86 Cards in this Set
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Cell Membrane
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-selectively permeable
-nutrients enter by
-passive diffusion, facilitated diffusion, active transport
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depending on the body's needs, protein, fat, and carbs from the diet are:
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-used for energy production
-used to synthesize new molecules
-transformed into energy storage molecules
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metabolic pathways are a series of chemical reactions which convert
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one molecule to another
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in metabolic pathways, each reaction requires an
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enzyme
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cofactor
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inorganic subtances (minerals) that help enzymes
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coenzyme
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organic molecule (vitamins) that help enzymes
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catabolic pathways
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break down complex molecules into smaller units
-releases energy
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anabolic pathways
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reactions that build complex molecules from smaller ones
-requires energy
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energy derived from catabolic reactions often drive
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anabolic reactions
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products of catabolic reactions may be used in
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anabolic reactions
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amphibolic pathways
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same pathway used for either catabolic or anabolic reactions
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metabolism is never
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inactive- some metabolism is always occuring in cells
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chemical energy in
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carbs, fat, protein
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3 steps of food energy to cellular energy
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1: digestion, absorption, transport
2: breakdown of molecules (catabolism)
3: transfer of energy to a form cells can use
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___ is the body's energy currency
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ATP
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ATP is used
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–Form of energy cells use
(anabolic processes)
–Form of energy produced
(catabolic processes)
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ATP energy is held in
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high energy phosphate bonds
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when extracting energy from nutrients, the formation of ATP from ADP + P captures
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energy
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breaking a phosphate bond in ATP to ADP + P, releases ______ for biosynthesis and work
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energy
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in cellular respiration, oxygen is delivered to cells via
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respiratory and circulatory system
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in cellular respiration, glucose, fatty acids and proteins are broken down in the presence of oxygen to produce
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ATP
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waste product CO2 is excreted from the body via
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circulatory and respiratory systems
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without O2, can only use ____ for energy production
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glucose
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Body's pool of ATP is small:
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-immediate source of energy
-not available for long term storage
-constantly producing ATP : amount in direct proportion to energy needs
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NADH & FADH2
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-coenzymes
-transport shuttles
-transfer high energy electrons (H+) to the electron transport chain to be used for ATP production
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4 main ways carbs broken down for energy production
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-glycolysis
-pyruvate -> acetyl CoA
-citric acid cycle (krebs cycle)
-electron transport chain
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glycolysis is ____ & occurs in the ______
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anaerobic & cytosol
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in glycolysis, pathway splits glucose into two
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pyruvates
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glycolysis requires ATP to initiate; then produces some __ & __
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ATP & NADH
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if no oxygen is available during glycolysis, pyruvate must form
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lactate
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Cori Cycle
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lactate released into the bloodstream, picked up by liver and converted to glucose
( No oxygen available during glycolysis )
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if oxygen is available during glycolysis:
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pyruvate forms acetyl CoA
-releases CO2
-transfers more energy to NAD+
-pyruvate moves into mitochondria
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pyruvate to acetyl CoA
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vitamins needed: thiamin, riboflavin, niacin, pantothenic acid
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Citric acid cycle
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aeoribic
-oxidizes acetyl CoA
-releases CO2
-produces GTP (ATP)
-produces NADH & FADH2
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citric acid cycle takes place in
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mitochondria
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citric acid cycle starts and ends with
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oxaloacetate (made from carbs)
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electron transport chain
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-inner mitochondrial membrane
-oxidative phosphorylation
-accepts energy (electrons) from NADH & FADH2
-produces larger amounts of ATP
-produces water (waste product)
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end products of glucose breakdown (catabolism)
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-36-38 ATP per molecule of glucose
-waste products: CO2 & H2O
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extract energy from fat
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-split triglycerides into glycerol and 3 fatty acids
-glycerol produces pyruvate
-pyruvate to Acetyl CoA and into citric acid cycle etc...
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beta oxidation takes place in the
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mitochondria
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carnitine
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molecule that transports fatty acids across the mitochondrial membrane
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beta-oxidation of fatty acids
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-clips the two-carbon end off a fatty acid until its degraded entirely
-forms NADH & FADH2
-each 2-C link forms Acetyl CoA
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during beta oxidation, NADH & FADH2 enter the
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electron transport chain
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during beta-oxidation, Acetyl CoA enters
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citric acid cycle
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1 triglyceride produces about
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360 ATP
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What is required to produce energy from body fat stores?
