Question

dna guided reading
(1)
dna, or deoxyribonucleic acid, is a fundamental molecule that serves as the genetic blueprint for all living organisms. it stores, copies, and transmits genetic information and carries the instructions necessary for the growth, development, functioning, and reproduction of an organism.
(2)
dna is found in all living cells. dna is located in the nucleus of eukaryotic cells, or the cells of animals, plants, protists, and fungi. in prokaryotic cells, or cells of bacteria and archaea, dna is found floating in the cytoplasm of the cell.
dna is a nucleic acid made up of nucleotides joined into long strands by covalent bonds. nucleic acids are long molecules made up smaller units called nucleotides. dna’s structure is characterized by a double helix, resembling a twisted ladder, with a covalently-bonded sugar-phosphate backbone as the sides of the ladder and nucleotides the rungs of the ladder.
each nucleotide in dna consists of a phosphate group, a deoxyribose sugar, and one of four nitrogenous bases: adenine (a), cytosine (c), guanine (g), and thymine (t). the nitrogenous bases base - pair in a highly specific manner—adenine pairs with thymine, and cytosine pairs with guanine—through hydrogen rds, stabilizing the helical structure.
1f. take note of the diagram to the
a nucleotide consists of a
deoxyribose sugar, a
phosphate group, and a
nitrogenous base
a sugar - phosphate backbone
uns down each side of a
dna molecule
bases are complementary to
one another

• a pairs with t
• c pairs with g

(5)
chargaff’s rule. formulated by biochemist erwin chargaff in 1949, states that in a dna molecule, the amount of adenine (a) is approximately equal to the amount of thymine (t), and the amount of cytosine (c) is approximately equal to the amount of guanine (g). chargaff’s rule demonstrates the complementary nature of the dna. explaining how the two strands are held together by specific bonding patterns between their nitrogenous bases.

1. what are the roles of dna?
2. explain the relationship between a nucleic acid and a nucleotide.
3. describe the structure of dna.
4. label the phosphate group, nitrogenous base, and deoxyribose sugar on the nucleotide diagram.
5. write the complementary nitrogenous base pair for each nucleotide in the diagram below. the first two are done for you
6. if a molecule of dna contains 20% adenine, what percent of guanine does it contain?

Explanation:

Chargaff's rule states that in DNA, the amount of adenine (A) is approximately equal to thymine (T), and the amount of cytosine (C) is approximately equal to guanine (G). If adenine is 20%, then thymine is also 20%. The total percentage of A + T is 40%, so the remaining 60% is for C + G. Since C = G, we divide 60% by 2.

Answer:

30%