The four major classes of biomolecules are carbohydrates, lipids, proteins, and nucleic acids.

Carbohydrates serve as a major source of energy for cellular processes through the breakdown of glucose in cellular respiration.

The three main types of lipids are triglycerides (energy storage), phospholipids (cell membrane components), and steroids (hormones and structural components).

Proteins are composed of amino acids and serve as enzymes, structural components, transport molecules, and signaling molecules in the body.

The two main types of nucleic acids are DNA (deoxyribonucleic acid), which stores genetic information, and RNA (ribonucleic acid), which is involved in the synthesis of proteins.

Glycolysis is the metabolic pathway that breaks down glucose into two pyruvate molecules, releasing energy in the form of ATP. It occurs in the cytoplasm of cells.

The citric acid cycle is a series of chemical reactions that completes the breakdown of glucose molecules into carbon dioxide and water, releasing energy in the form of ATP. It takes place in the mitochondrial matrix.

Oxidative phosphorylation is the metabolic pathway that uses energy released by the oxidation of molecules to produce ATP. It occurs in the inner membrane of the mitochondria.

ATP (adenosine triphosphate) is the primary energy currency of cells, providing energy for various cellular processes and chemical reactions.

Photosynthesis is the process by which plants and some other organisms convert light energy from the sun into chemical energy in the form of glucose. It occurs in the chloroplasts of plant cells.

Enzymes are protein catalysts that increase the rate of chemical reactions in metabolic pathways, allowing them to occur at biologically relevant rates and temperatures.

Transcription is the process of synthesizing RNA from a DNA template, and it occurs in the nucleus of eukaryotic cells or the cytoplasm of prokaryotic cells.

Translation is the process of synthesizing proteins from the information encoded in mRNA, and it occurs in the ribosomes of cells.

Lipids, particularly phospholipids, form the basic structure of cell membranes, providing a selectively permeable barrier and facilitating the movement of molecules in and out of cells.

DNA replication is the process of copying the genetic information in DNA, allowing cells to divide and pass on genetic information to daughter cells. It is essential for growth, reproduction, and repair.

Mitochondria are the powerhouses of cells, where the citric acid cycle and oxidative phosphorylation take place, generating the majority of ATP through the process of cellular respiration.

The three stages of cellular respiration are glycolysis (cytoplasm), the citric acid cycle (mitochondrial matrix), and oxidative phosphorylation (mitochondrial inner membrane).

Fatty acid oxidation is the metabolic pathway that breaks down fatty acids to produce acetyl-CoA, which can then enter the citric acid cycle. It occurs primarily in the mitochondrial matrix.

Vitamins are organic compounds that are essential for various metabolic pathways, often serving as cofactors for enzymes or participating in chemical reactions.

Gluconeogenesis is the metabolic pathway that synthesizes glucose from non-carbohydrate precursors, such as amino acids and glycerol. It is important for maintaining blood glucose levels during fasting or starvation.

Hormones, such as insulin and glucagon, play crucial roles in regulating metabolic pathways by signaling cells to increase or decrease specific metabolic processes, such as glucose uptake or breakdown.

Protein folding is the process by which a polypeptide chain acquires its three-dimensional structure, which is essential for the protein to function properly in various cellular processes.

Chaperone proteins assist in the proper folding and assembly of other proteins, preventing misfolding and aggregation, which can lead to various diseases.

Nucleic acids, specifically DNA and RNA, are responsible for storing and transmitting genetic information, as well as regulating gene expression, which ultimately determines the production of proteins and the characteristics of an organism.

Glycogenesis is the metabolic pathway that synthesizes glycogen, a storage form of glucose, from excess glucose molecules. It occurs primarily in the liver and muscle cells.

Glycogenolysis is the metabolic pathway that breaks down glycogen into glucose, providing a source of energy when glucose levels are low. It is important for maintaining blood glucose levels during fasting or exercise.

The electron transport chain is a series of protein complexes in the mitochondrial inner membrane that transfers electrons from electron carriers (like NADH and FADH2) to oxygen, generating a proton gradient used by ATP synthase to produce ATP.

