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AP Powerpoint 3

Terms in this set (72)

Nutrients
include most biomolecules, vitamins, and minerals
-required for synthesis of new molecules
-required for energy for maintenance, growth, and repair as obtained through the food we eat
-levels regulated during and following meals
Nutrition
study of how living organisms acquire needed nutrients
Water
considered by some to be a nutrient
Carbohydrates
simple sugar monomers, monosaccharides
-disaccharides with two monosaccharides
-polysaccharides from chains of monosaccharides
Lipids
diverse group of hydrophobic molecules, include triglycerides, phospholipids, steroids, and eicosanoids
Proteins
formed from amino acids, nonessential amino acids, able to be made in the body
-essential amino acids obtained from diet
complete protein, suppling all essential amino acids
-incomplete proteins, able to synthesize some, but not all
Nucleic acids
not considered nutrients, not required in the diet
Why do we eat?
Biological reason-must supply our cells with energy and building blocks
Social reasons- diet as child, ethnicity, socio-economic status, advertising, flavor, texture
Energy recommendations
carbohydrates: 45-65%
fat: 20-35%
protein: 10-35%
Using nutrient recommendations
estimates of energy and nutrient intakes apply to healthy people
-recommendations are not minimum requirements and are not optimal for all people
Water soluble vitamins
dissolve in water
-include B vitamins and vitamin C
-easily absorbed into blood from digestive tract
-excess excreted in the urine
-some coenzymes assisting with normal enzyme function
Fat soluble vitamins
dissolve in fat
-include vitamins A, D, E, and K
-absorbed from the GI tract within micelles
-excess stored within fat
-may become toxic if taken in excess
Vitamin A
precursor for formation of visual pigment retinal
Vitamin D
forms calcitrol, increasing calcium absorption form GI tract
Vitamin E
helps stabilize and prevent damage of cell membranes
Vitamin K
required for synthesis of specific blood clothing proteins
Essential vitamins
must be provided in diet, may result in deficient if intake or absorption is impaired, ex: vitamin C and A
Nonessential vitamins
cofactors the body produces and recycles as needed ex: NADH and FADH2
Minerals
inorganic ions obtained from the diet, required in daily amounts
iron: present in hemoglobin, binding oxygen, present in mitochondria in ETC binding electrons
calcium: required for formation and maintenance of skeleton, required for blood clotting and exocytosis of neurotransmitters
mineral contd
sodium and potassium: maintain resting membrane potential in excitable cells, and required to generate action potential
iodine: needed to produce thyroid hormone
zinc: roles in protein synthesis and wound healing
Major minerals
need at more than 100 mg/day, include calcium, potassium, phosphorus, and magnesium
Trace minerals
needed at less than 100 mg/day, include chromium, copper, iodine, iron, and zinc
Iron deficiency
iron required in hemoglobin and myoglobin
-component of electron transport proteins
-needed to synthesize certain hormones
-obtained from meat, poultry, fish
-most common deficiencies
-fatigue, weakness, pale skin
-insufficient intake or iron loss (excessive loss from bleeding)
Absorptive state
lasts about 4 hours after meal
-time eating, digesting, and absorbing nutrients
-concentration of glucose, triglycerides, and amino acids (increasing as they are absurd from GI tract)
-blood glucose levels maintained with 70-110
Isomers
molecules with the same molecular formula but different structural formulas
Insulin
major regulatory hormone released during absorptive state
-release occurring in response to increased blood glucose levels
-stimulates liver and muscle cells (form glycogen from glucose)
-affects adipose tissue (increases uptake of triglycerides from blood and stimulate lipogenesis and inhibits lipolysis)
-stimulates most cells to increase amino acid uptake (accelerated protein synthesis)
-Beta cells
Postabsorptive state
time between meals
-body relying on stores of nutrients
-body working to maintain homeostatic levels of nutrients
Glucagon
major regulatory hormone released during post absorptive state
-released in response to decreasing blood glucose levels
-stimulates liver to increase breakdown of glycogen to glucose
-stimulates gluconeogenesis from noncarbohydrate sources
-causes adipose tissue to break down triglycerides
-has no effect on amino acids or proteins in cells
-alpha cells
Lipids
non polar long chains of carbon atoms
Fatty acids
have carboxylic acid functional group-most often even number of C atoms
Saturated fats
contain only single covalent bonds
Unsaturated fats
contain one or more double covalent bonds
Alpha-lineolenic acid and lineolenic acid
only obtained form the foods we eat; these create eicosanoids
Eicosanoids
hormone-like compounds synthesized form polyunsaturated fatty acids that can make postaglandins, thromboxanes, and leukotrines, lipoxins, and prostacyclin
Prostaglandin
hormone-like compound that has various actions (uterine contraction, sleep cycle, body temp, vasoactive)
Prostacyclin
made by blood vessel walls, potent anticoagulent
Thromboxane
stimulant of blood clotting
Leukotrine
mediator of many diseases involved in inflammatory response pathway, hypersensitivity reactions, and asthma
Lipoxin
made by WBCs, involved in immune and allergic responses
Cholesterol synthesis
synthesized in the liver, fatty acids transported in blood to enter hepatocytes
-broken down into two-carbon units, acetyl CoA
-process termed beta oxidation
-molecules used to synthesize cholesterol
