romikgosai/squad_modified huggingface dataset:
Plants and various other groups of photosynthetic eukaryotes collectively known as "algae" have unique organelles known as chloroplasts. Chloroplasts are thought to be descended from cyanobacteria that formed endosymbiotic relationships with ancient plant and algal ancestors. Chloroplasts and cyanobacteria contain the blue-green pigment chlorophyll a. Chlorophyll a (as well as its plant and green algal-specific cousin chlorophyll b)[a] absorbs light in the blue-violet and orange/red parts of the spectrum while reflecting and transmitting the green light that we see as the characteristic colour of these organisms. The energy in the red and blue light that these pigments absorb is used by chloroplasts to make energy-rich carbon compounds from carbon dioxide and water by oxygenic photosynthesis, a process that generates molecular oxygen (O2) as a by-product.

Questions and answers:
['
Q: what parts of algae are unique to them?
A: chloroplasts', '
Q: From what ancient oxygen producing plant are chloroplasts descended?
A: cyanobacteria', '
Q: What color is chlorophyll?
A: blue-green', '
Q: What organelles are unique to algae?
A: chloroplasts', '
Q: From what ancient source are chloroplasts descended?
A: cyanobacteria', '
Q: What color does a plant with chlorophyll appear to be?
A: green']
The light energy captured by chlorophyll a is initially in the form of electrons (and later a proton gradient) that's used to make molecules of ATP and NADPH which temporarily store and transport energy. Their energy is used in the light-independent reactions of the Calvin cycle by the enzyme rubisco to produce molecules of the 3-carbon sugar glyceraldehyde 3-phosphate (G3P). Glyceraldehyde 3-phosphate is the first product of photosynthesis and the raw material from which glucose and almost all other organic molecules of biological origin are synthesized. Some of the glucose is converted to starch which is stored in the chloroplast. Starch is the characteristic energy store of most land plants and algae, while inulin, a polymer of fructose is used for the same purpose in the sunflower family Asteraceae. Some of the glucose is converted to sucrose (common table sugar) for export to the rest of the plant.

Questions and answers:
['
Q: What is the function of ATP and NADPH molecules?
A: store and transport energy', '
Q: When is the raw form of glucose formed?
A: first product of photosynthesis', '
Q: What is stored in the chloroplast?
A: starch', '
Q: What is used instead of glucose in sunflowers?
A: fructose', '
Q: Why is table sugar produced?
A: for export to the rest of the plant']
Plants synthesize a number of unique polymers like the polysaccharide molecules cellulose, pectin and xyloglucan from which the land plant cell wall is constructed. Vascular land plants make lignin, a polymer used to strengthen the secondary cell walls of xylem tracheids and vessels to keep them from collapsing when a plant sucks water through them under water stress. Lignin is also used in other cell types like sclerenchyma fibers that provide structural support for a plant and is a major constituent of wood. Sporopollenin is a chemically resistant polymer found in the outer cell walls of spores and pollen of land plants responsible for the survival of early land plant spores and the pollen of seed plants in the fossil record. It is widely regarded as a marker for the start of land plant evolution during the Ordovician period. The concentration of carbon dioxide in the atmosphere today is much lower than it was when plants emerged onto land during the Ordovician and Silurian periods. Many monocots like maize and the pineapple and some dicots like the Asteraceae have since independently evolved pathways like Crassulacean acid metabolism and the C4 carbon fixation pathway for photosynthesis which avoid the losses resulting from photorespiration in the more common C3 carbon fixation pathway. These biochemical strategies are unique to land plants.

