Cellular Metabolism - Human Anatomy & Physiology

Comprehensive practice flashcards covering cellular metabolism, enzymatic control, energy production (ATP and cellular respiration), and genetic information (DNA replication, transcription, and translation).

Metabolism

The sum of all chemical reactions occurring in the body.

Cellular Metabolism

The sum of all chemical reactions occurring in a cell, typically organized into pathways or cycles.

Anabolism

A type of metabolic reaction where small molecules are built into larger ones, requiring an input of energy.

Catabolism

A type of metabolic reaction where larger molecules are broken down into smaller ones, releasing energy.

Dehydration synthesis

An anabolic process where smaller molecules are bound together to form larger ones, such as polysaccharides or proteins, while producing $H_2O$.

Hydrolysis

A catabolic process used to decompose carbohydrates, proteins, and lipids by using $H_2O$ to split substances.

Enzymes

Globular protein catalysts that increase the rate of chemical reactions by lowering the activation energy required to start them.

Substrate

A specific molecule that an enzyme recognizes and acts upon.

Active site

The specific region of an enzyme molecule that binds to the substrate, relying on complementary shapes for recognition.

Metabolome

The collection of all small molecules, or metabolites, within a cell, tissue, organ, or organism.

Metabolic Pathways

A series of enzyme-controlled reactions where the product of one reaction becomes the substrate for the next.

Rate-limiting enzyme

A regulatory enzyme that catalyzes one step of a pathway and sets the rate for the entire reaction sequence.

Cofactor

A non-protein substance, such as an ion or element, that combines with an enzyme to activate it or help bind it to a substrate.

Coenzyme

An organic molecule, most often a vitamin, that acts as a cofactor for an enzyme.

Denaturation

The inactivation of an enzyme due to an irreversible change in its conformation, preventing it from binding to its substrate.

Phenylketonuria (PKU)

An inborn error of metabolism where a missing enzyme prevents the conversion of phenylalanine into tyrosine, leading to brain damage.

Energy

The capacity to change something or the ability to do work.

Cellular respiration

The process that transfers energy from molecules, such as glucose, and makes it available for cellular use.

ATP (Adenosine Triphosphate)

The main energy-carrying molecule in the cell, consisting of adenine, ribose, and three phosphates.

Phosphorylation

The process of converting ADP back into ATP by reattaching a third phosphate using energy from cellular respiration.

Glycolysis

The anaerobic first phase of glucose breakdown in the cytosol that yields a net gain of $2$ ATP molecules.

Citric Acid Cycle

An aerobic series of reactions in the mitochondria that begins when acetyl CoA combines with oxaloacetic acid to form citric acid.

Electron Transport Chain

A series of enzyme complexes in the inner mitochondrial membrane that transfers energy from high-energy electrons to ATP.

ATP synthase

The enzyme that uses energy from electrons to catalyze the phosphorylation of ADP to ATP in the electron transport chain.

Oxidation

The process that releases energy from glucose via the loss of hydrogen atoms and their electrons.

DNA (Deoxyribonucleic Acid)

The genetic material that stores information in nucleotide sequences to instruct the cell on protein synthesis.

Gene

A specific sequence of DNA that contains the instructions for synthesizing one protein.

Genome

The complete set of genetic information within a cell.

double helix

The twisted-ladder structure of DNA consisting of two chains of nucleotides linked by hydrogen bonds between bases.

Nucleotides

The building blocks of DNA, each composed of a 5-carbon sugar, a phosphate group, and a nitrogenous base.

Purines

The nitrogenous base family including Adenine (A) and Guanine (G).

Pyrimidines

The nitrogenous base family including Cytosine (C) and Thymine (T).

DNA Replication

The process that produces an exact copy of a DNA molecule during interphase.

Transcription

The process of copying a specific DNA sequence onto a strand of messenger RNA (mRNA) in the nucleus.

Translation

The process of converting the genetic code carried by mRNA into a sequence of amino acids to form a protein.

RNA polymerase

The enzyme that catalyzes the formation of mRNA from a DNA template during transcription.

Codon

A sequence of three nucleotide bases in mRNA that represents a specific amino acid or a start/stop signal.

Transfer RNA (tRNA)

The RNA molecule that transports specific amino acids to the ribosome and aligns them using its anticodon.

Anticodon

A sequence of three bases on a tRNA molecule that binds to a complementary codon on the mRNA strand.

Mutation

A change in the DNA sequence resulting from errors in replication, which can be spontaneous or induced by mutagens.