Primary Meanings of fold. 1  v bend or lay so that one part covers the other. 2  v become folded or folded up. 3  n the act of folding.  n an angular or rounded shape made by 1  folding. n a folded part (as in skin or muscle)  n a geological process that causes a bend in a stratum of 1  rock. n a pen for 2  sheep. n a group of sheep or  goats.
Each gene has a special job to do. The DNA in a gene spells out specific instructionsâmuch like in a cookbook recipe â for making proteins (say: PRO-teens) in the cell. Proteins are the building blocks for everything in your body. Bones and teeth, hair and earlobes, muscles and blood, are all made up of proteins.
Inside the nucleus of virtually all. of our cells are 46 chromosomes, the thread-like packages that. carry our genes. At the tips of. these chromosomes, like the hard. ends of shoelaces, are structures. called telomeres. While they do. not contain genes, telomeres. are important for replication or. duplication of the chromosomes.