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50 Cards in this Set

  • Front
  • Back
Who discovered the structure of DNA?
James Watson and Frances Crick
How long would the DNA molecule be in a bacterial chromosome measure if it were stretched out?
1 mm (1000 time longer than the cell itself)
The molecule is a string of______that are building blocks hooked together like a pearl necklace?
deoxyribonucleotide (nucleotide for short)
Each individual nucleotide consists of 3 smaller components. What are they?
1. A molecule of deoxyribose
2. A molecule of phosphate
3. A Nucleoside base (base)
List the 4 kinds of nucleoside bases.
1. adenine (A)
2. guanine (G)
3. cytosine (C)
4. thymine (T)
What is the term for the "linking together" of nucleotides?
What forms the long part of the DNA strand?
deoxyribose and phosphate portions
What forms the short part of the DNA strand?
nucleoside bases
Single strand of DNA
Where does a single strand of DNA occur?
In some viruses
double strand of DNA
What are the 2 strands in a dsDNA held together by?
They are held together by hydrogen bonds that form between pairs of nucleoside bases.
What shape is the dsDNA?
A double helix
Hydrogen bonds connect Adenine to...?
Hydrogen bonds connect Guanine to...?
Hydrogen bonds connect Thymine to...?
Hydrogen bonds connect Cytosine to...?
The critically important feature of DNA structure is__________________________.
The way the two strands are held together by hydrogen bonds between As and Ts and Gs and Cs
What are the two kinds of reactions for DNA?
Replication and Gene Expression
DNA molecule is precisely duplicated and accurate copies are passed on to progeny cells
Gene Expression
The process by which the information stored in DNA is used to tell the cell what to do.
What two things are determined by gene expression?
Which kinds of RNA and Protein molecules are made.
The two steps of gene expression are called...
Transcription and Translation
The first stage of Replication is______
Separating the double into two single strands.
The lineup of free nucleotides is_______, to the lineup of bases in the DNA strand. ie. G-C, A-T
Nucleotides that contain a single phosphate group.
nucleoside monophosphates
Free nucleotides contain 3 phosphate groups that are called______.
nucleoside triphosphates.
Whate are the activated forms of DNA building blocks?
Nucleoside triphosphates
What is a pyrophosphate?
two phosphates joined together?
How is a pyrophosphate formed?
As nucleotied triphosphates are polymerized to make a new strand of DNA, a pyrophosphate is split off each one of them.
The points of separation in the replication bubble are called_______?
Replication Forks or replisomes.
The old strands act as________ for forming the new strands
Because the new double helices are composed of one new and one old or conserved strand, the process is called__________.
Semi-conservative replication
The bubble that initiates replication of the circular bacterial chromosome forms at a genetically specified point on the chromosome called the_______.
The point where the 2 replication forks eventually meet.
The enzymes in a replication fork form a loose complex called the________.
Replication Apparatus
What 3 functions does the replication apparatus perform?
1. Separating the strands of the old dsDNA
2. Synthesizing two new single strands
3. Moving the replication fork
What two functions does the DNA helicase enzyme perform during replication?
1. Separating the stands of old double helix.
2. Moves the replication fork
What keepsthe exposed single strands of DNA separate during replication?
single-strand binding proteins (SSBP)
What enzyme synthesizes the two new single strands by joining the nucleoside triphosphates paired with the exposed bases on the single strands?
DNA polymerase III
The two strands of DNA in a double helix run in opposite directions. So they are ___________.
Any strand of DNA has direction called___________ because of the way its deoxyribose units are joined together.
What does Antiparallel mean?
It means that the two single strands in any double helix are aligned in opposite directions. The 3' end of one strand is next to the 5' end of the other.
A strand of DNA that is being lengthened by Polymerase III is called a __________.
Can DNA polymerase III move in many directions?
No it can only move in one direction.
Because DNA strands are antiparallel and because DNA polymerase III can only move in one direction, only one of the two strands at the replication fork can be extended continuously in the same direction that the replication fork is moving. This strand is called the ___________.
Leading strand
The other strand that doesn't move with the polymerase III is called the ___________.
Lagging strand
What direction must the lagging strand be replicated?
In the opposite direction to the forks movement.
How is the lagging strand replicated?
It's done by synthesizing short pieces of DNA as DNA polymerase III moves away from the fork.
What three enzymes are needed to replicate the lagging strand?
1. Primase
2. DNA plymerase I
3. DNA Ligase