A single chromosome typically contains one long DNA molecule, which includes a multitude of genes. The number of genes on a chromosome can vary widely between different organisms and even between different chromosomes within the same organism.
In humans, for example, chromosomes can carry anywhere from a few hundred to over a thousand genes. The exact number often depends on the specific chromosome and the genetic characteristics of the organism. Chromosomes are tightly packed structures made of DNA and proteins, ensuring that the genetic material is efficiently organized and stored within the cell nucleus.
To summarize, each chromosome has one DNA molecule, while the number of genes can range significantly based on the chromosome’s size and the organism’s genetics.