Answer:
A) milk
Explanation:
Pure substances are materials that have constant chemical composition and physical and chemical properties as they do not change at constant pressure and temperature. Examples of pure substances are oxygen, water and carbon dioxide.
On the other hand, there are compound substances, which unlike simple substances are chemical compounds formed by atoms of different chemical elements, such as milk that is formed from elements from the blood of the animal and contains amino acids, fatty acids. , lactose and certain minerals.
Milk is the only option that is not a pure substance.
In this question, all the options are actually examples of pure substances except for milk. A pure substance is one that is made up of only one type of particle and cannot be separated into simpler substances by physical means. Milk, on the other hand, is a mixture of various components including water, proteins, fats, and sugars.
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Elements on the periodic table are arranged into groups and periods, and are ordered according to atomic number, not the number of proteins or based solely on reactivity. Each element's place is determined by the number of protons in its nucleus, which also typically equals the number of electrons. Elements in the same group, or column, share similar chemical properties.
The elements on the periodic table are indeed arranged into groups and periods, but they are ordered in line with their atomic number. This atomic number reflects the number of protons in an element's nucleus and also typically matches the number of electrons surrounding the nucleus. Elements in the same vertical column, known as a group, share similar chemical properties.
Each box on the periodic table represents an element, and contains its atomic number, symbol, average atomic mass and (sometimes) name. The elements are arranged in seven horizontal rows, known as periods or series, and 18 vertical columns, called groups. The properties of the elements are periodic functions of their atomic numbers, hence the arrangements.
The reactivity of elements does have a role to play in the periodic table, as element groups possess similar chemical behaviors due to the similar configurations of their outermost electron shell. However, this reactivity does not determine the ordering of elements on the periodic table as the atomic number does. The numbering of proteins error seems to be a typographical mistake as proteins aren't a determinant in the configuration of the periodic table.
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Answer:1. Acetyl groups and methylated amino acids with a neighboring phosphate group
Explanation:
Option 4. Acetyl group only can loosen the chromatin structure.
Acetyl groups can loosen the chromatin structure by altering the charge of the histone proteins. When unmodified, the histone proteins have a large positive charge, but by adding acetyl groups, the charge becomes less positive, resulting in a looser packing of nucleosomes.
Histone acetylation affects nucleosome spacing and gene expression. When the chromatin structure is loosened through acetylation, transcription factors can bind to the DNA, allowing genes to be expressed. In conclusion, acetyl groups have the ability to loosen the chromatin structure, which allows for gene expression by enabling transcription factors to bind to the DNA. The correct answer is option 4: Acetyl groups ONLY!
Learn more about chromatin here:
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