoid. The nucleoid contains the chromosome with its associated proteins and RNA. The phylum Planctomycetes and candidate phylum Poribacteria may be exceptions to the general absence of internal membranes in bacteria, because they appear to have a double membrane around their nucleoids and contain other membrane-bound cellular structures. Like all living organisms, bacteria contain ribosomes, often grouped in chains called polyribosomes, for the production of proteins, but the structure of the bacterial ribosome is different from that of eukaryotes and Archaea. Bacterial ribosomes have a sedimentation rate of 70S (measured in Svedberg units): their subunits have rates of 30S and 50S. Some antibiotics bind specifically to 70S ribosomes and inhibit bacterial protein synthesis. Those antibiotics kill bacteria without affecting the larger 80S ribosomes of eukaryotic cells and without harming the host.

Question: What is genetic make of bacteria?
Answer: a single circular DNA chromosome

Question: Where is DNA chromosome of bacteria located?
Answer: in the cytoplasm

Question: How does nucleoid look?
Answer: irregularly shaped body

Question: What are the exceptions of non-internal membrane bacteria?
Answer: phylum Planctomycetes and candidate phylum Poribacteria

Question: What is the purpose of polyribosomes in bacteria?
Answer: production of proteins
Title: Bacteria

Some bacteria produce intracellular nutrient storage granules for later use, such as glycogen, polyphosphate, sulfur or polyhydroxyalkanoates. Certain bacterial species, such as the photosynthetic Cyanobacteria, produce internal gas vesicles, which they use to regulate their buoyancy – allowing them to move up or down into water layers with different light intensities and nutrient levels. Intracellular membranes called chromatophores are also found in membranes of phototrophic bacteria. Used primarily for photosynthesis, they contain bacteriochlorophyll pigments and carotenoids. An early idea was that bacteria might contain membrane folds termed mesosomes, but these were later shown to be artifacts produced by the chemicals used to prepare the cells for electron microscopy. Inclusions are considered to be nonliving components of the cell that do not possess metabolic activity and are not bounded by membranes. The most common inclusions are glycogen, lipid droplets, crystals, and pigments. Volutin granules are cytoplasmic inclusions of complexed inorganic polyphosphate. These granules are called metachromatic granules due to their displaying the metachromatic effect; they appear red or blue when stained with the blue dyes methylene blue or toluidine blue. Gas vacuoles, which are freely permeable to gas, are membrane-bound vesicles present in some species of Cyanobacteria. They allow the bacteria to control their buoyancy. Microcompartments are widespread, membrane-bound organelles that are made of a protein shell that surrounds and encloses various enzymes. Carboxysomes are bacterial microcompartments that contain enzymes involved in carbon fixation. Magnetosomes are bacterial microcompartments, present in magnetotactic bacteria, that contain magnetic crystals.

Question: What types of intracellar nutrient can bacteria produce?
Answer: glycogen, polyphosphate, sulfur or polyhydroxyalkanoates

Question: What gas vacuoles are respoonsible for in bacteria?
Answer: to control their buoyancy

Question: What are the most common nonliving compositions in bacteria?
Answer: glycogen, lipid droplets, crystals, and pigments

Question: How does gas vesicles produced by Cyanobacteria help her to move in water?
Answer: move up or down into water layers with different light intensities

Question: What are chromatophores used for?
Answer: photosynthesis
Title: Bacteria

In most bacteria, a cell wall is present on the outside of the cell membrane. The cell membrane and cell wall comprise the cell envelope. A common bacterial cell wall material is peptidoglycan (called "murein" in older sources), which is made from polysaccharide chains cross-linked by peptides containing D-amino acids. Bacterial cell walls are different from the cell walls of plants and fungi, which are made of cellulose and chitin, respectively. The cell wall of bacteria is also distinct from that of Archaea, which do not contain peptidoglycan. The cell wall is essential to the survival of many bacteria, and the antibiotic penicillin is able to kill bacteria by inhibiting a step in the synthesis of peptidoglycan.

Question: What composes the cell envelope?
Answer: cell membrane and cell wall

Question: What is most common cell wall material?
Answer: peptidoglycan

Question: Are cell walls of bacteria similar to cell walls of plants and fungi?
Answer: Bacterial cell walls are different

Question: How can antibiotic penicillin destroy bacteria?
Answer: by inhibiting a step in the synthesis of peptidoglycan

Question: What are the main materials of cell walls of plants and fungi?
Answer: cellulose and chitin
Title: Bacteria

Gram-positive bacteria possess a thick cell wall containing many layers of peptidoglycan and teichoic acids. In contrast, gram-negative bacteria have a relatively thin cell wall consisting of a few layers of peptidoglycan surrounded by a second lipid membrane containing lipopolysaccharides and lipoproteins. Lipopolysaccharides, also called endotoxins, are composed of polysaccharides and lipid A that is responsible for much of the toxicity of gram-negative bacteria. Most bacteria have the gram-negative cell wall, and only the Firmicutes and Actinobacteria have the alternative gram-positive arrangement. These two groups were previously known as the low G+C and high G+C Gram-positive bacteria, respectively. These differences in structure can produce differences in antibiotic susceptibility; for instance, vancomycin can kill only gram-positive bacteria and is ineffective against gram-negative pathogens, such as Haemophilus influenzae or Pseudomonas aeruginosa. If the bacterial cell wall is entirely removed, it is called a protoplast, whereas if it is partially removed, it is called a spheroplast. β-Lactam antibiotics, such as penicillin, inhibit the formation of peptidoglycan cross-links in the bacterial cell wall. The enzyme lysozyme, found in human tears, also digests the cell wall of bacteria and is the body's main defense against eye infections.

