DNA Structure & Molecular Genetics

Comprehensive vocabulary flashcards reviewing DNA structure, nucleotide anatomy, processes of molecular genetics, and the structural genetic hierarchy.

Nucleotide

The monomer building block of DNA, consisting of a phosphate group, a deoxyribose sugar, and a nitrogenous base.

Phosphate Group

A chemical component of a nucleotide that forms the structural sugar-phosphate backbone linking adjacent nucleotides.

Deoxyribose Sugar

A $5$-carbon ring molecule in DNA that attaches to both the phosphate group and a nitrogenous base.

Nitrogenous Base

A chemical base in a nucleotide that contains genetic instructions, categorized into purines (Adenine, Guanine) and pyrimidines (Thymine, Cytosine).

Purines

A class of nitrogenous bases comprising Adenine (A) and Guanine (G).

Pyrimidines

A class of nitrogenous bases comprising Thymine (T) and Cytosine (C).

Antiparallel Strands

The structural arrangement of DNA where two complementary strands run in opposite directions ($5'$ to $3'$ and $3'$ to $5'$).

Complementary Base Pairing

The hydrogen bonding rule where Adenine (A) pairs specifically with Thymine (T), and Cytosine (C) pairs with Guanine (G).

Central Dogma of Molecular Biology

The directional pathway of genetic expression describing DNA Replication $\rightarrow$ Transcription into mRNA $\rightarrow$ Translation into proteins.

Replication

The process by which DNA copies itself to ensure every daughter cell receives identical genetic information during cell division.

Transcription

The process inside the cell nucleus where a DNA sequence is transcribed into messenger RNA (mRNA) by RNA polymerase.

Translation

The ribosomal decoding of mRNA codons into amino acid chains to synthesize functional proteins.

Helicase

An enzyme that unzips the double helix by breaking hydrogen bonds between base pairs, forming a replication fork.

Single-Stranded Binding Proteins

Proteins that stabilize exposed template strands during replication to prevent them from re-annealing.

DNA Polymerase

An enzyme that reads template strands and synthesizes new DNA by attaching complementary free nucleotides in the $5'$ to $3'$ direction.

Semiconservative Model

The replication mechanism where each new DNA molecule is composed of one conserved parent strand and one newly synthesized strand.

Codon

A $3$-base unit of mRNA read by ribosomes to specify a particular amino acid during translation.

Transfer RNA (tRNA)

Molecules that carry specific amino acids and align their anticodons with complementary mRNA codons during translation.

Gene

A specific segment of DNA holding instructions for synthesizing a particular protein or polypeptide.

Histones

Proteins around which DNA strands wind to package and condense into chromatin.

Chromatin

A structural fiber formed from DNA wound around histone proteins.

Chromosome

A supercoiled, condensed chromatin structure formed during cell division that contains thousands of genes.

Chromosomal Packaging

The organization of DNA into $46$ chromosomes ($23$ pairs) in human somatic cells to ensure equal distribution during cell division.

Heritable Transmission

The passage of inherited traits to offspring through gametes that transfer one chromosomal set from each parent.