BIO 201: Chapter 4 - Metabolism and Gene Expression Flashcards

Comprehensive vocabulary flashcards generated from BIO 201 Chapter 4 lecture notes, covering metabolic pathways, enzyme functions, cellular respiration, DNA replication, gene expression, and DNA repair.

Metabolism

The sum total of chemical reactions used for biosynthetic and energy-harvesting processes.

Anabolism

Processes that utilize energy ($\text{ATP}$) to synthesize and assemble subunits of macromolecules; also known as biosynthesis.

Catabolism

Processes that harvest energy released during the breakdown of compounds to synthesize $\text{ATP}$.

Oxidation

A process in which an electron is removed from a molecule, resulting in the breaking of a chemical bond.

Reduction

A process in which an electron is gained by a molecule, resulting in the creation of a chemical bond.

Enzymes

Biological catalysts, typically proteins, that accelerate chemical reactions by lowering the activation energy.

Activation Energy

The energy needed to initiate a chemical reaction.

Active Site

A region on an enzyme where the substrate fits and is held by non-covalent bonds to undergo a reaction.

Enzyme-Substrate Complex

The temporary complex formed when a substrate molecule binds to the active site of an enzyme ($E + S \rightarrow E\text{-}S\text{ Complex} \rightarrow E + \text{Product}$).

Cofactors

Non-protein molecules required by some enzymes to function, which can be inorganic trace elements like magnesium, zinc, and copper.

Coenzymes

Organic cofactors derived from vitamins that assist enzyme function, such as $\text{NAD}^+$ and $\text{FAD}$.

Allosteric Regulation

A process where a molecule binds to a site outside the active site (allosteric site) on an enzyme, altering its structure and changing its affinity for the substrate.

Allosteric Site

A specific site on an enzyme, distinct from the active site, where a regulatory molecule binds.

Feedback Inhibition

A regulatory mechanism in which the end product of a biosynthetic pathway acts as an allosteric inhibitor of the first enzyme in that pathway.

Respiration

The process in which electrons are stripped from a chemical energy source and transferred to an electron transport chain, generating a proton motive force used to synthesize $\text{ATP}$.

Aerobic Respiration

A form of respiration that uses $\text{O}_2$ as the terminal electron acceptor of the electron transport chain.

Glycolysis

The metabolic process of oxidizing glucose, a 6-carbon molecule, into 2 pyruvates (3-carbon molecules).

Transition Step

The conversion of pyruvate into Acetyl-CoA through the removal of $\text{CO}_2$.

TCA (Krebs) Cycle

The cycle that completes the oxidation of Acetyl-CoA molecules, releasing $\text{CO}_2$ and transferring electrons to $\text{NADH}$ and $\text{FADH}_2$.

Oxidative Phosphorylation

The synthesis of $\text{ATP}$ from $\text{ADP}$ and phosphate using the energy generated by a proton gradient.

Fermentation

A metabolic process used when a suitable inorganic terminal electron acceptor is unavailable, generating $\text{ATP}$ only during glycolysis and using organic molecules as terminal electron acceptors.

Lactic Acid Fermentation

A pathway where electrons transferred to $\text{NAD}^+$ during glycolysis are donated back to pyruvate to form lactic acid, replenishing $\text{NAD}^+$.

Gene

A region of $\text{DNA}$ that codes for a single protein.

Genome

The complete set of genetic information, representing the total $\text{DNA}$ found in all chromosomes within a cell.

Nucleotide

The structural subunit of nucleic acids consisting of a pentose sugar (deoxyribose or ribose), a phosphate group, and a nitrogenous base.

Complementary Base Pairing

The specific pairing of nitrogenous bases via hydrogen bonds in $\text{DNA}$, specifically adenine pairing with thymine ($\text{A}\text{-}\text{T}$) and cytosine pairing with guanine ($\text{C}\text{-}\text{G}$).

Antiparallel

The arrangement of double-stranded $\text{DNA}$ where the $5'$ end of one strand is bound opposite to the $3'$ end of the complementary strand.

Semiconservative Replication

The mechanism of $\text{DNA}$ replication where each newly created chromosome consists of one original template strand and one newly synthesized strand.

Gene Expression

The overall process in which a gene is used as a template to synthesize a protein via transcription and translation.

Central Dogma of Molecular Biology

The framework describing the flow of genetic information: $\text{DNA} \rightarrow \text{RNA} \rightarrow \text{Proteins}$ via replication, transcription, and translation.

Transcription

The process of synthesizing a complementary and antiparallel strand of $\text{RNA}$ (mRNA) from a $\text{DNA}$ template using $\text{RNA}$ polymerase.

Messenger RNA (mRNA)

A single-stranded $\text{RNA}$ transcript complementary to a gene that carries the instructions for protein synthesis from $\text{DNA}$ to the ribosome.

Promoter

A specific sequence on $\text{DNA}$ where $\text{RNA}$ polymerase binds to designate the starting point and gene to be transcribed.

Terminator

A sequence on $\text{DNA}$ that signals $\text{RNA}$ polymerase to stop transcription and release the newly synthesized $\text{mRNA}$.

Translation

The process of decoding the sequence information carried on an $\text{mRNA}$ transcript to synthesize a specific protein using ribosomes and $\text{tRNA}$.

Codon

A sequence of three nucleotides on $\text{mRNA}$ that codes for a specific amino acid or a stop signal.

Anticodon

A sequence of three nucleotides on a $\text{tRNA}$ molecule that is complementary to a specific codon on an $\text{mRNA}$ strand.

Transfer RNA (tRNA)

An $\text{RNA}$ molecule that carries a specific amino acid to the ribosome during translation by recognizing $\text{mRNA}$ codons with its complementary anticodon.

Mutation

A change in the existing nucleotide sequence of a cell's $\text{DNA}$.