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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.

What are the main materials of cell walls of plants and fungi?
Answer: cellulose and chitin
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On March 30, 2015, it was announced that Beyoncé is a co-owner, with various other music artists, in the music streaming service Tidal. The service specialises in lossless audio and high definition music videos. Beyoncé's husband Jay Z acquired the parent company of Tidal, Aspiro, in the first quarter of 2015. Including Beyoncé and Jay-Z, sixteen artist stakeholders (such as Kanye West, Rihanna, Madonna, Chris Martin, Nicki Minaj and more) co-own Tidal, with the majority owning a 3% equity stake. The idea of having an all artist owned streaming service was created by those involved to adapt to the increased demand for streaming within the current music industry, and to rival other streaming services such as Spotify, which have been criticised for their low payout of royalties. "The challenge is to get everyone to respect music again, to recognize its value", stated Jay-Z on the release of Tidal.

What music service is accused of providing low royalty amounts?
Answer: Spotify
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He also developed Feynman diagrams, a bookkeeping device that helps in conceptualizing and calculating interactions between particles in spacetime, including the interactions between electrons and their antimatter counterparts, positrons. This device allowed him, and later others, to approach time reversibility and other fundamental processes. Feynman's mental picture for these diagrams started with the hard sphere approximation, and the interactions could be thought of as collisions at first. It was not until decades later that physicists thought of analyzing the nodes of the Feynman diagrams more closely. Feynman painted Feynman diagrams on the exterior of his van.

What is the name of the antimatter counterpart of electrons?
Answer:
positrons