Answer:
They are thick, strong and made up of thousands of tubulin which are spiral in shape.
Explanation:
In eukaryotic cells, they have microtubules which are fibres serving as tracks for cell to cell transport and regulate the shape of a cell.
Microtubules are different from other cytoskeletal filaments because they possesses a cylindrical shape with the tube having a larger diameter of 20-25 nm as compared to microfilament that have a diameter of 3-6 nm.
Microtubules are made of subunits of proteins called tubulin named alpha and beta that is not present in other cytoskeletal filaments.
Electron microscopes use _beam of electrons___ in order to allow for higher magnification and more detail when viewing specimens.
Explanation:
A beam of electrons has a shorter wavelength than normal light used in light microscopes, by approximately a factor of X 100000. Therefore, electrons microscope have the inherent attribute of having a very high resolution. They have been used to discover very small organelles in cells such as the ribosomes and mitochondria that cannot be clearly viewed even with the highest resolution in light microscopes.
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Answer: Climate change
Explanation:
UN Climate Action Summit 2019 was organized in 2019 to discuss the domain of global climate change research. According to this dangerous impact of climate will influence the growth of new generations to come. This included various participating organizations like World Meteorological Organization, Panel on Climate Change, Earth league and global framework, UN Environment, Global carbon project and others.
The sole reason why red blood cells are unable to replace damaged proteins is that red blood cells lack DNA and cell organelles such as the nucleus, ribosomes, and mitochondria which are crucial for protein synthesis, assembly, and repair. In other words, they lack both the information and the machinery for making or repair of proteins.
Due to lack of DNA and cell organelles, red blood cells cannot be able to satisfy the central dogma which summarizes synthesis of proteins as DNA → RNA → proteins.
DNA has the genetic information on how proteins should be made, RNA is responsible for transferring the information from DNA in the cell nucleus to the ribosomes in the cytoplasm, then translating or decoding this information, which results in the making of protein.
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