Question: What does gram-positive bacteria have?
Answer: thick cell wall containing many layers of peptidoglycan and teichoic acids

Question: Why gram-negative cell bacteria is more toxic than gram-positive bacteria?
Answer: polysaccharides and lipid A

Question: What can be endotoxins called?
Answer: Lipopolysaccharides

Question: What can different structure of the cell walls of bacteria effect?
Answer: differences in antibiotic susceptibility

Question: What is the main defense of human body against eye infections?
Answer: enzyme lysozyme, found in human tears
Title: Bacteria

Acid-fast bacteria, such as Mycobacteria, are resistant to decolorization by acids during staining procedures. The high mycolic acid content of Mycobacteria, is responsible for the staining pattern of poor absorption followed by high retention. The most common staining technique used to identify acid-fast bacteria is the Ziehl-Neelsen stain or acid-fast stain, in which the acid-fast bacilli are stained bright-red and stand out clearly against a blue background. L-form bacteria are strains of bacteria that lack cell walls. The main pathogenic bacteria in this class is Mycoplasma (not to be confused with Mycobacteria).

Question: What is the most typical staining technique used to identify acid-fast bacteria?
Answer: Ziehl-Neelsen stain

Question: What is mycolic acid is responsible for in Mycobacteria?
Answer: staining pattern of poor absorption followed by high retention.

Question: What helps Mycobacteria be resistant to decolorization?
Answer: high mycolic acid content

Question: What is the main pathogenic bacteria in L-form class ?
Answer: Mycoplasma
Title: Bacteria

Fimbriae (sometimes called "attachment pili") are fine filaments of protein, usually 2–10 nanometres in diameter and up to several micrometers in length. They are distributed over the surface of the cell, and resemble fine hairs when seen under the electron microscope. Fimbriae are believed to be involved in attachment to solid surfaces or to other cells, and are essential for the virulence of some bacterial pathogens. Pili (sing. pilus) are cellular appendages, slightly larger than fimbriae, that can transfer genetic material between bacterial cells in a process called conjugation where they are called conjugation pili or "sex pili" (see bacterial genetics, below). They can also generate movement where they are called type IV pili (see movement, below).

Question: What are fimbriae?
Answer: fine filaments of protein

Question: What are fimbriae liable for?
Answer: involved in attachment to solid surfaces or to other cells

Question: What is the diameter of fimbriae?
Answer: 2–10 nanometres

Question: What are pili?
Answer: cellular appendages
Title: Bacteria

Certain genera of Gram-positive bacteria, such as Bacillus, Clostridium, Sporohalobacter, Anaerobacter, and Heliobacterium, can form highly resistant, dormant structures called endospores. In almost all cases, one endospore is formed and this is not a reproductive process, although Anaerobacter can make up to seven endospores in a single cell. Endospores have a central core of cytoplasm containing DNA and ribosomes surrounded by a cortex layer and protected by an impermeable and rigid coat. Dipicolinic acid is a chemical compound that composes 5% to 15% of the dry weight of bacterial spores. It is implicated as responsible for the heat resistance of the endospore.

Question: What are highly resistant dormant structures of certain gram-positive bacteria called?
Answer: endospores

Question: Is creating endospore a reproductive process?
Answer: is not a reproductive process

Question: What are ribosomes in endospores are enclosed in?
Answer: cortex layer

Question: What chemical compound comprises 5% to 15% of the dry weight of bacterial spores?
Answer: Dipicolinic acid
Title: Bacteria

Endospores show no detectable metabolism and can survive extreme physical and chemical stresses, such as high levels of UV light, gamma radiation, detergents, disinfectants, heat, freezing, pressure, and desiccation. In this dormant state, these organisms may remain viable for millions of years, and endospores even allow bacteria to survive exposure to the vacuum and radiation in space. According to scientist Dr. Steinn Sigurdsson, "There are viable bacterial spores that have been found that are 40 million years old on Earth — and we know they're very hardened to radiation." Endospore-forming bacteria can also cause disease: for example, anthrax can be contracted by the inhalation of Bacillus anthracis endospores, and contamination of deep puncture wounds with Clostridium tetani endospores causes tetanus.

Question: Is there a metabolism in endospores?
Answer: show no detectable metabolism

Question: What extreme physical and chemical stresses can endospores endure?
Answer: UV light, gamma radiation, detergents, disinfectants, heat, freezing, pressure

Question: How long can endospores of bacteria stay alive in dormant state?
Answer: for millions of years

Question: What endospore-forming bacteria can cause tetanus disease?
Answer: Clostridium tetani
Title: Bacteria

Bacteria exhibit an extremely wide variety of metabolic types. The distribution of metabolic traits within a group of bacteria has traditionally been used to define their taxonomy, but these traits often do not correspond with modern genetic classifications. Bacterial metabolism is classified into nutritional groups on the basis of three major criteria: the kind of energy used for growth, the source of carbon, and the electron donors used for growth. An additional criterion of respiratory microorganisms are the electron acceptors used for aerobic or anaerobic respiration.

Question: What is commonly used to determine taxonomy of bacteria?
Answer: The distribution of metabolic traits

Question: How is bacterial metabolism determined?
Answer: nutritional groups

Question: What are electron acceptors accountable for?
Answer: aerobic or anaerobic respiration

Question: What are three main criterias of bacterial metabolism?
Answer: the kind of energy used for growth, the source of carbon, and the electron donors