United States passport. United States passports are passports issued to citizens and non-citizen nationals of the United States of America. They are issued exclusively by the U.S. Department of State. Besides passports (in booklet form), limited use passport cards are issued by the same organization subject to the same requirements.
DNA and histone proteins are packaged into structures called chromosomes. In the nucleus of each cell, the DNA molecule is packaged into thread-like structures called chromosomes.Each chromosome is made up of DNA tightly coiled many times around proteins called histones that support its structure.Chromosomes are not visible in the cellâs nucleusânot even under a microscopeâwhen the cell is not dividing.NA and histone proteins are packaged into structures called chromosomes. In the nucleus of each cell, the DNA molecule is packaged into thread-like structures called chromosomes.
Genes are made of a chemical called DNA, which is short for 'deoxyribonucleic acid'. The DNA molecule is a double helix: that is, two long, thin strands twisted around each other like a spiral staircase. The DNA double helix showing base pairs. The sides are sugar and phosphate molecules. The rungs are pairs of chemicals called 'nitrogenous bases', or 'bases' for short.