Video Transcript
Inside the nucleus of your cells,
DNA is wound and coiled into long strands. What are these long strands of DNA
called? (A) Nucleosomes, (B) ribosomes, (C)
chromosomes, (D) helices, or (E) genes.
As you can see in this diagram, DNA
is a long helical molecule which is usually double stranded. A section of DNA which codes for a
particular protein is known as a gene. Human DNA contains around 30000
genes, which contribute to our characteristics. This is why DNA is a very long
molecule. In fact, if you took all the DNA
from a single human cell and laid it out end to end, it would be between two and
three meters long. And yet it’s all found inside the
cellular compartment called the nucleus, which is only about six micrometers in
diameter. So how does the DNA fit inside a
space which is over 400000 times smaller than it?
The cell packages the DNA into
tightly wound and coiled structures called chromosomes, which can then be stored
inside the nucleus. Humans have 46 chromosomes, which
are found as 23 chromosome pairs, and they appear as thin threads if we look at them
under a microscope. The correct answer to the question
is therefore (C). The long strands of DNA that are
found inside the nucleus of your cells are called chromosomes.
