Comprehensive Biology and Biochemistry Glossary

A comprehensive vocabulary review of key biological and biochemical terms, including hormone functions, metabolic cycles, and genetic mechanisms.

A-site (Aminoacyl site)

The site on a ribosome where incoming tRNA carrying an amino acid attaches during translation.

Abiotic factors

Non-living environmental factors like temperature, water, sunlight, and pH.

Action potential

A rapid change in membrane potential that travels along a neuron.

Active transport

Movement of substances against a concentration gradient using energy (ATP).

Adrenocorticotropic hormone (ACTH)

Pituitary hormone that stimulates the adrenal cortex.

Allosteric site

Regulatory site on an enzyme separate from the active site.

Aminoacyl tRNA synthetase

Enzyme that attaches amino acids to tRNA.

Anticodon

Triplet on tRNA complementary to an mRNA codon.

ATP synthase

Enzyme that produces ATP using proton gradient energy.

Avery & McLeod

Scientists helping show DNA carries genetic information.

Beta-oxidation

The breakdown of fatty acids into acetyl-CoA.

Biuret reagent

Chemical used to test for proteins.

Bowman’s capsule

Nephron structure surrounding the glomerulus.

C3 photosynthesis

Photosynthesis pathway where $CO_2$ first forms a 3-carbon compound.

Calvin Cycle

Light-independent reactions producing sugars in photosynthesis.

Central Dogma of Molecular Biology

The flow of genetic information: DNA $\rightarrow$ RNA $\rightarrow$ Protein.

Chargaff’s Law

A=T and G=C in DNA.

Chemiosmosis

ATP production using a proton gradient.

Citric Acid Cycle

Cycle breaking down acetyl-CoA to produce energy carriers; also known as the Krebs cycle.

Competitive inhibition

An inhibitor competes for the enzyme active site.

CRISPR-Cas9

Gene-editing technology.

Diabetes Mellitus (Type I)

Autoimmune destruction of beta cells.

Electrochemical Gradient

Combined concentration and charge difference across a membrane.

Endosymbiotic theory

Theory that mitochondria and chloroplasts evolved from bacteria.

Feedback Inhibition

End product inhibits a metabolic pathway.

Fluid Mosaic Model

Membrane model with moving proteins and lipids.

Gel electrophoresis

Technique separating molecules by size and charge.

Glycolysis

The breakdown of glucose into pyruvate.

Homeostasis

Maintenance of stable internal conditions.

Human chorionic gonadotropin (hCG)

Hormone maintaining the corpus luteum during pregnancy.

Induced fit model

Model where an enzyme changes shape when a substrate binds.

Intron

Non-coding region removed from mRNA.

Lac operon

Bacterial gene system controlling lactose metabolism.

Leading strand

DNA strand synthesized continuously.

Light-compensation point

Light level where photosynthesis equals respiration.

Luteinizing hormone (LH)

Hormone that triggers ovulation.

Meselson & Stahl Experiment

Experiment proving semi-conservative DNA replication.

Negative Feedback Loop

A response that reverses the original change.

Okazaki Fragments

Short DNA fragments on the lagging strand.

Oxidative phosphorylation

ATP production using the ETC and chemiosmosis.

Phosphofructokinase

Key regulatory enzyme in glycolysis.

Plasmolysis

Shrinking of the membrane away from the cell wall due to water loss.

Quaternary Protein Structure

Arrangement of multiple polypeptide chains into one functional protein.

Restriction Endonucleases

Enzymes cutting DNA at specific sequences.

RuBisCO

Enzyme that fixes carbon dioxide in photosynthesis.

Semi-conservative DNA Replication

Each new DNA molecule contains one old and one new strand.

Sodium-Potassium Pump

Active transport protein moving $Na^+$ and $K^+$.

Substrate-Level Phosphorylation

ATP formation by direct phosphate transfer.

Transcription

The process of copying DNA into RNA.

Translation

The process of using RNA to build a protein.

Wobble Hypothesis

Flexibility in the third codon position during tRNA pairing.