Beta-oxidation is the metabolic pathway that breaks down fatty acids into acetyl-CoA molecules, which can then enter the citric acid cycle. It involves the sequential removal of two-carbon units from fatty acids.

Coenzymes are organic molecules that assist enzymes in catalyzing specific chemical reactions by temporarily binding to the enzyme and participating in the reaction mechanism.

Deamination is the removal of an amino group from an amino acid, producing ammonia and a keto acid. It is important in breaking down excess amino acids and generating intermediates for other metabolic pathways.

The urea cycle is a metabolic pathway that converts toxic ammonia into urea for excretion. It occurs primarily in the liver and is essential for removing excess nitrogen from the body.

Glycosylation is the enzymatic process of attaching carbohydrate (glycan) molecules to lipids or proteins, creating glycolipids or glycoproteins. It is important for various cellular functions, such as protein folding and signaling.

Lipolysis is the metabolic pathway that breaks down triglycerides (fats) into fatty acids and glycerol. It is important for providing energy during fasting or exercise and for maintaining proper lipid levels in the body.

Ketogenesis is the metabolic pathway that produces ketone bodies from fatty acids, primarily in the liver. It occurs during periods of low carbohydrate availability, such as fasting or a ketogenic diet, and provides an alternative energy source for tissues like the brain.

The pentose phosphate pathway is a metabolic pathway that generates NADPH (a reducing agent) and pentose sugars, which are important for biosynthesis and protection against oxidative stress. It occurs in the cytoplasm of cells.

Gluconeogenesis is the metabolic pathway that synthesizes glucose from non-carbohydrate precursors, such as amino acids and glycerol. It is important for maintaining blood glucose levels during fasting or starvation.

The glyoxylate cycle is a metabolic pathway that allows organisms to convert fatty acids into carbohydrates. It occurs in plants, bacteria, and fungi and is essential for growth on acetate or fatty acids as the sole carbon source.

Transamination is the transfer of an amino group from an amino acid to an alpha-keto acid, forming a new amino acid and a new alpha-keto acid. It is important for interconverting amino acids and synthesizing non-essential amino acids.

The shikimate pathway is a metabolic pathway that produces aromatic amino acids (phenylalanine, tyrosine, and tryptophan) and other aromatic compounds. It occurs in bacteria, fungi, algae, and plants but not in animals, making it a potential target for antibiotics and herbicides.

Glycosaminoglycan synthesis is the process of producing long, unbranched polysaccharides called glycosaminoglycans (GAGs), which are components of proteoglycans and important for the structure and function of the extracellular matrix.

The TCA cycle, also known as the citric acid cycle or Krebs cycle, is a central metabolic pathway that oxidizes acetyl-CoA derived from carbohydrates, fats, and proteins to produce NADH and FADH2, which are used in oxidative phosphorylation to generate ATP.

Amino acid activation is the process of attaching an amino acid to a transfer RNA (tRNA) molecule in preparation for protein synthesis. It is essential for incorporating amino acids into polypeptide chains during translation.

The Calvin cycle is the metabolic pathway that converts carbon dioxide into organic compounds, such as glucose, in plants and other autotrophs during photosynthesis. It occurs in the stroma of chloroplasts.

Proteolysis is the metabolic pathway that breaks down proteins into smaller polypeptides or amino acids through the action of proteases or peptidases. It is important for recycling amino acids, regulating protein levels, and activating or deactivating proteins.

The malate-aspartate shuttle is a transport system that moves electrons from the cytoplasm into the mitochondrial matrix, allowing the oxidation of cytoplasmic NADH during cellular respiration and maintaining the redox balance.

RNA splicing is the process of removing non-coding sequences (introns) from precursor messenger RNA (pre-mRNA) and joining the coding sequences (exons) to form mature mRNA. It is essential for proper gene expression and protein synthesis.

Ribosomes are complex molecular machines composed of RNA and proteins that serve as the site of protein synthesis, translating the genetic information from mRNA into functional proteins.

Post-translational modification is the chemical modification of a protein after its translation, such as adding or removing functional groups. It is important for regulating protein activity, localization, and interactions with other molecules.