Questions and answers:
['
Q: What polymer is used to strengthen cell walls?
A: lignin', '
Q: What weakens cell walls?
A: water stress', '
Q: What gas is in lower concentration now due to plants?
A: carbon dioxide', '
Q: What polymer is found in spores and pollen?
A: Sporopollenin', '
Q: What polymer is a major part of wood?
A: Lignin']
Phytochemistry is a branch of plant biochemistry primarily concerned with the chemical substances produced by plants during secondary metabolism. Some of these compounds are toxins such as the alkaloid coniine from hemlock. Others, such as the essential oils peppermint oil and lemon oil are useful for their aroma, as flavourings and spices (e.g., capsaicin), and in medicine as pharmaceuticals as in opium from opium poppies. Many medicinal and recreational drugs, such as tetrahydrocannabinol (active ingredient in cannabis), caffeine, morphine and nicotine come directly from plants. Others are simple derivatives of botanical natural products. For example, the pain killer aspirin is the acetyl ester of salicylic acid, originally isolated from the bark of willow trees, and a wide range of opiate painkillers like heroin are obtained by chemical modification of morphine obtained from the opium poppy. Popular stimulants come from plants, such as caffeine from coffee, tea and chocolate, and nicotine from tobacco. Most alcoholic beverages come from fermentation of carbohydrate-rich plant products such as barley (beer), rice (sake) and grapes (wine).

Questions and answers:
['
Q: What is the study of the chemicals that plants produce?
A: Phytochemistry', '
Q: Hemlock is what kind of chemical produced from a plant?
A: toxins', '
Q: Where do some medicines and recreational drugs come from?
A: from plants', '
Q: Where did aspirin originally come from?
A: bark of willow trees', '
Q: Where does morphine come from?
A: the opium poppy']
Sugar, starch, cotton, linen, hemp, some types of rope, wood and particle boards, papyrus and paper, vegetable oils, wax, and natural rubber are examples of commercially important materials made from plant tissues or their secondary products. Charcoal, a pure form of carbon made by pyrolysis of wood, has a long history as a metal-smelting fuel, as a filter material and adsorbent and as an artist's material and is one of the three ingredients of gunpowder. Cellulose, the world's most abundant organic polymer, can be converted into energy, fuels, materials and chemical feedstock. Products made from cellulose include rayon and cellophane, wallpaper paste, biobutanol and gun cotton. Sugarcane, rapeseed and soy are some of the plants with a highly fermentable sugar or oil content that are used as sources of biofuels, important alternatives to fossil fuels, such as biodiesel.

Questions and answers:
['
Q: How is charcoal made?
A: pyrolysis of wood', '
Q: Besides fire, what else is charcoal used for?
A: one of the three ingredients of gunpowder', '
Q: Plant oil is used for what kind of fuel?
A: biodiesel', '
Q: Rayon comes from what plant product?
A: cellulose']
Plant ecology is the science of the functional relationships between plants and their habitats—the environments where they complete their life cycles. Plant ecologists study the composition of local and regional floras, their biodiversity, genetic diversity and fitness, the adaptation of plants to their environment, and their competitive or mutualistic interactions with other species. The goals of plant ecology are to understand the causes of their distribution patterns, productivity, environmental impact, evolution, and responses to environmental change.

Questions and answers:
['
Q: What are plant habitats?
A: environments where they complete their life', '
Q: What is the goal of plant ecology?
A: to understand', '
Q: What is the study of plants and the environment in which they live?
A: Plant ecology', '
Q: What do plants do in their environment?
A: interactions with other species']
Plants depend on certain edaphic (soil) and climatic factors in their environment but can modify these factors too. For example, they can change their environment's albedo, increase runoff interception, stabilize mineral soils and develop their organic content, and affect local temperature. Plants compete with other organisms in their ecosystem for resources. They interact with their neighbours at a variety of spatial scales in groups, populations and communities that collectively constitute vegetation. Regions with characteristic vegetation types and dominant plants as well as similar abiotic and biotic factors, climate, and geography make up biomes like tundra or tropical rainforest.

