CHAPTER 25 METABOLISM
I.Diet/health and disease
A.Diet associated with diseases
1.vit E,A,C/cancer protection
2.selenium, superoxide dismutase- scavenger of oxygen free radicals
3.alcohol: lowers cholesterol
4.high fat - cancer
5.high sugar - diabetes
6.sugar /tooth decay
7.sugar-additives/hyperactivity
8.calcium/hypertension
9.protein/liver/kidney
10.low fiber/cancer
11.high fat, cholesterol - cardiovascular diseases
B.Risk factors
1.smoking
2.diet - fat, cholesterol, low fiber
3.gender
4. exercise
C.RDA
1.recommended dietary allowances for healthy persons
2.to promote dietary changes
3.not absolute - suggestions
4.to avoid deficiencies or excesses
D.Nutritional status
1.current health conditions as influenced by intake
and utilization of nutrients
2.lab measurements
a.blood- hct
b.urinalysis
II.NUTRIENTS
A. Required in diet to promote growth, maintain health, reproduction with roles in
1.structure
2.regulation of body processes, biochemical reactions
c.metabolism
3.energy
4.maintain homeostasis
B.essential
1.not made by body
2.not made by body in high enough amounts
3.how do we know what is essential?
a.leave it out of animal diets and observe
C.nonessential
1.made in body
D.6 classes
1.CHO
2.protein
3.lipids
4.water- 60% body
5.vitamins
6.minerals
(alcohol provides energy but not essential nutrient)
E. Macronutrients
1.CHO, pro, lipids (g or kg amounts)
F. Micronutrients
1.vitamins, minerals
2.required in mg amounts
G.Energy
1.CHO = 4kcal/g
2.pro = 4kcal/g
3.lipids = 9 kcal/g
4.alcohol = 7 kcal/g
5.kilocalorie ='calorie' (energy)
a.1kcal raises temp of 1 kg water 1 C
b. measure with bomb calorimeter
c.food composition not calculated
III.CARBOHYDRATES
A.simple
1.monosaccharides
2.disaccharides
a.sucrose = fruc+glu
b.maltose = glu+glu
c.lactose = galactose+glucose
B.complex
1.polysaccharides
a.glycogen
(1)glucose units in liver and muscle
b.starch
c.fiber
(1)lack enzymes to digest
(2)increase motility
(3)bind bile salts
(4)interfer with mineral absorption?
C.lactose intolerance
1.lactase insufficient or lacking to digest milk sugar
2.GI disturbances
3.use fermented products as calcium sources or break down lactose
before ingestion (Lact-aid)
D.recommendations
1.55-60% of dietary kilocalories
E.Glucose is major source of energy in body
1.substrate for making ATP
2.stored as glycogen or fat if not needed as ATP
IV.LIPIDS
A.most are triglycerides or neutral fats
B.glycerol backbone and 1,2,or3 fatty acids
C.saturated
1.has all Carbons with maximum H
D.unsaturated
1.double bonds made by removing H
2.omega refers to double bond
3.mono
4.poly
E.essential fatty acids
1.linoleic acid
F.absorbed via lacteals
1.lymph to venous circulation as chylomicrons
G.transported in blood as lipoproteins
1.mix of fats,proteins, cholesterol
2.Very low density lipoproteins
a.made in liver
3.low density lipoproteins
a.deliver to tissues
4.high density lipoproteins
a.return to liver
5.total cholesterol <200mg/dl
6.ratio of HDL/LDL important
a.want more HDL than LDL
b.exercise will increase HDL levels
H.hyperlipidemias
1.high lipids in blood
I.recommendations
1.30% of kcalories
