Biochemistry and Protein Quiz

Principles of Biochemistry and Protein Lecture Summary

• The tutorial covers essential and some non-essential principles of biochemistry, with a focus on cellular foundations, chemical foundations, and macromolecules.
• Cells are the basic building blocks of life, and can be prokaryotic or eukaryotic. Eukaryotic cells have a nucleus and membrane-bound organelles, including mitochondria and ribosomes.
• The cell membrane is the semi-permeable outer boundary of all cells, controlling which materials can enter and exit. It is made up of a phospholipid bilayer with a phosphate head and two fatty acid tails.
• Membrane transport includes osmosis, diffusion, facilitated diffusion, and active transport.
• Proteins are macronutrients that contain nitrogen and are made up of amino acids joined by peptide bonds. They vary in size and are continually turned over.
• Amino acids share common structural features and can be essential or non-essential. Non-essential amino acids can be made in the body through transamination.
• Branched-chain amino acids (BCAAs) like leucine, isoleucine, and valine are essential and may play a role in stimulating muscle protein synthesis and intracellular signaling pathways.
• The lecture covers the structures and properties of amino acids, and how they are used to make proteins.
• Protein synthesis involves transcription and translation, with the DNA code being transcribed into RNA and then translated into a chain of amino acids.
• Proteins have many functions in the body, including structural support, transport, enzyme catalysis, and signaling.
• Protein quality is determined by its amino acid composition and digestibility. Animal proteins generally have higher quality than plant proteins.
• The lecture emphasizes the importance of understanding biochemistry and protein principles for health, nutrition, and athletic performance.

Proteins, Enzymes and Protein Quality: Key Concepts

• Non-essential amino acids can be made in the body through transamination.
• Branched-chain amino acids (BCAAs) play a role in muscle protein synthesis and have unique capacity to stimulate it.
• Primary structure of a protein refers to its amino acid sequence and alterations can be caused by inherited genetic variation.
• Secondary structure results from weak chemical bonds and folding of the primary structure due to the charges of amino and carboxylic acid groups.
• Tertiary structure is the three-dimensional structure of a protein, determined by the interactions of the side chains.
• Quaternary structure refers to a protein made from more than one polypeptide chain, such as hemoglobin.
• Denaturation of proteins can be caused by various conditions including heat, acid, detergents, bases, salts, and heavy metals.
• Enzymes are catalysts that speed up chemical reactions by lowering the energy barrier and can speed up reactions by over a billion times.
• Enzyme nomenclature includes names such as kinase, phosphatase, synthase, carboxylase, decarboxylase, dehydrogenase, isomerase, and mutase, depending on the type of reaction catalyzed.
• Enzymatic reactions can be influenced by factors such as temperature, pH, enzyme and substrate concentrations, and presence of inhibitors or activators.
• All proteins are not of equal nutritional value and protein quality can be estimated through methods such as protein efficiency ratio, biological value, net protein utilization, and protein digestibility corrected amino acid score.
• Pigs fed on diets based on lentil protein grew faster than those on barley-based diets, despite the protein/nitrogen content being matched.

The Importance of Water and Electrolytes in the Body

• Biological value indicates the percentage of nitrogen utilized by the body and is higher in animal sources than vegetable sources due to essential amino acid content.
• Water makes up 45-75% of an average healthy adult's body, with distribution varying by age, gender, and muscle/fat composition.
• Water is a polar molecule with positive and negative areas, allowing for hydrogen bonding and properties such as high surface tension and a high heat of vaporization.
• Water is a universal solvent, dissolving more substances than any other liquid, and plays important roles in body temperature regulation, lubrication, transportation, and hydrolysis/condensation reactions.
• Electrolytes, such as sodium and potassium, participate in fluid balance and can cause fluid shifts between compartments in the body.
• Osmosis is the movement of water across a semi-permeable membrane from an area of low solute concentration to high solute concentration.
• The sodium-potassium pump and hormones such as ADH and aldosterone help regulate fluid intake and reabsorption in the body.
• Dehydration and overhydration can have negative effects on the body, and it is important to consume an appropriate amount of water and electrolytes.
• Caffeine and alcohol can act as diuretics and affect fluid balance.
• Hyponatremia, or low blood sodium levels, can occur from consuming too much water.
• Gut microbiota play important roles in digestion and overall health, and functional foods can help support a healthy microbiome.
• Understanding the importance of water and electrolytes in the body can help individuals make informed choices about their diet and hydration habits.

Importance of Water and Electrolytes in the Body

• Biological value measures the percentage of nitrogen utilized from food and is higher in animal sources due to their essential amino acid content.
• Water makes up 45-75% of the human body and its distribution depends on age, gender, and body composition.
• Water is a polar molecule with positive and negative areas, which creates hydrogen bonding and gives it unique properties like high surface tension and solubility.
• Water is a universal solvent and participates in body functions like temperature regulation, lubrication, and transportation of nutrients and waste.
• Electrolytes like sodium, potassium, and magnesium participate in fluid balance and can shift fluids between compartments.
• Osmosis is the movement of water through a semipermeable membrane from an area of low solute concentration to an area of high solute concentration.
• The sodium-potassium pump and hormones like ADH and aldosterone help stimulate fluid intake and regulate electrolyte balance.
• Marathon running can lead to dehydration and electrolyte imbalances, and it is important to drink enough water and consume electrolytes during exercise.
• The amount of water a person needs depends on their body weight and activity level, and can be obtained from both beverages and foods.
• Diuretics like caffeine and alcohol can affect fluid balance, and consuming too much or too little water can lead to dehydration or hyponatremia.
• Overhydration and dehydration can be measured using an osmometer, which measures the concentration of solutes in bodily fluids.
• Understanding the role of water and electrolytes in the body is crucial for maintaining fluid balance and overall health.