-produces cholesterol at basal level varying among individuals
-synthesis decreased with higher cholesterol intake and vice versa
Cholesterol synthesis cont
following cholesterol synthesis
-may be released into blood as component of very-low-density lipoproteins
-may be synthesized into bile salts as part of bile (90% of these reabsorbed while moving through ileum)
Lipoproteins
contain lipids and protein "wrap", ex: chylomicrons (absorbing lipids from the small intestine)
-other lipoproteins formed within the liver
---classified by relative density
---very low density lipoproteins containing the most lipid
---low density lipoproteins with less lipid
---high density with least amount of lipid
Very low density lipoproteins (VLDLs)
contain various types of lipids with protein
-assembled within liver and released into blood
-circulate in thee blood to release triglycerides to peripheral tissues (adipose)
-with release of triglycerides become low density lipoprotein
Low density lipoproteins
deliver cholesterol to cells
-bind LDL receptors in plasma membrane of cell
-engulfed by endocytosis
-cholesterol incorporated into plasma membrane
-used by certain cells to produce steroid hormones
-considered bad cholesterol
High density lipoproteins
proteins formed in the liver
-released into blood without addition of lipid
-circulate thru blood and fill with lipids from peripheral tissue
-make cholesterol available to steroid producing tissue
-lipids transported via HDLs to liver
-excess cholesterol converted to bile salts within the liver
-considered good cholesterol
Risk factors with high cholestrol
high fat intake, cigarette smoking, caffeine intake, and stress
Statin drugs
developed to lower blood cholesterol and is an inhibitor of HMG-CoA enzyme need for cholesterol synthesis
Transamination
common way of synthesizing amino acid in which one molecule accepts an amino group from another
Deamination
when an amino acid loses an amino group without transferring it to another molecule
PKU
person has decreased ability to metabolize amino acid phenylalanine, must carefully watch diet
Glycolysis
anaerobic metabolic pathway in cytoplasm
-glucose oxidized to pyruvate
-2 ATP formed, 2 NADH formed from NAD+
-pyruvate converted to lactate if insufficient O2 available
Intermediate stage
aerobic and within mitochondria
-pyruvate converted to acetyl coA
-CO2 formed and NADH produced
Citric acid cycle
acetyl CoA forming citric acid cycle
-CO2, ATP, FADH2, and NADH produced in each turn
ETC
transfer of hydrogen and electron from NADH and FADH2
-ATP formed through oxidative phosphorylation
Glycerol and fatty acid
building block of triglycerides
-Glycerol entering pathway of glycolysis: converted to glucose within the liver
-Carbons of fatty acids removed to form acetyl CoA: termed beta oxidation, molecules entering CAC
Amino acids
amine group of amino acids removed by deamination
-occurs within liver hepatocytes
-amine group converted to urea
-eliminated through kidney through urine
remaining portion entering metabolic pathway at different steps
-depends of specific amino acid
-may enter glycolysis, intermediate stage, or CAC
Calorie
energy required to increased the temp of one gram of water one degree centigrade
Basal metabolism
minimum energy expended in a fasting state, awake, at rest in a warm, quiet environment; 0.9 kcal/kg/hr in women and 1.0 kcal/kg/hr in men
Metabolic rate
measure of energy used in a given time
Basal metabolic rate
amount of energy used at rest, individual not eaten for 12 hours, relaxed, temp about 20 degress celcius, measured by calorimeter or respirometer
Calorimeter
water-filled chamber into which individual placed
-heat released from body altering temp of water
-change in temp measured
Respirometer
measures oxygen consumption
-indirectly measure BMR
-oxygen used to produce ATP and ATP utilized to produce heat
Factors that influence BMR
greater lean body mass, greater body surface area, gender, thyroid hormone, nervous system function, age, nutritional status, pregnancy, caffeine and tobacco
Total metabolic rate
BMR+metabolism associated with physical activity
Depends on several factors:
-amount of skeletal muscle and activity (rapid increase during exercise)
-food intake (increase in ingestion decrease in absorption)
-chanign environmental conditions (increase in cold temp)
Healthy BMI
men: 8-25%
women: 18-25%
Factors affecting obesity
Nature, set point, nuture, diet, exercise
Normal body temp
98.6 F or 37 C
Core body temp
temp of the vital portions of the body, temp kept relatively constant, maintained by allowing fluctuation in the peripheral organs
Nervous system control
*mediated primarily thru the hypothalamus
-motor pathways to sweat glands, skeletal muscles, monitors temp of blood
*with increase in body temp
-hypothalamus stimulating sweat glands and vasodilates peripheral vessels
*with decrease in body temp
-hypothalamus inhibiting sweat glands
-vasoconstricts peripheral vessels
-induces skeletal muscle contraction to generate heat
*behavior changing initiated in cortex in response to temp
-putting on coat if cold or jumping in pool when hot
Hormonal control
Mediated by multiple hormones (thyroid, NE, epi, GH, testosterone and estrogen)
Thyroid most significant
-establishes metabolic rate
-can raise body temp by increasing rate of all cells
Frostbite
damage to superficial cells due to extreme cold
-skin white with possible loss of sensation
Dry gangrene
may be caused by severe frostbite
-invovled by body part dry
-vasoconstriction of blood vessels in response to cold
-oxgyen deprivation and tisseu death
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