Questions and answers:
['
Q: On what do plants depend in their environment?
A: edaphic (soil) and climatic factors', '
Q: How do plants interact with other species in their environment?
A: for resources', '
Q: What is the collection of plants in the environment called?
A: vegetation', '
Q: What are groupings of similar plants?
A: biomes']
Plant responses to climate and other environmental changes can inform our understanding of how these changes affect ecosystem function and productivity. For example, plant phenology can be a useful proxy for temperature in historical climatology, and the biological impact of climate change and global warming. Palynology, the analysis of fossil pollen deposits in sediments from thousands or millions of years ago allows the reconstruction of past climates. Estimates of atmospheric CO2 concentrations since the Palaeozoic have been obtained from stomatal densities and the leaf shapes and sizes of ancient land plants. Ozone depletion can expose plants to higher levels of ultraviolet radiation-B (UV-B), resulting in lower growth rates. Moreover, information from studies of community ecology, plant systematics, and taxonomy is essential to understanding vegetation change, habitat destruction and species extinction.

Questions and answers:
['
Q: How can historical changes in the environment be detected?
A: plant phenology', '
Q: How can climate changes be determined from soil?
A: fossil pollen deposits in sediments', '
Q: What atmospheric gas can be determined from fossilized leaf sizes and shapes?
A: CO2', '
Q: What causes lower growth in plants?
A: Ozone depletion', '
Q: What does ozone depletion allow?
A: higher levels of ultraviolet radiation-B']
Inheritance in plants follows the same fundamental principles of genetics as in other multicellular organisms. Gregor Mendel discovered the genetic laws of inheritance by studying inherited traits such as shape in Pisum sativum (peas). What Mendel learned from studying plants has had far reaching benefits outside of botany. Similarly, "jumping genes" were discovered by Barbara McClintock while she was studying maize. Nevertheless, there are some distinctive genetic differences between plants and other organisms.

Questions and answers:
['
Q: Does inheritance work differently in plants?
A: same fundamental principles of genetics', '
Q: What plant did Mendel use to demonstrate inheritance?
A: Pisum sativum (peas)', '
Q: What other plant was used in the discovery of different genes?
A: maize', '
Q: Are plants and animals genetically the same?
A: distinctive genetic differences']
Species boundaries in plants may be weaker than in animals, and cross species hybrids are often possible. A familiar example is peppermint, Mentha × piperita, a sterile hybrid between Mentha aquatica and spearmint, Mentha spicata. The many cultivated varieties of wheat are the result of multiple inter- and intra-specific crosses between wild species and their hybrids. Angiosperms with monoecious flowers often have self-incompatibility mechanisms that operate between the pollen and stigma so that the pollen either fails to reach the stigma or fails to germinate and produce male gametes. This is one of several methods used by plants to promote outcrossing. In many land plants the male and female gametes are produced by separate individuals. These species are said to be dioecious when referring to vascular plant sporophytes and dioicous when referring to bryophyte gametophytes.

Questions and answers:
['
Q: Are plants able to mate across species?
A: hybrids are often possible', '
Q: What common grain is the result cultivated wild hybrids?
A: wheat', '
Q: How do some plants avoid cross pollination?
A: pollen either fails to reach the stigma', '
Q: Do all plants have male and female parts?
A: separate individuals']
Unlike in higher animals, where parthenogenesis is rare, asexual reproduction may occur in plants by several different mechanisms. The formation of stem tubers in potato is one example. Particularly in arctic or alpine habitats, where opportunities for fertilisation of flowers by animals are rare, plantlets or bulbs, may develop instead of flowers, replacing sexual reproduction with asexual reproduction and giving rise to clonal populations genetically identical to the parent. This is one of several types of apomixis that occur in plants. Apomixis can also happen in a seed, producing a seed that contains an embryo genetically identical to the parent.

