Cellular Function and Protein Synthesis Vocabulary

Comprehensive vocabulary flashcards covering membrane transport, protein synthesis, cellular respiration, cell division, and genetic mutations based on the lecture notes.

Simple Diffusion

Unimpeded movement of reasonably small, nonpolar compounds down their concentration gradient directly across the cell membrane.

Facilitated Diffusion

Permitted movement of molecules down their concentration gradient across a membrane using specific transport proteins such as channels or carriers.

Active Transport

Movement of compounds across a cell membrane driven by the cell's action that requires energy, often moving against a concentration gradient.

Phosphate Head

The charged ($PO_4^-$), polar, and hydrophilic portion of a membrane phospholipid that interacts with surrounding extracellular fluid.

Nonpolar Neutral Lipids

The uncharged, hydrophobic tail region of a phospholipid bilayer that repels water and prevents polar substances from freely diffusing through.

Transcription

The first step in protein synthesis where an RNA copy (mRNA) is synthesized from a DNA gene template inside the nucleus.

Helicase

An enzyme that unwinds and unzips short segments of double-stranded DNA to make the genetic sequence accessible for transcription.

RNA Polymerase

The enzyme that reads the DNA template strand and synthesizes a complementary single strand of mRNA from $3'$ to $5'$ relative to the template.

Histones

Proteins around which DNA is tightly wrapped and protected within the nucleus until transcription factors trigger dissociation.

Codon

A three-letter nucleotide sequence in mRNA that codes for a specific amino acid or signals translation initiation or termination.

Start Codon

The specific mRNA codon ($AUG$) that signals the ribosome to begin translation and codes for Methionine.

Transfer RNA (tRNA)

An RNA molecule that carries a specific amino acid and contains an anticodon sequence complementary to an mRNA codon.

Anticodon

A three-nucleotide sequence on a tRNA molecule that forms a reverse-complementary base pair with a corresponding mRNA codon.

Stop Codons

The mRNA codons ($UAG$, $UAA$, or $UGA$) that recruit a release factor to terminate translation instead of attaching a tRNA.

Golgi Apparatus

An organelle that applies finishing touches to proteins (such as folding, cleaving, and adding chemistry groups), sorting them, and packaging them into vesicles.

Primary Structure

The specific linear sequence of amino acids linked together in a polypeptide chain.

Secondary Structure

Regular local sub-structures in a protein chain, primarily consisting of alpha helices and beta sheets.

Tertiary Structure

The overall three-dimensional folded shape of a single protein molecule.

Quaternary Structure

The multi-protein complex formed by the assembly of multiple individual polypeptide subunits.

Adenosine Triphosphate (ATP)

The cell's main energy storage molecule, composed of adenine, ribose, and three high-energy phosphate groups.

Interphase

The phase of the cell cycle comprising $G_1$, $S$ phase (DNA replication), and $G_2$ phase, during which the cell grows and prepares for division.

Mitosis

The stage of nuclear division in the cell cycle consisting of prophase, prometaphase, metaphase, anaphase, and telophase.

Dystrophin

A structural protein that anchors intracellular actin to the dystrophin-associated protein complex embedded in the plasma membrane.

Nonsense Mutation

A genetic mutation that introduces a premature stop codon into an exon, preventing functional protein production.

Missense Mutation

A single point mutation that alters a single base pair, resulting in a single amino acid substitution in the translated protein.