Urea Synthesis and Protein Metabolism

Urea Synthesis

• Urea synthesis is a process to detoxify ammonia.
• During amino acid metabolism, deamination occurs, resulting in the loss of a nitrogen molecule.
• This deamination process disposes of nitrogen, producing ammonia.
• Ammonia, from deamination, is converted into urea in the liver.
• Urea safely travels in the bloodstream, is filtered by the kidneys, and is eliminated in urine.
• Urea is not created in the kidney.
• The amino groups (nitrogen) form ammonia, which is then converted into urea in the liver.
• Urea synthesis allows harmful free ammonia to be collected in a less toxic form.

Proteins and Amino Acids

• Protein completion requires a variety of sources since no single plant source is sufficient.
• Protein efficiency means a quality protein requires less protein.
• Protein quality is affected by digestibility, amino acid content in proper ratios, toxins (like trypsin inhibitors), and amino acid forms.
• Deamination must occur before amino acids can be metabolized to produce ATP or used to synthesize glucose or fat.
• Amino acids are deaminated before they can be metabolized or used to synthesize glucose or fat.
• Amino acid balance is crucial because limiting amino acids can decrease the utilization of other abundant amino acids.
• Essential amino acids must be consumed and cannot be made via transamination.
• Amino acids area re deaminated before they can be metabolized or used to synthesize glucose or fat.
• Since most amino acids are non-essential, they can be made in the body by transamination. This process involves taking one nitrogen from a component and adding it to the backbone.
• Denomination is the removal of nitrogen, which converts an amino acid into a keto acid.
• Synthesis of nonessential amino acids involves adding nitrogen to a keto acid to form an amino acid.
• Amino acid pool allows for amino acid availability:
  • Dietary proteins (digestion) are converted into digestion amino acid pool
  • Amino acid pool (protein synthesis) are converted into body protein
  • Body protein (protein breakdown) is converted into amino acid pool
• The function of the amino acid pool includes:
  • Energy production
  • Synthesis of glucose or fatty acid & nonprotein molecules that contain nitrogen
• No plant protein alone provides enough essential amino acids, protein complementation is required

Factors Affecting Carb Quality

• Carb quality is affected by the amount of fiber vs. starch.
  • Less fiber means less energy.

Kwashiorkor vs. Marasmus

• Kwashiorkor is malnutrition due to not enough protein.
  • Its effects include a bloated stomach, growth impairment, and weight loss.
• Marasmus results from not enough energy.
  • This results in severe weight loss, protein deficiency.
• Kwashiorkor is characterized by protein deficiency (moderate weight loss, fatty liver, maintenance of some muscle).
• Marasmus is characterized by a reduction in overall energy (protein and energy) i.e. severe weight loss, severe growth impairment, wasting of muscle and body.

Glucose and Carbohydrates

• The breakdown of glucose involves chains of polysaccharides being broken down into oligosaccharides, disaccharides, and finally monosaccharides.
• Amylase, found in salivary glands and the pancreas, breaks down glucose into disaccharides.
• Activate amylaze with Chloride, which occurs in the small intestines
• Insulin helps glucose enter cells, lowering blood glucose levels.
• Glycolysis, an anaerobic cellular respiration process, doesn't need oxygen to get glucose into cells.
• Glucose is the most abundant sugar and a good energy source.
• Simple carbohydrates include monosaccharides (e.g., glucose, fructose) and disaccharides (e.g., sugar, glucose).
• Complex carbohydrates include oligosaccharides and polysaccharides (starch, fiber, glycogen).
• Fructose is the sweetest sugar (i.e., high fructose corn syrup).
• Galactose does not occur alone in foods and binds with glucose to form lactose.
• Glucose + galactose results in Lactose.
• Glucose + glucose results in maltose.
• Glucose + fructose results in maltose which is found in sugarcane, sugar beets, and honey.
• The process of deamination is where the amino group is removed.
• The primary function of carbohydrates it is to provide energy.
• Glucose and fructose can be found in free form but galactose cannot.
• Those aren't digestible which is defined as Fiber

Hormones and Glucose Levels

• Glucagon is released by the pancreas to stabilize blood glucose levels (increase blood glucose) when they are too low. This occurs hours after eating when blood glucose levels decrease below normal.

Lipids

• Different types of lipid molecules: Includes free fatty acids, triglycerides (bound to back-bone) tri- 3 majority of the fat, phospholipids (added phosphate), sterol neutral, and cholesterol.
• To make a trans fat, take an unsaturated fat (saturated fat), put a hydrogen on it, higher level

Triglycerides

• The components required to make a tag (triglyceride) include a glycerol backbone and 3 fatty acids.
• Triglycerides are the major form of lipids found in both foods and the human body

Fatty Acids

• When carbohydrate intake is low, fatty acids are converted to ketone bodies, which can act as an alternative energy source.
• Insoluble fiber is not easily digestible in the small intestines.
• Short chain fatty acids, once absorbed from a meal, enter the portal circulation and travel to the liver before going to the rest of the body, as they are small enough and don't need to be packaged.

Grain Processing

• Processing whole grains removes the endosperm, germ, and bran.

