Chapter 8 Flashcards
What is DNA made of?
Nucleotides!
- Phosphate Group
- 5 Carbon Sugar (deoxyribose)
- Nitrogenous base
Types of Nitrogenous bases and their pairings
Purines: A and G
Pyrimidines: C and T
A+T and G+C
How many hydrogen bonds are between G and C and A and T?
There are 3 hydrogen bonds between G and C and 2 hydrogen bonds between A and T
This means that it’s easier to break apart a DNA strand in regions where it is “A-T rich”
Where is genetic info stored in DNA?
In the four bases
Function of RNA
- Transfer genetic information from nucleus to cytoplasm
- Protein synthesis
- Gene expression
DNA vs RNA
What does semiconservative replication mean?
When DNA is replicated, the two daughter DNA molecules will receive one original strand and one new strand
Leading vs lagging strand
Leading strand: Starts at 3’ end of original strand, continuous, goes toward replication fork
Lagging strand: Starts at 5’ end of original strand, discontinuous, goes away from replication fork
Replisome
The overall term used for the DNA copying machine that carries out DNA replication. Contains many enzymes with specific functions
Telomerase
Adds a repeat sequence of “non coding DNA” to the end of the lagging strand to keep its full length (normally TTAGGG). It can do this because it has the ability to synthesize DNA from an RNA template.
Helicase
The enzyme that unzips the DNA strand by breaking hydrogen bonds between bases
Primase
The enzyme that adds a short RNA primer so that DNA polymerase can begin adding complementary bases
Ligase
The enzyme that fills in the gaps between Okazaki fragments
DNA Polymerase
The enzyme that creates the complementary bases to the existing DNA strand
Levels of chromosome organization
Nucleosomes are made of DNA wrapped around a histone
