What threadlike structures contain the instructions for running a cell?
http://ghr.nlm.nih.gov/handbook/basics?show=all
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The threadlike structures that contain the instructions for running a cell are called chromosomes. More specifically, the instructions for running a cell are encoded in the DNA molecules found within the chromosomes. The DNA molecule is made up of two long strands twisted together in a double helix shape. Each strand consists of a sequence of nucleotides, which are the building blocks of DNA. These nucleotides contain the genetic information or code that determines the characteristics of an organism and how it functions.
To see chromosomes and the instructions encoded in DNA, we typically need to use a microscope and laboratory techniques. The process of extracting DNA from cells, isolating and visualizing chromosomes, and analyzing their genetic instructions is often performed in specialized scientific laboratories. This field of study is known as genetics or molecular biology.
It's important to note that different types of organisms have varying numbers and shapes of chromosomes. For example, human cells usually have 23 pairs of chromosomes, while fruit fly cells have 4 pairs. The unique arrangement and sequence of nucleotides within an organism's DNA are what make each organism genetically distinct.