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digestion
- breakdown of large molecules to simpler, smaller chemical compounds that can be absorbed
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Absorption
- set of processes that result in passage of small molecules from lumen of gut through cells of G.I. tract to bloodstream
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Metabolism
- Ø sum of processes of chemical changes in living cells by which energy and nutrients are provided for vital processes and activities and new materials are assimilated
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Anabolism
- constructive part of metabolism involving synthesis
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Catabolism
- destructive part of metabolism involving the release of energy and breakdown of complex material
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metabolism provides
- energy storage
- (glycogen) (glucose)
- energy
- amino acid precursor
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2 forms of long term energy storage
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3 pathways of CHO metabolism, where they occur and if O2 is needed
pathway-location-O2
- glycolysis-cytosol-anaerobic
- krebs cycle-mitochondria-aerobic
- oxidative phosphorylation-mitochondria-aerobic
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metabolic fuel and ATP equivalent
- ATP
- NADH=3 ATP
- FADH2= 2 ATP
- GTP= 1 ATP
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end product of glycolysis form glucose
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how many ATP are produced during glycolysis from 1 glucose
8 ATP
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pyruvate is converted to what before the krebs cycle
Acetyl CoA
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conversion of pyruvate to acetyl CoA produced how many ATP from 1 pyruvate? How many from 1 glucose?
- 15 ATP per pyruvate
- 30 ATP per glucose
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what is acetyl CoA converted to during the Krebs Cycle
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How many ATP are produced from 1 acetyl CoA during the krebs cycle; how many from 1 glucose?
- 24 ATP per Acetyl CoA
- 38 ATP per 1 glucose
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what is the purpose of the electron transport chain
moves hydrogen and allows ATP to be produced
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how many ATP are generated from 1 NADH and 1 FADH2
- 3 ATP per 1 NADH
- 2 ATP per 1 FADH2
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how many total ATP are generated from catobolism of 1 glucose
38 ATP
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what is the energy efficiency of glucose oxidation
42%
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what is produced from pyruvate during anaerobic exercise
lactic acid
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what pathway do MCO in the rumen use to make VFA from glucose
glycolysis
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relative efficiency of the 3 VFAs
- Acetic acid=62%
- Butanic acid= 78%
- Propanoic acid= 109%
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what pathway is used to catabolize VFAs in all animals
krebs cycle
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what point does each of the 3 VFAs enter the krebs cycle
- A and B enter as Acetyl CoA
- P enters as Sucinyl CoA
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2 hormones involved in maintaining blood glucose levels on a daily basis which increases blood glucose and which decreases blood glucose?
- insulin-lowers
- glucagon- raises
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2 hormones increase blood glucose in response to fight or flight
- glucocorticords
- epinephrine
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what is glycogenolysis
breakdown of glycogen
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what is glycogenesis
making of glycogen
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what is gluconeogenesis
- making of glucose form non-CHO sources
- (glycolysis in reverse)
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why is gluconeogenesis so important in the ruminant
- utilize VFAs
- Propionate converted to glucose
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which VFA is converted to glucose in the ruminant
propionate
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5 hormones involved in control of fat storage
- insulin
- epinephrine
- cortisol
- glucagon
- growth hormone
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primary precursor for milk fat synthesis in monogastric vs ruminant
- monogastric-glucose
- ruminante- acetate
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4 sources of Acetyl CoA
- CHO
- protien
- VFA
- Degraded Fat
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what location does fatty acid synthesis occur
cytosol
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how are fats made
2 carbons at a time, addition of acetyl coA until 16 C long
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what is the enzyme for fatty acid synthesis
fatty acid synthase
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what does tissue lipase do during fatty acid degradation
breaks triglycerides to fatty acids and glycerol
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what happens to glycerol after it is separated from the fatty aid in a triglyceride
enters glycolysis
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what is beta oxidation
removal of Acetyl CoA until a fatty acid completely degraded
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what happens to acetyl CoA from beta oxidation of fatty acid
enters krebs cycle
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where does beta oxidation occur
mitochondria
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what is the amount of ATP produced from beta-oxidation of fatty acids; how does this compare to the amount of ATP produced from glucose oxidation
- 131 ATP- fatty acid
- 38 ATP- glucose
