DNA is stored in loosely wound euchromatin before mitosis. During mitosis, the DNA condenses into chromosomes, which are made of heterochromatin. It becomes more dense during prophase, and stays that way until the end of mitosis. Euchromatin is more lightly packed than heterochromatin.

Mitosis follows the following sequence: prophase, metaphase, anaphase, telophase, cytokinesis. Interphase refers to the time period between mitotic divisions. During interphase, most DNA is euchromatin, but some regions remain as heterochromatin to prevent unwanted transcription; thus DNA exists as both types of chromatin during interphase, but only as heterochromatin during mitosis. Matching euchromatin to telophase is the answer, as this is a false statement.

Nucleosomes are the basic, repeating units of eukaryotic chromatin. They consist of chromosomal DNA wrapped around special DNA-binding proteins called histones. There are many examples of non-chromosomal DNA, such as plasmids, but they do not contain nucleosomes. Nuclear import is controlled by importin proteins.

Histones are proteins that bind and package DNA. The strand of DNA is wound around histone proteins, condensing it to fit in the nucleus and acting to moderate gene expression. Chromatin is the term given to the complex of DNA associated with histones. A nucleosome is the smallest repeating unit of chromatin, formed from eight histone proteins and two loops of coiled DNA. Telomerase is an enzyme responsible for maintaining the integrity of the telomeres.

Euchromatin is the name given to chromatin that appears lighter when viewed under a microscope. It is actually relatively decondensed chromatin that is available for active transcription. Because it is decondensed it is more accessible to RNA polymerase and, therefore, easier to transcribe. In contrast, heterochromatin is tightly wound, dense DNA that is inaccessible by RNA polymerase and is considered inactive.

Translation is the process of synthesizing proteins from mRNA transcripts and does not directly involve DNA or chromatin.

Chromatin is not present in all eukaryotic and prokaryotic DNA; most prokaryotic DNA is circular and does not require the complex folding of eukaryotic chromatin. Chromatin exists in more compacted states than 10nm. In particular, the 30nm version is commonly recognized as heterochromatin (DNA that is not being actively transcribed). Packaging can also be more condensed during certain stages of mitosis. Nucleosomes are the smallest units of chromatin and are strands of DNA wrapped in proteins known as histones.

Patterns of methylation and acetylation of these histones have been shown to repress and activate gene expression, respectively, and are important factors in regulating gene expression and epigenetics.

Human beings have somatic (body) cells that are diploid. This means that each cell has two copies of each of the 23 chromosomes: one from the father and one from the mother. As a result, the karyotype of a human being would show 23 pairs of chromosomes, for a total of 46. Diploid cells contain two non-identical copies of the same genes. All diploid cells will contain two separate alleles for each gene in the genome, represented by the two homologous chromosomes.

An important note to make is that human germ (sex) cells are haploid, meaning that the chromosomes are not paired in sperm cells and egg cells.

A nucleosome is defined as a core region of histones plus one stretch of linker DNA. This gives a "beads on a string" shape, which can be further packaged into chromatin. These nucleosomes contain a DNA wrapped histone octamer in the core region, and a linker histone in the linker DNA region. The histone octamer has 2 each of H2A, H2B, H3, and H4 histones. The linker DNA has an H1 histone. 

Karyotypes describe whole chromosome structure, including the number and size of chromosomes, position of centromeres, distribution of heterochromatin versus euchromatin, and the presence of satellite chromosomes that are found near the centromeres. However, a karyotype is unable to label specific gene sequences and determine their chromosomal locations. Most karyotypes depict chromosomes of a cell in metaphase.

Chromosomes have a great deal of protein involved in their structure so that DNA can be tightly coiled in order to fit into the nucleus. At the smallest level of organization, the DNA wraps itself around small globular proteins called histones. Complexes of histones and DNA form nucleosomes, which appear as "beads" on the DNA strand.

Chromatin refers to the decondensed DNA that has not formed separate chromosomes. The nucleolus is a nuclear structure where ribosomal subunits are synthesized.

The correct answer is histones. Histones are alkaline proteins in the nucleus that organize DNA into structural units called nucleosomes. Chromatin and chromosomes are more complex structural units composed of DNA, histones, nucleosomes, and other proteins.