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carnitine
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fat burns in a
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carbohydrate flame
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Acetyl CoA cannot enter citric acid cycle without available oxaloacetate which can only be produced from
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glucose oxidation
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must have glucose available when FAs are being oxidized or Acetyl CoA forms ___ instead
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ketones
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extracting energy from protein
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-split protein into amino acids
-remove amino group
-deamination (strips amino group from amino acid - converted in liver to urea )
-carbon skeletons enters breakdown pathways of glycolysis or citric acid cycle
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end products of extracting energy from protein
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urea, CO2, H2O & ATP
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amount of ATP used by protein varies depending on
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amino acids
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synthesizing carbohydrates (glucose)
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-anabolic
-gluconeogenesis (making new glucose)
-uses pyruvate, lactate, glycerol, most amino acids
- priority: maintaining blood glucose levels
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olysis
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breakdown
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genesis
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creation (synthesis anabolic)
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gluconeogenesis
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reverse of glycolysis using 3 different enzymes
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gluconeogenesis uses ____ & ____ cells to make glucose from ____
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liver; kidney; pyruvate
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gluconeogenesis is mainly in the ____ to supply glucose to the body
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liver
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glycogenolysis
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-removing glucose from glycogen stores
-liver: supplies glucose for blood glucose maintenance
-muscle: supplies glucose for work energy (ATP)
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lipogenesis
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-making fat
-uses acetyl coa from fat, amino acids, and/or glucose *
-builds fatty acids 2-C at a time
-*insignificant amounts (most glucose is used to make glycerol)
-also elongating fatty acids (16c-18c)
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storing fat
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-triglycerides
-glycerol and 3 fatty acids
-stored in adipose tissue
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fatty acids yield ___ amounts of energy
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large
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glycerol yields ___ amounts of energy
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small
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are fatty acids convertible to glucose?
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no
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proteins are made from a combination of
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Essential amino acids and nonessential amino acids
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the body synthesizes nonessential amino acids from ____
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pyruvate
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a transamination reaction transfers the ____ ____ from one amino acid to form a different amino acid
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amino group
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which vitamin is always used as a coenzyme during transamination
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vitamin B6
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ketogenesis
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made from Acetyl CoA when:
-inadequate glucose, so too little oxaloacetate for the citric acid cycle to function
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acetyl coa builds up and forms the 3 ketone bodies during ketogenesis:
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beta-hydroxy butyrate, acetoacetate, acetone
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ketobodies are sent from liver out to cells to be used for energy or
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excreted in the urine
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ketosis
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high fat-low carb diets
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ketoacidosis
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a rise in ketone levels in the blood, characterized by a decrease in the pH of the blood
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Regulation of cellular metabolism
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either anabolic or catabolic reactions favored, but not both at the same time
insulin (anabolic)
glucagon (catabolic)
cortisol (catabolic)
epinephrine (catabolic)
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feasting
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influx of carbs, proteins, fats
6 hours later blood glucose increases which triggers insulin release
inhibits glucagon, epinephrine and cortisol
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insulin during feasting
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glycogenesis: adding glucose to liver/muscle storage
lipogenesis
protein synthesis
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what is the primary energy fuel during feasting?
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glucose
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when blood glucose begins to drop during feasting
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glucagon is released
glycogenolysis (liver)
gluconeogenesis (from AAs)
epinephrine released
glycogenolysis (muscle & liver)
If low blood glucose continues
cortisol- use of FA for energy, growth hormones
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First priority of fasting
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-provide glucose for RBCs, brian & CNS
-will use glucose stores first
-gluconeogensis from circulating AAs
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Second Priority of fasting
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-maintain muscle mass
-utilization of fat stores for energy
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the prolonged fast: initially,
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-glycogen supplies glucose
-gluconeogenesis begins
-liver shifts to using fatty acids for energy
-muscle uses fatty acids
-CHO stores used up at 12 hours
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the prolonged fast: then,
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-fat and protein are the primary fuels
-nonstructural proteins used to make glucose and produce energy
-Alanine (AA) and glycerol (TG) used for glucose for brain
-ketone formation begins after a few days
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the prolonged fast: after a few days
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-body adaptations to conserve energy
-lower body temp, pulse rate, BP & metabolic rate
-lethargy
-gluconeogenesis and protein use drops 2/3rds
-fat catabolism doubles to supply fatty acids and glycerol
-ketones main energy source; gluconeogensis supplies glucose for tissues t…
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the prolonged fast: several weeks of fasting
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-susceptible to disease and infections
-poor micronutrient status
-B vitamins & minerals
-as fat stores used up, protein lone energy source and its use accelerates
-ex: kwashiorkor - edema
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the prolonged fast: the end is near
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as protein is depleted, body deteriorates rapidly
-muscle atrophy and emaciation
-body sacrifices muscle to save brain function
-loss of ~1/2 body proteins...death
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the prolonged fast: survival factors
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-survival time for total starvation is 1-3 months with an average of ~60 days
-factors increasing survival: more body fat, middle aged vs children or elderly, female vs male, reduced energy expenditure
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FCS 102: EXAM 3