Questions and answers:
['
Q: Why do plants develop bulbs?
A: opportunities for fertilisation of flowers by animals are rare', '
Q: What do plants do when the environment makes fertilization especially difficult?
A: replacing sexual reproduction with asexual reproduction', '
Q: How different are the children produced by asexual parents?
A: genetically identical to the parent', '
Q: What is the term for asexual cloning?
A: Apomixis', '
Q: Does apomixis only occur in the parent?
A: can also happen in a seed']
Most sexually reproducing organisms are diploid, with paired chromosomes, but doubling of their chromosome number may occur due to errors in cytokinesis. This can occur early in development to produce an autopolyploid or partly autopolyploid organism, or during normal processes of cellular differentiation to produce some cell types that are polyploid (endopolyploidy), or during gamete formation. An allopolyploid plant may result from a hybridisation event between two different species. Both autopolyploid and allopolyploid plants can often reproduce normally, but may be unable to cross-breed successfully with the parent population because there is a mismatch in chromosome numbers. These plants that are reproductively isolated from the parent species but live within the same geographical area, may be sufficiently successful to form a new species. Some otherwise sterile plant polyploids can still reproduce vegetatively or by seed apomixis, forming clonal populations of identical individuals. Durum wheat is a fertile tetraploid allopolyploid, while bread wheat is a fertile hexaploid. The commercial banana is an example of a sterile, seedless triploid hybrid. Common dandelion is a triploid that produces viable seeds by apomictic seed.

Questions and answers:
['
Q: What can cause the doubling of chromosome pairs?
A: errors in cytokinesis', '
Q: Are the plants produced by this error, able to reproduce?
A: often reproduce normally', '
Q: Can these plants cross breed with the parent population of plants?
A: unable to cross-breed successfully', '
Q: What happens to these new plants if they are able to reproduce?
A: form a new species', '
Q: What is a yellow example of a sterile,hybrid plant with no seeds?
A: commercial banana']
A considerable amount of new knowledge about plant function comes from studies of the molecular genetics of model plants such as the Thale cress, Arabidopsis thaliana, a weedy species in the mustard family (Brassicaceae). The genome or hereditary information contained in the genes of this species is encoded by about 135 million base pairs of DNA, forming one of the smallest genomes among flowering plants. Arabidopsis was the first plant to have its genome sequenced, in 2000. The sequencing of some other relatively small genomes, of rice (Oryza sativa) and Brachypodium distachyon, has made them important model species for understanding the genetics, cellular and molecular biology of cereals, grasses and monocots generally.

Questions and answers:
['
Q: What was the first plant to have its genome sequenced?
A: Thale cress, Arabidopsis thaliana', '
Q: In what year was this genome sequenced?
A: 2000', '
Q: Why was this plant chosen for sequencing?
A: one of the smallest genomes', '
Q: Why is sequencing done on plants?
A: understanding the genetics', '
Q: What results from  sequencing of DNA pairs?
A: new knowledge about plant function']
Model plants such as Arabidopsis thaliana are used for studying the molecular biology of plant cells and the chloroplast. Ideally, these organisms have small genomes that are well known or completely sequenced, small stature and short generation times. Corn has been used to study mechanisms of photosynthesis and phloem loading of sugar in C4 plants. The single celled green alga Chlamydomonas reinhardtii, while not an embryophyte itself, contains a green-pigmented chloroplast related to that of land plants, making it useful for study. A red alga Cyanidioschyzon merolae has also been used to study some basic chloroplast functions. Spinach, peas, soybeans and a moss Physcomitrella patens are commonly used to study plant cell biology.

Questions and answers:
['
Q: Why is a plant chosen for the study of its cells?
A: small genomes', '
Q: What mechanism can be studied through chromosome sequencing?
A: photosynthesis', '
Q: What common plant has been used for studying the production of sugar?
A: Corn', '
Q: What simple plant has been used to study plant cells?
A: red alga']
Agrobacterium tumefaciens, a soil rhizosphere bacterium, can attach to plant cells and infect them with a callus-inducing Ti plasmid by horizontal gene transfer, causing a callus infection called crown gall disease. Schell and Van Montagu (1977) hypothesised that the Ti plasmid could be a natural vector for introducing the Nif gene responsible for nitrogen fixation in the root nodules of legumes and other plant species. Today, genetic modification of the Ti plasmid is one of the main techniques for introduction of transgenes to plants and the creation of genetically modified crops.

