DNA Replication
DNA replication :
● Produces two identical molecules of DNA from the original.
● Occurs during S phase of interphase.
● Is described as “ semi-conservative”, because the two new molecules each will contain half of the
original; and half from newly matched nucleotides.
The duplicated molecules :
● Remain attached at a DNA sequence known as the centromere.
● Are referred to as “ sister” chromatids
One DNA molecule in eukaryotes :
● Is a long linear piece - equal to one chromosome.
○ However , the term ‘ chromosome’ also includes all the accompanying proteins that congregate on
a molecule of DNA
● Contains 50 - 250 million base pairs. Base pairs are bonded together with hydrogen bonds.
● The DNA code consists of matching nucleotides - adenine with thymine; and guanine with cytosine.
DNA is oriented :
● With anti-parallel strands.
● One end is oriented 5 prime to 3 prime; the complementary strand is oriented 3 prime to 5 prime.
● The numbers refer to the carbons in the deoxyribose sugar .
● The carbons are numbered 1 - 5, starting with the carbon that binds the base.
● The rest are numbered clockwise from the one that binds the base
● One side of the molecule starts with the deoxyribose sugar with its 5 carbon pointing up, and the
other side starts with its 3 carbon pointing up.
DNA replication :
● Produces two identical molecules of DNA from the original.
● Occurs during S phase of interphase.
● Is described as “ semi-conservative”, because the two new molecules each will contain half of the
original; and half from newly matched nucleotides.
The duplicated molecules :
● Remain attached at a DNA sequence known as the centromere.
● Are referred to as “ sister” chromatids
One DNA molecule in eukaryotes :
● Is a long linear piece - equal to one chromosome.
○ However , the term ‘ chromosome’ also includes all the accompanying proteins that congregate on
a molecule of DNA
● Contains 50 - 250 million base pairs. Base pairs are bonded together with hydrogen bonds.
● The DNA code consists of matching nucleotides - adenine with thymine; and guanine with cytosine.
DNA is oriented :
● With anti-parallel strands.
● One end is oriented 5 prime to 3 prime; the complementary strand is oriented 3 prime to 5 prime.
● The numbers refer to the carbons in the deoxyribose sugar .
● The carbons are numbered 1 - 5, starting with the carbon that binds the base.
● The rest are numbered clockwise from the one that binds the base
● One side of the molecule starts with the deoxyribose sugar with its 5 carbon pointing up, and the
other side starts with its 3 carbon pointing up.
