Quiz 6
Lipoproteins - what is relationship between composition of lipids: protein and lipoprotein density?
Lipoproteins are particles consisting of a central lipid core encased in protein and phospholipids. •
What is the role of glucagon?
Low blood glucose triggers pancreatic cells to increase the release of glucagon, which causes blood glucose levels to increase. The role of glucagon is to increase blood glucose and to prevent blood glucose levels from decreasing further.
Dietary protein to maintain protein status
Maintenance - dietary protein is adequate to replace daily loss
Definition of lipids
Lipid is a general term for a class of molecules that tend to be water insoluble, and dissolve in solvents (alcohol, acetone, ether).
Defining the nutrient category of lipids - based on physical property of solubility
Lipid is a general term for a class of molecules that tend to be water insoluble, and dissolve in solvents (alcohol, acetone, ether).Fatty acids (Triglycerides)PhospholipidsSterols (cholesterol)
What does leptin communicate? What makes leptin levels increase and decrease? How does increases/decreases in leptin impact body weight?
1994 - identified a gene expressed by adipocytes encoded for a hormone called leptin.•When leptin injected into obmouse - corrected obesity by reducing hunger and increasing energy expenditure. •Brain receptors for leptin were discovered shortly thereafter.
What is the difference between complete and incomplete proteins?
A complete protein provides all essential amino acids in required amounts.An incomplete protein is lacking or has significantly low amounts of one or more essential amino acids
What is an A1c test and what does it measure? What does an elevated A1c mean?
A1c test indicates overall blood glucose management over the past 3 months
What is the difference between absolute and relative insulin deficiency?
Absolute means not enough of whatever, in this case insulin, like in type 1 diabetics, where insulin production is compromised due to autoimmune damage to the beta cells of the islets of the pancreas. Relative means not enough related to what is needed, in this case more insulin than "usual", but not enough due to the very high needs that person has, due to insulin resistance, like in type 2 diabetics.
What is amphipathic?
Amphipathic lipids are both hydrophobic parts (water insoluble) and hydrophilic (water soluble) parts.
What is a cis FA and a trans FA?
Arrangement of hydrogen atoms around double bonds - cisvs. transCisconfiguration, hydrogen atoms are on the same side of the double bond. Most naturally occurring fatty acids are in the cis configuration.Transconfiguration, hydrogen atoms are on the opposite side of the double bond.Althoughsomenaturallyoccurring trans fatty acids,most wereindustrial made and found processed foods. Largely been removed from processed foods found to be associated with cardiovascular disease.
What is the prognosis of bariatric surgery on weight loss and weight loss maintenance?
Bariatric surgery (alterations to the GI tract) - mixed resultsMaximum weight loss 1-3 years following surgery30% of weight loss regained after 10 years25% regain all of the lost weight by 10 years
cholesterol - used for cell membrane structure and parent compound to make certain hormones and vitamin D
Cholesterol - most abundant sterol in the body (not an energy source)•1. Important component of cell membranes -maintains stability and fluidity•Parent compounds used to make other sterolsVitamin DStress hormones (cortisol)Reproductive hormones (estrogen and testosterone)•3. Nonessential nutrient - made by the liver
What is the role of lipoprotein lipase? Where is it found?
Circulating chylomicrons interact lipoprotein lipase (LPL), an enzyme along the lining of capillaries associated with adipose tissue and muscle cells.LPL hydrolyzes the ester bonds, which enables fatty acids to be taken up by cells.•Chylomicron remnants are taken up by the liver.
Why is DHA important for fetal development and during infancy?
DHA is important during pregnancy and infancy for optimal visual and cognitive development.•DHA concentration in breastmilk is influenced by DHA in the mother's diet.•Recommendation pregnant women consume fish 2-3/wk (8-12 oz fish low in mercury)•Prenatal and postnatal DHA supplementation recommended for breastfeeding mothers who do not regularly eat fish.
what happens when a protein is denatured? What structures are disrupted?
Denaturation disrupts the weak bonds that are responsible for maintaining the three-dimensional structure of the protein.•Denaturing agents (heat, pH, heavy metals) disrupt the hydrogen and ionic bonds, that hold the secondary and tertiary structures together, causing the protein to unfold.•Denaturing agents do not disrupt peptide bonds -therefore the primary structure is unaffected.•In most situations, denatured (altered shape) proteins become dysfunctional.