Questions and answers:
['
Q: How can a bacteria in the soil affect a plant?
A: can attach to plant cells', '
Q: How can scientists use bacteria in the study of plants?
A: introducing the Nif gene', '
Q: How are genes transferred to a plant by scientists?
A: in the root nodules', '
Q: What is this kind of introduction and transfer used for?
A: creation of genetically modified crops', '
Q: Who developed the procedures used in this transfer?
A: Schell and Van Montagu']
Epigenetics is the study of mitotically and/or meiotically heritable changes in gene function that cannot be explained by changes in the underlying DNA sequence but cause the organism's genes to behave (or "express themselves") differently. One example of epigenetic change is the marking of the genes by DNA methylation which determines whether they will be expressed or not. Gene expression can also be controlled by repressor proteins that attach to silencer regions of the DNA and prevent that region of the DNA code from being expressed. Epigenetic marks may be added or removed from the DNA during programmed stages of development of the plant, and are responsible, for example, for the differences between anthers, petals and normal leaves, despite the fact that they all have the same underlying genetic code. Epigenetic changes may be temporary or may remain through successive cell divisions for the remainder of the cell's life. Some epigenetic changes have been shown to be heritable, while others are reset in the germ cells.

Questions and answers:
['
Q: What does epigenetics study?
A: changes in gene function', '
Q: How do DNA changes affect plants?
A: express themselves") differently', '
Q: When DNA has different markers, how it that presented in plants?
A: prevent that region of the DNA code', '
Q: What is a result of changes in DNA markers within a plant species?
A: differences', '
Q: Are the changes then presented, permanent?
A: may be temporary']
Epigenetic changes in eukaryotic biology serve to regulate the process of cellular differentiation. During morphogenesis, totipotent stem cells become the various pluripotent cell lines of the embryo, which in turn become fully differentiated cells. A single fertilized egg cell, the zygote, gives rise to the many different plant cell types including parenchyma, xylem vessel elements, phloem sieve tubes, guard cells of the epidermis, etc. as it continues to divide. The process results from the epigenetic activation of some genes and inhibition of others.

Questions and answers:
['
Q: What process causes changes in plant cells?
A: Epigenetic changes', '
Q: What is the original cell of the plant?
A: the zygote', '
Q: How are the different cells formed?
A: continues to divide', '
Q: How is it determined, which cells will be formed?
A: activation of some genes and inhibition of others']
Unlike animals, many plant cells, particularly those of the parenchyma, do not terminally differentiate, remaining totipotent with the ability to give rise to a new individual plant. Exceptions include highly lignified cells, the sclerenchyma and xylem which are dead at maturity, and the phloem sieve tubes which lack nuclei. While plants use many of the same epigenetic mechanisms as animals, such as chromatin remodeling, an alternative hypothesis is that plants set their gene expression patterns using positional information from the environment and surrounding cells to determine their developmental fate.

Questions and answers:
['
Q: Does cell division end in plants?
A: remaining totipotent', '
Q: What happens when a plant remains totipotent?
A: ability to give rise to a new individual plant', '
Q: Why do phloem sieve tubes stop forming?
A: lack nuclei', '
Q: Why are plants able to stop and start dividing cells?
A: information from the environment', '
Q: Are lignified cells able to continue dividing?
A: dead at maturity']
The algae are a polyphyletic group and are placed in various divisions, some more closely related to plants than others. There are many differences between them in features such as cell wall composition, biochemistry, pigmentation, chloroplast structure and nutrient reserves. The algal division Charophyta, sister to the green algal division Chlorophyta, is considered to contain the ancestor of true plants. The Charophyte class Charophyceae and the land plant sub-kingdom Embryophyta together form the monophyletic group or clade Streptophytina.

Questions and answers:
['
Q: Are all algae different from land plants?
A: some more closely related', '
Q: What algae is the ancestor of true plants?
A: Charophyta', '
Q: Are all species of algae similar?
A: many differences', '
Q: To what species of algae is Charophyta related?
A: Chlorophyta']