Transcript Nutrition & Metabolism

NUTRITION
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A proper diet requires a balance
of carbohydrates, fats, and
proteins. In addition the body
requires many phytochemicals,
vitamins, minerals, enzymes,
and water.
Food Intake
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Food energy measured in Calories
Carbohydrates  obtained primarily through plants
 Monosaccharides used for cellular fuel
 Minimum carbohydrates = 100 g/day
Lipids < 30% of calories
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Mostly triglycerides
Saturated fats usually from animals
Cholesterol only from animals
Neutral fats provide insulation and energy
reserves
Phospholipids for membranes and myelin
Cholesterol for membranes, vitamin D,
steroid hormones, and bile salts
Proteins = 0.8 g/kg of body wt
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8 Essential amino acids
Plants usually lack 1 or more essential amino
acids / Animal protein usually contains all
Amino acids used to build structural proteins
and enzymes
VITAMINS:
"vita" = Latin word for life.
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Vitamins are organic substances
that act as coenzymes, chemicals
that assist the enzymes in the
bodies reactions. They do not
provide energy or calories.
Vitamins may be either Fat Soluble
or Water Soluble.
Fat soluble vitamins
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are stored in the body's fatty
tissues. Fat soluble vitamins
include the vitamins
A
 D
 E
 K.
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Vitamin A
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Found in fish, liver, eggs, butter,
yellow & green vegetables, fruits
Needed for healthy skin, eyes,
bones, teeth.
Deficiency causes night blindness,
skin disorders, kidney stones
Vitamin D
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Found in liver, fish, eggs,
milk, sunlight
Needed for growth,
healthy bones,
metabolism of calcium &
phosphorus
Deficiency causes rickets,
poor teeth and bones.
Vitamin E
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Found in whole grains, leafy
vegetables, milk, butter, vegetable
oils
Needed for healthy cell
membranes, red blood cells
Deficiency causes red cell rupture,
muscle disorders
Vitamin K
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Found in leafy vegetables,
soybeans, made by intestinal
bacteria
Needed for normal blood clotting
Deficiency causes slow clotting,
hemorrhaging.
Water soluble vitamins
can be dissolved in water but
cannot be stored in the tissues.
 They must be obtained each
day from food.
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Water soluble vitamins include
B1 (Thiamine)
 B2 (Riboflavin)
 Niacin
 B6 (Pyridoxine)
 Pantothenic
Acid
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Biotin
 B12
 Folic Acid
 C (Ascorbic acid)
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Vitamin B1 (Thiamine)
Found in organ meats, whole
grains, vegetables
 Needed for proper functioning
of heart, nervous system,
digestion
 Deficiency causes beriberi,
cardiovascular disorders.
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Vitamin B2 (Riboflavin)
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Found in liver, poultry, milk, eggs,
cheese, fish, green vegetables, whole
grain
Needed for metabolism of protein,
carbohydrates, and fats, healthy skin
Used to make FAD for metabolism
Deficiency causes dim vision,
premature aging, sore mouth
Vitamin B6 (Pyridoxine)
Found in meats, liver, whole
grains, vegetables
 Needed for sodium and
phosphorus balance
 Deficiency causes anemia,
nausea, loss of appetite,
nervousness
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Vitamin B12
Found in Liver, meats, eggs,
cheese, dairy products
 Needed for red cell production,
healthy nervous system.
 Deficiency causes pernicious
anemia.
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Vitamin C
Found in citrus and other fruits, leafy
vegetables, tomatoes, potatoes
 Needed for healthy blood vessels,
resistance to infection, healing
 Deficiency causes scurvy, bruising,
bleeding gums
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Niacin
Found in red meats, organ meats,
fish, green vegetables
 Needed for metabolism, digestion,
nerves, skin
 Used to make NAD for metabolism
 Deficiency causes pellagra, sore
mouth, diarrhea, depression
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Folic Acid
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Found in green vegetables, liver,
whole grains, legumes
Needed for manufacture of proteins
and red blood cells, needed for cell
division, helps prevent spina bifida
Deficiency causes inflamed tongue,
diarrhea, B12 deficiency.
MINERALS:
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Inorganic substances that are used in
the chemical reactions of the body.
Major minerals needed include:
Calcium, Iodine, Iron, Magnesium,
Phosphorus, Potassium, and Sodium.