What can cause blood glucose levels to decrease?
Elevated blood glucose triggers pancreatic beta cells to increase the release of insulin, which causes blood glucose levels to decrease.
How can the parent compound of omega-3 and omega-6 fatty acids altered to make other omega-3 and omega-6 FA?
Elongation•Increasing the length of the carbon chain by the addition of carbon atoms•Desaturation•Increasing the number of double bonds by the removal of hydrogen atoms.
What makes a FA essential vs. nonessential?
Essentiality is based on the position of the first double bond from the methyl end.•If the first double bond occurs before the 9th carbon atom, the FA is essential. •Humans lack the enzymes needed to synthesize double bonds occurring before C-9.
What is the role between diet and heart disease?
Diet recommendation that has dominated health literature for 50+ years -replacing saturated fat in the diet with unsaturated fat lowers risk of heart disease.
If cells make EPA and DHA, why is DHA commonly added to food?
EPA and DHA can be synthesized but the conversion is slow and limited.Most practical way increasing EPA and DHA in the body is dietary/supplementatin.
What are the components of an amino acid? Common structure?
Each amino acid (~20 total) consists of a nitrogen-containing amino group, central carbon, a carboxyl group, and a side-chain "R" (functional group).All amino acids have the same common structure (amino group, carboxyl group and the central carbon), however each amino acid has a unique side-chain "R"
What ways do functional groups differ. What makes an amino acid essential or nonessential?
Each amino acid has a different side-chain, but the common structure is the same for all amino acidsIf cells can make the "R" group - nonessential amino acidIf cells CANNOT make the "R" group - essential amino acid
Outline the exogenous and Endogenous lipid pathways
Exogenous Pathway (chylomicrons)•Circulating chylomicrons interact lipoprotein lipase (LPL), an enzyme along the lining of capillaries associated with adipose tissue and muscle cells. •LPL hydrolyzes the ester bonds, which enables fatty acids to be taken up by cells.•Chylomicron remnants are taken up by the liver.The endogenous lipoprotein pathway begins in the liver with the formation of very low density lipoproteins (VLDLs)•VLDLs circulate lipids (triglycerides and cholesterol) made by the liver to muscle and adipose tissue.•VLDL more lipid (92%) relative to protein (8%), therefore VERY LOW DENSITY
FA nomenclature
Fatty acid nomenclature (system of naming) - based on number of carbons, the number of double bonds, and the position of the double bonds.
Fatty acids cannot be converted to glucose!
Fatty acids can't be used to make glucose, only certain amino acids.
Fatty acids - methyl vs alpha ends
Fatty acids consist carbon, hydrogen, and oxygen atoms with an acid (- COO-) group at one end. The other end contains a methyl (- CH3) group.
How does chain length influence the physical property of solubility?
Fatty acids differ by:•The type of carbon-to-carbon bond•Single or double•Double - cisor trans•The number of carbons in the chain Short-chain, medium-chain, and long-chain fatty acids•The shorter the chain (fewer carbon atoms, the more soluble the FA)•Essential and nonessential
What makes a fatty acid saturated vs unsaturated?
Fatty acids with single bonds between carbon atoms are called saturated fatty acids (SFA). SFA contain the maximum number of hydrogen atoms. Monounsaturated fatty acid (MUFA) - fatty acid with one double bond is aPolyunsaturated fatty acid (PUFA) - fatty acid with two or more double bonds. For each double bond, there are 2 less hydrogen atoms compared to a SFA with equal number of carbons atoms
What 3 metabolic pathways are stimulated by a rise in glucagon?
Glucose metabolism involves multiple processes, including glycolysis, gluconeogenesis, and glycogenolysis, and glycogenesis.
What is ketogenesis and how does it help reduce the body's need for glucose?
Ketogenesis -the process of breaking down of fatty acids and subsequent conversion into ketones.•Occurs in semi-starvation mode to ensure survival.•Ketone bodies are a form of energy used by the heart and brain. •Ketogenesis allows glucose to be used sparingly by providing the brain and heart with an alternate energy source (ketones).
Ketogenic diets have been used to treat seizure disorders.
Ketogenic diets may have therapeutic benefitsKetogenic diets are sometimes used to control seizure disorders in children
What is reactive postprandial syndrome? What is recommended to control fluctuations in blood glucose?
