DNA Polymerase III
is the enzyme that adds nucleotides to make the continuous leading strand.
What enzyme matches DNA nucleotides to an opened strand of DNA?
The primary enzyme involved in this is
DNA polymerase
which joins nucleotides to synthesize the new complementary strand. DNA polymerase also proofreads each new DNA strand to make sure that there are no errors.
How do nucleotides connect to the strand of DNA?
When nucleotides are incorporated into DNA, adjacent nucleotides are linked by
a phosphodiester bond
: a covalent bond is formed between the 5′ phosphate group of one nucleotide and the 3′-OH group of another (see below). In this manner, each strand of DNA has a “backbone” of phosphate-sugar-phosphate-sugar-phosphate.
What enzyme can connect the 2 strands of DNA?
| Important Enzymes in DNA Replication | Enzyme Function | DNA polymerase Synthesizes the new DNA strand; also proofreads and corrects some errors | DNA ligase Re-joins the two DNA strands into a double helix and joins Okazaki fragments of the lagging strand |
|---|
What is the complementary strand of DNA?
Complementary DNA (cDNA) is
a copy of a region of a strand of DNA
. For example, if the original DNA stand had a sequence of ATT, the complementary sequence will be TAA. The cDNA will bind to the complementary site on the DNA strand.
What links nucleotides together?
A sugar-phosphate backbone (alternating grey-dark grey)
joins together nucleotides in a DNA sequence. The sugar-phosphate backbone forms the structural framework of nucleic acids, including DNA and RNA. This backbone is composed of alternating sugar and phosphate groups, and defines directionality of the molecule.
How do nucleotides make up DNA?
A nucleotide consists of a sugar molecule
(either ribose in RNA or deoxyribose in DNA) attached to a phosphate group and a nitrogen-containing base
. The bases used in DNA are adenine (A), cytosine (C), guanine (G), and thymine (T). In RNA, the base uracil (U) takes the place of thymine.
What type of reaction links nucleotides together?
Nucleotides are joined together by
covalent bonds
between the phosphate group of one nucleotide and the third carbon atom of the pentose sugar in the next nucleotide. This produces an alternating backbone of sugar – phosphate – sugar – phosphate all along the polynucleotide chain.
Why does DNA synthesis occur in the 5 ‘- 3 direction?
DNA is always synthesized in the 5′-to-3′ direction, meaning
that nucleotides are added only to the 3′ end of the growing strand
. As shown in Figure 2, the 5′-phosphate group of the new nucleotide binds to the 3′-OH group of the last nucleotide of the growing strand. … Two phosphates are cleaved off.
What are the four base pairs in DNA?
There are four nucleotides, or bases, in DNA:
adenine (A), cytosine (C), guanine (G), and thymine (T)
. These bases form specific pairs (A with T, and G with C).
What do you call the adenine thymine pair?
A (
adenine
): In genetics, A stands for adenine, one member of the A-T (adenine-thymine) base pair in DNA. The other base pair in DNA is G-C (guanine-cytosine). Each base pair forms a “rung of the DNA ladder.” A DNA nucleotide is made of a molecule of sugar, a molecule of phosphoric acid, and a molecule called a base.
Why are DNA strands complementary?
The discovery of the structure of DNA also revealed the principle that makes this copying possible: because each
strand of DNA contains a sequence of nucleotides that is exactly complementary to the nucleotide sequence of its partner strand
, each strand can act as a template, or mold, for the synthesis of a new …
What is the strongest bond in DNA?
A covalent bond
is stronger than a hydrogen bond (hydrogen bonds hold pairs of nucleotides together on opposite strands in DNA). Thus, the covalent bond is crucial to the backbone of the DNA.
What is the weakest bond in DNA?
A hydrogen bond
is a weak chemical bond that occurs between hydrogen atoms and more electronegative atoms, like oxygen, nitrogen and fluorine. The participating atoms can be located on the same molecule (adjacent nucleotides) or on different molecules (adjacent nucleotides on different DNA strands).
