Lecture 1/17/25 Flashcards
What is the structural difference between Purines and Pyrimidines?
Purines (A, G) have two rings; Pyrimidines (C, T, U) have one ring.
What are the two common chemical modifications made to DNA bases?
Methylation and deamination modify DNA bases, affecting gene expression and stability.
What is the difference between dNTPs and rNTPs?
dNTPs (deoxyribonucleotides) are for DNA synthesis; rNTPs (ribonucleotides) are for RNA synthesis.
How does ATP act as an energy source?
ATP stores energy in phosphate bonds; hydrolysis releases energy for cellular processes.
How is ATP regenerated?
ATP is regenerated by phosphorylation of ADP during cellular respiration.
What is a free energy diagram?
A graph showing reactants, products, activation energy, and ΔG to illustrate energy changes in a reaction.
What is an enzyme?
A protein catalyst that lowers activation energy and speeds up reactions.
What does a positive ΔG mean?
The reaction is non-spontaneous and requires energy input.
What does a negative ΔG mean?
The reaction is spontaneous and releases energy.
How does entropy relate to an ATP-coupled reaction?
ATP hydrolysis increases entropy, driving unfavorable reactions forward.
How can a protein be denatured?
Heat, pH changes, or chemicals disrupt its structure, leading to loss of function.
How is DNA melted?
Heating disrupts hydrogen bonds between base pairs, separating the strands.
What is a buffer?
A solution that resists pH changes by neutralizing acids or bases.
Why do G-C-rich DNA sequences require more energy to melt?
G-C pairs have three hydrogen bonds, making them more stable than A-T pairs.