Hypoglycemia - characterized by a dramatic drop in blood glucose following a meal.Symptoms of low blood glucose (weakness, rapid heartbeat, sweating, anxiety, hunger, trembling caused by release of hormone epinephrine and cortisol from the adrenal glands (stress hormones). •Recommendation - small frequent meals consisting of low glycemic response foods
What is the role of the hypothalamus in hunger and satiety? What is the role of anabolic and catabolic neuropeptides?
Hypothalamus - area of the brain regulates food intake (hunger, satiety, and appetite) and energy expenditure (EE).Neurons within the hypothalamus release either anabolic neuropeptides (ANP) or catabolic neuropeptides (CNP).ANP promote weight gain by increasing hunger (EI) and decreasing energy expenditure ( ̄EE) CNP promote weight loss by decreasing hunger ( ̄EI) and by an increasing energy expenditure (EE)
What is protein complementation?
If a variety of incomplete protein sources are consumed, collectively they provide a complete protein source (protein complementation)
What activates protease enzymes
In order to activate it, the bond in between the 15th amino acid (Arg) and 16th amino acid (Ile) has to be cleaved by the enzyme (trypsin). The simple cleavage of the single bond activates the enzyme.
What are the typical signs/symptoms of type 2 diabetes
Increased thirst. Frequent urination. Increased hunger. Unintended weight loss. Fatigue. Blurred vision. Slow-healing sores. Frequent infections.T2D early stages -can be asymptomatic in early stage•Presence of glucose in the urine•Increased frequency urination•Increased thirst•Fatigue•Progresses -more serious/noticeable•Blurred vision•Skin irritations/poor wound healing•Numbness and tingle sensation in extremities
What are gluconeogenesis, lipogenesis, glycogenolysis, lipolysis and proteolysis, and ketogenesis?
Inhibits catabolic pathways that break down energy reserves 1. Glycogenolysis - Glycogen is broken down and glucose is released2. Lipolysis - Stored fat is broken down and fatty acids are released3. Proteolysis -Muscle (protein) is broken down and amino acids are released. Favors biosynthetic (anabolic) pathways that store energy 1. Glycogen formation -Excess glucose is converted to glycogen (reversible) 2. Lipogenesis - Excess glucose is converted to fatty acids (irreversible)
What takes place inside enterocytes to prepare lipids to be circulated?
Inside the enterocyte, fatty acids are reattached to monoglycerides forming triglycerides.
Describe insulin resistance and how it can spiral to lead to more insulin resistance?
Insulin resistance - cell signaling is impaired, decreasing the amount of glucose taken up by adipose and skeletal muscle tissues. •Adequate insulin production, but decreased insulin receptor response (insulin resistance).•Signaling cascade that normally results in the translocation (movement) of GLUT4 to cell membrane is impaired.•Result, glucose entry into cell impeded and blood glucose concentration remains elevated.
What is an omega-3 FA vs. an omega 6 FA?
Linolenic Acid18:3 omega-3 FAFoods: Walnuts, flaxseed oil, fortified foods, and fatty fish. Linoleic Acid18:2 omega-6 FAFoods: Seeds, nuts, and made from nuts and seeds oils
Chylomicrons - where to they originate, how are chylomicrons formed, and what do they circulate?
Monoglycerides and free fatty acids absorbed into the enterocyte (intestinal cell).
Triglycerides - energy source - 3 fatty acids attached to glycerol by ester bonds
Most fatty acids in the body and in food are in the form of triglycerides (glycerol with 3 FA attached).
Although dietary fat was thought to be the driver of heart disease, what does more recent research suggest?
Most recent research reveals that dietary fat restriction does not reduce risk of coronary heart disease.Lower CVD risk - Reduce ultra-processed foods•Higher consumption of ultra-processed foods is associated with increased risk of CVD incidence and mortality.•Participants consumed average 7.5 servings per day of ultra-processed foods•Each additional daily serving of ultra-processed foods was associated with a 7%•Recommendation:•Minimize foods made with refined carbohydrates and added sugar•Increase consumption of fresh fruits and vegetables•Increasing fiber-rich foods
What is the prognosis of diet/exercise on weight loss and weight loss maintenance?
No single weight-loss approach that works for everyone•Lifestyle - Diet and Exercise•Bariatric surgery (alterations to the GI tract)•Off-label prescription drugs - Ozempic and Wegovy
If people with obesity make leptin, why does it not affectively regulate body weight?
