12.3 DNA Replication
An enzyme that joins individual nucleotides to produce a new strand of DNA is called (a) DNA polymerase (b) telomerase (c) RNA telomerase (d) amylase
(a) DNA polymerase
In Eukaryotes, DNA replication begins at (a) dozens or even hundreds of places on the DNA molecule (b) a single location on the DNA molecule (c) the center of the DNA molecule (d) the end of the DNA molecule
(a) dozens or even hundreds of places on the DNA molecule
The DNA that results from Replication consists of: (a) one molecule with two new strands and one molecule with the 2 original strands (b) two molecules that each contain one new strand and one original strand (c) two molecules composed of new strands (d) two molecules composed of old strands
(b) two molecules that each contain one new strand and one original strand
Before a cell divides, it duplicates its DNA in a process called: (a) transformation (b) duplication (c) replication (d) base pairing
(c) replication
DNA at the tips of chromosomes are known as? (a) Centromeres (b) chromatin (c) telomeres (d) replication forks
(c) telomeres
If the percent of Guanine (G), in a DNA sample, is 20%, what is the percent of Cytosine (C)?
20%
If the percent of Adenine (A), in a DNA sample, is 31.5%, what is the percent of Thymine (D) in the same DNA sample?
31.5%
What is a Replication Fork?
A Replication ZFork is a point in a DNA molecule where the two strands separate during replication.
Each time a chromosome is replicated some DNA may be lost from the tip of the chromosome, also known as _____
A Telomere
In DNA, the fit between Thymine and Adenine and the fit between Cytosine and Guanine is called?
Base Pairing
Which of Watson and Crick's discovery's helps to explain how DNA can be copied or replicated?
Base Pairings in the double helix explain how DNA can be copied or replicated. Each base one strand pairs with one (and only one) base on the opposite strand. Each strand of the double helix has all of the information needed to construct the other half - using Base Pairing.
The double-helix model explains Chargaff's rule of ___________
Base pairing
What is meant when we say that DNA strands are Complementary?
Because each DNA strand can be used to make the other Strand, the strands are said to be complementary.
Why are the strands of a DNA molecule said to be complementary?
Because each strand can be used to make the other strand.
The enzyme that "proof reads" each new DNA strand so that each molecule is near-perfect copy of the original is __________
DNA Polymerase
The principal enzyme involved in DNA replication is ______
DNA Polymerase
What enzyme helps to join individual nucleotides to produce the new strand of DNA?
DNA Polymerase. DNA Polymerase produces the sugar-phosphate bonds that join nucleotides together and "proof-reads" the new DNA strands to ensure the molecule is a near perfect copy of the original.
What is the location of DNA in Eukaryotes?
DNA in Eukaryotes is packaged in chromosomes. located in the nucleus
When does Replication occur?
During later Interphase
DNA replication is carried out by a series of _______
Enzymes
Name the Scientist: This scientist showed that percentages of Adenine (A) and Thymine (T) are equal in any sample of DNA. The same thing is true for the other two nucleotides Guanine (G) and cytosine (C).
Erwin Chargaff
How does Telometase work?
It adds short, repeated DNA sequences to Telomeres.
Name the Scientist: This scientist built a model of the DNA molecule that explained both the structure and properties of DNA.
James Watson and Francis Crick
Is DNA replication always a foolproof process? Explain.
No. Although many proteins check the DNA for damage or errors, damaged regions can still be replicated. This may result in gene alterations and serious complications for the organism.
Does DNA replication take place in the same direction along both strands of the DNA molecule that is being replicated? Explain.
No. DNA replication proceeds in opposite directions between replication forks.
DNA Polymerase
Principle enzyme involved in DNA replication
Replication
Process of copying DNA prior to cell division. Ensures that each resulting cell has the same complete set of DNA molecules.
What is the location of DNA in Prokaryotes?
Prokaryotes have a singular (one); circular DNA molecule located in the cytoplasm
In Eukaryotic cells, ________ can begin at dozens or even hundreds of places on the DNA molecule.
Replication
The DNA molecule separates into two strands during ____________
Replication
How does Replication in Eukaryotes begin?
Replication may begin at dozens of points in the DNA molecule, proceeding in both directions until each chromosome is completely copied.
Name the Scientist: This scientist took X-ray diffraction pictures that revealed the double-helix structure of DNA.
Rosalind Franklin
In what phase of the cell cycle does DNA replication take part?
S Phase
Amount of DNA in Prokaryotes?
Single DNA molecule
How does Replication in Prokaryotes begin?
Starts at a single point and proceeds in two directions until the entire Chromosome is copied.
What enzyme makes it less likely that DNA will be lost from Telomeres during replication?
Telomerase is the enzyme used to prevent shortening of the DNA as it gets replicated.
Telomere
Telomeres are repetitive DNA at the tips/ends of chromosomes. This DNA is particularly difficult to copy and a special Enzyme is needed to copy it (Telomerase) The ends of the DNA are tricky to copy over because there's nowhere for DNA Polymerase to latch on.
If the base sequence on a separated DNA strand is CGTAGG, what will the base sequence on its Complementary Strand be?
The Complementary Strand will be GCATCC.
What happens during Replication?
The DNA molecules separate into two strands. Then, 2 new complementary strands are produced following the rules of Base Pairing.
What is the first step in DNA replication?
The two strands of the double helix separate or unzip, allowing two Replication Forks to form.
T/F - An enzyme called Helicase helps to unzip the DNA molecule by breaking the hydrogen bonds between base pairs and unwinding the two strands of the molecule.
True
Amount of DNA in Eukaryotes?
Up to 1000X more DNA than prokaryotes.
