Nucleic Acids, DNA Structure, and Protein Synthesis

Flashcards covering DNA structure, complementary base pairing, RNA types, and translation stages in protein synthesis.

Antiparallel Strands

The orientation of the two intertwined polynucleotide chains in DNA, running in opposite directions with the $5'$ end of one chain on the same side as the $3'$ end of the other.

DNA Sequence Orientation

The standard convention of writing the base sequence of a DNA strand, which is always written from the $5'$ end to the $3'$ end.

Complementary Base Pairing

The specific hydrogen bonding pairing of nitrogenous bases in DNA, where Guanine (G) pairs with Cytosine (C) and Adenine (A) pairs with Thymine (T).

Sugar-Phosphate Backbone

The outer structural chain of the DNA double helix, with the nitrogenous bases pointing inwards to form hydrogen bonds with each other.

$3' \rightarrow 5'$ Phosphodiester Linkage

The phosphate ester chemical linkage connecting adjacent nucleotide units along a nucleic acid strand.

Messenger RNA (mRNA)

A single-stranded RNA molecule that encodes a copy of genetic information, serving as the blueprint for protein synthesis.

Transfer RNA (tRNA)

An RNA molecule that carries specific amino acids to the ribosome for incorporation into a growing protein chain.

Ribosomal RNA (rRNA)

An RNA component that forms part of the ribosome structure, where protein synthesis occurs.

Ribose vs. Deoxyribose

The five-carbon sugar components distinguishing RNA (containing ribose) from DNA (containing deoxyribose).

Uracil

The pyrimidine base present in RNA that pairs with adenine, replacing thymine found in DNA.

Translation Initiation Stage

The beginning phase of protein synthesis where the small ribosomal subunit and the first tRNA arrive at the mRNA start codon, after which the small and large subunits interlock around the mRNA strand.

Translation Elongation Stage

The phase of protein synthesis where tRNA carrying amino acid 2 binds to its codon, a peptide bond forms between amino acids, the first tRNA is released, and the ribosome shifts one codon to the right.

Translation Termination Stage

The final phase of protein synthesis occurring when a stop codon is reached, causing the ribosomal subunits, mRNA, and completed polypeptide chain to separate.

Comparison of DNA and RNA

A table detailing differences between DNA and RNA in sugar type, nitrogenous bases, overall shape/size, and biological function.