Obesity is not a leptin deficiency syndrome, rather it is a hormone resistance syndrome.•Hyperleptinemia and a diminished response to leptin implies a hormone resistance syndrome (much the same as type 2 diabetes)•Leptin resistance - caused by an impaired ability of leptin to signal the hypothalamus.
What are the health benefits of DHA?
Omega-3 FAs (Linolenic acid, EPA, DHA) are particularly important:•Moderate evidence lower cardiovascular disease risk•Brain and eye development fetus•Brain development throughout infancy
Why do long term health complications arise with poor control of blood glucose?
Over time, elevated blood glucose can cause vascular and nerve damage.•Major complications include:•Cardiovascular disease•Heart attacks, strokes•Amputation - poor circulation•Neuropathy (nerve damage)•Numbness, pain •Nephropathy (kidney damage)•Impaired filtration•Dialysis•Retinopathy (eye damage)•Blindness
What is the defect in the ob mouse that made it obese?
Parabiosis (shared circulating blood) •Lean + obese (ob) mouse•Obese (ob) mouse lost weight•No change in weight of lean mouse•Explanation:•ob mouse lacked a circulating satiety factor that made the mouse obese.•When the ob mouse received the satiety factor from the lean mouse, it lost weight.
Phospholipids - cell membranes, lipoproteins, lipid digestion
Phospholipids (glycerol, 2 fatty acids, and a phosphate group) Fatty acids are nonpolar, hydrophobic.Phosphate group is polar, hydrophilic.Phospholipids are amphipathic. Phospholipids -ideal structural component of cell membranes.Polar head (hydrophilic) oriented towards intracellular (inside cells) fluid and extracellular (outside cells) fluid while nonpolar (hydrophobic FA) orient inwards, away from intracellular and extracellular fluid.
How do phospholipids aid in the circulation of lipids?
Phospholipids and proteins are water soluble, which enables lipids to circulate in the lymph and blood.
How do phospholipids differ from triglycerides?
Phospholipids form lipoproteins, complexes that transport insoluble lipids in the blood. Phospholipids in bile aid in lipid digestion by breaking up (emulsify) dietary lipids into lipid droplets (micelles).
Primary structure = polypeptide chainThe sequence of amino acids in the primary structure is unique to each protein.
Polypeptide -chain of amino acids linked together by peptide bonds •Mostproteins are made up of a 1 polypeptide chains•Someproteinshave more than 1 polypeptide chain.•The sequence and number of amino acids in the polypeptide chain is encoded in genes (DNA) and is unique to each protein.•Gene variant can alter the primary structure, causing it to fold incorrectly (misshapen).•Leads to loss of protein function.
How do Ozempic and Wegovy facilitate weight loss? What are the limitations
Prescription drugs -effective, but limitations •2017 - FDA approved an Ozempic (injectable medication) for treating T2D.•2021 Wegovy (same drug, higher dose) was approved to treat obesity.•Addresses pathophysiology of obesity by imitating a hormone called glucagon-like peptide-1 (produced naturally by intestine).•Causes fullness by slowing gastric emptying.•Turns on pathway communicates eat less/store less•Turns off pathway communicates eat more/store more•Results - improved metabolic profile (lowers blood pressure, blood glucose, blood lipids) which subsequently reduces obesity-related morbidity/mortality.Limitations•Expensive without insurance —•Wegovy ~ $1,300 /mo•Ozempic ~ $892 /mo•Insurance unlikely to cover the cost •Side-effects:•GI side-effects (nausea and diarrhea/constipation) fatigue, and dehydration•If stopped, weight lost is regained•Not intended for people with lower body weight•Created a drug shortage for those taking the drug to treat T2D
What is the physiological adaptation to semi-starvation?
Prolonged hypoglycemia is semi starvation. If cells depended solely on protein to meet existing need for glucose (gluconeogenesis), survive < 3 wks.•The body adapts to semi-starvation (limited glucose availability) by using glucose sparingly.•This is accomplished by an adaptive response to semi-starvation -ketogenesis.
What makes oils liquid and fats solid?
Proportion of saturated to unsaturated fatty acids in a food determines whether it is solid at room temperature (fat) or liquid at room temperature (oil).Fats are solid at room temperature because they have a high percent of saturated fatty acids•Oils are liquid at room temperature because they have a high percent of unsaturated fatty acids.Why does unsaturation/saturation influence physical properties?SFA pack closely together in an orderly array and therefore are solid at room temperature (e.g., butter)UFA have bends and kinks that prevent close orderly packing and therefore are liquid at room temperature (e.g., oils)
What activates pepsinogen and trypsinogen?
