What is the shape of a DNA molecule called?
The double helix is a description of the molecular shape of a double-stranded DNA molecule. In 1953, Francis Crick and James Watson first described the molecular structure of DNA, which they called a “double helix,” in the journal Nature.
What is the molecular structure of DNA?
A DNA molecule consists of two long polynucleotide chains composed of four types of nucleotide subunits. Each of these chains is known as a DNA chain, or a DNA strand. Hydrogen bonds between the base portions of the nucleotides hold the two chains together (Figure 4-3).
Why is one strand of DNA upside down?
What is meant by DNA being antiparallel? One strand of DNA is upside down due to the nitrogen bases or organic bases joining the sugar molecule at carbon 1. If one side is 5′ then the other side must be 3′.
What role does base pairing play in transcription?
complementary base pairing ensures that the two daughter molecules are exact copies of the parent molecule. when the two strands of the parent molecule separate, each serves as a template on which the nucleotides are arranged by the base pairing rules into new complementary strands.
What is the base pairing pattern of DNA?
The rules of base pairing (or nucleotide pairing) are: A with T: the purine adenine (A) always pairs with the pyrimidine thymine (T) C with G: the pyrimidine cytosine (C) always pairs with the purine guanine (G)
What are the differences between the 5 and 3 ends of a DNA strand?
Each DNA strand has two ends. The 5′ end of the DNA is the one with the terminal phosphate group on the 5′ carbon of the deoxyribose; the 3′ end is the one with a terminal hydroxyl (OH) group on the deoxyribose of the 3′ carbon of the deoxyribose. 4.
What would happen if DNA was not antiparallel?
In antiparallel DNA, one strand runs from 5´ to 3´ prime and the other strand runs form 3´ to 5 ´. If the DNA strand was parallel, replication would not be possible. The nucleotides would not be complementary to each other and, as a result, would not pair in a genetic molecule.