- 3.44 times more ATP from 16 C fatty acid
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what is ketosis; how does it occur
- build up of ketones
- blood pH decreases
- metabolic acidosis
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what is the primary treatment for ketosis
injection in the jugular or subcutaneous of glucose
- Ca-gluconoate
- Na-propionate
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10 essential amino acids
- phenylalanine
- valine
- threonine
- tryptophan
- isoleucine
- methionine
- histidine
- argine
- leucine
- lycine
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bond joining 2 amino acids
peptide
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Ø Methods of absorption used for amino acid absorption and which is primary method
- o Active transport = primary
- o Passive diffusion
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3 fates of NH3 form MCO degradation of protiens in the rumen
- incorporated into the MCO protein
- absorbed through the rumen wall
- ammonia in bloodstream converted to urea
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enzymes used for protein digestion, where they are produced, and where they are used
Stomach
- stomach
- HCl (parietal cells) disrupts H bonds and denatures proteins
pepsin (chief cells) breaks peptide bonds, cleaves proteins at specific AA
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enzymes used for protein digestion, where they are produced, and where they are used
small intestine
- trypsin
- chymotrypsin
- carboxypeptidases
all three break peptide bonds at specific area of protein
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enzymes used for protein digestion, where they are produced, and where they are used
Brush Border
di and tri peptiddases
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3 ways amino acids are used in protein synthesis (anabolism)
- tissue synthesis
- synthesis of enzymes and hormones
- synthesis of nonessential AA
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what are 2 things that can happen to NH3 following deamination during amino acid catabolism
- N recycling to other AA
- enter urea cycle
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5 things that can happen to carbon skeleton during amino acid catabolism
- other amino acid
- energy via krebs cycle
- ketones via krebs cycle the acetyl coa
- fat via krebs cycle then acetyl coa
- glucose via krebs cycle
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site of protein digestion in non-ruminants
- stomach
- small intestine
- large intestine
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enzymes of protein digestion in non-ruminants
stomach
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enzymes of protein digestion in non-ruminants
small intestine
- enterokinase
- trypsin
- chymotrypsin
- carboxypeptidases
- aminopeptidases
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absorbed end products of protein digestion in non-ruminants
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site of protein digestion in ruminants
- rumen
- stomach
- Small intestine
- large intestine
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enzymes of protein digestion in ruminants
rumen
MCO proteases
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enzymes of protein digestion in ruminants
stomach
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enzymes in protein digestion in ruminants
small intestine
- enterokinase
- trypsin
- chymostrypsin
- aminopeptidases
- carboxypeptidases
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end products of protein digestion in ruminants
MCO protein
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absorbed end products of protein digestion in ruminants
- rumen= NH3
- small intestine= AA
- Large intestine= NH3 VFA
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recycling of N
- MCO hydrolyze most feed protein to peptides and amino acids
- peptides and amino acids further degraded to ammonia and C skeleton
- ammonia is incorporated to MCO protein or absorbed through the rumen wall
- urea is excreted through urine or recycled back to rumen via saliva or absorbed across rumen wall
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Synthesis of microbial protein
- Protein enters rumen
- Deamination
- 1. C skeleton
- 2. NH3
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NH3 and C skeleton= MCO ProteinC skeleton → VFA→ to abomassum & small intestine
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site of lipid digestion
stomach:churning creates small fat droplets and the pyloric sphincter meters fate droplets to small intestine
small intestine: bile and lipase
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enzymes of lipid digestion
- gastic lipase
- found in stomach
- not very active in mature animals
- functional in young animals
- pancreatic lipase
- primary fat digestion
- secreted with pancreatic juice
- secreted in inactive form
- activated by Ca in lumen of small intestine
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glycolysis starts with ?
1 glucose and is primed with 2 ATP
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glycolysis ends with ?
2 pyruvates
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glyoclysis produces ?
- 2 ATP
- 2 NADH
- overall 8 ATP
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krebs cycle starts with?
2 pyruvates
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krebs cycle produces
- 3 NADH
- 1 FADH2
- 1 GTP
- overall 30 ATP
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what is the importance of oxidative phosphorylation
drives ATP synthesis down a concentration gradient
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what is the ATP equivalence of NADH
yields 3 ATP
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what is the FADH2 ATP equivalence
2 ATP
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beta oxidation
- stepwise removal of 2 C from fatty acid
- steps repeat until fat is completly broken down
- fatty acid is degraded acetyl CoA
- Acetyl CoA enters the Krebs cycle
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