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KEY CONCEPT DNA replication copies the genetic information of a cell. Replication copies the genetic information. A single strand of DNA serves as a template for a new strand. The rules of base pairing control replication. DNA is replicated during the S (synthesis) stage of the cell cycle.
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KEY CONCEPT DNA replication copies the genetic information of a cell.
Replication copies the genetic information. • A single strand of DNA serves as a template for a new strand. • The rules of base pairing controlreplication. • DNA is replicated during theS (synthesis) stage of thecell cycle. • Each body cell gets acomplete set ofidentical DNA.
nucleotide The DNA molecule unzips in both directions. Proteins carry out the process of replication. • DNA serves as a template. • Enzymes and other proteins do the actual work of replication. • Enzymes unzip the double helix. • Free-floating nucleotides form hydrogen bonds with the template strand.
nucleotide new strand DNA polymerase • DNA polymerase enzymes bond the nucleotides together to form the double helix. • Polymerase enzymes form covalent bonds between nucleotides in the new strand.
new strand original strand Two molecules of DNA • Two new molecules of DNA are formed, each with an original strand and a newly formed strand. • DNA replication is semiconservative.
There are many origins of replication in eukaryotic chromosomes. Replication is fast and accurate. • DNA replication starts at many points in eukaryotic chromosomes. • DNA polymerases can find and correct errors.
The process that makes an exact copy of a cell’s DNA is called • Conservation • Preservation • Replication • Synthesis
What are the main functions of DNA polymerase? • Breaks down hydrogen bonds and exposes bases • Holds DNA strands apart and attracts bases • Zips and unzips the double-stranded DNA • Binds nucleotides and corrects base pair errors
Which of the following events occurs directly after a DNA molecule is unzipped? • Mismatched nucleotides bases are identified and replaced • Free-floating nucleotides pair up with exposed bases • Identical double stranded DNA molecules are formed • Enzymes break down hydrogen bonds between base pairs
The process of making new DNA molecules is semiconservative. This means that every new DNA molecule is composed of • Two completely identical strands of DNA • One original and one new strand of DNA • One strand of DNA and one strand of RNA • Two strands that mix original and new DNA
When new DNA molecules are formed, almost all errors are detected and fixed by • The correct nucleotide • The sugar-phosphate backbone • DNA polymerase • One DNA strand