Protease enzymes needed for digestion include:
Protein turnover and amino acid pool
Protein Turnover•All proteins eventually wear out and must be replaced•Protein Turnover - cycle of protein synthesis and protein degradation (breakdown)•Why dietary protein requirements are relatively low (contribute smallest % to total daily energy requirements).Amino acid pool refers to amino acids disbursed throughout the body that are available for protein synthesis.•Amino acid pool come from:•1) Protein turnover•Not all amino acids are recovered, some are lost (skin, hair, loss of cells, injury)•Protein turnover alone is not enough to supply enough amino acids needed for protein synthesis.•2) Dietary protein (eating more protein does not increase the amino acid pool)
What organs provide proteolytic enzymes?
Protein digestion accomplished by protein-splitting enzymes (hydrolyze peptide bonds) collectively referred to as proteases (proteolytic enzymes).In the human body, they are produced by the pancreas and stomach
Protein shape = protein function
Protein shape determines whether the protein can interact with other molecules (shape = function).
Why are LDLS and HDLS associated with cardiovascular risk?
Protein-rich high-density lipoproteins (HDLs) helps cells remove excess cholesterol .•HDLs transport cholesterol from cells back to the liver.•This function, referred to as reverse cholesterol transport, protects against atherosclerotic lesions.•Low HDLs associated with increased CVD risk.
For some genetic obesity prone individuals, the physiologic response mimics starvation. Why?What is the starvation response?
Regardless of fat mass accumulation, the inability of leptin to signal the hypothalamus is perceived by the brain as a state of starvation.•Physiological response:•Increase in hunger •Reduction in energy expenditure•Reproduction dysfunction
What is the end-products of triglyceride digestion?
Results - 2 free FAs and 1 monoglyceride. Monoglycerides and free fatty acids absorbed into the enterocyte (intestinal cell).•Inside the enterocyte, fatty acids are reattached to monoglycerides forming triglycerides.
What is sarcopenia - how does this impact protein requirements?
Sarcopenia - Age-related loss of muscle mass and muscle function.Evidence that increased protein intake (1.5 g protein/kg body weight/day) can improve muscle mass and function in frail, elderly people .•Resistance and aerobic exercise can slow rate of sarcopenia and improve muscle size/strength.
What determines the secondary and tertiary structure to form?
Secondary Structure:Positive charge on amino groups and negative charge on carboxyl groups attract each other. These attractions cause the primary structure to fold in organized and predictable patterns that are held together by hydrogen bonds.Two common folding patterns -a-helix and b-folded sheet.What forms the tertiary structure of a protein? 1) Interactions between the R-groups of amino acids (positive/negative charges) 2) Interactions between R-groups and the surrounding environment (hydrophobic/hydrophilic). These interactions cause the protein to bend and twist in such a way that it forms a 3-dimensional shape.
Short term meal-related peripheral signals - neural, hormonal, and blood glucose
Short-term meal-related peripheral signals that influence food intake (hunger) and terminate food intake (satiety).Neural - Gastric distention (triggers satiety)•Hormonal signals -derived from the GI tract•Ghrelin - hungerCCK - satiety•Increase blood glucose and insulin levels trigger satiety
What is a myocardial infarction and what is a cerebral vascular accident?
Small, dense LDL particles more readily infiltrate the arterial wall, triggering an inflammatory response that promotes the formation of plaque. •Results in a condition called atherosclerosis.•Cardiovascular Disease:If blood vessels that circulate blood to cardiac muscle are obstructed - myocardial infarction (heart attack).•If blood vessels that circulate blood to the brain are obstructed - cerebral vascular accident (stroke)
Additional protein beyond maintenance is required during periods of growth and repair•
States of growth (pregnancy, infants, children, adolescents, and athletes) require additional (maintain protein status (0.8 g/kg body weight) plus protein to support growth)•Athletes (1.2 - 1.7 g protein/kg body weight)•Pregnancy (additional 25 g protein/day)•Infancy (1.2 g protein/kg body weight)•Period of recovery (illness, surgery, aging) additional protein is needed for replace protein loss
Protein digestion - protease enzymes-Sources
Stomach - Enzymatic protein digestion begins with pepsin:Pepsinogen (zymogen) is converted to the active enzyme form pepsin when exposed to gastric juice (HCl).•Pepsin hydrolyzes peptide bonds, resulting in multiple polypeptide chains.