2.10% of kcalories for saturated fat
3.<300mg cholesterol
V.PROTEINS
A.amino acids joined with peptide bonds
B.essential amino acids
1.Phenylalanine
2.Valine
3.Tryptophan
4.Threonine
5.Isoleucine
6.Methionine
7.Histadine - child
8.Arginine - child
9.Leucine
10.Lysine
C.complete protein
1.meet requirements for all amino acids
D.all amino acids must be present to make protein
E.complementary proteins
1.cereal/milk
2.peanut butter/bread
3.rice/beans
F.if energy is low protein spent as energy
G.recommendations
1.0.8 g/kg
a.2.2lbs/kg
H.amino acids deaminated (remove N)
1.increases work of liver and kidney
2.protein restriction with damage to above organs
3.high protein diets for weight loss harmful
4.forces body to use fats - ketosis
I.Nitrogen balance
1.rate of protein synthesis equals break-down
2.positive balance
a.excretion of nitrogen is less than ingested
b.occurs with growth,repair,pregnance
3.negative balance
a.excretion of nitrogen is more than ingested
breaks down protein to use as energy
b. injury, illness
VI.MALNUTRITION
A.kwashiorkor
1.protein deficiency
2.age 1-3, edema-pot belly, thin extremities
B.marasmus
1.all nutrients deficient
2.wasting away
VII.VITAMINS
A.Fat soluble
1. A,D,E,K
2.stored
3.toxicity from excesses
4.growth and maintenance roles
B.Water soluble
1.B's,C
2.required frequently
3.less likely toxic due to excretion in urine
4.most important as coenzymes
C.Vitamin A
1.retinol,retinal,retinoic acid
2.roles
a.vision
(1)piggment molecules in retina -rods/cones
b.mucous membrane integrity
c.immunity
d.growth
3.recommendations
a.1000ug RE men
b.800ug RE women
4.deficiency
a.night blindess
b.decreased membrane integrity
5.toxicity
a.birth defects
6.sources
a.deep green,gold,red, orange foods
b.fruits, vegetables,dairy
D.Vitamin D
1.UV radiation of precursor molecule in skin
2.converted to active form in liver,kidney
3.acts like hormone in bone formation
a.promotes bone mineralization
b.absorption of calcium from GI
4.deficiency
a.rickets -bowed legs
b.osteomalacia
(1)bone softens
5.toxicity
a.kidney stones
6.recommendations
a.10ug/day
7.sources
a.fortified milk,margarines
E. Vitamin E
1.antioxidant role
2.immune system
3.deficiency
a.neuralmuscular disfunction
b.legs cramping
c.breaking of RBCs
4.sources
a.plant oils
b.green leafy vegetables
c.liver,egg yolks
F. Vitamin K
1.functions in blood clotting
2.made by E. coli in large intestine
3.recommendations
a.65 ug/day women
b.80 ug/day men
4.deficiency
a.hemorrhagic disease
b.newborns
(1)sterile gut
(2)injection
5.source
a.cabbage-type veggies
b.liver
c.milk
G.The B vitamins
1.thiamin
a.functions
(1)part of thiamin pyrophosphate
(2)coenzyme
(3)supports appetite and nerve function
b.recommendations
(1)0.5 mg/1000 kcal/day
c.deficiency
(1)beriberi
(2)heart problems
(3)muscle and nerve problems
d.sources
(1)pork,liver
(2)whole grain and enriched breads
(3)legumes,nuts
2.riboflavin
a.functions
(1)energy release
(2)part of coenzymes:FAD and FMN
b.recommendations
(1)0.6 mg/1000kcal
c.deficiency
(1)ariboflavinosis
(2)mouth,gums,tongue
(3)skin rash
(4)nervous system and eyes
d.sources
