IntroNucleicAcids Flashcards
What are the pyrimidines?
Cytosine
Uracil
Thymine
What are the Purines?
Adenine
Guanine
How do Phosphodiester bonds form in DNA synthesis?
5 —> 3
5’ end of incoming nucleotide attacks 3’ hydroxide group
How is Base sequence of DNA written?
5’ —> 3’
What is Chargaff’s Rule?
Purines = # Pyrimidines
Due to H bonds only forming between specific base paring
What are the three main types of DNA structures?
B-DNA: Most common in normal cells
A-DNA: Water removed; More compact
Z-DNA: High C-G Base pairing; Left handed Helix; No major groove; Biological function unknown
What are the different types or RNA?
RRNA: Structural component of ribosome
TRNA: Carries AAs to ribosome
MRNA: Carries information to ribosome
HnRNA: mRNA precursor in nucleus
SmRNA: Splicing and removal of Introns
Ribozymes: RNA which acts as an enzyme
How does adenosine act as a neuromodulator? How is caffeine involved?
- Adenosine is a byproduct of ATP use and signals low energy
- Wakefulness neurons have A Adenosine receptors
- Sleepiness Neurons have A2A Receptors
- Caffeine is competitive inhibitor of adenosine receptors and decreases sensitivity of neurons
How does caffeine affect other organs in the body?
- decreases activity of A1 receptors in other organs
- Increases HR
- Increases Urine production
How many cAMPs are needed to bind PKA in Gs activation?
4 cAMPs
How is caffeine involved in breakdown of glycogen in the liver?
Coffee inhibits phosphodiesterase —> Prolonged glycogen breakdown
How does mitochondrial DNA differ structurally from nuclear DNA?
- Mitochondrial DNA has a circular structure
Differentiate Positive and Negative Supercoiling.
Positive: Wound more tightly; Faster gyrase; Lower cleavage
Negative: Wound more loosely; Slower gyrase; higher cleavage
What two amino acids are most common in histone proteins?
Arginine and Lysine
Which part of wound DNA is most sensitive to nuclease activity?
Naked linker DNA between each 10 nm bead
