Cellular Respiration and Protein Synthesis

Vocabulary flashcards detailing mitochondrial anatomy, the chemical stages of cellular respiration (glycolysis, intermediate, citric acid cycle, and ETS), and the mechanics of protein synthesis (transcription and translation).

Cristae

Inward folds of the inner membrane of a mitochondrion where the electron transport system molecules are embedded.

Matrix

The innermost space of the mitochondrion containing enzymes for the intermediate stage and citric acid cycle.

Cellular Respiration

A multistep metabolic pathway where organic molecules are broken down by enzymes to create and store energy, following the general reaction: $C_6H_{12}O_6 + 6 O_2 \rightarrow 6 CO_2 + 6 H_2O + 38 ATP$.

Glycolysis

The first step of cellular respiration occurring in the cytosol, requiring $2 ATP$ activation energy to break 1 glucose into 2 pyruvate molecules, yielding a net of $2 ATP$ and 2 NADH.

NAD+ (Nicotinamide adenine dinucleotide)

A coenzyme that carries hydrogen ions ($H^+$) and electrons released during glucose breakdown to the electron transport system.

Anaerobic Respiration

A metabolic process that occurs without oxygen, such as glycolysis or the conversion of pyruvate into Lactate by lactate dehydrogenase.

Aerobic Respiration

Energy-producing processes that require oxygen to occur, including the intermediate stage, citric acid cycle, and electron transport system within the mitochondria.

Pyruvate Dehydrogenase

The enzyme that converts pyruvate into acetyl CoA, $NADH + H^+$, and $CO_2$ inside the mitochondrial matrix when oxygen is present.

Citric Acid Cycle (Krebs Cycle)

A nine-enzyme cycle in the mitochondrial matrix that converts Acetyl-CoA into oxaloacetate (OAA), producing $2 CO_2$, $1 ATP$, $3 NADH$, and $1 FADH_2$ per cycle.

FAD (Flavin adenine dinucleotide)

A coenzyme that carries hydrogens and their electrons to the electron transport system during the citric acid cycle.

ATP Synthetase

A structure in the electron transport system that uses the kinetic energy of $H^+$ moving down its concentration gradient to bind a phosphate to ADP, generating ATP.

Total ATP Yield

The total production of ATP per glucose molecule is 38, with 34 coming from the electron transport system, 2 from Glycolysis, and 2 from the Citric acid cycle.

Transcription

The first process of protein synthesis, occurring in the nucleus, where a gene's DNA sequence is rewritten into an mRNA strand.

RNA Polymerase

The enzyme responsible for attaching to the promoter region and binding ribonucleotides together to form an mRNA strand during transcription.

Promoter Region

The 'start' region of the DNA template strand, consisting of three deoxyribonucleotides, where RNA polymerase attaches to begin transcription.

Codon

A grouping of three ribonucleotides on an mRNA strand; start codons include AUG (Methionine), and stop codons include UAA, UAG, and UGA.

Translation

The synthesis of an amino acid chain from mRNA, occurring at the ribosome and involving tRNA and rRNA.

tRNA (Transfer RNA)

A type of RNA that brings specific amino acids to the ribosome; it contains an anticodon at one end and an amino acid acceptor end.

Anticodon

A specific sequence of three nucleotides on tRNA that binds to a complementary codon on mRNA to ensure the correct amino acid is added.

Peptide Bond

A chemical bond that forms between two amino acids during the elongation phase of translation.

Release Factor

A protein that binds to the mRNA instead of tRNA when the ribosome reaches a stop codon, causing the polypeptide and ribosome complex to separate.