(1)milk,yougurt,cottage cheese
(2)meat
(3)leafy green veggies
(4)whole grains and enriched breads
e.light sensitive
3.niacin
a.functions
b.coezymes:NAD and NADH
c.recommendation
(1)6.6 NE/1000kcal
d.deficiency
(1)pellagra
(2)digestive and nervous problems
(3)skin problems
e.sources
(1)milk eggs
(2)meat,puoltry,fish
(3)whole grain and enriched
(4)nuts and all protein foods
4.biotin
a.coenzyme
(1)energy metabolism
(2)fat metabolism
(3)amino acid etabolism
(4)glycogen syntheses
b.recommendations
(1)no RDA 30-100ug
c.deficiency
(1)loss of appetite
(2)muscle pain
(3)dry scaly skin
d.egg hite protien avidin binds biotin
e.synthesized in GI
5.pantothenic acid
a.funciton
(1)part of Co A
(2)energy metabolism
b.recommendations
(1)no RDA
(a)4-7mg
c.deficiency
(1)intestinal distress
(2)fatigue
(3)insomnia
d.heat labile
6.B6
a.Functions
(1)part of Pyridoxal phosphate
(2)converts tryptophan to niacin
(3)RBC formation
b.recommendations
(1)RDA 0.016 mg/g protein/day
c.deficiency
(1)weakness, irritability,insomnia
(2)impaired motor function
d.toxicity
(1)numbness of mouth
(2)nerve damage
e.sources
(1)green leafy vegetables
(2)meats,fish,poultry,shellfish,legumes
(3)fruits
(4)whole-grains
7.Folate
a.function
(1)part of THF tetrahydrofolate and
DHF dihydrofolate
(2)coenzyme in DNA synthesis
b.recommendations
(1)3ug/kg body weight
c.deficiency
(1)impairs cell division
(2)impairs protein synthesis
(3)anemia
d.sources
(1)leafy green veggies
(2)fruits
(3)legumes and seeds
(4)liver
8.Vitamin B12
a.function
(1)coenzyme in cell shythesis
(a)maintains nerve cells
b.recommendations
(1)2mg/day
c.deficiency
(1)lack of intrinsic factor
(2)paralysis
(3)large cell type anemia
(a)pernicious anemia
d.sources
(1)meat, fish,poultry,shellfish
(2)milk,cheese,eggs
H.Vitamin C
1.functions
a.antioxidant
b.collagen formation
c.stress hormones
2.recommendations
a.RDA 60 mg/day
3.deficiency
a.scurvy
b.capillary hemorrhages
4.toxicity
a.GI distress
b.kidney stones
c.dependency
5.sources
a.fruits and veggies(bell pepper)
b.citrus
c.potatoes
VIII.MINERALS
A.sodium
1.roles
a.regulates extracellular fluid
b.acid-base balance
2.recommendations
a.min 500mg
b.max 2000-3000mg
c.1 tsp table salt =2000mg
3.deficiency
a.vomiting,diarrhea,sweating depletes
b.dehydration
4.toxicity
a.edema
b.hypertension
B.chlorine (as chloride ion)
1.roles
a.anion in extracellular fluid
b.part of HCl
2.recommendations
a.750mg/day
3.source in all foods
C.potassium
1.roles
a.muscle contraction
b.major intracellular cation
c.fluid/electrolyte balance
d.nerve transmission
2.recommendations
a.2000mg/day
3.sources
a.fresh fruits,veggies,legumes
b.bananas,oranges
4.deficiency
a.with diuretics
D.calcium
1.role
a.bones,teeth
b.blood clotting
c.intracellular signal
d.muscle contraction
e.nerve impulses
2.recommendations
a.RDA 1200 mg/day
3.sources
a.milk products
4.absorption aided by vitamin D
5.deficiency
a.improper bone formation, etc for roles
b.osteoporosis,osteomalacia, rickets
c.tetany
6.toxicity
a.calcification (kidney)
b.depressed neural function
E.phosphorus
1.roles
a.bones,teeth
b.buffer
c.part of nucleic acids, ATP, etc.
