!Nucleic acids
DNA -"The Double Helix
Recall that the nucleus is a small spherical, dense body in a cell.! It is
often called the "control center" because it controls all the activities of
the cell including cell reproduction, and heredity.! Chromosomes are
microscopic, threadlike strands composed of the chemical DNA (short for
deoxyribonucleic acid).! In simple terms, DNA controls the production of
proteins within the cell.! These proteins in turn, form the structural units
of cells and control all chemical processes within the cell.! Think of proteins
as the building blocks for an organism, proteins make up your skin, your
hair, and parts of individual cells. The proteins that are made largely
determine how you look. The proteins that will be made for your body are
determined by the sequence of DNA in the nucleus.
What important polymer is located in the nucleus? _____DNA___
___DNA_____ is the instructions for making a cell's __proteins_____.
Chromosomes are composed of genes, which is a segment of DNA that
codes for a particular protein, which in turn codes for a trait.! Hence you
hear it commonly referred to as the gene for baldness or the gene for blue
eyes.! Meanwhile, DNA is the chemical that genes and chromosomes are
made of. DNA is called a nucleic acid because it was first found in the
nucleus.! We now know that DNA is also found in some organelles such as
the mitochondria and chloroplasts. It is the DNA in the nucleus that
actually controls the cell's workings.
genes __ on chromosomes code for specific ___ traits ___ in a cell.
DNA is also found in _ mitochondria _ and chloroplasts _.
In 1953, James Watson and Francis Crick established the structure
of DNA.! The shape of DNA is a double helix, which is like a twisted ladder.
The sides of the ladder are made of alternating sugar and phosphate
molecules.! The sugar is a pentose called deoxyribose. Color all the
phosphates pink (one is labeled with a "p"). Color all the deoxyribose
sugars blue (one is labeled with a "D").
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