Advanced Molecular Biology - MCB 121 Lecture Notes

A collection of flashcards summarizing key concepts from Advanced Molecular Biology lecture notes.

What is the Central Dogma of Molecular Biology?

Describes the flow of genetic information from DNA to RNA to Protein.

What role does mRNA play in the Central Dogma?

Encodes the amino acid sequence.

Define 'genotype'.

Genetic constitution of a cell, including all allelic variants.

Define 'phenotype'.

Observable characteristics of a cell or organism.

What are noncoding RNAs (ncRNA)?

RNA molecules that do not encode proteins, examples include rRNA and tRNA.

What is Chargaff’s rule?

In any genome, the amount of adenine (A) equals that of thymine (T) and the amount of guanine (G) equals that of cytosine (C).

How is DNA packaged in eukaryotic cells?

In the nucleus, separate from transcription and translation.

What is the significance of the 2’ hydroxyl group in RNA?

It makes RNA more reactive and less stable than DNA.

What stabilizes the double-helical structure of DNA?

Hydrogen bonding between base pairs and base-stacking interactions.

What is the overall charge of a DNA molecule at neutral pH?

Negative, due to the phosphate groups.

How do prokaryotes differ from eukaryotes in terms of transcription and translation?

In prokaryotes, transcription and translation occur simultaneously in the same compartment, while in eukaryotes they are separated by the nuclear membrane.

What is the chemical composition of a nucleotide?

Base + sugar + phosphate.

What types of bonds link nucleotides in a strand of DNA?

Phosphodiester linkages.

What is one of the unique features of RNA that allows for its structural versatility?

2’OH mediated hydrogen bonding allows for alternative helical states.

What is the role of ribosomes in the Central Dogma?

They translate mRNA into proteins.

What is the predominant conformation of DNA in cells?

B-form DNA, which is a right-handed helix.

What is the role of metal ions in stabilizing RNA structures?

They neutralize the negative charge of the phosphodiester backbone, helping to stabilize 3D structures.

Describe the difference between RNA's C-2' and C-3' endo sugar puckers.

C-2' endo predominates in DNA; C-3' endo is more compact and stabilizes RNA helices.

What are some structural types of nucleic acids?

Polynucleotides, oligonucleotides, and nucleosides.

What is the significance of the major and minor grooves in DNA?

They provide access for DNA-binding proteins to interact with the base pairs.

What does a ribosome's function entail regarding tRNAs?

tRNAs help decode the mRNA and are charged with amino acids by aminoacyl synthetases.

Summarize the process of transcription regulation.

It involves controlling the timing and amount of gene expression.