2.recommendations
a.RDA 800 mg/day
3.sources
a.animal protein
4.absorption balanced with calcium
5.excess phosphorus can cause excretion of Ca
F.magnesium
1.cofactor of enzymes
2.recommendation
a.350mg/day males
b.280 mg/day females
3.deficiency
a.tremors (neuromuscular problems
b.alcoholism
4.toxicity
a.diarrhea
G.Sulfur
1.part of molecules (amino acids)
2.disulfide bonds
H.Trace minerals
1.iron
a.roles
(1)oxidation/reduction reactions
(2)hemoglobin
(3)myoglobin
b.absorption
(1)carriers
(2)aided by vitamin C
(3)body recycles
(4)lose with bleeding
(5)phytates and fibers inhibit
(6)calcium/phosphorus inhibit
c.deficiency
(1)anemia
(2)low hemoglobin
(3)iron-deficiency anemia
(4)microcytic hypochromic anemia
(5)most common deficiency
(6)fatigue
(7)pica (clay eating)
(8)anorexia
(9)pallor
(10)feces light color
d.toxicity
(1)tissue damage(liver, heart, pancreas)
(2)
e.recommendations
(1)10mg/day male
(2)15 mg/day women
f.sources
(1)meat, fish, poultry (1/3)
(2)milk,cheese,eggs (1/4)
(3)enriched grains(1/4)
(4)legumes, dark leafy veggies,fruits
(5)liver
(6)iron cookware
2.zinc
a.roles
(1)cofactor
b.metallothionein
(1)zinc binding protein
(2)for absorption
c.transported bound to albumin
d. deficiency
(1)loss of taste and smell
(2)learning impairment
(3)depressed immunity
(4)phytates inhibit absorption
e.toxicity
(1)slurred speech
(2)tremors
(3)difficulty walking
(4)acidic foods in galvanized containers
f.recommendations
(1)15 mg/day
3.copper
a.roles
(1)cofactor
(2)absorption and use of iron
b.deficiency
(1)disturbed growth and metabolism
c.toxicity
(1)vomiting and diarrhea
d.recommendations
(1)1.5-3 mg/day
4.iodide
a.roles
(1)thyroid hormones
b.deficiency
(1)goiter
(2)sluggishness
(3)cretinism
c.toxicity
(1)enlarge thyroid
d.sources
(1)seafood
(2)soil content varies
e.recommendations
(1)150 ug
5.manganese
a.role
(1)cofactor
b.deficiency
(1)iron and calcium inhibit absorption
c.toxicity
(1)nervous system disorders
(2)from environmental contaminants
6.fluoride
a.roles
(1)bones and teeth are more resistant to decay
b.deficiency
(1)dental decay
c.toxicity
(1)mottling of teeth
(2)bone spurs
d.sources
(1)tea
(2)supplements
e.recommendations
(1)1.5-4 mg/day
7.chromium
a.roles
(1)associated with insulin to facilitate glucose uptake
(a)glucose tolerance factor
b.recommendations
(1)50-200 ug/day
c.sources
(1)brewer's yeast, liver, whole grains, nuts
8. selenium
a.part of enzyme
(1)superoxide dismutase
b. recommendations
(1)70 ug/day m
(2)55 ug/day f
c.sources
(1)animal products
d.toxicity
(1)vomiting, diarrhea, loss of hair and nails, skin lesions
9. molybdenum
a.roles
(1)cofactor
b.toxicity
(1)goutlike symptoms
c.recommendations
(1)75-250ug/day
d.sources
(1)legumes, cereals, organ meats
10.other trace menerals
nickel, silicon, tin,Vanadium, cobalt
boron, and others
IX.METABOLISM
A.define
1.sum of all chemical reactions in body
2.catabolic reactions
a.break down, usually release energy
3.anabolic reactions
a.build up, require energy
B.Cellular respiration
1.hydrolysis or breaking of nutrients (glucose) to release energy and
capture in form of ATP
a.reactions are oxidation/reduction reactions
(1)redox
(2)oxidation
(a)rusting of iron
(b)releases energy
(3)cannot have something oxidized unless
another molecule is reduced(valence or oxidation number increases) gains energy
b.FAD is reduced to FADH2
c.NAD is reduced to NADH
2.ATP
a.adenosine triphosphate
b.high energy phosphate bond
3.Draw the reaction to make ATP from ADP.
4.Draw the reaction to release energy from ATP.