What is protein energy malnutrition and what are the benefits of ready-to-use therapeutic foods?
The amount and variety of foods limited:- Protein energy malnutrition (PEM)Leads to a decline in lean body mass (wasting) and functional impairment (impaired immunity/infection).PEM occurs more frequently in poverty-stricken countries and is the most common cause of death in children living in developing countries.• Ready-to-use therapeutic foods save lives. ◦ Energy dense, micronutrient paste made using peanuts, sugar, milk powder, oil, vitamins and minerals used to treat severely undernourished infants/children.
How are LDLs removed from the blood?
The endogenous lipoprotein pathway begins in the liver with the formation of very low density lipoproteins (VLDLs)•VLDLs circulate lipids (triglycerides and cholesterol) made by the liver to muscle and adipose tissue.VLDLs leave the liver and circulate in the blood.•Triglycerides are removed by lipoprotein lipase and taken up by tissues.•Changes the ratio of lipid toprotein•Lipoprotein is now referred to as a low density lipoprotein.•The most abundant lipid associated with LDLs is cholesterol.
Fate of nitrogen from amino groups after deamination?
The liver converts nitrogen-containing amine group (nitrogenous waste) to urea.•The liver releases urea into the blood.•Kidneys filter urea out the the blood, which is then excreted in the urine.
In what ways are type 1 and type 2 diabetes similar and in what ways are they different?
The main difference between the type 1 and type 2 diabetes is that type 1 diabetes is a genetic condition that often shows up early in life, and type 2 is mainly lifestyle-related and develops over time.
What are the 2 essential FA?
There are only 2 essential fatty acids -linolenic acid and linoleic acid
Glycogenolysis in the liver helps increase blood glucose.Stimulated by rise in glucagon
To prevent blood glucose levels from dropping too low, glucagon acts on the live.Stimulates glycogenolysis -the break down of stored liver glycogen to glucose, which is released into the blood (increases blood glucose).•Stimulates gluconeogenesis -making glucose from noncarbohydrate sources (muscle protein)
4 levels of protein structure: primary, secondary, tertiary, and quaternary
To understand how a protein gets its final shape (conformation): Four levels of protein structure - primary, secondary, tertiary, and sometimes a quaternary structure.
What is the underlying cause of type 1 diabetes?
Type 1 diabetes mellitus (T1D) -Absolute or near absolute insulin deficiency.
What underlying mechanism cause blood glucose level to increase in response to type 2 diabetes.
Type 2 diabetes mellitus (T2D) -Relative insulin insufficiency Release of insulin is low relative to the elevated levels of glucose in the blood (insulin resistance).
What signs/symptoms are unique to type 1 diabetes?
Typical age of onset childhood and adolescence•Accounts for 5-10% cases diabetes•Autoimmune disease•Although trigger unknown, immune system produces antibodies which attack and destroy beta cells (insulin producing cells) of the pancreas. Rapid weight loss •Extreme hunger•Extreme fatigue•Extreme thirst•Ketosis•Frequent urination
How is type 1 diabetes managed?
Without insulin production, individuals with T1D must utilize an insulin delivery method.•Multiple daily insulin injections
Interactions between genetics and environment (calorie restrictive vs. obesogenic) and obesity phenotypes. What is the meaning of an obesogenic environment?
What is an obesogenic environment?•Environment that helps, or contributes to, obesity.•Lack of access to healthy foods (food dessert)•Cost of healthy foods/low cost of unhealthy foods•Sedentary jobs•Unsafe communities.Body fat phenotype (observable trait) is determined by: Genetics - inheritable traits passed on parents to offspringEnvironment - food availability.Genetics - Human obesity rarely caused by a single gene (few known cases), but rather numerous genes that make people obesity prone, obesity resistant, and somewhere in between.Environment - Caloric-restrictive When food is not abundant or easily assessable - regardless of genetics, see little variation in phenotypes (thin).Environment - ObesogenicHighly palatable food is abundant and easily assessable, see higher proportion of the population with overweight-to-obese phenotypes.
