Eukaryotic chromosomes are composed of which of the following macromolecules? Chromosomes are made of DNA, which is a macromolecule. DNA stands for deoxyribonucleic acid, and it is the genetic material that makes up chromosomes. It is a double-stranded molecule, meaning that it has two strands coiled around each other. Each strand is made up of nucleotides, which are the building blocks of DNA. There are four types of nucleotides: adenine (A), thymine (T), cytosine (C), and guanine (G). The order of these nucleotides determines the sequence of the DNA strand.
Eukaryotic chromosomes contain hundreds to thousands of genes, the basic units of heredity. Most eukaryotic genes are composed of exons, the coding regions, and introns, the non-coding regions. Introns separate the exons, and they are transcribed into mRNA. The mRNA is then translated into proteins.
Eukaryotic chromosomes also contain various other elements, such as regulatory sequences, centromeres, and telomeres. Regulatory sequences control gene expression. Centromeres are required for proper chromosome segregation during cell division. Telomeres protect the ends of chromosomes from deterioration.
Most eukaryotic genes are inherited in a Mendelian fashion, which means that they are passed down from parent to offspring through the generations in a predictable manner. However, some genes are acquired through horizontal gene transfer, which is the movement of genes between organisms other than through vertical descent.
Eukaryotic chromosomes are composed of both DNA and protein. The DNA is wrapped around proteins called histones, and the combination of the two is called chromatin. Chromatin is further divided into euchromatin (which is actively transcribed) and heterochromatin (inactive or has a lower transcription level).
Eukaryotic chromosomes are found in the nucleus of cells. In some organisms, such as yeast, the chromosomes are circular. In others, such as humans, the chromosomes are linear. Each chromosome has a centromere required for proper segregation during cell division and telomeres, which protect the ends of the chromosome from deterioration.
Most eukaryotic genes are passed down in a Mendelian fashion through the generations. However, some genes are acquired through horizontal gene transfer. Horizontal gene transfer is the movement of genes between organisms other than through vertical descent. For example, bacteria can transfer genes to one another through conjugation. Viruses can also transfer genes to both prokaryotic and eukaryotic cells through transduction. Finally, genes can be acquired by humans through gene therapy.