5.phosphorylation
a.adds a phosphate group
b.dephosphorylation-takes off phosphate
6.to extract maximum energy requires oxygen
7.waste product is carbon dioxide
8.each step requires a specific enzyme
a.absence of enzyme cannot proceed
C.Glycolysis
1.activates by making glucose-6-phosphate
2.splitting of glucose - 6 carbon molecule
3.yields 2 3-carbon with a phosphate group on each
a.glyceraldehyde phosphate
b.dephosphorylate to make 2 pyruvate molecules
4.energy captured at substrate level by phosphorylation of ADP to make ATP
5. occurs in cytoplasm
6.anaerobic or without oxygen
7.See handout
D.Anaerobic metabolism
1.pyruvate -> lactic acid
E.Aerobic metabolism - "Prep Step"
1. in mitochondria
2. pyruvate is oxidized to acetate and coenzyme A is attached
3. CO2 is released since go from 3 to 2 carbons
4.remember
a.from glucose there a two 3-carbon fragments
F.Kreb's Cycle
1.in mitochondria
2.2-carbon acetyl CoA enters cycle
3.to completely oxidize this fragment two CO2 released
4.REMEMBER
a.from glucose there are two 2-carbon fragments that can enter
Kreb's so must go through cycle twice
5.Oxaloacetate
6.add the acetyl-CoA to get CITRATE
7.isocitrate
8.alpha-ketogluarate
9.succinyl-CoA
10.succinic acid
11.fumarate
12.malate
13.back to oxaloacetate and picks up another acetyl-CoA
14.ATP made once at substrate level
G.ELECTRON TRANSPORT CHAIN
1.linked to all above metabolic pathways
2.oxygen is final acceptor of H (electron and proton)
a.makes a molecule of water
3.in mitochondria
4.most of energy from a molecule of glucose
5.Count ATPs from glucose that are made from
NAD of FAD
6.SEE HANDOUT - add coenzyme Q as starting point
a.to cytochrome b to c1 to c to a to a3
7.NAD = 3ATPs
8.FAD = 2ATPs
9.oxidative phosphorylation
a.H removed with oxidation reactions used to make ATP
10.H's transported down the chain of cytochromes
a.iron is part of the molecule and it is alternately oxidized, reduced to pass down the electron
H.glycogenesis
1.making glycogen
2.excess glucose phosphorylated t
a.glucose-6-phosphate
(1)convert to glucose-1-phosphate
3.glycogen synthase
a.removes phosphate and adds glucose to chain
I.glycogenolysis
1.splitting of glycogen
a.glycogen phosphorylase
(1)releases gluc-1-phosphate
b.convert to glu-6-phosphate
c.ready to enter glycolysis
J.gluconeogenesis
1.making glucose from new substances
2.in liver
3.from fats, proteins
K.Lipid metabolism
1.beta oxidation in mitochondria
2.2 carbon fragments released
3.ready to join with CoA and enter Kreb's
4.metabolic pathways are irreversible past pyruvate
a.cannot make glucose form acetyl coA from fats
L.Lipogenesis
1.making lipids (triglycerides)
2.from acetate and glyceraldehyde (from glycolysis) normally would go to Kreb's if energy was needed
M.Lipolysis
1.breakdown of fats to glycerol and fatty acids
2.liver, cardiac muscle and resting skeletal muscles prefer burning fat
3.in dieting
a.carbohydrates are needed to keep Kreb's intermediates (often taken out as needed in other molecules)
b.if oxaloacetate is depleted then fat will be not be completely oxidized and KETONEs accumulate in blood, urine
c.ketosis
N.Protein metabolism
1.constantly breaking , rebuilding
2.transmination
a.can form glutamic acid by transferring an amine group from an amino acid to alpha-ketoglutarate
3.deamination
a.to burn for energy must remove amine (nitrogen)
b.in liver, kidney
O. Integration of Metabolism
1.glucose sources from blood glucose
a.glycogen
(1)100g in liver
(2)skeletal muscle stores used in Sk M to lactic acid which is
returned to liver to be made into glucose
b.lipolysis
c.tissue proteins
(1)glucogenic amino acids
2.glucose sparing
a.save glucose by using fat
3.hormonal regulation
a.insulin
b.glucagon
c.epinephrine
d.thyroxine
e.growth hormone
f.testosterone
g.cortisol
X.Energy Balance
A.basal metabolic rate
1.energy needed to maintain resting levels
B.Regulation of body temperature
1.heat produced by metabolically active tissue
a.BMR
b.muscular activity
c.hormone
2.lose heat
a.radiation
b.evaporation
c.conduction
3.core
a.organs
b.highest temp
4.shell
a.extremities
b.more surface area more heat loss
5.blood
a.heat transfer medium
b.vasoconstriction and dilation of vessels to skin to regulate body temp
6.shivering
a.muscle activity produces heat