Basic Molecular Mechanisms and Nuclei Acids Flashcards
What are the 4 genetic molecular processes, and where do they occur in the cell?
REPLICATION - Nucleus
TRANSCRIPTION - Nucleus
RNA PROCESSING - Nucleus
TRANSLATION - Cytosol
What happens during the G1 cell phase?
CELL GROWTH:
- The cell grows physically larger, copies organelles, and makes the molecular building blocks it will need.
- Cell “recuperates” from mitosis
What happens during the S cell phase?
- The cell undergoes DNA REPLICATION in preparation for mitosis.
- It also duplicates a CENTROSOME, which will help separate the DNA in the M phase
What happens during the G2 cell phase?
CELL GROWTH AND REORGANIZATION:
During the second gap phase, or G2 phase, the cell grows more, makes proteins and organelles, and begins to reorganize its contents in preparation for mitosis.
How can DNA be denatured?
- Raising the temperature
- Reduction of the ion concentration
- Adding agents to destabilize Hydrogen bonds (urea, formaldehyde)
Which are larger: purines or pyrimidines?
PURINES
Purines: Pair of fused rings
Pyrimidines: Contain a single ring
What are the Watson and Crick DNA base pairings?
A - T (DNA)
A - U (RNA)
G - C
Which enzyme relieves torsional stress of circular DNA by creating a knick in both DNA strands, and then reattaching them together?
TOPOISOMERASE II
- Because of this, it can also link together two circular DNA molecules.
- Topoisomerase I only creates a knick in one of the strands.
How do topoisomerase I and topoisomerase II relieve torsional stress in circular DNA molecules?
They break one or 2 phosphodiester bonds in the DNA backbone. Once the torsional stress it relieved (DNA has re-twisted itself properly), they re-ligate them.
Name the secondary and tertiary structures that can be formed by ssRNA.
- HAIRPIN: 5-10 nucleotides
- STEM-LOOP: 11-several hundred nucleotides
- PSEUDO-KNOT
What are the factors that explain B-form DNA’s stability?
- Hydrogen bonding
- Van der Waals interactions
- Hydrophobic interactions
What factor explains DNA’s flexibility and why is it essential?
There is NO HYDROGEN BONDING along its long axis.
It is essential for…
- DNA binding protein
- Chromatin packing
What are the 4 stages of mitosis?
PMAT
- PROPHASE
- METAPHASE
- ANAPHASE
- TELOPHASE
What is Nucleic Acid Hybridization?
A technique in which single-stranded nucleic acids (DNA or RNA) are allowed to interact so that complexes called hybrids are formed by molecules with similar, complementary sequences.
What makes deoxyribose more stable than ribose in DNA/RNA molecules?
Deoxyribose is stabilized by the H at 2’
Ribose’s OH group on 2’ can be deprotonated to give O-, which participates in the slow hydrolysis of the phosphodiester bonds (part of the backbone) at neutral pH.
