Senior Undergraduate Biochemistry Comprehensive Exam Study Guide

Flashcards covering key concepts in biochemistry related to carbohydrates, lipids, proteins, vitamins, minerals, and digestion.

Monosaccharides

The simplest form of carbohydrates, monosaccharides are the building blocks of more complex carbohydrates. They include glucose, fructose, and galactose. These are single sugar molecules that are absorbed directly into the bloodstream.

Glucose

An aldohexose and the primary fuel for the brain and red blood cells, glucose is absorbed in the intestine via the sodium-glucose transport protein SGLT1 and exits the enterocytes into the bloodstream through the glucose transporter GLUT2.

Fructose

A ketohexose, fructose is primarily found in fruits and honey. It is absorbed in the intestine via GLUT5 and can be converted to glucose or fatty acids in the liver, potentially leading to the formation of triglycerides.

Galactose

An aldohexose derived from lactose, galactose is absorbed through SGLT1. It undergoes conversion to glucose-1-phosphate via the Leloir pathway, allowing it to enter glycolysis.

Disaccharides

Carbohydrates formed by two monosaccharides linked by glycosidic bonds. They must be hydrolyzed by enzymes in the brush border of the intestine for absorption, with examples including sucrose and lactose.

Sucrose

A disaccharide composed of glucose and fructose. It is hydrolyzed by the enzyme sucrase into its monosaccharide components before absorption occurs.

Lactose

A disaccharide made up of glucose and galactose, lactose is hydrolyzed into its constituents by the enzyme lactase. A deficiency in lactase leads to lactose intolerance, causing gastrointestinal discomfort upon consumption.

Polysaccharides

Complex carbohydrates made of long chains of monosaccharides. They include starch (plant storage form of glucose) and glycogen (animal storage form), which require enzymatic breakdown before absorption.

Dietary Fiber

Plant-based non-digestible carbohydrates classified into soluble (which can help lower cholesterol) and insoluble (which aids in digestion). Fiber is vital for gut health and may regulate blood sugar levels.

Lipids

A diverse group of compounds, including fats, oils, and sterols, that are essential for energy storage, cellular structure, and signaling. They play a significant role in hormone production and nutrient absorption.

Cholesterol

A sterol lipid crucial for maintaining cell membrane fluidity and serving as a precursor for steroid hormones and vitamin D. It is essential for numerous physiological processes but can pose health risks if present in excess.

Proteins

Large macromolecules composed of long chains of amino acids. They play critical roles in structure, function, and regulation of cells, and are involved in metabolic pathways, immune responses, and muscle contraction.

Essential Amino Acids (EAAs)

Nine amino acids that cannot be synthesized by the body and must be obtained from dietary sources. These are crucial for protein synthesis, making them a vital part of nutrition.

Vitamins

Organic compounds required in small quantities for various metabolic processes. They function primarily as coenzymes or cofactors in biochemical reactions, influencing processes like energy production and immune function.

Minerals

Inorganic elements essential for numerous bodily functions, including enzyme activity, bone structure, and electrolyte balance. Key minerals include calcium, potassium, and iron.

Water

The most essential nutrient in the body, making up a significant portion of total body mass. It is crucial for maintaining homeostasis, enabling biochemical reactions, and facilitating nutrient transport.

Digestion

The complex process of breaking down food into absorbable components through mechanical and chemical processes, involving enzymes and acids to transform macromolecules into their simpler forms.

Absorption

The process by which nutrients from ingested food are transported from the gastrointestinal tract into the bloodstream, primarily occurring in the small intestine, where specialized transport mechanisms operate.

Caloric Measurement

The method used to determine the energy content of food, usually expressed in kilocalories (kcal), which defines the amount of energy available to the body through metabolic processes.

Dietary Recommendations

Standards established to guide healthy eating patterns and nutrient intake levels, aimed at promoting health, preventing chronic diseases, and addressing individual dietary needs.

Nutrition Labeling

Regulations that standardize food labels to provide consumers with clear information about nutritional content, helping them make informed dietary choices and promote healthier eating habits.