What is deamination? What happens when amino acids for glucose (semi-starvation) and fatty acids (excess)
When amino acids (C, H, O, and N) are needed to synthesize glucose (CHO) and when amino acids are in excess and converted to fatty acids (CHO) - carbon skeleton (CHO) and nitrogen must part ways.
What is the role of bile and pancreatic lipase in triglyceride digestion?
When fat-rich chyme reaches the SI, cholecystokinin signals the gallbladder to release bile.•Bile is amphipathic - allows fat globules to disperse in the aqueous environment.•Results in the formation of small lipid spheres (droplets) called micelles. Pancreatic lipase, responsible for almost all TG digestion, hydrolyzes the ester bonds that attach FAs to the glycerol molecule.Results - 2 free FAs and 1 monoglyceride.
What is protein turnover and why does it help reduce protein requirements?
When protein enters the stomach, the hormone gastrin is released, which stimulates the release of gastric juice. •The acid (HCl) in gastric juice denatures food proteins, causing the protein to unfold.•This exposes the peptide bonds, which makes the enzymatic hydrolysis of peptide bonds more efficient.
What does nitrogen balance mean about adequacy of dietary protein?
When protein intake is adequate to replace daily loss, a person is in a state of nitrogen balance.•Nitrogen balance means that nitrogen intake (dietary protein) equals nitrogen loss (urea) from the body.When protein intake is adequate to replace daily loss, a person is in a state of nitrogen balance.•Nitrogen balance means that nitrogen intake (dietary protein) equals nitrogen loss (urea) from the body.
Why do some people with type 2 diabetes require an external source of insulin
Why some people with T2D require exogenous insulinRelative lack of insulin - insulin producing cells are unable to produce enough insulin (relative to blood glucose) needed to lower blood glucose.Hyperglycemia may cause pancreas inflammation, which may decrease insulin production.
What causes gestational diabetes?What is macrosomia and why can this occur in babies born to mothers with gestational diabetes?
Women without pre-existing diabetes that develop hyperglycemia while pregnant.•Caused by pregnancy-related hormonal changes that make maternal tissue insulin resistant.•Develops 24th to 28th wk (last trimester)•Risk factors similar Type 2 diabetes•Family history of type 2 diabetes•Overweight at onset of pregnancy•Ethnicity (African American, Latina, or American Indian)•Previous pregnancy baby's birth weight greater than 9 lbs.Hyperglycemia mother exposes fetus high levels of glucose•Fetal pancreas increases insulin release, increases fat stores fetus.•Increased risk large gestational age and macrosomia (large body)•Increases risk C-section and Type 2 diabetes mother and child
What is a zymogen and what function to zymogens serve?
Zymogen - inactive form of an enzyme that is transformed into an active form.Because protease enzymes would destroy the tissues that produce and amass these enzymes, they are stored in inactive form called a zymogen.•Zymogens are inactive enzyme precursors that require a biochemical change to become an active enzyme.
What is gluconeogenesis and how does it help increase blood glucose?
gluconeogenesis -making glucose from noncarbohydrate sources (muscle protein). Gluconeogenesis: producing glucose from non-carbohydrate sources. The gluconeogenesis pathway (see metabolism figure below) synthesises new glucose using non-carbohydrate precursors (glycerol from the breakdown of triglycerides, lactate during anaerobic glycolysis and amino acids from muscle protein degradation).
What is ketogenesis and why is it the basis for weight loss diets?
low carbohydrate diet. By restricting CHO intake, blood glucose levels are low.•This stimulates ketogenesis and promotes the use of fatty acids as a source of energy.
What is the difference between an insulin pump and continuous glucose monitor?
nsulin pump (IP)•Delivers a continuous supply of background insulin.•Deliver additional insulin to cover rise in blood glucose from meals.Continuous glucose monitoring - Device measures blood glucose at set intervals throughout the day and nightInterfaces with smartphone/smartwatchInterfaces with insulin pump
Pepsin (stomach) trypsin, chymotrypsin, carboxypeptidase (pancreas) enterokinase (SI)
•Digestion of protein in the SI by pancreatic protease enzymes: •Trypsinogen is converted into trypsin by the brush border enzyme enterokinase (1)•Trypsin converts chymotrypsinogenand procarboxypeptidase into chymotrypsin and carboxypeptdiase, respectively. (2)•Complete hydrolysis of polypeptides into amino acids occurs along the brush border.•AA absorbed into enterocytes. (3)
