Chapter 9: DNA & RNA Structure, DNA Replication Flashcards
What is the 4 criteria needed for Genetic Material?
Ch 9.1
1) Information
2) Replication
3) Transmission
4) Variation
Ch 9.1
What does genetic material need to contain the information for?
Ch 9.1
It contains information
necessary to construct entire organism
Ch 9.1
What does it mean for the genetic material to undergo the process of REPLICATION?
Ch 9.1
The genetic material must be accurately copied
Ch 9.1
What does it mean for genetic material to undergo the process of TRANSMISSION?
Ch 9.1
The genetic materials pass from parents to offspring and from cell to cell during cell division.
Ch 9.1
Why must genetic material have variation?
Ch 9.1
To be able to account for differences between individuals and species
Ch 9.1
What did Frederick Griffith identify the existence of and how?
Ch 9.1
The existence of genetic material with Streptococcus pneumoniae bacteria and mice
Ch 9.1
What are two types of bacteria?
Ch 9.1
- Smooth - (secrete capsules) typically deadly
- Rough - (not secrete capsules) survivable
live bacteria is the one that kills you
dead bacteria doesnt do no harm!!!
What did Griffith find out but could not explain in his experiment?
Ch 9.1
Griffith found our that in a mix of the live type R and heat-killed type S bacteria, a substance (genetic material) from the dead type S cells had transformed the type R cells into type S.
Who identified the genetic material based on Griffith’s observations?
Ch 9.1
Avery, MacLeod, and McCarty
Is it true that only purified DNA could convert R type cell to S type cell?
Ch 9.1
It is false. Purified DNA might still contain traces of contamination that may be the transforming principle.
What is a transforming principle?
Ch 9.1
Term given to the substance that could be transferred from non living cells to living cells, causing the living cell to show characteristics of the non living cell.
Define DNA and RNA & what they are responsible for
Ch 9.2
DNA and RNA are nucleic acids, polymers of nucleotides that are responsible for the storage, expression, and transmission of genetic information.
What are the 5 levels of DNA structure?
Ch 9.2
- Nucleotides - serves as building blocks
- Strand - is a linear polymer
- Double helix - two strands twisted together
- Chromosomes - DNA associated with different proteins
- Genome - the complement of genetic material in an organism
What are the three components of a nucleotide?
Ch 9.2
A pentose sugar, a phosphate group, and a nitrogen-containing base.
How does a DNA strand form?
Ch 9.2
A DNA strand is formed when nucleotides are covalently attached.
What are phosphodiester bonds?
Ch 9.2
Phosphodiester bonds are covalent bonds that link nucleotides together in a DNA strand (Key structural feature of a DNA strand).
What is a sugar-phosphate backbone?
Ch 9.2
Sugar-phosphate backbone is a result of a sugar in one nucleotide linking to a phosphate group in the next nucleotide (Key structural feature of a DNA strand).
What are DNA strands’ directionality?
Ch 9.2
5’ to 3’. The 5’ end has a free phosphate group and the 3’ end has a free hydroxyl group.
What kind of bonds stabilize base pairs in the DNA?
Ch 9.2
Hydrogen bonds.
What is the AT/CG rule?
Ch 9.2
AT/CG refers to a specific base pairing. Adenine - Thymine; Cytosine - Guanine.
What can DNA be described as?
Ch 9.2
DNA is a double-stranded helix with outer backbone and bases on the inside.
What are the two characteristics of the DNA strands?
Ch 9.2
Strands are antiparallel and complimentary to each other.
What kind of grooves does DNA contain?
Ch 9.2
Major groove and minor groove.
What is a function of the major groove in DNA?
Ch 9.2
The major groove provides a binding site for many proteins.
What was a key experimental tool that led to the discovery of the DNA double helix structure?
Ch 9.3
X-ray diffraction.
What did Rosalind Franklin discover?
Ch 9.3
A helical structure, a uniform diameeter (~2nm), a diameter too big to be a single strand.
What did Erwin Chargaff discover?
Ch 9.3
A pattern in the base DNA composition. The amount of adenine was similar to the amount of thymine and the amount of cytosine was similar to guanine.
Who discovered the structure of DNA using other scientists’ work?
Ch 9.3
James Watson and Francis Crick
What are the three different mechanisms of DNA replication that had been proposed? Who proposed them?
Ch 9.4
- Semiconservative mechanism
- Conservative mechanism
- Dispersive mechanism
They were proposed by Meselson and Stahl.
What are parent and daughter strands?
Ch 9.3
Original strands are parent strands and newly made strands are daughter strands.
What did Matthew Meselson and Franklin Stahl discover in their experiment?
Ch 9.4
DNA replication process is semiconservative.
What is a semiconservative mechanism?
Ch 9.4
DNA replication produces DNA molecules with 1 parental strand and 1 newly made daughter strand.
What is a conservative mechanism?
Ch 9.4
DNA replication produces 1 double helix with both parental strands and the other with 2 new daughter strands.
What is a dispersive mechanism?
Ch 9.4
DNA replication produces DNA strands in which segments of new DNA are interspersed with the parental DNA.
What are template strands?
Ch 9.4
They are parental strands that separate and serve as a template for the synthesis of daughter strands.
What is an origin of replication?
Ch 9.5
An origin of replication is a site within a chromosome that serves as a starting point for DNA replication.
What is a replication bubble?
Ch 9.5
It is an opening formed by the unwinding of the DNA strands
What is a replication fork?
Ch 9.5
A region where the replication proceeds to outward from in both directions (bidirectional replication)
How are eukaryotic chromosomes different from prokaryotic chromosomes?
Ch 9.5
Eukaryotic chromosomes are larger and have a linear structure with multiple origins of replication.
What proteins are responsible for fork formation and movement?
9.5
DNA helicase, DNA topoisomerase, and a single-strand binding proteins.
What is the function of DNA helicase?
Ch 9.5
It travels along one DNA strand in the 5’ to 3’ direction and separate the DNA strands.
What is the function of DNA topoisomerase?
Ch 9.5
It travels slightly ahead of the replication fork and alleviates coiling caused by the action of helicase.
What is the function of single-strand binding proteins?
Ch 9.5
It coats the DNA strands to prevent them from re-forming a double helix.
What are the two enzymes that are needed to synthesize DNA strands during replication?
9.5
DNA polymerase and DNA primase.
What is the function of DNA polymerase?
Ch 9.5
It covalently links nucleotides together.
What is the function of DNA primase?
Ch. 9.5
It makes a complimentary primer of RNA (10 to 12 nucleotides in length) that can be extended by DNA polymerase.
What are the two important functional constraints that DNA polymerase has?
Ch 9.5
- DNA polymerase cannot begin synthesis on a bare template strand; it can only extend a pre-existing strand
- DNA polymerase synthesizes DNA in a 5’ to 3’ direction.