Protein, Vegetarianism, and Allergies

• Animal products provides sources of protein, B vitamins and minerals, but less in absorbable forms
• Semi-vegetarian, lacto-voo vegetarians, vegan are all types of vegetarianism
• Compared to animal foods, plant products are lower in fat
• Meat contains vitamin B12
• Animal products provide protein and minerals (iron, zinc, and calcium), with lower fiber but they are high in fat
• Plants provide B vitamins, iron, zinc, fiber, and calcium, but in less absorbable forms.
• The protein efficiency ratio for egg = 3.9.
• Food protein allergies are an (immune response) allergic reaction
• The most common allergy is the peanuts, tree nuts milk egg, fish shellfish soy & wheat
• Excess protein can cause osteoporosis (losing bone calcium).

Potential Problems with Too Much Protein

• Affects hydration and kidney function by increasing urinary calcium excretion (protein leads to protein break down +urinary calcium excretion) leading to must be removed by kidney which can be risk of water loss, risk of kidney stones
• Higher protein leads to higher fat (typically protein comes from animal) which can cause heart disease and cancer

Celiac Disease

• Celiac disease is a gluten intolerance/allergy (found in wheat, rye, and barley).

Photosynthesis

• Photosynthesis uses water and carbon dioxide which are converted to carbohydrates, glucose, and oxygen.
• Everything starts with the sun and carbs come from plants

Carbohydrates

• Carbohydrates are macronutrients composed of carbon, oxygen, hydrogen (4kcal)
• Carbohydrates provide energy, spare protein, provide sweetness and fiber, and enhance the function of many proteins

Lactose Intolerance

• Lactose intolerance means that an individual doesn't have enough lactase in the small intestine to digest lactose.
• When undigested starch appears in the colon, or undigested starch, it can cause diarhea because the patient has a shortage for the carbs

Glucose Fate

• Absorption mainly takes place in the small intestine. Digestion and absorption are in the small intestine
• Fate of glucose - Monosaccharides enters capillaries and travels to liver, Fructose & galactose turns into glucose
• Energy for liver, passed into blood for other cells to use for energy, Stored in liver & muscle as glycogen

Energy

• Consume in excess energy need to sythesize fatty acids

Fiber

• Insoluble: Part of the cell wall, Doesn't dissolve in water, Contributes bulk to stool, grains, fruits, veggies Soluble: Dissolves in water and is viscous + gel-forming, Gums, pectins, fruit, berries, oats, beans
• Starch, Glycogen, and Fiber are three of the many types of Polysaccharides
• Whole grains have a brain layer: source source of fiber & vitamins, good source of Germs: good source of veggy oil & vitamin e, enosperm: contain starch & some protein.
• If you remove the bran and germ? loss of nutreint will occur

Which of the following is not a role of the

amino acid pool in the human body?

• It is a source for the synthesisof essential amino acids

• Glycolysis:*

• Glycolysis converts glucose into Pyruvate. Free energy release in this process is use to form ATP

• Glucose fructose = → sucrose

• Those aren't digestible which is defined as Fiber

• dietary carbs → small intestine → excess store as glycogen → raise blood level if needed for brain & brody cells → trasnporter to muscles → energy & glycogen

Hormones and Glucose regulation

• Insulin lowers blood glucose
• Glucagen raises blood glucose

Diabetes

• Diabetes is where there is a Inability to regulate blood sugar causing high levels of blood sugar over a prolonged period of time
• What happens if you have all the glucose in the world but the cells doesn't recognize it? This calls for cells need to recognize it, otherwise it is useless
• If you are type 2 given in the lecture? You have a doorbell but it doesn't respond inresponsive doorbell which causes you to have insulin insenstive, high glucose → down regulates
• What is Trans-fatty acid, and what is the process that can create it? Hydrogenaion → double bonds to become saturated,Found in margarines, veggie shortening, Raise blood levels & increase risk of heart disease

Lecture #12 March 10, 2025

• Vitamins & minerals are micronutrients
• Carbs, protein, and fat are macro nutrients
• B1, b2, b3, biotin pantohetnic acid, b6, b,12, vitamin c, folate b9 (B, and C) are water soluble vitamins A, d, e, k are all fat-soluble vitamins
• RDA rrecmmmended dietary allowance - satisfies 97.5 percent of health people
• Fat are stored in livers, and stored as fat while as water-soluble aren't store, function as coenzyme
• Whole grain contain original nutrients, remove of husk remove most the nutrient, Grain/cereral enrich with thiamin, riboflavin, nacin iron from 1930s, Folate from 1998
• Functions: Protein metabolism, carbohydrates metabolism, fat metabolism → energy to perfom all body functions
• Bi involved deeply with energy metabolism and it contains whole grains - Damage to nervous system, heart, muscle weakness, common in alcoholics. - Has whole grains, enriched ofood
• B2 deficiency symptoms and involves sore throat, swollen mucous membranes, stunted growth. Milk, enriched foods, meats
• Biotin is impossible to be defienct of if t. Not toxic if consumed too much & Required for synthesizing cholotesol and steroids
• B3: Causes Diarrehea, dematitis, dementia, death and is Usually people who have low protein & corn-based diet
• Corn resulted in defiecny of B3 - Low levels of tryptophan

Lecture 13 of Nutrition

• If you are a vegan, u need b12 crystal, fermented type food
• Elderly parents → dementia qualities, defiency of b12
• Not enough b12 can impact your mental and brain capacity
• if you are b12 Deficient there can be resulting result, and a Megaloblastic anemia (lack of instric factor)
• Transcobalamin ii carries b12 around the circulation & Requires the small intestine
• Types of food source that contain folic acid is Fortified food (add folate onto food): enriched bread, flours, pasta, grain products
• What is the the main result of the deficiency of vitamin c- scurvy,, loss of appetite,retarded wound healing, bleeding gums & capillaries