Calcium
Found in milk, cheese,
vegetables
 Needed for strong bones and
teeth, blood clotting
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Iodine
Found in
seafoods,
iodized salt
 Needed for
normal thyroid
metabolism,
prevents goiter
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Iron
Found in liver, meat, eggs
 Needed for red cell production,
prevents anemia
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Magnesium
Found in milk, meat, whole
grains, legumes
 Needed for proper nerve and
muscle functioning
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Phosphorus
Found in milk, whole grains,
meats, nuts, legumes
 Needed for tooth and bone
development, ATP, nucleic acids
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Potassium
Found in whole grains, fruits,
legumes, meat
 Needed for proper nerve and
muscle function
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Sodium
Found in seafood, table salt
 Needed for water balance,
proper nerve and muscle
function
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Free Radicals
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charged molecules that become oxidized
by combining with oxygen or the removal
of hydrogen, causing electron deficiency.
seek to regain the electron by removing it
from other molecules, thus oxidizing them.
set up a chain reaction that may damage
cell structures such as DNA, cell
membranes, or needed enzymes.
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Free radicals may be produced by
normal metabolic processes, the
immune system in response to
disease, exposure to chemicals,
toxins, or radiation. Free radical
generation may be increased by
exercise and stress.
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Damage caused by free radical
generation is a major cause of the
degenerative effects of aging, may
cause cancers, damage to arterial walls
leading to heart disease and/or stroke,
and lead to other degenerative diseases
such as Alzheimer’s.
Antioxidants
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have a protective effect by neutralizing
free radicals.
best known antioxidants are Vitamin C,
Vitamin E, and beta carotene.
many others and possibly many yet to be
discovered.
proper number, types, and balance of is
an important part of nutrition.
METABOLISM
Sum of all the chemical
reactions occurring within the
body
Types of Metabolic Reactions
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Anabolic reactions - energy requiring
synthesis reactions
Catabolic reactions - energy releasing
reactions that generate ATP
Enzymes - globular proteins
that act as catalysts
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Increase reaction rates
Holoenzyme - a two-part enzyme
consisting of a protein part and an
organic cofactor
Apoenzyme - the protein portion
 Coenzyme - the organic cofactor; usually
a vitamin
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Energy Production
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Oxidation reactions - loss of an
electron by an atom or molecule
Reduction reactions - involves the gain
of electrons by a molecule
Coupled redox reactions
Cellular Respiration
Oxidation of Glucose
Glucose Metabolism
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Glycolysis
Acetyl Coenzyme A
Krebs Cycle
Electron Transport Chain
Glycolysis
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Glucose molecules are broken down into
two molecules of pyruvic acid in the
cytoplasm of the cell
Net gain of 2 molecules of ATP
No oxygen required
Fate of pyruvic acid depends on the
oxygen availability
Glycolysis
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Glucose C6H12O6
Glucose-6-phosphate
ATP
Fructose-6-phosphate
ADP
ATP
Fructose 1,6, diphosphate
ADP
Glyceraldehyde-3-Phosphate or
Dihydroxyacetone Phosphate
2Pyruvate (pyruvic acid) + 2NAD + 4ATP
2C3H4O3
+ 2NADH+ + 2ATP (net)
Acetyl CoA Formation
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Pyruvic acid is decarboxylated by the
removal of CO2 into a two carbon acetyl
group
Occurs in the mitochondria of the cell
Krebs Cycle - TCA Cycle
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Formation of citric acid when
oxaloacetic acid combines
with acetyl CoA
Organic molecules are
broken down, carbon dioxide
is released and hydrogen
atoms are removed &
transferred by coenzymes
NAD & FAD
Kreb’s Cycle
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Acetyl CoA + Oxalocetic Acid
Citric Acid
Isocitric Acid
CO2 NADH2
alpha-Ketoglutaric Acid
CO2 NADH2
Succinyl CoA
ATP
Succinnic Acid FADH2
Fumaric Acid
Malic Acid
NADH2
Electron Transport
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Involves electron carrier molecules that
will release energy in a controlled way
This energy is used to generate ATP
Occurs inner mitochondrial membrane
Chemiosmosis
Glucose Anabolism
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Glycogenesis - conversion of glucose to
glycogen; stimulated by insulin
Glycogenolysis - hydrolysis of glycogen
to form glucose; stimulated by
glucagon
Gluconeogenesis - synthesis of glucose
from non-carbohydrates such as fats
and amino acids
Lipid Metabolism
Lipid Catabolism - Lipolysis
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Hydrolysis of triglycerides into glycerol
and fatty acids
Glycerol converted to G 3-P and then
into pyruvic acid, then into the Kreb’s
cycle
Beta -oxidation of fatty acids occurs
forming two-carbon fragments which is
then attached to coenzyme A, forming
acetyl CoA
Protein Metabolism
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Proteins are converted into substances
than can enter the Kreb’s cycle by
 deamination - loss of (NH2) from amino
group
 decarboxylation - loss of CO2 molecule
 dehydrogenation - loss of hydrogen
atom
Protein synthesis involves transcription and
translation